LIBRARY 
 
 UNIVERSITY OF 
 CALIFORNIA 
 
 SAN DIEGO 
 
 presented to the 
 
 UNIVERSITY LIBRARY 
 
 UNIVERSITY OF CALIFORNIA 
 
 SAN DIEGO 
 
 by 
 
 MRS ETHEL ROGERS

 
 THE 
 
 ANCIENT LIFE -HI STORY 
 
 THE EARTH
 
 THE 
 
 ANCIENT LIFE -HISTORY 
 
 THE EARTH 
 
 A COMPREHENSIVE OUTLINE OF THE PRINCIPLES 
 
 AND LEADING FACTS OF FALCON- 
 
 TOLOGICAL SCIENCE 
 
 BY 
 
 H. ALLEYNE NICHOLSON 
 
 M.D., D.Sc., M.A., PH.D. (Gorr.), F.R.S.E., F.L.S. 
 
 ISTORY IN 
 \NDREWS 
 
 NEW YORK: 
 D. APPLETON AND COMPANY, 
 
 72 FIFTH AVENUE. 
 I8 97 .
 
 Authorized Edition.
 
 PREFACE. 
 
 THE study of Palaeontology, or the science which is 
 concerned with the living beings which flourished upon 
 the globe during past periods of its history, may be 
 pursued by two parallel but essentially distinct paths. 
 By the one method of inquiry, we may study the 
 anatomical characters and structure of the innumerable 
 extinct forms of life which lie buried in the rocks 
 simply as so many organisms, with but a slight and 
 secondary reference to the time at which they lived. 
 By the other method, fossil animals are regarded prin- 
 cipally as so many landmarks in the ancient records of 
 the world, and are studied historically and as regards 
 their relations to the chronological succession of the 
 strata in which they are entombed. In so doing, it is 
 of course impossible to wholly ignore their structural 
 characters, and their relationships with animals now 
 living upon the earth ; but these points are held to 
 occupy a subordinate place, and to require nothing 
 more than a comparatively general attention. 
 
 In a former work, the Author has endeavoured to 
 furnish a summary of the more important facts of
 
 vi PREFACE. 
 
 Palaeontology regarded in its strictly scientific aspect, 
 as a mere department of the great science of Biology. 
 The present work, on the other hand, is an attempt to 
 treat Palaeontology more especially from its historical 
 side, and in its more intimate relations with Geology. 
 In accordance with this object, the introductory portion 
 of the work is devoted to a consideration of the general 
 principles of Palaeontology, and the bearings of this 
 science upon various geological problems such as the 
 mode of formation of the sedimentary rocks, the reac- 
 tions of living beings upon the crust of the earth, and 
 the sequence in time of the fossiliferous formations. 
 The second portion of the work deals exclusively with 
 Historical Palaeontology, each formation being consid- 
 ered separately, as regards its lithological nature and 
 subdivisions, its relations to other formations, its geo- 
 graphical distribution, its mode of origin, and its char- 
 acteristic life-forms. 
 
 In the consideration of the characteristic fossils of 
 each successive period, a general account is given of 
 their more important zoological characters and their 
 relations to living forms ; but the technical language of 
 Zoology has been avoided, and the aid of illustrations 
 has been freely called into use. It may therefore be 
 hoped that the work may be found to be available for 
 the purposes of both the Geological and the Zoological 
 student ; since it is essentially an outline of Historical 
 Palaeontology, and the student of either of the above- 
 mentioned sciences must perforce possess some know- 
 ledge of the last. Whilst primarily intended for stu- 
 dents, it may be added that the method of treatment 
 adopted has been so far untechnical as not to render 
 the work useless to the general reader who may desire
 
 PREFACE. Vll 
 
 to acquire some knowledge of a subject of such vast 
 and universal interest. 
 
 In carrying out the object which he has held before 
 him, the Author can hardly expect, from the nature of 
 the materials with which he has had to deal, that he has 
 kept himself absolutely clear of errors, both of omission 
 and commission. The subject, however, is one to which 
 he has devoted the labour of many years, both in 
 studying the researches of others and in personal 
 investigations of his own ; and he can only trust that 
 such errors as may exist will be found to belong chiefly 
 to the former class, and to be neither serious nor 
 numerous. It need only be added that the work is 
 necessarily very limited in its scope, and that the 
 necessity of not assuming a thorough previous acquaint- 
 ance with Natural History in the reader has inexorably 
 restricted its range still further. The Author does not, 
 therefore, profess to have given more than a merely 
 general outline of the subject ; and those who desire 
 to obtain a more minute and detailed knowledge of 
 Palaeontology, must have recourse to other and more 
 elaborate treatises. 
 
 UNITED COLLEGE, ST ANDREWS, 
 October 2, 1876.
 
 CONTENTS. 
 
 PART I. 
 PRINCIPLES OF PALEONTOLOGY. 
 
 INTRODUCTION. 
 
 PAGE 
 
 The general objects of geological science The older theories of 
 catastrophistic and intermittent action The more modem doc- 
 trines of continuous and uniform action Bearing of these doc- 
 trines respectively on the origin of the existing terrestrial order 
 Elements of truth in Catastrophism General truth of the doc- 
 trine of Continuity Geological time, .... l-io 
 
 CHAPTER I. 
 
 Definition of Palaeontology Nature of Fossils Different processes 
 
 of fossilisation, . 10-14 
 
 CHAPTER II. 
 
 Aqueous and igneous rocks General characters of the sedimentary 
 rocks Mode of formation of the sedimentary rocks Definition 
 of the term " formation " Chief divisions of the aqueous rocks 
 Mechanically-formed rocks, their characters and mode of origin 
 Chemically and organically f&rmed rocks Calcareous rocks 
 Chalk, its microscopic structure and mode of formation Lime- 
 stone, varieties, structure, and origin Phosphate of lime Con- 
 cretions Sulphate of lime Silica and siliceous deposits of vari- 
 ous kinds Greensands Red clays Carbon and carbonaceous 
 deposits, 14-36 
 
 CHAPTER III. 
 
 Chronological succession of the fossiliferous rocks Tests of age of 
 strata Value of Palaeontological evidence in stratigraphical Geo- 
 logy General sequence of the great formations, . . 37-44
 
 CONTENTS. 
 
 CHAPTER IV. 
 
 The breaks in the pabeontological and geological record Use of 
 the term "contemporaneous" as applied to groups of strata- 
 General sequence of strata and of life-forms interfered with by 
 more or less extensive gaps Unconformability Phenomena im- 
 plied by this Causes of the imperfection of the palaeontological 
 record, 44-$2 
 
 CHAPTER V. 
 
 Conclusions to be drawn from fossils -Age of rocks Mode of origin 
 of any fossiliferous bed Fluviatile, lacustrine, and marine de- 
 posits Conclusions as to climate Proofs of elevation and subsi- 
 dence of portions of the earth's crust derived from fossils, . 52-56 
 
 CHAPTER VI. 
 
 The biological relations of fossils Extinction of life-forms Geolo- 
 gical range of different species Persistent types of life Modern 
 origin of existing animals and plants Reference of fossil forms 
 to the existing primary divisions of the animal kingdom Depart- 
 ure of the older types of life from those now in existence Re- 
 semblance of the fossils of a given formation to those of the for- 
 mation, next above and next below Introduction of new life- 
 forms, . 57-6l 
 
 PART II. 
 HISTORICAL PALEONTOLOGY. 
 
 CHAPTER VII. 
 
 The Laurentian and Huronian periods General nature, divisions, 
 and geographical distribution of the Laurentian deposits Lower 
 and Upper Laurentian Reasons for believing that the Lauren- 
 tian rocks are not azoic based upon their containing limestones, 
 beds of oxide of iron, and graphite The characters, chemical 
 composition, and minute structure of Eozoon Canadense Compar- 
 ison of Eozoon with existing F'oraminifera Archieosphcerintz 
 Huronian formation Nature and distribution of Huronian de- 
 positsOrganic remains of the Huronian Literature, 65-76 
 
 CHAPTER VIII. 
 
 The Cambrian period General succession of Cambrian deposits in 
 Wales Lower Cambrian and Upper Cambrian Cambrian de- 
 posits of the continent of Europe and North America Life of the 
 Cambrian period Fucoids Eophy ton Oldhamia Sponges 
 Echinoderms Annelides Crustaceans Structure of Trilobites 
 Brachiopods Pteropods, Gasteropods, and Bivalves Cephalo- 
 pods Literature, 77-9
 
 CONTENTS. xi 
 
 CHAPTER IX. 
 
 The Lower Silurian period The Silurian rocks generally Limits of 
 Lower and Upper Silurian General succession, subdivisions, and 
 characters of the Lower Silurian rocks of Wales General succes- 
 sion, subdivisions, and characters of the Lower Silurian rocks 
 of the North American continent Life of the period Fucoids 
 Protozoa Graptolites Structure of Graptolites Corals : Gene- 
 ral structure of Corals Crinoids Cystideans General characters 
 of Cystideans Annelides Crustaceans Polyzoa Brachiopods 
 Bivalve and Univalve Molluscs Chambered Cephalopods 
 General characters of the Cephalopoda Conodoiits, . . 90-114 
 
 CHAPTER X. 
 
 The Upper Silurian period General succession of the Upper Silurian 
 deposits of Wales Upper Silurian deposits of North America 
 Life of the Upper Silurian Plants Protozoa Graptolites 
 Corals Crinoids General structure of Crinoids Star-fishes 
 Annelides Crustaceans ^-Eurypterids Polyzoa Brachiopods 
 Structure of Brachiopods Bivalves and Univalves Pteropods 
 Cephalopods Fishes Silurian literature, . . 115-132 
 
 CHAPTER XI. 
 
 The Devorfian period Relations between the Old Red Sandstone 
 and the marine Devonian deposits The Old Red Sandstone of 
 Scotland The Devonian strata of Devonshire Sequence and 
 subdivisions of the Devonian deposits of North America Life of 
 the period Plants Protozoa Corals Crinoids Pentremites 
 Annelides Crustaceans Insects Polyzoa Brachiopods Bi- 
 valves Univalves Pteropods Cephalopods Fishes General 
 divisions of the Fishes Palseontological evidence as to the inde- 
 pendent existence of the Devonian system as a distinct formation 
 Literature, 132-157 
 
 CHAPTER XII. 
 
 The Carboniferous period Relations of Carboniferous rocks to De- 
 vonian The Carboniferous Limestone or Sub - Carboniferous 
 series The Millstone-grit and the Coal-measures Life of the 
 period Structure and mode of formation of Coal Plants of the 
 Coal, . 157-170 
 
 CHAPTER XIII. 
 
 Animal life of the Carboniferous period Protozoa Corals Crinoids 
 Pentremites Structure of Pentremites Echinoids Structure 
 of Echinoidea Annelides Crustacea Insects Arachnids 
 Myriapods Polyzoa Brachiopods Bivalves and Univalves 
 Cephalopods Fishes Labyrinthodont Amphibians Litera- 
 ture, 170-192
 
 CONTENTS. 
 
 CHAPTER XIV. 
 
 The Permian period General succession, characters, and mode of 
 formation of the Permian deposits Life of the period Plants 
 Protozoa Corals Echinoderms Annelides Crustaceans 
 Polyzoa Brachiopods Bivalves Univalves Pteropods 
 Cephalopods Fishes Amphibians Reptiles Literature, 192-203 
 
 CHAPTER XV. 
 
 The Triassic period General characters and subdivisions of the Trias 
 of the Continent of Europe and Britain Trias of North America 
 Life of the period Plants Echinoderms Crustaceans Poly- 
 zoa Brachiopods Bivalves Univalves Cephalopods Inter- 
 mixture of Palaeozoic with Mesozoic types of Molluscs Fishes 
 Amphibians Reptiles Supposed footprints of Birds Mammals 
 Literature, 203-225 
 
 CHAPTER XVI. 
 
 The Jurassic period General sequence and subdivisions of the Juras- 
 sic deposits in Britain Jurassic rocks of North America Life 
 of the period Plants Corals Echinoderms Crustaceans In- 
 sects Brachiopods Bivalves Univalves Pteropods Tetra- 
 branchiate Cephalopods Dibranchiate Cephalopods Fishes 
 Reptiles Birds Mammals Literature, . . . 226-256 
 
 CHAPTER XVII. 
 
 The Cretaceous period General succession and subdivisions of the 
 Cretaceous rocks in Britain Cretaceous rocks of North America 
 Life of the period Plants Protozoa Corals Echinoderms 
 Crustaceans Polyzoa Brachiopods Bivalves Univalves 
 Tetrabranchiate and Dibranchiate Cephalopods Fishes Rep- 
 tiles Birds Literature 256-284 
 
 CHAPTER XVIII. 
 
 The Eocene period Relations between the Kainozoic and Mesozoic 
 rocks in Europe and in North America Classification of the 
 Tertiary deposits The sequence and subdivisions of the Eocene 
 rocks of Britain and France Eocene strata of the United States 
 Life of the period Plants Foraminifera Corals Echino- 
 derms Mollusca Fishes Reptiles Birds Mammals, . 284-305 
 
 CHAPTER XIX. 
 
 The Miocene period Miocene strata of Britain Of France Of 
 Belgium Of Austria Of Switzerland Of Germany Of Greece 
 Of India Of North America Of the Arctic regions Life of 
 the period Vegetation of the Miocene period Foraminifera 
 Corals Echinoderms Articulates Mollusca Fishes Amphi- 
 bians Reptiles Mammals, . . . . . 305-323
 
 CONTENTS. 
 
 CHAPTER XX. 
 
 The Pliocene period Pliocene deposits of Britain Of Europe Of 
 North America Life of the period Climate of the period as 
 indicated by the Invertebrate animals The Pliocene Mammalia 
 Literature relating to the Tertiary deposits and their fossils, 323-333 
 
 CHAPTER XXI. 
 
 The Post-Pliocene period Division of the Quaternary deposits into 
 Post-Pliocene and Recent Relations of the Post-Pliocene de- 
 posits of the northern hemisphere to the " Glacial period " 
 Pre-Glacial deposits Glacial deposits Arctic Mollusca in Gla- 
 cial beds Post-Glacial deposits Nature and mode of formation 
 of high-level and low-level gravels Nature and mode of forma- 
 tion of cavern-deposits Kent's Cavern Post-Pliocene deposits 
 of the southern hemisphere, 334-344 
 
 CHAPTER XXII. 
 
 Life of the Post-Pliocene period Effect of the coming on and de- 
 parture of the Glacial period upon the animals inhabiting the 
 northern hemisphere Birds of the Post-Pliocene Mammalia of 
 the Post- Pliocene Climate of the Post-Glacial period as deduced 
 from the Post- Glacial Mammals Occurrence cf the bones and 
 implements of Man in Post-Pliocene deposits in association with 
 the remains of extinct Mammalia Literature relating to the Post- 
 Pliocene period, 344-366 
 
 CHAPTER XXIII. 
 
 The succession of life upon the globe Gradual and successive intro- 
 duction of life-forms What is meant by "lower " and "higher" 
 groups of animals and plants Succession in time of the great 
 groups of animals in the main corresponding with their zoological 
 order Identical phenomena in the vegetable kingdom Persist- 
 ent types of life High organisation of many early forms Bear- 
 ings of Palaeontology on the general doctrine of Evolution, 367-374 
 
 APPENDIX. Tabular view of the chief Divisions of the Animal 
 
 Kingdom, 375-37^ 
 
 GLOSSARY 379-395 
 
 INDEX, 396-407
 
 LIST OF ILLUSTRATIONS. 
 
 FIG. 
 
 
 PAGE FIG. 
 
 
 Cast of Trigonia longa, . 
 
 12 
 
 1 8. Unc 
 
 2. 
 
 Microscopic section of the 
 
 
 
 
 
 wood of a fossil Conifer, 
 
 13 
 
 n 
 
 3- 
 
 Microscopic section of the 
 
 
 19. Ere 
 
 
 wood of the Larch, 
 
 13 
 
 20. Dia 
 
 4- 
 
 Section of Carboniferous 
 
 
 tl 
 
 
 strata, Kinghorn, Fife, 
 
 16 
 
 21. Mic 
 
 5- 
 
 Diagram illustrating the 
 
 
 L 
 
 
 formation of stratified 
 
 
 22. Fraj 
 
 
 deposits, 
 
 17 
 
 L 
 
 6. 
 
 Microscopic section of a 
 
 
 23. Diaj 
 
 
 calcareous breccia, 
 
 19 
 
 st 
 
 7- 
 
 Microscopic section of 
 White Chalk, . 
 
 22 
 
 24. Mic 
 E 
 
 8. 
 
 Organisms in Atlantic 
 
 
 25. Non 
 
 
 Ooze, 
 
 23 
 
 26. Gro 
 
 9- 
 
 Crinoidal marble, . 
 
 24 
 
 P 
 
 10. 
 
 Piece of Nummulitic lime- 
 
 
 27. Diaj 
 
 
 stone, Pyramids, 
 
 2 5 
 
 C 
 
 11. 
 
 Microscopic section of Fo- 
 
 
 28. Eop 
 
 
 raminiferal limestone 
 
 
 29. Old) 
 
 
 Carboniferous, Amer- 
 
 
 30. Scoli 
 
 
 ica, .... 
 
 27 
 
 31. Gro 
 
 12. 
 
 Microscopic section of 
 
 
 b 
 
 
 Lower Silurian lime- 
 
 
 32. Gro 
 
 
 stone, . . 
 
 27 
 
 C 
 
 13- 
 
 Microscopic section of 
 
 
 33- Fra^ 
 
 
 oolitic limestone, Ju- 
 
 
 tt 
 
 
 rassic, 
 
 29 
 
 34- Gen 
 
 14. 
 
 Microscopic section of 
 
 
 L 
 
 
 ooolitic limestone, Car- 
 
 
 
 
 
 boniferous, 
 
 3 
 
 35. Gen 
 
 IS- 
 
 Organisms in Barbadces 
 
 
 L 
 
 
 earth, 
 
 33 
 
 ol 
 
 16. 
 
 Organisms in Richmond 
 
 
 36. Licr 
 
 
 earth, 
 
 33 
 
 37- A sty 
 
 '7- 
 
 Ideal section of the crust 
 
 
 38. Stro 
 
 
 of the earth, 
 
 43 
 
 39. Diet 
 
 Unconformable junction 
 
 of Chalk and Eocene 
 
 rocks, ... 49 
 Erect trunk of a Sigillaria, 54 
 Diagrammatic section of 
 
 he Laurentian rocks, 66 
 Microscopic section of 
 
 Laurentian limestone, 67 
 Fragment of a mass of 
 
 Eozoon Canadense, . 69 
 Diagram illustrating the 
 
 structure of Eozoon, . 70 
 Microscopic section of 
 
 Eozoon Canadense, . 71 
 Nonionina and Grotnia, . 72 
 Group of shells of living 
 
 foraminifera, . . 73 
 Diagrammatic section of 
 
 Cambrian strata, . 78 
 
 Eophyton Linneanum, . 8 1 
 Oldhamia antiqua, . 82 
 
 Scolithus Canadensis, . 83 
 Group of Cambrian Trilo- 
 
 bites, ... 85 
 
 Group of characteristic 
 
 Cambrian fossils, . 88 
 Fragment of Dictyonema 
 
 sodale, ... 89 
 Generalised section of the 
 
 Lower Silurian rocks 
 
 of Wales, ... 94 
 Generalised section of the 
 
 Lower Silurian rocks 
 
 of North America, . 96 
 Licrophycus Ottaivaensis, 97 
 Astylospongia framorsa^ . 98 
 Stromatopora rugosa, . 99 
 iptus octobrachiatus , 101
 
 xvi 
 
 LIST OF 
 
 ILLUSTE 
 
 ATIONS. 
 
 
 40. 
 
 Didymograptus divarica- 
 
 
 78. 
 
 Prototaxitcs Logani, 
 
 139 
 
 
 tus, .... 
 
 102 
 
 79 
 
 Stromatopora tubercidata, 
 
 140 
 
 41. 
 
 Diplograpttis pristis, 
 
 102 
 
 80. 
 
 Cystiphyllum vesicnlosum, 
 
 141 
 
 42. 
 
 Phyllograpius typus, 
 
 102 
 
 81. 
 
 Zaphrentis corniatla, 
 
 141 
 
 43- 
 
 Zaphrentis Stokesi, . 
 
 104 
 
 82. 
 
 Heliophyllum exiguuin, 
 
 141 
 
 44- 
 
 Strombodes pentagonus, . 
 
 I0 4 
 
 83- 
 
 Crepidophylhim A rchiaci, 
 
 142 
 
 45- 
 
 Colwnnaria alveolata, 
 
 I5 
 
 84. 
 
 Favosites Gothlaudica, . 
 
 H3 
 
 46. 
 
 Group of Cystideans, 
 
 106 
 
 85- 
 
 Favosites hemisphierica, 
 
 1 43 
 
 47- 
 
 Group of Lower Silurian 
 
 
 86. 
 
 Spirorbis omphalodes and 
 
 
 
 Crustaceans, 
 
 107 
 
 
 S. Arkonensis, . 
 
 144 
 
 48. 
 
 Ptilodictya falciform is, 
 
 109 
 
 87. 
 
 Spirorbis lax j is and S. 
 
 
 49- 
 
 Ptilodictya Scha/eri, 
 
 109 
 
 
 spimilifera, 
 
 144 
 
 5- 
 
 Group of Lower Silurian 
 
 
 88. 
 
 Group of Devonian Tri- 
 
 
 
 Brachiopods, 
 
 109 
 
 
 lobites, 
 
 144 
 
 5 1 - 
 
 Group of Lower Silurian 
 
 
 89. 
 
 Wing of Platepheinera 
 
 
 
 Brachiopods, 
 
 no 
 
 
 antiqna, 
 
 145 
 
 52. 
 
 Murchisonia gracilis, 
 
 III 
 
 90. 
 
 Clathropora intertexta, . 
 
 146 
 
 53- 
 
 Bellerophon argo, 
 
 III 
 
 9i- 
 
 Ceriopora Hamiltoneiisis, 
 
 146 
 
 54- 
 
 Maclurea crenulata, 
 
 112 
 
 92. 
 
 Fenestella magnified, 
 
 146 
 
 55- 
 
 Orthoceras crebriseptiim, 
 
 "3 
 
 93- 
 
 Retepora Phillipsi, 
 
 146 
 
 56. 
 
 Restoration of Orthoceras, 
 
 113 
 
 94- 
 
 Fenestella cribrosa, 
 
 146 
 
 57- 
 
 Generalised section of the 
 
 
 95- 
 
 Spirifcra scnlptilis, 
 
 147 
 
 
 Upper Silurian rocks, 
 
 117 
 
 96. 
 
 Spirifera tmicronata, 
 
 147 
 
 58. 
 
 Monograptus priodon, 
 
 119 
 
 
 Atrypa reticnlaris, 
 
 148 
 
 59- 
 
 Halysites catenularia and 
 
 
 98. 
 
 Strophoinena rhomboid- 
 
 
 
 H. agglomerata, . 
 
 1 20 
 
 
 alis, .... 
 
 148 
 
 60. 
 
 Group of Upper Silurian 
 
 
 99- 
 
 Platyceras diimosiirn, 
 
 148 
 
 
 Star- fishes, 
 
 121 
 
 IOO. 
 
 Conularia ornata, 
 
 149 
 
 61. 
 
 Protasler Sedgwickii, 
 
 121 
 
 IOI. 
 
 Clymenia Sedg^uickii, 
 
 149 
 
 62. 
 
 Group of Upper Silurian 
 
 
 1 02. 
 
 Group of Fishes from 
 
 
 
 Crinoids, . 
 
 122 
 
 
 the Devonian rocks of 
 
 
 63- 
 
 Planolitcs vulgaris, . 
 
 123 
 
 
 North America, 
 
 151 
 
 64. 
 
 Group of Upper Silurian 
 Trilobites, . . . 
 
 124 
 
 103. 
 
 104. 
 
 Cephalaspis Lydlii, 
 Pterichlhys cornutus, 
 
 152 
 53 
 
 65- 
 66. 
 
 Pterygotus Anglicus, 
 Group of Upper Silurian 
 
 I2S 
 
 & 
 
 Polypterus and Osteolepis, 
 Holoptychhis nobilissi- 
 
 154 
 
 
 Polyzoa, 
 
 126 
 
 
 mus, .... 
 
 J S4 
 
 67. 
 
 Spirt/era hysterica, . 
 
 126 
 
 107. 
 
 Generalised section of 
 
 
 68. 
 
 Group of Upper Silurian 
 
 
 
 the Carboniferous rocks 
 
 
 
 Brachiopods, 
 
 127 
 
 
 of the North of Eng- 
 
 
 69. 
 
 Group of Upper Silurian 
 
 
 
 land, .... 
 
 161 
 
 
 Brachiopods, 
 
 127 
 
 108. 
 
 Odontopteris Schlotheimii, 
 
 164 
 
 70. 
 
 Pentamerus Knightii, 
 
 128 
 
 109. 
 
 Calamites cannaformis, 
 
 165 
 
 7i- 
 
 Cardiola interrupta, C. 
 fibrosa, and Ptej-intza 
 
 
 no. 
 III. 
 
 Lepidodendron Stern bergii, 
 Sigillaria Gr&seri, 
 
 167 
 1 68 
 
 
 subfalcata, . 
 
 128 
 
 112. 
 
 Stigmaria ficoides, 
 
 169 
 
 72. 
 
 Group of Upper Silurian 
 
 
 "3- 
 
 Trigonocarpum ovatum, 
 
 170 
 
 
 Univalves, 
 
 129 
 
 114. 
 
 Microscopic section of 
 
 
 73- 
 
 Tentaculites ornatus, 
 
 129 
 
 
 Foram iniferal limestone 
 
 
 74- 
 
 Pferaspis Banksii, . 
 
 130 
 
 
 Carboniferous, North 
 
 
 75- 
 
 Onckus tenuistriatus and 
 
 
 
 America, . 
 
 172 
 
 
 Thelodus, . . . 
 
 130 
 
 "5- 
 
 Fiisulina cylindrica, 
 
 172 
 
 76. 
 
 Generalised section of the 
 
 
 116. 
 
 Group of Carboniferous 
 
 
 
 Devonian rocks of 
 
 
 
 Corals, 
 
 r 74 
 
 
 North America, 
 
 137 
 
 117. 
 
 Platycrimis tricontadac- 
 
 
 77- 
 
 Psilophyton princeps, . 
 
 138 
 
 
 tylits, .... 
 
 175
 
 LIST OF ILLUSTRATIONS. 
 
 118. 
 
 Pmtremites pyriformis and 
 
 
 157- 
 
 Molar tooth of Micro- 
 
 
 
 P. conoideus, 
 
 I 7 6 
 
 
 lestes antiquus, . 
 
 223 
 
 119. 
 
 Archceocidaris ellipticus, 
 
 177 
 
 158. 
 
 Myrmecobius jasciatus, . 
 
 224 
 
 1 20. 
 
 Spirorbis Carbonarius, . 
 
 178 
 
 159- 
 
 Generalised section of 
 
 
 121. 
 
 Preshuic/iia rotundata, . 
 
 179 
 
 
 the Jurassic rocks, 
 
 229 
 
 122. 
 
 Group of Carboniferous 
 
 
 160. 
 
 Maiitellia megalophylla, 
 
 230 
 
 
 Crustaceans, 
 
 1 80 
 
 161. 
 
 Thecosmilia annularis, . 
 
 2 3i 
 
 123. 
 
 Cyclophthalmus senior, . 
 
 181 
 
 162. 
 
 Pentacritms fasciculosus, 
 
 232 
 
 124. 
 
 Xylobius Sigillariie, 
 
 182 
 
 163. 
 
 Hemicidaris crenularis, . 
 
 233 
 
 125. 
 
 Haplophlebium Barnesi, 
 
 182 
 
 164. 
 
 Eryon arctiformis, 
 
 2 34 
 
 126. 
 
 Group of Carboniferous 
 
 
 165. 
 
 Group of Jurassic Bra- 
 
 
 
 Polyzoa, 
 
 183 
 
 
 chiopods, . 
 
 2 35 
 
 127. 
 
 Group of Carboniferous 
 
 
 1 66. 
 
 Ostrea Marshii, 
 
 236 
 
 
 Brachiopoda, 
 
 185 
 
 167. 
 
 Gryph<za inctirva, . 
 
 236 
 
 128. 
 
 Pupa vetusta, 
 
 186 
 
 1 68. 
 
 Diceras arietina, . 
 
 236 
 
 129. 
 
 Goniatites Jossa, . 
 
 187 
 
 169. 
 
 Nerin&a Goodhallii, 
 
 237 
 
 I 3 0. 
 
 Amblypterus macropterus, 
 
 1 88 
 
 170. 
 
 Ammonites Humphresi- 
 
 
 IS*- 
 
 Cochliodus contortus, 
 
 189 
 
 
 anus, 
 
 238 
 
 132. 
 
 Anthracosaurus Russelli, 
 
 190 
 
 171. 
 
 Ammonites bifrons, 
 
 238 
 
 133- 
 
 Generalised section of 
 
 
 172. 
 
 Beloteuthis subcostafa, 
 
 240 
 
 
 the Permian rocks, 
 
 J 95 
 
 J 73- 
 
 Belemnite restored ; dia- 
 
 
 134- 
 
 Walchia piniformis, 
 
 196 
 
 
 gram of Belemnite ; 
 
 
 135- 
 
 Group of Permian Bra- 
 
 
 
 Belemnites canaliculata, 
 
 241 
 
 
 chiopods, . 
 
 198 
 
 174- 
 
 Tetragonolepis, 
 
 241 
 
 I 3 6. 
 
 Area antiqua, 
 
 199 
 
 175- 
 
 Acrodus nobilis, 
 
 242 
 
 $ 
 
 Platysomus gibbosns, 
 Protorosaurus Speneri, . 
 
 199 
 
 201 
 
 176. 
 177. 
 
 Ichthyosaurus communis, 
 Plesiosaurus dolich odeirus, 
 
 242 
 244 
 
 139- 
 
 Generalised section of the 
 
 
 178. 
 
 Pterodactylus crassiros- 
 
 
 
 Triassic rocks, . 
 
 206 
 
 
 iris, . . 
 
 246 
 
 140. 
 
 Zamia spiralis, 
 
 208 
 
 179. 
 
 Ramphorhynchus Buck- 
 
 
 141. 
 
 Triassic Conifers and 
 
 
 
 landi, restored, . 
 
 248 
 
 
 Cycads, 
 
 209 
 
 1 80. 
 
 Skull of Megalosaums, . 
 
 249 
 
 142. 
 
 Encrinus liliiformb, 
 
 210 
 
 181. 
 
 Archceopteryx macrura, 
 
 252 
 
 143- 
 144. 
 
 Aspidura loricafa, 
 Group of Triassic Bi- 
 
 2IO 
 
 182. 
 183. 
 
 Arch(Eopteryx, restored, 
 Jaw of Amphitheriuin 
 
 252 
 
 
 valves, 
 
 211 
 
 
 Prevostii, . 
 
 2 S4 
 
 145. 
 
 Ceratites nodosus, . 
 
 212 
 
 184. 
 
 Jaws of Oolitic Mam- 
 
 
 146. 
 
 Tooth of Ceratodus ser- 
 
 
 
 mals, 
 
 254 
 
 
 ratus and C. altus, 
 
 214 
 
 185. 
 
 Generalised section of 
 
 
 147. 
 
 Ceratodus Fosteri, 
 
 2I 5 
 
 
 the Cretaceous rocks, . 
 
 260 
 
 148. 
 
 Footprints of Cheiro- 
 therium, 
 
 216 
 
 1 86. 
 
 187. 
 
 Cretaceous Angiosperms, 
 Rotalia Boueana, . 
 
 263 
 264 
 
 149. 
 
 Section of tooth of Laby- 
 rinthodont, 
 
 217 
 
 1 88. 
 189. 
 
 Siphonia ficus, 
 Ventriculites simplex, 
 
 265 
 265 
 
 150. 
 
 Skull of Afastodonsaurus, 
 
 217 
 
 190. 
 
 Synhelia Sharpeana, 
 
 266 
 
 151- 
 
 Skull of Rhynchosaurus, 
 
 218 
 
 191. 
 
 Galerites albogalerus* 
 
 267 
 
 152. 
 
 Bdodon, Nothosaurus, 
 
 
 192. 
 
 Discoidea cylindrica, 
 
 267 
 
 
 PalcEosauws, &c., 
 
 219 
 
 193- 
 
 Escharina Oceani, 
 
 268 
 
 i53- 
 
 Placodus gigas, 
 
 220 
 
 194. 
 
 Terebratella Astieriana, . 
 
 268 
 
 i54- 
 
 Skulls of Dicynodon and 
 
 
 195- 
 
 Crania^ fgnabergensis, . 
 
 269 
 
 
 Oudenodon, 
 
 221 
 
 196. 
 
 Ostrea Couloni, 
 
 269 
 
 i55- 
 
 Supposed footprint of 
 
 
 197. 
 
 Spondylus spinosus, 
 
 270 
 
 
 Bird, from the Trias 
 
 
 198. 
 
 Inoceramus sulcatus, 
 
 270 
 
 
 of Connecticut, . 
 
 222 
 
 199. 
 
 Ilippurites Toucasiana, . 
 
 271 
 
 156. 
 
 Lower jaw of Droma- 
 
 
 200. 
 
 Valuta elongata, 
 
 271 
 
 
 iherium sylvestre, 
 
 22 3 
 
 201. 
 
 Nautilus Danicus, 
 
 272
 
 XVlli LIST OF 
 
 ILLUSTRATIONS. 
 
 202. 
 
 Ancyloceras Matheroni- 
 
 
 239- 
 
 Hyalea Orbignyana, 
 
 312 
 
 
 anus, 
 
 273 
 
 240. 
 
 Tooth of Oxyrhina, 
 
 313 
 
 203. 
 
 Turrilites catenatus, 
 
 2 74 
 
 241. 
 
 Tooth of Carcharodon, 
 
 
 204. 
 
 Forms of Cretaceous 
 
 
 242. 
 
 Andrias Scheuchzeri, 
 
 3H 
 
 
 Ammonitidce, 
 
 274 
 
 243- 
 
 Skull of Brontotlurium 
 
 
 205. 
 
 Belemnilella mucronata, 
 
 275 
 
 
 ingens, 
 
 316 
 
 206. 
 
 Tooth of Hybodus, 
 
 275 
 
 244. 
 
 Hippopotamus Sivalcnsis, 
 
 
 207. 
 208. 
 
 Fin-spine of Hybodus, . 
 Beryx Lewesiensis and 
 
 275 
 
 245. 
 246. 
 
 Skull of Sivatherium, 
 Skull of Deinotlierittm, 
 
 320 
 
 
 Osmeroides Mantelli, . 
 
 276 
 
 247. 
 
 Tooth of Elephas flani- 
 
 
 209. 
 
 Teeth of Iguanodon, 
 
 278 
 
 
 frons and of Mastodon 
 
 
 2IO. 
 
 Skull of Mosasaurus 
 
 
 
 Sivalensis, . 
 
 321 
 
 
 Cam peri, 
 
 279 
 
 248. 
 
 Jaw of Pliopitheais, 
 
 323 
 
 211. 
 
 Chelone Bensttdi, . 
 
 280 
 
 249. 
 
 Rhinoceros Elruscus and 
 
 
 212. 
 
 Jaws and vertebrae of 
 
 
 
 R. megarhinus, . 
 
 328 
 
 
 Odontornithes, 
 
 282 
 
 250. 
 
 Molar tooth of Mastodon 
 
 
 213. 
 
 Fruit of Nipadites, 
 
 290 
 
 
 Arvernensis, 
 
 329 
 
 214. 
 
 Nummulina lievigata, . 
 
 291 
 
 251- 
 
 Molar tooth of Elephas 
 
 
 215. 
 
 Turbinolia sulcata, 
 
 292 
 
 
 meridionalis, 
 
 330 
 
 216. 
 
 Cardita planicosta, 
 
 293 
 
 252. 
 
 Molar tooth of Elephas 
 
 
 217. 
 
 Typhis tubifer, 
 
 293 
 
 
 antiquus, 
 
 330 
 
 218. 
 
 Cyprcea elegans, 
 
 293 
 
 253- 
 
 Skull and tooth of Ma- 
 
 
 219. 
 
 Cerithium hexagonum, . 
 
 294 
 
 
 chairodus c^lltridens, 
 
 331 
 
 22O. 
 
 Limncea pyramidalis, 
 
 294 
 
 254- 
 
 Pecten Jslandicus, 
 
 338 
 
 221. 
 222. 
 
 Physa columnaris, 
 Cyclostoma Arnoudii, 
 
 294 
 294 
 
 255- 
 
 Diagram of high-level 
 and low-level gravels, 
 
 34 
 
 223. 
 
 Rhombus minimus, 
 
 295 
 
 256. 
 
 Diagrammatic section of 
 
 
 224. 
 
 Otodus obliquus, . 
 
 296 
 
 
 Cave, 
 
 343 
 
 225. 
 226. 
 
 Myliobatis Edwardsii, . 
 Upper jaw of Alligator, 
 
 296 
 297 
 
 257- 
 
 258. 
 
 Dinomis elephantopus, . 
 Skull of Diprotodon, 
 
 347 
 348 
 
 227. 
 
 Skull of Odontopteryx 
 
 
 259- 
 
 Skull of Thylacoleo, 
 
 349 
 
 
 toliapicus, . 
 
 298 
 
 260. 
 
 Skeleton of Megatherium, 
 
 350 
 
 228. 
 
 Zeuglodon cetoides, 
 
 299 
 
 261. 
 
 Skeleton of Mylodon, . 
 
 352 
 
 229. 
 
 Palceotherium magnum, 
 
 
 262. 
 
 Glyptodon clavipes, 
 
 352 
 
 
 restored, 
 
 301 
 
 263. 
 
 Skull of Rhinoceros ticho- 
 
 
 230. 
 
 Feet of Equidce, . 
 
 302 
 
 
 rhinus, 
 
 353 
 
 23I- 
 
 Anoplot}ierium commune, 
 
 33 
 
 264. 
 
 Skeleton of Cervusmega- 
 
 
 232. 
 
 Skull of Dinoceras mir- 
 
 
 
 ceros, 
 
 355 
 
 
 abilis, 
 
 304 
 
 265. 
 
 Skull of Bos primigenitts, 
 
 356 
 
 233- 
 
 Vespertilio Parisiensis, . 
 
 305 
 
 266. 
 
 Skeleton of Mammoth, 
 
 358 
 
 234- 
 
 Miocene Palms, . 
 
 309 
 
 267. 
 
 Molar tooth of Mam- 
 
 
 235- 
 
 Platanus aceroides, 
 
 39 
 
 
 moth, 
 
 359 
 
 2 3 6. 
 
 Cinnamomum folymor- 
 
 
 268. 
 
 Skull of Ursus speZc&is, 
 
 360 
 
 
 phum, 
 
 309 
 
 269. 
 
 Skull of Hycena spelcea, 
 
 361 
 
 237- 
 
 Textularia Meyeriana, . 
 
 3 11 
 
 270. 
 
 Lower jaw of Trogon- 
 
 
 2 3 8. 
 
 Scutella subrotunda, 
 
 312 
 
 
 therium Cuvieri, 
 
 361
 
 PART I. 
 
 PRINCIPLES OF PALEONTOLOGY.
 
 THE 
 
 ANCIENT LIFE -HISTORY 
 
 OF 
 
 THE EARTH. 
 
 INTRODUCTION. 
 
 THE LAWS OF GEOLOGICAL ACTION. 
 
 UNDER the general title of " Geology " are usually included at 
 least two distinct branches of inquiry, allied to one another in 
 the closest manner, and yet so distinct as to be largely capable 
 of separate study. Geology* in its strict sense, is the science 
 which is concerned with the investigation of the materials which 
 compose the earth, the methods in which those materials have 
 been arranged, and the causes and modes of origin of these 
 arrangements. In this limited aspect, Geology is nothing more 
 than the Physical Geography of the past, just as Physical Geo- 
 graphy is the Geology of to-day ; and though it has to call in 
 the aid of Physics, Astronomy, Mineralogy, Chemistry, and 
 other allies more remote, it is in itself a perfectly distinct and 
 individual study. One has, however, only to cross the thresh- 
 old of Geology to discover that the field and scope of the 
 science cannot be thus rigidly limited to purely physical pro- 
 blems. The study of the physical development of the earth 
 throughout past ages brings us at once in contact with the 
 forms of animal and vegetable life which peopled its surface in 
 bygone epochs, and it is found impossible adequately to com- 
 * Gr. ge, the earth ; logos, a discourse.
 
 2 PRINCIPLES OF PALEONTOLOGY. 
 
 prebend the former, unless we possess some knowledge of the 
 latter. However great its physical advances may be, Geology 
 remains imperfect till it is wedded with Palaeontology,* a study 
 which essentially belongs to the vast complex of the Biologi- 
 cal Sciences, but at the same time has its strictly geological 
 side. Dealing, as it does, wholly with the consideration of 
 such living beings as do not belong exclusively to the present 
 order of things, Paleontology is, in reality, a branch of Natu- 
 ral History, and may be regarded as substantially the Zoology 
 and Botany of the past. It is the ancient life-history of the 
 earth, as revealed to us by the labours of palaeontologists, 
 with which we have mainly to do here ; but before entering 
 upon this, there are some general questions, affecting Geology 
 and Palaeontology alike, which may be very briefly discussed. 
 
 The working geologist, dealing in the main with purely phy- 
 sical problems, has for his object to determine the material 
 structure of the earth, and to investigate, as far as may be, the 
 long chain of causes of which that structure is the ultimate re- 
 sult. No wider or more extended field of inquiry could be 
 found ; but philosophical geology is not content with this. At 
 all the confines of his science, the transcendental geologist 
 finds himself confronted with some of the most stupendous 
 problems which have ever engaged the restless intellect of 
 humanity. The origin and primaeval constitution of the terres- 
 trial globe, the laws of geologic action through long ages of 
 vicissitude and development, the origin of life, the nature and 
 source of the myriad complexities of living beings, the advent 
 of man, possibly even the future history of the earth, are 
 amongst the questions with which the geologist has to grapple 
 in his higher capacity. 
 
 These are problems which have occupied the attention of 
 philosophers in every age of the world, and in periods long 
 antecedent to the existence of a science of geology. The mere 
 existence of cosmogonies in the religion of almost every nation, 
 both ancient and modern, is a sufficient proof of the eager de- 
 sire of the human mind to know something of the origin of the 
 earth on which we tread. Every human being who has gazed 
 on the vast panorama of the universe, though it may have been 
 but with the eyes of a child, has felt the longing to solve, how- 
 ever imperfectly, " the riddle of the painful earth," and has, 
 consciously or unconsciously, elaborated some sort of a theory 
 as to the why and wherefore of what he sees. Apart from the 
 profound and perhaps inscrutable problems which lie at the 
 bottom of human existence, men have in all ages invented 
 * Gr. palaios, ancient ; onta, beings ; logos, discourse.
 
 THE LAWS OF GEOLOGICAL ACTION. 3 
 
 theories to explain the common phenomena of the material 
 universe ; and most of these theories, however varied in their 
 details, turn out on examination to have a common root, and 
 to be based on the same elements. Modern geology has its 
 own theories on the same subject, and it will be well to glance 
 for a moment at the principles underlying the old and the new 
 views. 
 
 It has been maintained, as a metaphysical hypothesis, that 
 there exists in the mind of man an inherent principle, in virtue 
 of which he believes and expects that what has 'been, will be ; 
 and that the course of nature will be a continuous and unin- 
 terrupted one. So far, however, from any such belief existing 
 as a necessary consequence of the constitution of the human 
 mind, the real fact seems to be that the contrary belief has 
 been almost' universally prevalent. In all old religions, and 
 in the philosophical systems of almost all ancient nations, the 
 order of the universe has been regarded as distinctly unstable, 
 mutable, and temporary. A beginning and an end have always 
 been assumed, and the course of terrestrial events between 
 these two indefinite points has been regarded as liable to con- 
 stant interruption by revolutions and catastrophes of different 
 kinds, in many cases emanating from supernatural sources. 
 Few of the more ancient theological creeds, and still fewer of 
 the ancient philosophies, attained body and shape without 
 containing, in some form or another, the belief in the existence 
 of periodical convulsions, and of alternating cycles of destruc- 
 tion and repair. 
 
 That geology, in its early infancy, should have become im- 
 bued with the spirit of this belief, is no more than might have 
 been expected ; and hence arose the at one time powerful and 
 generally-accepted doctrine of " Catastrophism." That the 
 succession of phenomena upon the globe, whereby the earth's 
 crust had assumed the configuration and composition which 
 we find it to possess, had been a discontinuous and broken 
 succession, was the almost inevitable conclusion of the older 
 geologists. Everywhere in their study of the rocks they met 
 with apparently impassable gaps, and breaches of continuity 
 that could not be bridged over. Everywhere they found them- 
 selves conducted abruptly from one system of deposits to 
 others totally different in mineral character or in stratigraphical 
 position. Everywhere they discovered that well-marked and 
 easily recognisable groups of animals and plants were succeeded, 
 without the intermediation of any obvious lapse of time, by 
 other assemblages of organic beings of a different character. 
 Everywhere they found evidence that the earth's crust had
 
 4 PRINCIPLES OF PALEONTOLOGY. 
 
 undergone changes of such magnitude as to render it seemingly 
 irrational to suppose that they could have been produced by 
 any process now in existence. It" we add to the above the 
 prevalent belief of the time as to the comparative brevity of 
 the period which had elapsed since the birth of the globe, we 
 can readily understand the general acceptance of some form of 
 catastrophism amongst the earlier geologists. 
 
 As regards its general sense and substance, the doctrine of 
 catastrophism held that the history of the ea-rth, since first it 
 emerged from the primitive chaos, had been one of periods of 
 repose, alternating with catastrophes and cataclysms of a more 
 or less violent character. The periods of tranquillity were sup- 
 posed to have been long and protracted ; and during each of 
 them it was thought that one of the great geological " forma- 
 tions " was deposited. In each of these periods, therefore, the 
 condition of the earth was supposed to be much the same as it 
 is now sediment was quietly accumulated at the bottom of the 
 sea, and animals and plants flourished uninterruptedly in suc- 
 cessive generations. Each period of tranquillity, however, was 
 believed to have been, sooner or later, put an end to by a 
 sudden and awful convulsion of nature, ushering in a brief and 
 paroxysmal period, in which the great physical forces were 
 unchained and permitted to spring into a portentous activity. 
 The forces of subterranean fire, with their concomitant pheno- 
 mena of earthquake and volcano, were chiefly relied upon as 
 the efficient causes of these periods of spasm and revolution. 
 Enormous elevations of portions of the earth's crust were thus 
 believed to be produced, accompanied by corresponding and 
 equally gigantic depressions of other portions. In this way 
 new ranges of mountains were produced, and previously exist- 
 ing ranges levelled with the ground, seas were converted into 
 dry land, and continents buried beneath the ocean catastrophe 
 following catastrophe, till the earth was rendered uninhabitable, 
 and its races of animals and plants were extinguished, never to 
 reappear in the same form. Finally, it was believed that this 
 feverish activity ultimately died out, and that the ancient peace 
 once more came to reign upon the earth. As the abnormal 
 throes and convulsions began to be relieved, the dry land and 
 sea once more resumed their relations of stability, the condi- 
 tions of life were once more established, and new races of ani- 
 mals and plants sprang into existence, to last until the super- 
 vention of another fever-fit. 
 
 Such is the past history of the globe, as sketched for us, in 
 alternating scenes of fruitful peace and revolutionary destruc- 
 tion, by the earlier geologists. As before said, we cannot
 
 THE LAWS OF GEOLOGICAL ACTION. 5 
 
 wonder at the former general acceptance of Catastrophistic 
 doctrines. Even in the light of our present widely-increased 
 knowledge, the series of geological monuments remains a broken 
 and imperfect one ; nor can we ever hope to fill up completely 
 the numerous gaps with which the geological record is defaced. 
 Catastrophism was the natural method of accounting for these 
 gaps, and, as we shall see, it possesses a basis of truth. At 
 present, however, catastrophism may be said to be nearly ex- 
 tinct, and its place is taken by the modern doctrine of " Con- 
 tinuity " or " Uniformity" a doctrine with which the name of 
 Lyell must ever remain imperishably associated. 
 
 The fundamental thesis of the doctrine of Uniformity is, 
 that, in spite of all apparent violations of continuity, the se- 
 quence of geological phenomena has in reality been a regular 
 and uninterrupted one ; and that the vast changes which can 
 be shown to have passed over the earth in former periods have 
 been the result of the slow and ceaseless working of the ordi- 
 nary physical forces acting with no greater intensity than they 
 do now, but acting through enormously prolonged periods. 
 The essential element in the theory of Continuity is to be found 
 in the allotment of indefinite time for the accomplishment of 
 the known series of geological changes. It is obviously the 
 case, namely, that there are two possible explanations of all 
 phenomena which lie so far concealed in " the dark backward 
 and abysm of time," that we can have no direct knowledge of 
 the manner in which they were produced. We may, on the 
 one hand, suppose them to be the result of some very powerful 
 cause, acting through a short period of time. That is Catas- 
 trophism. Or, we may suppose .them to be caused by a much 
 weaker force operating through a proportionately prolonged 
 period. This is the view of the Uniformitarians. It is a ques- 
 tion of energy versus time ; and it is time which is the true ele- 
 ment of the case. An earthquake may remove a mountain in 
 the course of a few seconds ; but the dropping of the gentle 
 rain will do the same, if we extend its operations over a millen- 
 nium. And this is true of all agencies which are now at work, 
 or ever have been at work, upon our planet. The Catastro- 
 phists, believing that the globe is but, as it were, the birth of 
 yesterday, were driven of necessity to the conclusion that its 
 history had been checkered by the intermittent action of par- 
 oxysmal and almost inconceivably potent forces. The Unifor- 
 mitarians, on the other hand, maintaining the " adequacy of 
 existing causes," and denying that the known physical forces 
 ever acted in past time with greater intensity than they do at 
 present, are, equally of necessity, driven to the conclusion that
 
 6 PRINCIPLES OF PALEONTOLOGY. 
 
 the world is truly in its " hoary eld," and that its present state 
 is really the result of the tranquil and regulated action of 
 known forces through unnumbered and innumerable centuries. 
 
 The most important point for us, in the present connection, 
 is the bearing of these opposing doctrines upon the question 
 as to the origin of the existing terrestrial order. On any doc- 
 trine of uniformity that order has been evolved slowly, and, 
 according to law, from a pre-existing order. Any doctrine of 
 catastrophism, on the other hand, carries with it, by implica- 
 tion, the belief that the present order of things was brought 
 about suddenly and irrespective of any pre-existent order; and 
 it is important to hold clear ideas as to which of these beliefs 
 is the true one. In the first place, we may postulate that the 
 world had a beginning, and, equally, that the existing terrestrial 
 order had a beginning. However far back we may go, geology 
 does not, and cannot, reach the actual beginning of the world ; 
 and we are, therefore, left simply to our own speculations on 
 this point. With regard, however, to the existing terrestrial 
 order, a great deal can be discovered, and to do so is one of 
 the principal tasks of geological science. The first steps in the 
 production of that order lie buried in the profound and un- 
 searchable depths of a past so prolonged as to present itself to 
 our finite minds as almost an eternity. The last steps are in 
 the prophetic future, and can be but dimly guessed at. Be- 
 tween the remote past and the distant future, we have, however, 
 a long period which is fairly open to inspection ; and in saying 
 a "long" period, it is to be borne in mind that this term is 
 used in its geological sense. Within this period, enormously 
 long as it is when measured by human standards, we can trace 
 with reasonable certainty the progressive march of events, and 
 can determine the laws of geological action, by which the pre- 
 sent order of things has been brought about. 
 
 The natural belief on this subject doubtless is, that the 
 world, such as we now see it, possessed its present form and 
 configuration from the beginning. Nothing can be more 
 natural than the belief that the present continents and oceans 
 have always been where they are now ; that we have always 
 had the same mountains and plains ; that our rivers have 
 always had their present courses, and our lakes their present 
 positions ; that our climate has always been the same ; and 
 that our animals and plants have always been identical with 
 those now -familiar to us. Nothing could be more natural 
 than such a belief, and nothing could be further removed from 
 the actual truth. On the contrary, a very slight acquaintance 
 with geology shows us, in the words of Sir John Herschel, that
 
 THE LAWS OF GEOLOGICAL ACTION. 7 
 
 "the actual configuration of our continents and islands, the 
 coast-lines of our maps, the' direction and elevation of our 
 mountain-chains, the courses of our rivers, and the soundings 
 of our oceans, are not things primordially arranged in the con- 
 struction of our globe, but results of successive and complex 
 actions on a former state of things ; that, again, of similar 
 actions on another still more remote ; and so on, till the ori- 
 ginal and really permanent state is pushed altogether out of 
 sight and beyond the reach even of imagination ; while on the 
 other hand, a similar, and, as far as we can see, interminable 
 vista is opened out for the future, by which the habitability of 
 our planet is secured amid the total abolition on it of the 
 present theatres of terrestrial life." 
 
 Geology, then, teaches us that the physical features which 
 now distinguish the earth's surface have been produced as the 
 ultimate result of an almost endless succession of precedent 
 changes. Palaeontology teaches us, though not yet in such 
 assured accents, the same lesson. Our present animals and 
 plants have not been produced, in their innumerable forms, 
 each as we now know it, as the sudden, collective, and simul- 
 taneous birth of a renovated world. On the contrary, we have 
 the clearest evidence that some of our existing animals and 
 plants made their appearance upon the earth at a much earlier 
 period than others. In the confederation of animated nature 
 some races can boast of an immemorial antiquity, whilst others 
 are comparative parvenus. We have also the clearest evidence 
 that the animals and plants which now inhabit the globe have 
 been preceded, over and over again, by other different assem- 
 blages of animals and plants, which have flourished in succes- 
 sive periods of the earth's history, have reached their culmina- 
 tion, and then have given way to a fresh series of living beings. 
 We have, finally, the clearest evidence that these successive 
 groups of animals and plants (faunas and florae) are to a greater 
 or less extent directly connected with one another. Each 
 group is, to a greater or less extent, the lineal descendant of 
 the group which immediately preceded it in point of time, and 
 is more or less fully concerned with giving origin to the group 
 which immediately follows it. That this law of "evolution" 
 has prevailed to a great extent is quite certain ; but it does not 
 meet all the exigencies of the case, and it is probable that its 
 action has been supplemented by some still unknown law of a 
 different character. 
 
 We shall have to consider the question of geological " con- 
 tinuity" again. In the meanwhile, it is sufficient to state that 
 this doctrine is now almost universally accepted as the basis
 
 8 PRINCIPLES OF PALEONTOLOGY. 
 
 of all inquiries, both in the domain of geology and that of 
 palaeontology. The advocates of continuity possess one im- 
 mense advantage over those who believe in violent and revo- 
 lutionary convulsions, that they call into play only agencies 
 of which we have actual knowledge. We know that certain 
 forces are now at work, producing certain modifications in the 
 present condition of the globe ; and we know that these forces 
 are capable of producing the vastest of the changes which 
 geology brings under our consideration, provided we assign a 
 time proportionately vast for their operation. On the other 
 hand, the advocates of catastrophism, to make good their 
 views, are compelled to invoke forces and actions, both de- 
 structive and restorative, of which we have, and can have, no 
 direct knowledge. They endow the whirlwind and the earth- 
 quake, the central fire and the rain from heaven, with powers 
 as mighty as ever imagined in fable, and they build up the 
 fragments of a repeatedly shattered world by the intervention 
 of an intermittently active creative power. 
 
 It should not be forgotten, however, that from one point of 
 view there is a truth in catastrophism which is sometimes 
 overlooked by the advocates of continuity and uniformity. 
 Catastrophism has, as its essential feature, the proposition that 
 the known and existing forces of the earth at one time acted 
 with much greater intensity and violence than they do at pre- 
 sent, and they carry down the period of this excessive action 
 to the commencement of the present terrestrial order. The 
 Uniformitarians, in effect, deny this proposition, at any rate as 
 regards any period of the earth's history of which we have 
 actual cognisance. If, however, the " nebular hypothesis " of 
 the origin of the universe be well founded as is generally ad- 
 mitted- then^ beyond question, the earth is a gradually cooling 
 body, which has at one time been very much hotter than it is 
 at present. There has been a time, therefore, in which the 
 igneous forces of the earth, to which we owe the phenomena of 
 earthquakes and volcanoes, must have been far more intensely 
 active than we can conceive of from anything that we can see 
 at the present day. By the same hypothesis, the sun is a 
 cooling body, and must at one time have possessed -a much 
 higher temperature than it has at present. But increased heat 
 of the sun would seriously alter the existing conditions affect- 
 ing the evaporation and precipitation of moisture on our earth ; 
 and hence the aqueous forces may also have acted at one time 
 more powerfully than they do now. The fundamental prin- 
 ciple of catastrophism is, therefore, not wholly vicious ; and 
 we have reason to think that there must have been periods
 
 THE LAWS OF GEOLOGICAL ACTION. 9 
 
 very remote, it is true, and perhaps unrecorded in the history 
 of the earth in which the known physical forces may have 
 acted with an intensity much greater than direct observation 
 would lead us to imagine. And this may be believed, alto- 
 gether irrespective of those great secular changes by which hot 
 or cold epochs are produced, and which can hardly be called 
 " catastrophistic," as they are produced gradually, and are 
 liable to recur at definite intervals. 
 
 Admitting, then, that there is a truth at the bottom of the 
 once current doctrines of catastrophism, still it remains certain 
 that the history of the earth has been one of law in all past 
 time, as it is now. Nor need we shrink back affrighted at the 
 vastness of the conception the vaster for its very vagueness 
 that we are thus compelled to form as to the duration of 
 geological time. As we grope our way backward through the 
 dark labyrinth of the ages, epoch succeeds to epoch, and 
 period to period, each looming more gigantic in its outlines 
 and more shadowy in its features, as it rises, dimly revealed, 
 from the mist and vapour of an older and ever-older past. It 
 is useless to add century to century or millennium to millen- 
 nium. When we pass a certain boundary-line, which, after all, 
 is reached very soon, figures cease to convey to our finite 
 faculties any real notion of the periods with which we have 
 to deal. The astronomer can employ material illustrations 
 to give form and substance to our conceptions of celestial 
 space ; but such a resource is unavailable to the geologist. 
 The few thousand years of which we have historical evidence 
 sink into absolute insignificance beside the unnumbered aeons 
 which unroll themselves one by one as we penetrate the dim 
 recesses of the past, and decipher with feeble vision the pon- 
 derous volumes in which the record of the earth is written. 
 Vainly does the strained intellect seek to overtake an ever- 
 receding commencement, and toil to gain some adequate grasp 
 of an apparently endless succession. A beginning there must 
 have been, though we can never hope to fix its point. Even 
 speculation droops her wings in the attenuated atmosphere of 
 a past so remote, and the light of imagination is quenched in 
 the darkness of a history so ancient. In time, as in space, the 
 confines of the universe must ever remain concealed from us , 
 and of the end we know no more than of the beginning. In- 
 conceivable as is to us the lapse of "geological time," it is no 
 more than "a mere moment of the past, a mere infinitesimal 
 portion of eternity." Well may "the human heart, that weeps 
 and trembles," say, with Richter's pilgrim through celestial 
 space, " I will go no farther ; for the spirit of man acheth with
 
 10 PRINCIPLES OF PALAEONTOLOGY. 
 
 this infinity. Insufferable is the glory of God. Let me lie 
 down in the grave, and hide me from the persecution of the 
 Infinite, for end, I see, there is none." 
 
 CHAPTER I. 
 THE SCOPE AND MATERIALS OF PALEONTOLOGY. 
 
 The study of the rock-masses which constitute the crust of the 
 earth, if carried out in the methodical and 'scientific manner of 
 the geologist, at once brings us, as has been before remarked, 
 in contact with the remains or traces of living beings which 
 formerly dwelt upon the globe. Such remains are found, in 
 greater or less abundance, in the great majority of rocks; and 
 they are not only of great interest in themselves, but they have 
 proved of the greatest importance as throwing light upon vari- 
 ous difficult problems in geology, in natural history, in botany, 
 and in philosophy. Their study constitutes the science of 
 paleontology ; and though it is possible to proceed to a cer- 
 tain length in geology and zoology without much palseontolo- 
 gical knowledge, it is hardly possible to attain to a satisfac- 
 tory general acquaintance with either of these subjects with- 
 out having mastered the leading facts of the first. Similarly, 
 it is not possible to study palaeontology without some ac- 
 quaintance with both geology and natural history. 
 
 PALAEONTOLOGY, then, is the science which treats of the 
 living beings, whether animal or vegetable, which have in- 
 habited the earth during past periods of its history. Its object 
 is to eludicate, as far as may be, the structure, mode of exist- 
 ence, and habits of all such ancient forms of life ; to determine 
 their position in the scale of organised beings ; to lay down 
 the geographical limits within which they flourished ; and to 
 fix the period of their advent and disappearance. It is the 
 ancient life-history of the earth ; and were its record complete, 
 it would furnish us with a detailed knowledge of the form and 
 relations of all the animals and plants which have at any period 
 flourished upon the land-surfaces of the globe or inhabited its 
 waters; it would enable us to determine precisely their succes- 
 sion in time ; and it would place in our hands an unfailing key 
 to the problems of evolution. Unfortunately, from causes 
 which will be subsequently discussed, the palaeontological 
 record is extremely imperfect, and our knowledge is inter-
 
 THE SCOPE OF PALAEONTOLOGY. II 
 
 rupted by gaps, which not only bear a large proportion to our 
 solid information, but which in many cases are of such a nature 
 that we can never hope to fill them up. 
 
 FOSSILS. The remains of animals or vegetables which we 
 now find entombed in the solid rock, and which constitute the 
 working material of the palaeontologist, are termed "fossils,"* 
 or " petrifactions." In most cases, as can be readily under- 
 stood, fossils are the actual hard parts of animals and plants 
 which were in existence when the rock in which they are now 
 found was being deposited. Most fossils, therefore, are of the 
 nature of the shells of shell-fish, the skeletons of coral-zoophytes, 
 the bones of vertebrate animals, or the wood, bark, or leaves 
 of plants. All such bodies are more or less of a hard consist- 
 ence to begin with, and are capable of resisting decay for a 
 longer or shorter time hence the frequency with which they 
 occur in the fossil condition. Strictly speaking, however, by 
 the term " fossil " must be understood " any body, or the traces 
 of the existence of any body, whether animal or vegetable, which 
 has been buried in the earth by natural causes " (Lyell). 
 We shall find, in fact, that many of the objects which we have 
 to study as "fossils" have never themselves actually formed 
 parts of any animal or vegetable, though they are due to the 
 former existence of such organisms, and indicate what was the 
 nature of these. Thus the footprints left by birds, or reptiles, 
 or quadrupeds upon sand or mud, are just as much proofs of 
 the former existence of these animals as would be bones, 
 feathers, or scales, though in themselves they are- inorganic. 
 Under the head of fossils, therefore, come the footprints of 
 air-breathing vertebrate animals ; the tracks, trails, and bur- 
 rows of sea-worms, crustaceans, or molluscs; the impressions 
 left on the sand by stranded jelly-fishes ; the burrows in stone 
 or wood of certain shell-fish ; the " moulds " or " casts " of 
 shells, corals, and other organic remains; and various other 
 bodies of a more or less similar nature. 
 
 FOSSILISATION. The term " fossilisation " is applied to all 
 those processes through which the remains of organised beings 
 may pass in being converted into fossils. These processes are 
 numerous and varied ; but there are three principal modes of 
 fossilisation which alone need be considered here. In the first 
 instance, the fossil is to all intents and purposes an actual 
 portion of the original organised being such as a bone, a shell, 
 or a piece of wood. In some rare instances, as in the case of 
 the body of the Mammoth discovered embedded in ice at the 
 mouth of the Lena in Siberia, the fossil may be preserved 
 * Lat. fossiis, dug up.
 
 12 PRINCIPLES OF PALAEONTOLOGY. 
 
 almost precisely in its original condition, and even with its 
 soft parts uninjured. More commonly, certain changes have 
 taken place in the fossil, the principal being the more or less 
 total removal of the organic matter originally present. Thus 
 bones become light and porous by the removal of their gela- 
 tine, so as to cleave to the tongue on being applied to that 
 organ ; whilst shells become fragile, and lose their primitive 
 colours. In other cases, though practically the real body it 
 represents, all the cavities of the fossil, down to its minutest 
 recesses, may have become infiltrated with mineral matter. It 
 need hardly be added, that it is in the more modern rocks that 
 -we find the fossils, as a rule, least changed from their former 
 condition; but the original structure is often more or less com- 
 pletely retained in some of the fossils from even the most 
 ancient formations. 
 
 In the second place, we very frequently meet with fossils in 
 the state of " casts " or moulds of the original organic body. 
 What occurs in this case will be readily understood if we ima- 
 gine any common bivalve shell, as an Oyster, or Mussel, or 
 Cockle, embedded in clay or mud. If the clay were sufficiently 
 soft and fluid, the first thing would be that it would gain access 
 to the interior of the shell, and would completely fill up the 
 space between the valves. The pressure, also, of the surround- 
 ing matter would insure that the clay would everywhere ad- 
 here closely to the exterior of the shell. If now we suppose 
 the clay to be in any way hardened so as to be converted into 
 stone, and if we were to break up the stone, we should obvi- 
 ously have the following state of parts. The clay which filled 
 the shell would form an accurate cast of the interior of the 
 shell, and the clay outside would give us an exact impression 
 or cast of the exterior of the shell (fig. i). We should have, 
 then, two casts, an interior and 
 an exterior, and the two would 
 be very different to one another, 
 since the inside of a shell is 
 very unlike the outside. In 
 the case, in fact, of many uni- 
 valve shells, the interior cast or 
 "mould" is so unlike the ex- 
 terior cast, or unlike the shell 
 
 Fig. i. Trigonia lo'i~a, showing casts itself, that it may be difficult tO 
 
 of the shell '~ determine the true origin of the 
 
 former. 
 
 It only remains to add that there is sometimes a further 
 complication. If the rock be very porous and permeable by
 
 THE SCOPE OF PALEONTOLOGY. 13 
 
 water, it may happen that the original shell is entirely dissolved 
 away, leaving the interior cast loose, like the kernel of a nut, 
 within the case formed by the exterior cast. Or it may happen 
 that subsequent to the attainment of this state of things, the 
 space thus left vacant between the interior and exterior cast 
 the space, that is, formerly occupied by the shell itself may 
 be filled up by some foreign mineral deposited there by the 
 infiltration of water. In this last case the splitting open of the 
 rock would reveal an interior cast, an exterior cast, and finally 
 a body which would have the exact form of the original shell, but 
 which would be really a much later formation, and which would 
 not exhibit under the microscope the minute structure of shell. 
 In the third class of cases we have fossils which present 
 with the greatest accuracy the external form, and even some- 
 times the internal minute structure, of the original organic 
 body, but which, nevertheless, are not themselves truly organic, 
 but have been formed by a " replacement " of the particles of 
 the primitive organism by some mineral substance. The most 
 elegant example of this is afforded by fossil wood which has 
 been " silicified " or converted into flint (silex). In such cases 
 we have fossil wood which presents the rings of growth and 
 fibrous structure of recent wood, and which under the micro- 
 scope exhibits the minutest vessels which characterise ligneous 
 tissue, together with the even more minute markings of the 
 vessels (fig. 2). The whole, however, instead of being com- 
 
 Fiff 2. Microscopic section of the Fig. 3. Microscopic section of the wood 
 
 silicified wood of a Conifer (Sequoia) cut of the common Larch (Abies larix), cut in 
 in the long direction of the fibres. Post- the long direction of the fibres. In both the 
 tertiary? Colorado. (Original.) fresh and the fossil wood (fig. 2) are seen 
 
 the discs characteristic of coniferous wood. 
 
 (Original.) 
 
 posed of the original carbonaceous matter of the wood, is now 
 converted into flint. The only explanation that can be given
 
 14 PRINCIPLES OF PALAEONTOLOGY. 
 
 of this by no means rnre phenomenon, is that the wood must 
 have undergone a slow process of decay in water charged with 
 silica or flint in solution. As each successive particle of wood 
 was removed by decay, its place was taken by a particle of 
 flint deposited from the surrounding water, till ultimately the 
 entire wood was silicified. The process, therefore, resembles 
 what would take place if we were to pull down a house built 
 of brick by successive bricks, replacing each brick as removed 
 by a piece of stone of precisely the same size and form. The 
 result of this would be that the house would retain its primi- 
 tive size, shape, and outline, but it would finally have been 
 converted from a house of brick into a house of stone. Many 
 other fossils besides wood such as shells, corals, sponges, 
 &c. are often found silicified ; and this may be regarded as 
 the commonest form of fossilisation by replacement. In other 
 cases, however, though the principle of the process is the same, 
 the replacing substance may be iron pyrites, oxide of iron, 
 sulphur, malachite, magnesite, talc, &c. ; but it is rarely that 
 the replacement with these minerals is so perfect as to preserve 
 the more delicate details of internal structure. 
 
 CHAPTER II. 
 THE FOSSILIFEROUS ROCKS. 
 
 Fossils are found in rocks, though not universally or pro- 
 miscuously ; and it is therefore necessary that the palaeonto- 
 logist should possess some acquaintance with, at any rate, those 
 rocks which yield organic remains, and which are therefore 
 said to be " fossiliferous." In geological language, all the 
 materials which enter into the composition of the solid crust 
 of the earth, be their texture what it may from the most im- 
 palpable mud to the hardest granite are termed "rocks;" 
 and for our present purpose we may divide these into two great 
 groups. In the first division are the Igneous Rocks such as 
 the lavas and ashes of volcanoes which are formed within the 
 body of the earth itself, and which owe their structure and 
 origin to the action of heat. The Igneous Rocks are formed 
 primarily below the surface of the earth, which they only reach 
 as the result of volcanic action ; they are generally destitute of 
 distinct " stratification," or arrangement in successive layers; 
 and they do not contain fossils, except in the comparatively
 
 THE FOSSILIFEROUS ROCKS. 15 
 
 rare instances where volcanic ashes have enveloped animals 
 or plants which were living in the sea or on the land in the 
 immediate vicinity of the volcanic focus. The second great 
 division of rocks is that of the fbssiliferous, Aqueous, or Sedi- 
 mentary Rocks. These are formed at the surface of the earth, 
 and, as implied by one of their names, are invariably deposited 
 in water. They are produced by vital or chemical action, or 
 are formed from the " sediment" produced by the disintegra- 
 tion and reconstruction of previously existing rocks, without 
 previous solution ; they mostly contain fossils ; and they are 
 arranged in distinct layers or " strata." The so-called "aerial" 
 rocks which, like beds of blown sand, have been formed by 
 the action of the atmosphere, may also contain fossils; but 
 they are not of such importance as to require special notice 
 here. 
 
 For all practical purposes, we may consider that the Aque- 
 ous Rocks are the natural cemetery of the animals and plants 
 of bygone ages ; and it is therefore essential that the palaeon- 
 tological student should be acquainted with some of the prin- 
 cipal facts as to their physical characters, their minute structure 
 and mode of origin, their chief varieties, and their historical 
 succession. 
 
 The Sedimentary or Fossiliferous Rocks form the greater 
 portion of that part of the earth's crust which is open to our 
 examination, and are distinguished by the fact that they are 
 regularly " stratified" or arranged in distinct and definite layers 
 or " strata." These layers may consist of a single material, 
 as in a block of sandstone, or they may consist of different 
 materials. When examined on a large scale, they are always 
 found to consist of alternations of layers of different mineral 
 composition. We may examine any given area, and find in it 
 nothing but one kind of rock sandstone, perhaps, or lime- 
 stone. In all cases', however, if we extend our examination 
 sufficiently far, we shall ultimately come upon different rocks ; 
 and, as a general rule, the thickness of any particular set of 
 beds is comparatively small, so that different kinds of rock 
 alternate with one another in comparatively small spaces. 
 
 As regards the origin of the Sedimentary Rocks, they are 
 for the most part " derivative " rocks, being derived from the 
 wear and tear of pre-existent rocks. Sometimes, however, they 
 owe their origin to chemical or vital action, when they would 
 more properly be spoken of simply as Aqueous Rocks. As to 
 their mode of deposition, we are enabled to infer that the 
 materials which compose them have formerly been spread out 
 by the action of water, from what we see going on every day
 
 i6 
 
 PRINCIPLES OF PALEONTOLOGY. 
 
 at the mouths of our great rivers, and on a smaller scale wher- 
 ever there is running water. Every stream, where it runs into 
 
 
 
 Fig. 4. Sketch of Carboniferous strata at Kinghorn, in Fife, showing stratified beds 
 (limestone and shales) surmounted by an unstratified mass of trap. (Original.) 
 
 a lake or into the sea, carries with it a burden of mud, sand, 
 and rounded pebbles, derived from the waste of the rocks 
 which form its bed and banks. When these materials cease 
 to be impelled by the force of the moving water, they sink to 
 the bottom, the heaviest pebbles, of course, sinking first, the 
 smaller pebbles and sand next, and the finest mud last. Ulti- 
 mately, therefore, as might have been inferred upon theoretical 
 grounds, and as is proved by practical experience, every lake 
 becomes a receptacle for a series of stratified rocks produced 
 by the streams flowing into it. These deposits may vary in 
 different parts of the lake, according as one stream brought 
 down one kind of material and another stream contributed 
 another material ; but in all cases the materials will bear ample 
 evidence that they were produced, sorted, and deposited by 
 running water. The finer beds of clay or sand will all be 
 arranged in thicker or thinner layers or laminae; and if there 
 are any beds of pebbles these will all be rounded or smooth, 
 just like the water-worn pebbles of any brook-course. In all 
 probability, also, we should find in some of the beds the re-
 
 THE FOSSILIFEROUS ROCKS. I/ 
 
 mains of fresh-water shells or plants or other organisms which 
 inhabited the lake at the time these beds were being de- 
 posited. 
 
 In the same way large rivers such as the Ganges or 
 Mississippi deposit all the materials which they bring down 
 at their mouths, forming in this way their " deltas." When- 
 ever such a delta is cut through, either by man or by some 
 channel of the river altering its course, we find that it is com- 
 posed of a succession of horizontal layers or strata of sand or 
 mud, varying in mineral composition, in structure, or in grain, 
 according to the nature of the materials brought down by the 
 river at different periods. Such deltas, also, will con-tain the 
 remains of animals which inhabit the river, with fragments of 
 the plants which grew on its banks, or bones of the animals 
 which lived in its basin. 
 
 Nor is this action confined, of course, to large rivers only, 
 though naturally most conspicuous in the greatest bodies of 
 water. On the contrary, all streams, of whatever size, are 
 engaged in the work of wearing down the dry land, and of 
 transporting the materials thus derived from higher to lower 
 levels, never resting in this work till they reach the sea. 
 
 Fig. 5. Diagram to illustrate the formation of sedimentary deposits at the point 
 where a river debouches into the sea. 
 
 Lastly, the sea itself irrespective of the materials delivered 
 into it by rivers is constantly preparing fresh stratified de-
 
 1 8 PRINCIPLES OF PALEONTOLOGY. 
 
 posits by its own action. Upon every coast-line the sea is 
 constantly eating back into the land and reducing its com- 
 ponent rocks to form the shingle and sand which we see upon 
 every shore. The materials thus produced are not, however, 
 lost, but are ultimately deposited elsewhere in the form of new 
 stratified accumulations, in which are buried the remains of 
 animals inhabiting the sea at the time. 
 
 Whenever, then, we find anywhere in the interior of the land 
 any series of beds having these characters composed, that is, 
 of distinct layers, the particles of which, both large and small, 
 show distinct traces of the wearing action of water whenever 
 and wherever we find such rocks, we are justified in assuming 
 that they have been deposited by water in the manner above 
 mentioned. Either they were laid down in some former lake 
 by the combined action of the streams which flowed into it ; 
 or they were deposited at the mouth of some ancient river, 
 forming its delta ; or they were laid down at the bottom of the 
 ocean. In the first two cases, any fossils which the beds 
 might contain would be the remains of fresh-water or terres- 
 trial organisms. In the last case, the majority, at any rate, of 
 the fossils would be the remains of marine animals. 
 
 The term " formation " is employed by geologists to express 
 " any group of rocks which have some character in common, 
 whether of origin, age, or composition " (Lyell) ; so that we 
 may speak of stratified and unstratified formations, aqueous 
 or igneous formations, fresh-water or marine formations, and 
 so on. 
 
 CHIEF DIVISIONS OF THE AQUEOUS ROCKS. 
 
 The Aqueous Rocks may be divided into two great sections, 
 the Mechanically-formed and the Chemically-formed, includ- 
 ing under the last head all rocks which owe their origin to 
 vital action, as well as those produced by ordinary chemical 
 agencies. 
 
 A. MECHANICALLY-FORMED ROCKS. These are all those 
 Aqueous Rocks of which we can obtain proofs that their 
 particles have been mechanically transported to their present 
 situation. Thus, if we examine a piece of conglomerate or 
 puddingstone, we find it to be composed of a number of 
 rounded pebbles embedded in an enveloping matrix or paste, 
 which is usually of a sandy nature, but may be composed of 
 carbonate of lime (when the rock is said to be a " calcareous 
 conglomerate "). The pebbles in all conglomerates are worn 
 and rounded by the action of water in motion, and thus show
 
 THE FOSSILIFEROUS ROCKS. 19 
 
 that they have been subjected to much mechanical attrition, 
 whilst they have been mechanically transported for a greater 
 or less distance from the rock of which they originally formed 
 part. The analogue of the old conglomerates at the present 
 day is to be found in the great beds of shingle and gravel 
 which are formed by the action of the sea on every coast-line, 
 and which are composed of water-worn and well-rounded 
 pebbles of different sizes. A breccia is a mechanically-formed 
 rock, very similar to a conglomerate, and consisting of larger 
 or smaller fragments of rock embedded in a common matrix. 
 The fragments, however, are in this case all more or less 
 angular, and are not worn or rounded. The fragments in 
 breccias may be of large size, or they may be comparatively 
 small (fig. 6); and the matrix may be composed of sand (aren- 
 aceous) or of carbonate of 
 lime (calcareous). In the case 
 of an ordinary sandstone, again, 
 we have a rock which may be 
 regarded as simply a very fine- 
 grained conglomerate or brec- 
 cia, being composed of small 
 grains of sand (silica), some- 
 timesrounded,sometimesmore 
 or less angular, cemented to- 
 gether by some such substance 
 as oxide of iron, silicate of 
 iron, or carbonate of lime. A 
 sandstone, therefore, like a Fig. 6. -Microscopic section of a caicar 
 
 ic o m^^lr-ini ous breccia in the Lo\ver Silurian (Coniston 
 
 is a mecnani- Limestone) of Shap Wells> Westmoreland. 
 
 rOCk, itS COlTlpO- Th e fragments are all of small size, and 
 
 nent grains being equally the ~ ^iS'asheta'nd j mSf?m' 
 
 rCSlllt Of mechanical attrition bedded in a matrix of crystalline limestone, 
 i i - (Original.) 
 
 and having equally been trans- 
 ported from a distance ; and the same is true of the ordinary 
 sand of the sea-shore, which is nothing more than an uncon- 
 solidated sandstone. Other so-called sands and sandstones, 
 though equally mechanical in their origin, are truly calcareous 
 in their nature, and are more or less entirely composed of 
 carbonate of lime. Of this kind are the shell-sand so com- 
 mon on our coasts, and the coral-sand which is so largely 
 formed in the neighbourhood of coral-reefs. In these cases 
 the rock is composed of fragments of the skeletons of shell- 
 fish, and numerous other marine animals, together, in many 
 instances, with the remains of certain sea-weeds (Corallines^ 
 Nullipores, &c.) which are endowed with the power of secret-
 
 20 PRINCIPLES OF PALEONTOLOGY. 
 
 ing carbonate of lime from the sea-water. Lastly, in cer- 
 tain rocks still finer in their texture than sandstones, such 
 as the various mud-rocks and shales, we can still recognise a 
 mechanical source and origin. If slices of any of these rocks 
 sufficiently thin to be transparent are examined under the 
 microscope, it will be found that they are composed of minute 
 grains of different sizes, which are all more or less worn and 
 rounded, and which clearly show, therefore, that they have 
 been subjected to mechanical attrition. 
 
 All the above-mentioned rocks, then, are mechanically -formed 
 rocks ; and they are often spoken of as " Derivative Rocks," 
 in consequence of the fact that their particles can be shown to 
 have been mechanically derived from other pre-existent rocks. 
 It follows from this that every bed of any mechanically-formed 
 rock is the measure and equivalent of a corresponding amount 
 of destruction of some older rock. It is not necessary to 
 enter here into a minute account of the subdivisions of these 
 rocks, but it may be mentioned that they may be divided into 
 two principal groups, according to their chemical composition. 
 In the one group we have the so-called Arenaceous (Lat. arena, 
 sand) or Siliceous Rocks, which are essentially composed of 
 larger or smaller grains of flint or silica. In this group are 
 comprised ordinary sand, the varieties of sandstone and grit, 
 and most conglomerates and breccias. We shall, however, after- 
 wards see that some siliceous rocks are of organic origin. In 
 the second group are the so-called Argillaceous (Lat. argilla, 
 clay) Rocks, which contain a larger or smaller amount of clay or 
 hydrated silicate of alumina in their composition. Under this 
 head come clays, shales, marls, marl-slate, clay-slates, and 
 most flags and flagstones. 
 
 B. CHEMI-CALLY-FORMED ROCKS. In this section are com- 
 prised all those Aqueous or Sedimentary Rocks which have 
 been formed by chemical agencies. As many of these chemi- 
 cal agencies, however, are exerted through the medium of 
 living beings, whether animals or plants, we get into this 
 section a number of what may be called " organically -formed 
 rocks." These are of the greatest possible importance to the 
 palaeontologist, as being to a greater or less extent composed 
 of the actual remains of animals or vegetables, and it will 
 therefore be necessary to consider their character and struc- 
 ture in some detail. 
 
 By far the most important of the chemically-formed rocks 
 are the so-called Calcareous Rocks (Lat. calx, lime), com- 
 prising all those which contain a large proportion of carbonate 
 of lime, or are wholly composed of this substance. Carbonate
 
 THE FOSSILIFEROUS ROCKS. 21 
 
 of lime is soluble in water holding a certain amount of car- 
 bonic acid gas in solution ; and it is, therefore, found in larger 
 or smaller quantity dissolved in all natural waters, both fresh 
 and salt, since these waters are always to some extent charged 
 with the above-mentioned solvent gas. A great number of 
 aquatic animals, however, together with some aquatic plants, 
 are endowed with the power of separating the lime thus held 
 in solution in the water, and of reducing it again to its solid 
 condition. In this way shell-fish, crustaceans, sea-urchins, 
 corals, and an immense number of other animals, are enabled 
 to construct their skeletons ; whilst some plants form hard 
 structures within their tissues in a precisely similar manner. 
 We do meet with some calcareous deposits, such as the 
 "stalactites" and " stalagmites " of caves, the "calcareous 
 tufa" and "travertine" of some hot springs, and the spongy 
 calcareous deposits of so-called "petrifying springs," which 
 are purely chemical in their origin, and owe nothing to the 
 operation of living beings. Such deposits are formed simply 
 by the precipitation of carbonate of lime from water, in con- 
 sequence of the evaporation from the water of the carbonic 
 acid gas which formerly held the lime in solution ; but, though 
 sometimes forming masses of considerable thickness and of 
 geological importance, they do not concern us here. Almost 
 all the limestones which occur in the series of the stratified 
 rocks are, primarily at any rate, of organic origin, and have 
 been, directly or indirectly, produced by the action of certain 
 lime-making animals or plants, or both combined. The pre- 
 sumption as to all the calcareous rocks, which cannot be 
 clearly shown to have been otherwise produced, is that they 
 are thus organically formed ; and in many cases this presump- 
 tion can be readily reduced to a certainty. There are many 
 varieties of the calcareous rocks, but the following are those 
 which are of the greatest importance : 
 
 Chalk is a calcareous rock of a generally soft and pulver- 
 ulent texture, and with an earthy fracture. It varies in its 
 purity, being sometimes almost wholly composed of carbonate 
 of lime, and at other times more or less intermixed with foreign 
 matter. Though usually soft and readily reducible to powder, 
 chalk is occasionally, as in the north of Ireland, tolerably hard 
 and compact ; but it never assumes the crystalline aspect 
 and stony density of limestone, except it be in immediate 
 contact with some mass of igneous rock. By means of the 
 microscope, the true nature and mode of formation of chalk 
 can be determined with the greatest ease. In the case of the 
 harder varieties, the examination can be conducted by means
 
 22 
 
 PRINCIPLES OF PALEONTOLOGY. 
 
 of slices ground down to a thinness sufficient to render them 
 transparent ; but in the softer kinds the rock must be disinte- 
 grated under water, and the debris examined microscopically. 
 When investigated by either of these methods, chalk is found 
 to be a genuine organic rock, being composed of the shells or 
 hard parts of innumerable marine animals of different kinds, 
 some entire, some fragmentary, cemented together by a matrix 
 of very finely granular carbonate of lime. Foremost amongst 
 the animal remains which so largely compose chalk are the 
 shells of the minute creatures which will be subsequently 
 spoken of under the name of Foraminifera (fig. 7), and which, 
 in spite of their microscopic 
 dimensions, play a more im- 
 portant part in the process of 
 lime-making than perhaps any 
 other of the larger inhabitants 
 of the ocean. 
 
 As chalk is found in beds 
 of hundreds of feet in thick- 
 ness, and of great purity, there 
 was long felt much difficulty 
 in satisfactorily accounting for 
 its mode of formation and ori- 
 gin. By the researches of 
 Carpenter, Wyville Thomson, 
 Huxley, Wallich, and others, 
 it has, however, been shown 
 that there is now forming, in 
 the profound depths of our 
 great oceans, a deposit which 
 is in all essential respects identical with chalk, and which is 
 generally known as the " Atlantic ooze," from its having been 
 first discovered in that sea. This ooze is found at great 
 depths (5000 to over 15,000 feet) in both the Atlantic and 
 Pacific, covering enormously large areas of the sea-bottom, 
 and it presents itself as a whitish-brown, sticky, impalpable mud, 
 very like greyish chalk when dried. Chemical examination 
 shows that the ooze is composed almost wholly of carbonate of 
 lime, and microscopical examination proves it to be of organic 
 origin, and to be made up of the remains of living beings. 
 The principal forms of these belong to the Foraminifera, and 
 the commonest of these are the irregularly-chambered shells of 
 G/obigerina, absolutely indistinguishable from the Globigerince 
 which are so largely present in the chalk (fig. 8). Along with 
 these occur fragments of the skeletons of other larger creatures. 
 
 Fig. 7. Section of Gravesend Chalk, 
 examined by transmitted light and highly 
 magnified. Besides the entire shells 
 Globigerina, Rotalia, and Textularia 
 numerous detached chambers of Globi 
 gerina are seen. (Original.) 
 
 of
 
 THE FOSSILIFEROUS ROCKS. 
 
 . 8. Organisms in the Atlantic Oo/.e, 
 y Foraminiftra. (Globigtrina and 
 
 and a certain proportion of the flinty cases of minute animal 
 and vegetable organisms (Polycystiua and Diatoms). Though 
 many of the minute animals, 
 the hard parts of which form 
 the ooze, undoubtedly live at 
 or near the surface of the sea, 
 others, probably, really live 
 near the bottom ; and the ooze 
 itself forms a congenial home 
 for numerous sponges, sea- 
 lilies, and other marine ani- 
 mals which flourish at great 
 depths in the sea. There is 
 thus established an intimate 
 and most interesting parallel- 
 ism between the chalk and 
 the ooze of modern oceans. 
 Both are formed essentially in 
 the same way, and the latter 
 only requires consolidation to become actually converted into 
 chalk. Both are fundamentally organic deposits, apparently 
 requiring a great depth of water for their accumulation, and 
 mainly composed of the remains of Foramimfera, together 
 with the entire or broken skeletons of other marine animals of 
 greater dimensions. It is to be remembered, however, that the 
 ooze, though strictly representative of the chalk, . cannot be 
 said in any proper sense to be actually identical with the for- 
 mation so called by geologists. A great lapse of time separates 
 the two, and though composed of the remains of representative 
 classes or groups of animals, it is only in the case of the lowly- 
 organised Globigcrince, and of some other organisms of little 
 higher grade, that we find absolutely the same kinds or species 
 of animals in both. 
 
 Limestone, like chalk, is composed of carbonate of lime, 
 sometimes almost pure, but more commonly with a greater or 
 less intermixture of some foreign material, such as alumina or 
 silica. The varieties of limestone are almost innumerable, 
 but the great majority can be clearly proved to agree with 
 chalk in being essentially of organic origin, and in being more 
 or less largely composed of the remains of living beings. In 
 many instances the organic remains which compose limestone 
 are so large as to be readily visible to the naked eye, and the 
 rock is at once seen to be nothing more than an agglomera- 
 tion of the skeletons, generally fragmentary, of certain marine 
 animals, cemented together by a matrix of carbonate of lime.
 
 24 PRINCIPLES OF PALEONTOLOGY. 
 
 This is the case, for example, with the so-called " Crinoidal 
 Limestones " and " Encrinital Marbles " with which the geolo- 
 gist is so familiar, especially as occurring in great beds amongst 
 the older formations of the earth's crust. These are seen, on 
 weathered or broken surfaces, or still better in polished slabs* 
 (fig. 9), to be composed more or less exclusively of the broken 
 
 Fig 9 Slab of Crinoidal marble, from the Carboniferous limestone of Dent, in York- 
 shire, of the natural size. The polished surface intersects the columns of the Crinoids at 
 different angles, and thus gives rise to varying appearances. (Original.) 
 
 stems and detached plates of sea-lilies (Crinoids}. Similarly, 
 other limestones are composed almost entirely of the skeletons 
 of corals; and such old coralline limestones can readily be 
 paralleled by formations which we can find in actual course of 
 production at the present day. We only need to transport 
 ourselves to th'e islands of the Pacific, to the West Indies, or 
 to the Indian Ocean, to find great masses of lime formed simi- 
 larly by living corals, and well known to every one under the 
 name of "coral-reefs." Such reefs are often of vast extent, 
 both superficially and in vertical thickness, and they fully equal 
 in this respect any of the coralline limestones of bygone ages. 
 Again, we find other limestones such as the celebrated 
 " Nummulitic Limestone" (fig. 10), which sometimes attains a 
 thickness of some thousands of feet which are almost entirely 
 made up of the shells of Foraminifera. In the case of the 
 " Nummulitic Limestone," just mentioned, these shells are of 
 large size, varying from the size of a split pea up to that of a
 
 THE FOSSILIFEROUS ROCKS. 25 
 
 florin. There are, however, as we shall see, many other lime- 
 stones, which are likewise largely made up of Foraminijera, 
 
 Fig. io. Piece of Nummulitic Limestone from the Great Pyr 
 Of the natural size. (Original.) 
 
 but in which the shells are very much more minute, and would 
 hardly be seen at all without the microscope. 
 
 We may, in fact, consider that the great agents in the pro- 
 duction of limestones in past ages have been animals belonging 
 to the Crinoids, the Corals, and the Foraminifera. At the pre- 
 sent day, the Crinoids have been nearly extinguished, and the 
 few known survivors seem to have retired to great depths in 
 the ocean ; but the two latter still actively carry on the work 
 of lime-making, the former being very largely helped in their 
 operations by certain lime producing marine plants (Nulliporcs 
 and Corallines]. We have to remember, however, that though 
 the limestones, both ancient and modern, that we have just 
 spoken of, are truly organic, they are not necessarily formed 
 out of the remains of animals which actually lived on the 
 precise spot where we now find the limestone itself. We may 
 find a crinoidal limestone, which we can show to have been 
 actually formed by the successive growth of generations of 
 sea-lilies in place ; but we shall find many others in which the 
 rock is made up of innumerable fragments of the skeletons of 
 these creatures, which have been clearly worn and rubbed by 
 the sea-waves, and which have been mechanically transported 
 to their present site. In the same way, a limestone may be 
 shown to have been an actual coral-reef, by the fact that we 
 find in it great masses of coral, growing in their natural post-
 
 26 PRINCIPLES OF PALAEONTOLOGY. 
 
 tion, and exhibiting plain proofs that they were simply quietly 
 buried by the calcareous sediment as they grew ; but other 
 limestones may contain only numerous rolled and water-worn 
 fragments of corals. This is precisely paralleled by what we 
 can observe in our existing coral-reefs. Parts of the modern 
 coral-islands and coral-reefs are really made up of corals, dead 
 or alive, which actually grew on the spot where we now find 
 them ; but other parts are composed of a limestone-rock 
 ("coral-rock"), or of a loose sand ("coral-sand"), which is 
 organic in the sense that it is composed of lime formed by 
 living beings, but which, in truth, is composed of fragments 
 of the skeletons of these living beings, mechanically trans- 
 ported and heaped together by the sea. To take another 
 example nearer home, we may find great accumulations of 
 calcareous matter formed in place, by the growth of shell-fish, 
 such as oysters or mussels ; but we can also find equally great 
 accumulations on many of our shores in the form of " shell- 
 sand," which is equally composed of the shells of molluscs, but 
 which is formed by the trituration of these shells by the 
 mechanical power of the sea-waves. We thus see that though 
 all these limestones are primarily organic, they not uncom- 
 monly become "mechanically-formed" rocks in a secondary 
 sense, the materials of which they are composed being formed 
 by living beings, but having been mechanically transported to 
 the place where we now find them. 
 
 Many limestones, as we have seen, are composed of large 
 and conspicuous organic remains, such as strike the eye at 
 once. Many others, however, which at first sight appear com- 
 pact, more or less crystalline, and nearly devoid of traces of 
 life, are found, when properly examined, to be also composed 
 of the remains of various organisms. All the commoner lime- 
 stones, in fact, from the Lower Silurian period onwards, can 
 be easily proved to be thus organic rocks, if we investigate 
 weathered or polished surfaces with a lens, or, still better, if 
 we cut thin slices of the rock and grind these down till they 
 are transparent. When thus examined, the rock is usually 
 found to be composed of innumerable entire or fragmentary 
 fossils, cemented together by a granular or crystalline matrix 
 of carbonate of lime (figs, n and 12). When the matrix is 
 granular, the rock is precisely similar to chalk, except that it 
 is harder and less earthy in texture, whilst the fossils are only 
 occasionally referable to the Foraminifera. In other cases, 
 the matrix is more or less crystalline, and when this crystallisa- 
 tion has been carried to a great extent, the original organic 
 nature of the rock may be greatly or completely obscured
 
 THE FOSSILIFEROUS ROCKS. 2/ 
 
 thereby. Thus, in limestones which have been greatly altered 
 or " metamorphosed" by the combined action of heat and pres- 
 
 Fig. n. Section of Carboniferous Fig 12. Section of Coniston Limestone 
 
 Limestone from Spergen Hill, Indiana, (Lower Silurian) from Keisley, Westmore- 
 U.S., showing numerous large-sized land; magnified. The matrix is very coarse- 
 Foraminifera (Endothyra) and a few ly crystalline, and the included organic re- 
 oolitic grains ; magnified. (Original.) mains are chiefly stems of Crinoids. (Ori- 
 ginal.) 
 
 sure, all traces of organic remains become annihilated, and the 
 rock becomes completely crystalline throughout. This, for 
 example, is the case with the ordinary white "statuary marble," 
 slices of which exhibit under the microscope nothing but an 
 aggregate of beautifully transparent crystals of carbonate of 
 lime, without the smallest traces of fossils. There are also 
 other cases, where the limestone is not necessarily highly 
 crystalline, and where no metamorphic action in the strict 
 sense has taken place, in which, nevertheless, the microscope 
 fails to reveal any evidence that the rock is organic. Such 
 cases are somewhat obscure, and doubtless depend on differ- 
 ent causes in different instances ; but they do not affect the 
 important generalisation that limestones are fundamentally the 
 product of the operation of living beings. This fact remains 
 certain ; and when we consider the vast superficial extent 
 occupied by calcareous deposits, and the enormous collective 
 thickness of these, the mind cannot fail to be impressed with 
 the immensity of the period demanded for the formation of 
 these by the agency of such humble and often microscopic 
 creatures as Corals, Sea-lilies, Foraminifers, and Shell fish. 
 
 Amongst the numerous varieties of limestone, a few are of 
 such interest as to deserve a brief notice. Magnesian limestone- 
 or dolomite, differs from ordinary limestone in containing a cer- 
 tain proportion of carbonate of magnesia along with the carbon, 
 ate of lime. The typical dolomites contain a large proportion of
 
 28 PRINCIPLES OF PALAEONTOLOGY. 
 
 carbonate of magnesia, and are highly crystalline. The ordi- 
 nary magnesian limestones (such as those of Durham in the 
 Permian series, and the Guelph Limestones of North America 
 in the Silurian series) are generally of a yellowish, buff, or 
 brown colour, with a crystalline or pearly aspect, effervescing 
 with acid much less freely than ordinary limestone, exhibiting 
 numerous cavities from which fossils have been dissolved out, 
 and often assuming the most varied and singular forms in con- 
 sequence of what is called " concretionary action." Examina- 
 tion with the microscope shows that these limestones are 
 composed of an aggregate of minute but perfectly distinct 
 crystals, but that minute organisms of different kinds, or 
 fragments of larger fossils, are often present as well. Other 
 magnesian limestones, again, exhibit no striking external pecu- 
 liarities by which the presence of magnesia would be readily 
 recognised, and though the base of the rock is crystalline, they 
 are replete with the remains of organised beings. Thus many 
 of the magnesian limestones of the Carboniferous series of the 
 North of England are very like ordinary limestone to look at, 
 though effervescing less freely with acids, and the microscope 
 proves them to be charged with the remains of Foraminifera 
 and other minute organisms. 
 
 Marbles are of various kinds, all limestones which are suffi- 
 ciently hard and compact to take a high polish going by this 
 name. Statuary marble, and most of the celebrated foreign 
 marbles, are " metamorphic " rocks, of a highly crystalline 
 nature, and having all traces of their primitive organic struc- 
 ture obliterated. Many other marbles, however, differ from 
 ordinary limestone simply in the matter of density. Thus, 
 many marbles (such as Derbyshire marble) are simply "cri- 
 noidal limestones " (fig. 9) ; whilst various other British 
 marbles exhibit innumerable organic remains under the mi- 
 croscope. Black marbles owe their colour to the presence of 
 very minute particles of carbonaceous matter, in some cases 
 at any rate; and they may either be metamorphic, or they 
 may be charged with minute fossils such as Foraminifera (e.g., 
 the black limestones of Ireland, and the black marble of Dent, 
 in Yorkshire). 
 
 "Oolitic" limestones, or "oolites" as they are often called, 
 are of interest both to the palaeontologist and geologist. The 
 peculiar structure to which they owe their name is that the 
 rock is more or less entirely composed of spheroidal or oval 
 grains, which vary in size from the head of a small pin or less 
 up to the size of a pea, and which maybe in almost immediate 
 contact with one another, or may be cemented together by a
 
 THE FOSSILIFEROUS ROCKS. 29 
 
 more or less abundant calcareous matrix. When the grains 
 are pretty nearly spherical and are in tolerably close contact, 
 the rock looks very like the roe of a fish, and the name of 
 " oolite " or " egg-stone " is in allusion to this. When the 
 grains are of the size of peas or upwards, the rock is often 
 called a " pisolite " (Lat. pisum, a pea). Limestones having 
 this peculiar structure are especially abundant in the Jurassic 
 formation, which is often called the " Oolitic series " for this 
 reason ; but .essentially similar limestones occur not uncom- 
 monly in the Silurian, Devonian, and Carboniferous forma- 
 tions, and, indeed, in almost all rock-groups in which limestones 
 are largely developed. Whatever may be the age of the for- 
 mation in which they occur, and whatever may be the size of 
 their component " eggs," the structure of oolitic limestones is 
 fundamentally the same. All the ordinary oolitic limestones, 
 namely, consist of little spherical or ovoid " concretions," as 
 they are termed, cemented together by a larger or smaller 
 amount of crystalline carbonate of lime, together, in many 
 instances, with numerous organic remains of different kinds 
 (fig. 13). When examined in polished slabs, or in thin sec- 
 tions prepared for the micro- 
 scope, each of these little con- 
 cretions is seen to consist of 
 numerous concentric coats of 
 carbonate of lime, which some- 
 times simply surround an ima- 
 ginary centre, but which, more 
 commonly, have been suc- 
 cessively deposited round 
 some foreign body, such as a 
 little crystal of quartz, a clus- 
 ter of sand-grains, or a minute 
 shell. In other cases, as in 
 
 SOme Of the beds Of the Car- Fig. 13. Slice of oolitic limestone 
 
 boniferous limestone in the we^mouth^mlgnifi^d! 6 "^^^! 1 ) 118 ^ oi 
 North of England, where the 
 
 limestone is highly " arenaceous," there is a modification of the 
 oolitic structure. Microscopic sections of these sandy lime- 
 stones (fig. 14) show numerous generally angular or oval grains 
 of silica or flint, each of which is commonly surrounded by a 
 thin coating of carbonate of lime, or sometimes by several such 
 coats, the whole being cemented together along with the shells 
 of Foraminifera and other minute fossils by a matrix of crystal- 
 line calcite. As compared with typical oolites, the concretions 
 in these limestones are usually much more irregular in shape,
 
 PRINCIPLES OF PALEONTOLOGY. 
 
 often lengthened out and almost cylindrical, at other times 
 angular, the central nucleus being of large size, and the sur- 
 rounding envelope of lime be- 
 ing very thin, and often exhib- 
 iting no concentric structure. 
 In both these and the ordinary 
 oolites, the structure is funda- 
 mentally the same. Both have 
 been formed in a sea, probably 
 of no great depth, the waters 
 of which were charged with 
 carbonate of lime in solution, 
 whilst the bottom was formed 
 of sand intermixed with minute 
 shells and fragments of the 
 skeletons of larger marine ani- 
 mals. The excess of lime in 
 the sea-water was precipitated 
 round the sand-grains, or round 
 the smaller shells, as so many 
 nuclei, and this precipitation must often have taken place time 
 after time, so as to give rise to the concentric structure so char- 
 acteristic of oolitic concretions. Finally, the oolitic grains thus 
 produced were cemented together by a further precipitation of 
 crystalline carbonate of lime from the waters of the ocean. 
 
 Phosphate of Lime v=, another lime-salt, which is of interest 
 to the palaeontologist. It does not occur largely in the strati- 
 series, but it is found in considerable beds * in the 
 
 Fig. 14. Slice of arenaceous and 
 oolitic limestone from the Carbonifer- 
 ous series of Shap, Westmoreland ; mag- 
 nified. The section also exhibits Fnra- 
 ini>tifera and other minute fossils. (Ori- 
 ginal.) 
 
 fied 
 
 Laurentian formation, and less abundantly in some later rock- 
 groups, whilst it occurs abundantly in the form of nodules in 
 parts of the Cretaceous (Upper Greensand) and Tertiary 
 deposits. Phosphate of lime forms the larger proportion of 
 the earthy matters of the bones of Vertebrate animals, and also 
 occurs in less amount in the skeletons of certain of the Inver- 
 tebrates (e.g., Crustacea). It is, indeed, perhaps more dis- 
 tinctively than carbonate of lime, an organic compound ; and 
 though the formation of many known deposits of phosphate of 
 
 * Apart from the occurrence of phosphate of lime in actual beds in the 
 stratified rocks, as in the Laurentian and Silurian series, this salt may also 
 occur disseminated through the rock, when it can only be detected by 
 chemical analysis. It is interesting to note that Dr Hicks has recently 
 proved the occurrence of phosphate of lime in this disseminated form in 
 rocks as old as the Cambrian, and that in quantity quite equal to what is 
 generally found to be present in the later fossiliferous rocks. This affords 
 a chemical proof that animal life flourished abundantly in the Cambrian 
 seas.
 
 THE FOSSILIFEROUS ROCKS. 3! 
 
 lime cannot be positively shown to be connected with the 
 previous operation of living beings, there is room for doubt 
 whether this salt is not in reality always primarily a product 
 of vital action. The phosphatic nodules of the Upper Green- 
 sand are erroneously called " coprolites," from the belief 
 originally entertained that they were the droppings or fossilised 
 excrements of extinct animals ; and though this is not the case, 
 there can be little doubt but that the phosphate of lime which 
 they contain is in this instance of organic origin.* It appears, 
 in fact, that decaying animal matter has a singular power of 
 determining the precipitation around it of mineral salts dis- 
 solved in water. Thus, when any animal bodies are undergo- 
 ing decay at the bottom of the sea, they have a tendency to 
 cause the precipitation from the surrounding water of any 
 mineral matters which may be dissolved in it ; and the organic 
 body thus becomes a centre round which the mineral matters 
 in question are deposited in the form of a "concretion" or 
 " nodule." The phosphatic nodules in question were formed 
 in a sea in which phosphate of lime, derived from the destruc- 
 tion of animal skeletons, was held largely in solution ; and a 
 precipitation of it took place round any body, such as a decay- 
 ing animal substance, which happened to be lying on the sea- 
 bottom, and which offered itself as a favourable nucleus. In 
 the same way we may explain the formation of the calcareous 
 nodules, known as "septaria" or "cement stones," which 
 occur so commonly in the London Clay and Kimmeridge 
 Clay, and in which the principal ingredient is carbonate of 
 lime. A similar origin is to be ascribed to the nodules of 
 clay iron-stone (impure carbonate of iron) which occur so 
 abundantly in the shales of the Carboniferous series and in 
 other argillaceous deposits ; and a parallel modern example is 
 to be found in the nodules of manganese, which were found 
 by Sir Wyville Thomson, in the Challenger, to be so numer- 
 ously scattered over the floor of the Pacific at great depths. 
 In accordance with this mode of origin, it is exceedingly 
 common to find in the centre of all these nodules, both old 
 and new, some organic body, such as a bone, a shell, or a 
 tooth, which acted as the original nucleus of precipitation, and 
 
 * It has been maintained, indeed, that the phosphatic nodules so largely 
 worked for agricultural purposes, are in themselves actual organic bodies 
 or true fossils. In a few cases this admits of demonstration, as it can be 
 shown that the nodule is simply an organism (such as a sponge) infiltrated 
 with phosphate of lime (Sollas) ; but there are many other cases in which 
 no actual structure has yet been shown to exist, and as to the true origin 
 of which it would be hazardous to offer a positive opinion.
 
 32 PRINCIPLES OF PALAEONTOLOGY. 
 
 was thus preserved in a shroud of mineral matter. Many 
 nodules, it is true, show no such nucleus ; but it has been 
 affirmed that all of them can be shown, by appropriate 
 m'croscopical investigation, to have been formed round an 
 original organic body to begin with (Hawkins Johnson). 
 
 The last lime-salt which need be mentioned is gypsum, or 
 sulphate of lime. This substance, apart from other modes of 
 occurrence, is not uncommonly found interstratified with the 
 ordinary sedimentary rocks, in the form of more or less irregu- 
 lar beds ; and in these cases it has a palaeontological import- 
 ance, as occasionally yielding well-preserved fossils. Whilst 
 its exact mode of origin is uncertain, it cannot be regarded as 
 in itself an organic rock, though clearly the product of chemical 
 action. To look at, it is usually a whitish or yellowish-white 
 rock, as coarsely crystalline as loaf-sugar, or more so ; and the 
 microscope shows it to be composed entirely of crystals of 
 sulphate of lime. 
 
 We have seen that the calcareous or lime-containing rocks 
 are the most important of the group of organic deposits; whilst 
 the siliceous or flint-containing rocks may be regarded as the 
 most important, most typical, and most generally distributed 
 of the mechanically-formed rocks. We have, however, now 
 briefly to consider certain deposits which are more or less 
 completely formed of flint ; but which, nevertheless, are essen- 
 tially organic in their origin. 
 
 Flint or silex, hard and intractable as it is, is nevertheless 
 capable of solution in water to a certain extent, and even of 
 assuming, under certain circumstances, a gelatinous or viscous 
 condition. Hence, some hot -springs are impregnated with 
 silica to a considerable extent ; it is present in small quantity 
 in sea-water ; and there is reason to believe that a minute pro- 
 portion must very generally be present in all bodies of fresh 
 water as well. It is from this silica dissolved in the water that 
 many animals and some plants are enabled to construct for 
 themselves flinty skeletons; and we find that these animals and 
 plants are and have been sufficiently numerous to give rise to 
 very considerable deposits of siliceous matter by the mere 
 accumulation of their skeletons. Amongst the animals 'which 
 require special mention in this connection are the microscopic 
 organisms which are known to the naturalist as Polycystina. 
 These little creatures are of the lowest possible grade of organ- 
 isation, very closely related to the animals which we have pre- 
 viously spoken of as Foraminifera, but differing in the fact that 
 they secrete a shell or skeleton composed of flint instead of 
 lime. The Polycystina occur abundantly in our present seas;
 
 THE FOSSILIFEROUS ROCKS. 
 
 33 
 
 and their shells are present in some numbers in the ooze which 
 is found at great depths in the Atlantic and Pacific oceans, 
 being easily recognised by their exquisite shape, their glassy 
 'transparency, the general presence of longer or shorter spines, 
 and the sieve-like perforations in the walls. Both in Barbadoes 
 and in the Nicobar islands occur geological formations which 
 are composed of the flinty skeletons of these microscopic 
 animals ; the deposit in the former locality attaining a great 
 thickness, and having been long known to workers with the 
 microscope under the name of " Barbadoes earth " (fig. 15). 
 
 In addition to flint- producing animals, we have also the 
 great group of fresh -water and marine microscopic plants 
 
 Fig. 15. Shells of Potycystina from 
 "Barbadoes earth;" greatly magnified. 
 (Original.) 
 
 Fig. 16 Cases of Diatoms in the Rich- 
 mond '* Infusorial earth;" highly magni- 
 fied. (Original.) 
 
 known as Diatoms, which likewise secrete a siliceous skeleton, 
 often of great beauty. The skeletons of Diatoms are found 
 abundantly at the present day in lake-deposits, guano, the silt 
 of estuaries, and in the mud which covers many parts of the 
 sea-bottom ; they have been detected in strata of great age ; 
 and in spite of their microscopic dimensions, they have not un- 
 commonly accumulated to form deposits of great thickness, 
 and of considerable superficial extent. Thus the celebrated 
 deposit of " tripoli" (" Polir-schiefer ") of Bohemia, largely 
 worked as polishing-powder, is composed wholly, or almost 
 wholly, of the flinty cases of Diatoms, of which it is calculated 
 that no less than forty-one thousand millions go to make up a 
 single cubic inch of the stone. Another celebrated deposit is 
 the so-called "Infusorial earth" of Richmond in Virginia, 
 where there is a stratum in places thirty feet thick, composed 
 almost entirely of the microscopic shells of Diatoms. 
 
 Nodules or layers of flint, or the impure variety of flint
 
 34 PRINCIPLES OF PALEONTOLOGY. 
 
 known as chert, are found in limestones of almost all ages from 
 the Silurian upwards ; but they are especially abundant in the 
 chalk. When these flints are examined in thin and trans- 
 parent slices under the microscope, or in polished sections, 
 they are found to contain an abundance of minute organic 
 bodies such as Foraminifera, sponge-spicules, &c. embedded 
 in a siliceous basis. In many instances the flint contains 
 larger organisms such as a Sponge or a Sea-urchin. As the 
 flint has completely surrounded and infiltrated the fossils which 
 it contains, it is obvious that it must have been deposited from 
 sea-water in a gelatinous condition, and subsequently have 
 hardened. That silica is capable of assuming this viscous and 
 soluble condition is known ; and the formation of flint may 
 therefore be regarded as due to the separation of silica from 
 the sea-water and its deposition round some organic body in a 
 state of chemical change or decay, just as nodules of phos- 
 phate of lime or carbonate of iron are produced. The exist- 
 ence of numerous organic bodies in flint has long been known; 
 but it should be added that a recent observer (Mr Hawkins 
 Johnson) asserts that the existence of an organic structure can 
 be demonstrated by suitable methods of treatment, even in the 
 actual matrix or basis of the flint.* 
 
 In addition to deposits formed of flint itself, there are other 
 siliceous deposits formed by certain silicates, and also of 
 organic origin. It has been shown, namely by observations 
 carried out in our present seas -that the shells of Foraminifera 
 are liable to become completely infiltrated by silicates (such 
 as " glauconite," or silicate of iron and potash). Should the 
 actual calcareous shell become dissolved away subsequent to 
 this infiltration as is also liable to occur then, in place of 
 the shells of the Foraminifera, we get a corresponding number 
 of green sandy grains of glauconite, each grain being the cast 
 of a single shell. It has thus been shown that the green sand 
 found covering the sea-bottom in certain localities (as found 
 by the Challenger expedition along the line of the Agulhas 
 current) is really organic, and is composed of casts of the 
 shells of Foraminifera. Long before these observations had 
 been made, it had been shown by Professor Ehrenberg that 
 the green sands of various geological formations are composed 
 mainly of the internal casts of the shells of Foraminifera ; and 
 
 * It lias been asserted that the flints of the chalk are merely fossil 
 sponges. No explanation of the origin of flint, however, can be satisfac- 
 tory, unless it embraces the origin of chert in almost all great limestones 
 from the Silurian upwards, as well as the common phenomenon of the 
 silicification of organic bodies (such as corals and shells) which are known 
 with certainty to have been originally calcareous.
 
 THE FOSSILIFEROUS ROCKS. 35 
 
 we have thus another and a very interesting example how rock- 
 deposits of considerable extent and of geological importance 
 can be built up by the operation of the minutest living beings. 
 
 As regards argillaceous deposits, containing alumina or clay 
 as their essential ingredient, it cannot be said that any of 
 these have been actually shown to be of organic origin. A 
 recent observation by Sir Wyville Thomson would, however, 
 render it not improbable that some of the great argillaceous 
 accumulations of past geological periods maybe really organic. 
 This distinguished observer, during the cruise of the Chal- 
 lenger, showed that the calcareous ooze which has been 
 already spoken of as covering large areas of the floor of the 
 Atlantic and Pacific at great depths, and which consists almost 
 wholly of the shells of Foraminifera, gave place at still greater 
 depths to a red ooze consisting of impalpable clayey mud, 
 coloured by oxide of iron, and devoid of traces of organic 
 bodies. As the existence of this widely-diffused red ooze, in 
 mid-ocean, and at such great depths, cannot be explained on 
 the supposition that it is a sediment brought down into the 
 sea by rivers, Sir Wyville Thomson came to the conclusion 
 that it was probably formed by the action of the sea-water 
 upon the shells of Foraminifera. These shells, though mainly 
 consisting of lime, also contain a certain proportion of alumina, 
 the former being soluble in the carbonic acid dissolved in the 
 sea-water, whilst the latter is insoluble. There would further 
 appear to be grounds for believing that the solvent power of 
 the sea -water over lime is considerably increased at great 
 depths. If, therefore, we suppose the shells of Foraminifera 
 to be in course of deposition over the floor of the Pacific, at 
 certain depths they would remain unchanged, and would ac- 
 cumulate to form a calcareous ooze; but at greater depths they 
 would be acted upon by the water, their lime would be dis- 
 solved out, their form would disappear, and we should simply 
 have left the small amount of alumina which they previously 
 contained. In process of time this alumina would accumulate 
 to form a bed of clay; and as this clay had been directly 
 derived from the decomposition of the shells of animals, it 
 would be fairly entitled to be considered an organic deposit. 
 Though not finally established, the hypothesis of Sir Wyville 
 Thomson on this subject is of the greatest interest to the palae- 
 ontologist, as possibly serving to explain the occurrence, espe- 
 cially in the older formations, of great deposits of argillaceous 
 matter which are entirely destitute of traces of life. 
 
 It only remains, in this connection, to shortly consider the 
 rock-deposits in which carbon is found to be present in greater
 
 36 PRINCIPLES OF PALEONTOLOGY. 
 
 or less quantity. In the great majority of cases where rocks 
 are found to contain carbon or carbonaceous matter, it can be 
 stated with certainty that this substance is of organic origin, 
 though it is not necessarily derived from vegetables. Carbon 
 derived from the decomposition of animal bodies is not uncom- 
 mon ; though it never occurs in such quantity from this source 
 as it may do when it is derived from plants. Thus, many 
 limestones are more or less highly bituminous ; the celebrated 
 siliceous flags or so-called " bituminous schists " of Caithness 
 are impregnated with oily matter apparently derived from the 
 decomposition of the numerous fishes embedded in them ; 
 Silurian shales containing Graptolites, but destitute of plants, 
 are not uncommonly "anthracitic," and contain a small per- 
 centage of carbon derived from the decay of these zoophytes; 
 whilst the petroleum so largely worked in North America has 
 not improbably an animal origin. That the fatty compounds 
 present in animal bodies should more or less extensively im- 
 pregnate fossiliferous rock-masses, is only what might be ex- 
 pected ; but the great bulk of the carbon which exists stored 
 up in the earth's crust is derived from plants ; and the form in 
 which it principally presents itself is that of coal. We shall 
 have to speak again, and at greater length, of coal, and it is 
 sufficient to say here that all the true coals, anthracites, and 
 lignites, are of organic origin, and consist principally of the 
 remains of plants in a more or less altered condition. The 
 bituminous shales which are found so commonly associated 
 with beds of coal also derive their carbon primarily from 
 plants ; and the same is certainly, or probably, the case with 
 similar shales which are known to occur in formations younger 
 than the Carboniferous. Lastly, carbon may occur as a con- 
 spicuous constituent of rock-masses in the form of graphite or 
 black-lead. In this form, it occurs in the shape of detached 
 scales, of veins or strings, or sometimes of regular layers;* 
 and there can be little doubt that in many instances it has 
 an organic origin, though this is not capable of direct proof. 
 When present, at any rate, in quantity, and in the form of layers 
 associated with stratified rocks, as is often the case in the Lau- 
 rentian formation, there can be little hesitation in regarding it 
 as of vegetable origin, and as an altered coal. 
 
 * In the Huronian formation at Steel River, on the north shore of Lake 
 Superior, there exists a bed of carbonaceous matter which is regularly in- 
 terstratified with the surrounding rocks, and has a thickness of from 30 to 
 40 feet. This bed is shown by chemical analysis to contain about 50 per 
 cent of carbon, partly in the form of graphite, partly in the form of anthra- 
 cite ; and there can be little doubt but that it is really a stratum of "meta- 
 morphic " coal.
 
 CHRONOLOGICAL SUCCESSION. 37 
 
 CHAPTER III. 
 
 CHRONOLOGICAL SUCCESSION OF THE 
 FOSSILIFEROUS ROCKS. 
 
 The physical geologist, who deals with rocks simply as rocks, 
 and who does not necessarily trouble himself about what fossils 
 they may contain, finds that the stratified deposits which form 
 so large a portion of the visible part of the earth's crust are 
 not promiscuously heaped together, but that they have a cer- 
 tain definite arrangement. In each country that he examines, 
 he finds that certain groups of strata lie above certain other 
 groups ; and in comparing different countries with one another, 
 he finds that, in the main, the same groups of rocks are always 
 found in the same relative position to each other. It is pos- 
 sible, therefore, for the physical geologist to arrange the known 
 stratified rocks into a successive series of groups, or " forma- 
 tions," having a certain definite order. The establishment of 
 this physical order amongst the rocks introduces, however, at 
 once the element of time, and the physical succession of the 
 strata can be converted directly into a historical or chronologi- 
 cal succession. This is obvious, when we reflect that any bed 
 or set of beds of sedimentary origin is clearly and necessarily 
 younger than all the strata upon which it rests, and older than 
 all those by which it is surmounted. 
 
 It is possible, then, by an appeal to the rocks alone, to de- 
 termine in each country the general physical succession of the 
 strata, and this " stratigraphical " arrangement, when once de- 
 termined, gives us the relative ages of the successive groups. 
 The task, however, of the physical geologist in this matter is 
 immensely lightened when he calls in palaeontology to his aid, 
 and studies the evidence of the fossils embedded in the rocks. 
 Not only is it thus much easier to determine the order of suc- 
 cession of the strata in any given region, but it becomes now 
 for the first time possible to compare, with certainty and pre- 
 cision, the order of succession in one region with that which 
 exists in other regions far distant. The value of fossils as tests 
 of the relative ages of the sedimentary rocks depends on the 
 fact that they are not indefinitely or promiscuously scattered 
 through the crust of the earth, as it is conceivable that they 
 might be. On the contrary, the first and most firmly estab- 
 lished law of Palaeontology is, that particular kinds of fossils
 
 38 PRINCIPLES OF PALEONTOLOGY. 
 
 are confined to particular rocks, and particular groups of fossils 
 are confined to particular groups of rocks. Fossils, then, are 
 distinctive of the rocks in which they are found much more 
 distinctive, in fact, than the mere mineral character of the rock 
 can be, for that commonly changes as a formation is traced 
 from one region to another, whilst the fossils remain unaltered. 
 It would therefore be quite possible for the palaeontologist, 
 by an appeal to the fossils alone, to arrange the series of sedi- 
 mentary deposits into a pile of strata having a certain definite 
 order. Not only would this be possible, but it would be found 
 if sufficient knowledge had been brought to bear on both 
 sides that the palaeontological arrangement of the strata would 
 coincide in its details with the stratigraphical or physical 
 arrangement. 
 
 Happily for science, there is no such division between the 
 palaeontologist and the physical geologist as here supposed ; 
 but by the combined researches of the two, it has been found 
 possible to divide the entire series of stratified deposits into a 
 number of definite rock -groups or formations, which have a 
 recognised order of succession, and each of which is charac- 
 terised by possessing an assemblage of organic remains which 
 do not occur in association in any other formation. Such an 
 assemblage of fossils, characteristic of any given formation, re- 
 presents the life of the particular period in which the formation 
 was deposited. In this way the past history of the earth 
 becomes divided into a series of successive life-periods, each of 
 which corresponds with the deposition of a particular forma- 
 tion or group of strata. 
 
 Whilst particular assemblages of organic forms characterise 
 particular groups of rocks, it may be further said that, in a 
 general way, each subdivision of each formation has its own 
 peculiar fossils, by which it may be recognised by a skilled 
 worker in Palaeontology. Whenever, for instance, we meet 
 with examples of the fossils which are known as Graptolites, we 
 may be sure that we are dealing with Silurian rocks (leaving 
 out of sight one or two forms doubtfully referred to this family). 
 We may, however, go much farther than this with perfect 
 safety. If the Graptolites belong to certain genera, we may 
 be quite certain that we are dealing with Lower Silurian rocks. 
 Furthermore, if certain special forms are present, we may be 
 even able to say to what exact subdivision of the Lower Silu- 
 rian series they belong. 
 
 As regards particular fossils, however, or even particular 
 classes of fossils, conclusions of this nature require to be accom- 
 panied by a tacit but well-understood reservation. So far as
 
 CHRONOLOGICAL SUCCESSION. 39 
 
 our present observation goes, none of the undoubted Grapto- 
 lites have ever been discovered in rocks later than those known 
 upon other grounds to be Silurian ; but it is possible that they 
 might at any time be detected in younger deposits. Similarly, 
 the species and genera which we now regard as characteristic 
 of the Lower Silurian, may at some future time be found to 
 have survived into the Upper Silurian period. We should not 
 forget, therefore, in determining the age of strata by palseonto- 
 logical evidence, that we are always reasoning upon generalisa- 
 tions which are the result of experience alone, and which are 
 liable to be vitiated by further and additional discoveries. 
 
 When the palaeontological evidence as to the age of any 
 given set of strata is corroborated by the physical evidence, our 
 conclusions may be regarded as almost certain ; but there are 
 certain limitations and fallacies in the palaeontological method 
 of inquiry which deserve a passing mention. In the first 
 place, fossils are not always present in the stratified rocks ; 
 many aqueous rocks are unfossiliferous, through a thickness of 
 hundreds or even thousands of feet of little-altered sediments; 
 and even amongst beds which do contain fossils, we often meet 
 with strata of many feet or yards in thickness which are wholly 
 destitute of any traces of fossils. There are, therefore, to 
 begin with, many cases in which there is no palaeontological 
 evidence extant or available as to the age of a given group 
 of strata. In the second place, palseontological observers in 
 different parts of the world are liable to give different names 
 to the same fossil, and in all parts of the world they are occa- 
 sionally liable to group together different fossils under the 
 same title. Both these sources of fallacy require to be guarded 
 against in reasoning as to the age of strata from their fossil 
 remains. Thirdly, the mere fact of fossils being found in beds 
 which are known by physical evidence to be of different ages, 
 has commonly led palaeontologists to describe them as dif- 
 ferent species. Thus, the same fossil, occurring in successive 
 groups of strata, and with the merely trivial and varietal differ- 
 ences due to the gradual change in its environment, has been 
 repeatedly described as a distinct species, with a distinct 
 name, in every bed in which it was found. We know, however, 
 that many fossils range vertically through many groups of strata, 
 and there are some which even pass through several forma- 
 tions. The mere fact of a difference of physical position 
 ought never to be taken into account at all in considering and 
 determining the true affinities of a fossil. Fourthly, the 
 results of experience, instead of being an assistance, are some- 
 times liable to operate as a source of error. When once,
 
 40 PRINCIPLES OF PALAEONTOLOGY. 
 
 namely, a generalisation has been established that certain 
 fossils occur in strata of a certain age, palaeontologists are apt 
 to infer that all beds containing similar fossils must be of the 
 same age. There is a presumption, of course, that this infer- 
 ence would be correct; but it is not a conclusion resting upon 
 absolute necessity, and there might be physical evidence to 
 disprove it. Fifthly, the physical geologist may lead the palae- 
 ontologist astray by asserting that the physical evidence as to 
 the age and position of a given group of beds is clear and un- 
 equivocal, when such evidence may be, in reality, very slight 
 and doubtful. In this way, the observer may be readily led 
 into wrong conclusions as to the nature of the organic remains 
 often obscure and fragmentary which it is his business to 
 examine, or he may be led erroneously to think that previous 
 generalisations as to the age of certain kinds of fossils are 
 premature and incorrect. Lastly, there are cases in which, 
 owing to the limited exposure of the beds, to their being 
 merely of local development, or to other causes, the physical 
 evidence as to the age of a given group of strata may be en- 
 tirely uncertain and unreliable, and in which, therefore, the 
 observer has to rely wholly upon the fossils which he may 
 meet with. 
 
 In spite of the above limitations and fallacies, there can be 
 no doubt as to the enormous value of palaeontology in enab- 
 ling us to work out the historical succession of the sedimentary 
 rocks. It may even be said that in any case where there 
 should appear to be a clear and decisive discordance between 
 the physical and the palseontological evidence as to the age 
 of a given series of beds, it is the former that is to be distrusted 
 rather than the latter. The records of geological science con- 
 tain not a few cases in which apparently clear physical evi- 
 dence of superposition has been demonstrated to have been 
 wrongly interpreted ; but the evidence of palaeontology, when 
 in any way sufficient, has rarely been upset by subsequent 
 investigations. Should we find strata containing plants of the 
 Coal-measures apparently resting upon other strata with Am- 
 monites and Belemnites, we may be sure that the physical 
 evidence is delusive ; and though the above is an extreme case, 
 the presumption in all such instances is rather that the physical 
 succession has been misunderstood or misconstrued, than that 
 there has been a subversion of the recognised succession of 
 life-forms. 
 
 We have seen, then, that as the collective result of observa- 
 tions made upon the superposition of rocks in different locali- 
 ties, from their mineral characters, and from their included
 
 CHRONOLOGICAL SUCCESSION. 4! 
 
 fossils, geologists have been able to divide the entire stratified 
 series into a number of different divisions or formations, each 
 characterised by a general uniformity of mineral composition, 
 and by a special and peculiar assemblage of organic forms. 
 Each of these primary groups is in turn divided into a series of 
 smaller divisions, characterised and distinguished in the same 
 way. It is not pretended for a moment that all these primary 
 rock-groups can anywhere be seen surmounting one another 
 regularly.* There is no region upon the earth where all 
 the stratified formations can be seen together; and, even 
 when most of them occur in the same country, they can 
 nowhere be seen all succeeding each other in their regular and 
 uninterrupted succession. The reason of this is obvious. 
 There are many places to take a single example where one 
 may see the the Silurian rocks, the Devonian, and the Carbon- 
 iferous rocks succeeding one another regularly, and in their 
 proper order. This is because the particular region where this 
 occurs was always submerged beneath the sea while these for- 
 mations were being deposited. There are, however, many 
 more localities in which one would find the Carboniferous 
 rocks resting unconformably upon the Silurians without the 
 intervention of any strata which could be referred to the 
 Devonian period. This might arise from one of two causes : 
 i. The Silurians might have been elevated above the sea im- 
 mediately after their deposition, so as to form dry land during 
 the whole of the Devonian period, in which case, of course, 
 no strata of the latter age could possibly be deposited in that 
 area. 2. The Devonian might have been deposited upon the 
 Silurian, and then the whole might have been elevated above 
 the sea, and subjected to an amount of denudation sufficient to 
 remove the Devonian strata entirely. In this case, when the 
 land was again submerged, the Carboniferous rocks, or any 
 younger formation, might be deposited directly upon Silurian 
 strata. From one or other of these causes, then, or from subse- 
 quent disturbances and denudations, it happens that we can 
 
 * As we have every reason to believe that dry land and sea have existed, at 
 any rate from the commencement of the Laurentian period to the present day, 
 it is quite obvious that no one of the great formations can ever, under any cir- 
 cumstances, have extended over the entire globe. In other words, no one of 
 the formations can ever have had a greater geographical extent than that of 
 the seas of the period in which the formation was deposited. Nor is there any 
 reason for thinking that the proportion of dry land to ocean has ever been 
 materially different to what it is at present, however greatly the areas of sea 
 and land may have changed as regards their place. It follows from the above, 
 that there is no sufficient basis for the view that the crust of the earth is com- 
 posed of a succession of concentric layers, like the coats of an onion, each 
 layer representing one formation.
 
 42 PRINCIPLES OF PALEONTOLOGY. 
 
 rarely find many of the primary formations following one 
 another consecutively and in their regular order. 
 
 In no case, however, do we ever find the Devonian resting 
 upon the Carboniferous, or the Silurian rocks reposing on the 
 Devonian. We have therefore, by a comparison of many 
 different areas, an established order of succession of the strati- 
 fied formations, as shown in the subjoined ideal section of the 
 crust of the earth (fig. 1 7). 
 
 The main subdivisions of the stratified rocks are known by 
 the following names : 
 
 1. Laurentian. 
 
 2. Cambrian (with Huronian ?). 
 
 3. Silurian. 
 
 4. Devonian or Old Red Sandstone. 
 
 5. Carboniferous. 
 
 8. Jurassic or Oolitic. 
 
 9. Cretaceous. 
 
 10. Eocene. 
 
 11. Miocene. 
 
 12. Pliocene. 
 
 13. Post-tertiary.
 
 CHRONOLOGICAL SUCCESSION. 
 
 43 
 
 IDEAL SECTION OF THE CRUST OF THE EARTH. 
 
 Fig. 17. 
 
 Post-tertiary and Recent. 
 Pliocene. 
 
 Devonian or Old Red Sandstone. 
 
 Laurentian.
 
 44 PRINCIPLES OF PALEONTOLOGY. 
 
 Of these primary rock divisions, the Laurentian, Cambrian, 
 Silurian, Devonian, Carboniferous, and Permian are collec- 
 tively grouped together under the name of the Primary or 
 Paltzozoic rocks (Gr. palaios, ancient ; zoe, life). Not only do 
 they constitute the oldest stratified accumulations, but from 
 the extreme divergence between their animals and plants and 
 those now in existence, they may appropriately be considered 
 as belonging to an " Old-Life " period of the world's history. 
 TheTriassic, Jurassic, and Cretaceous systems are grouped to- 
 gether as the Secondary or Mesozoic formations (Gr. mesos, inter- 
 mediate ; zoe, life) ; the organic remains of this " Middle- Life " 
 period being, on the whole, intermediate in their characters 
 between those of the palaeozoic epoch and those of more 
 modern strata. Lastly, the Eocene, Miocene, and Pliocene 
 formations are grouped together as the Tei'tiary or Kainozoic 
 rocks (Gr. kainos, new ; zoe, life) ; because they constitute a 
 "New- Life" period, in which the organic remains approximate 
 in character to those now existing upon the globe. The so- 
 called Post-Tertiary deposits are placed with the Kainozoic, or 
 may be considered as forming a separate Quaternary system. 
 
 CHAPTER IV. 
 
 THE BREAKS IN THE GEOLOGICAL AND 
 PAL&ONTOLOGICAL RECORD. 
 
 The term " contemporaneous " is usually applied by geolo- 
 gists to groups of strata in different regions which contain the 
 same fossils, or an assemblage of fossils in which many iden- 
 tical forms are present. That is to say, beds which contain 
 identical, or nearly identical, fossils, however widely separated 
 they may be from one another in point of actual distance, are 
 ordinarily believed to have been deposited during the same 
 period of the earth's history. This belief, indeed, constitutes 
 the keystone of the entire system of determining the age of 
 strata by their fossil contents ; and if we take the word " con- 
 temporaneous " in a general and strictly geological sense, this 
 belief can be accepted as proved beyond denial. We must, 
 however, guard ourselves against too literal an interpretation 
 of the word " contemporaneous," and we must bear in mind 
 the enormously - prolonged periods of time with which the 
 geologist has to deal. When we say that two groups of strata
 
 BREAKS IN THE GEOLOGICAL RECORD. 45 
 
 in different regions are "contemporaneous," we simply mean 
 that they were formed during the same geological period, and 
 perhaps at different stages of that period, and we do not mean to 
 imply that they were formed at precisely the same instant of time. 
 A moment's consideration will show us that it is only in the 
 former sense that we can properly speak of strata being " con- 
 temporaneous ;" and that, in point of fact, beds containing 
 the same fossils, if occurring in widely distant areas, can hardly 
 be " contemporaneous " in any literal sense ; but that the very 
 identity of their fossils is proof that they were deposited one 
 after the other. If we find strata containing identical fossils 
 within the limits of a single geographical region say in Europe 
 then there is a reasonable probability that these beds are 
 strictly contemporaneous, in the sense that they were deposited 
 at the same time. There is a reasonable probability of this, 
 because there is no improbability involved in the idea of an 
 ocean occupying the whole area of Europe, and peopled 
 throughout by many of the same species of marine animals. At 
 the present day, for example, many identical species of animals 
 are found living on the western coasts of Britain and the 
 eastern coasts of North America, and beds now in course of 
 deposition off the shores of Ireland and the seaboard of the 
 state of New York would necessarily contain many of the 
 same fossils. Such beds would be both literally and geologi- 
 cally contemporaneous; but the case is different if the distance 
 between the areas where the strata occur be greatly increased. 
 We find, for example, beds containing identical fossils (the 
 Quebec or Skiddaw beds) in Sweden, in the north of England, 
 in Canada, and in Australia. Now, if all these beds were con- 
 temporaneous, in the literal sense of the term, we should have 
 to suppose that the ocean at one time extended uninterrup- 
 tedly between all these points, and was peopled throughout 
 the vast area thus indicated by many of the same animals. 
 Nothing, however, that we see at the present day would justify 
 us in imagining an ocean of such enormous extent, and at the 
 same time so uniform in its depth, temperature, and other 
 conditions of marine life, as to allow the same animals to. 
 nourish in it from end to end ; and the example chosen is 
 only one of a long and ever-recurring series. It is therefore 
 much more reasonable to explain this, and all similar cases, as 
 owing to the migration of the fauna, in whole or in part, from 
 one marine area to another. Thus, we may suppose an ocean 
 to cover what is now the European area, and to be peopled by 
 certain species of animals. Beds of sediment clay, sands, 
 and limestones will be deposited over the sea-bottom, and 
 o
 
 46 PRINCIPLES OF PALEONTOLOGY. 
 
 will entomb the remains of the animals as fossils. After this 
 has lasted for a certain length of time, the European area may 
 undergo elevation, or may become otherwise unsuitable for the 
 perpetuation of its fauna; the result of which would be that 
 some or all of the marine animals of the area would migrate to 
 some more suitable region. Sediments would then be accumu- 
 lated in the new area to which they had betaken themselves, 
 and they would then appear, for the second time, as fossils in 
 a set of beds widely separated from Europe. The second set 
 of beds would, however, obviously not be strictly or literally 
 contemporaneous with the first, but would be separated from 
 them by the period of time required for the migration of the 
 animals from the one area into the other. It is only in a wide 
 and comprehensive sense that such strata can be said to be 
 contemporaneous. 
 
 It is impossible to enter further into this subject here ; but 
 it may be taken as certain that beds in widely remote geogra- 
 phical areas can only come to contain the same fossils by 
 reason of a migration having taken place of the animals of 
 the one area to the other. That such migrations can and do 
 take place is quite certain, and this is a much more reasonable 
 explanation of the observed facts than the hypothesis that in 
 former periods the conditions of life were much more uniform 
 than they are at present, and that, consequently, the same 
 organisms were able to range over the entire globe at the same 
 time. It need only be added, that taking the evidence of the 
 present as explaining the phenomena of the past the only 
 safe method of reasoning in geological matters we have 
 abundant proof that deposits which are actually contempo- 
 raneous, in the strict sense of the term, do not contain the same 
 fossils, if far removed from one another in point of distance. 
 Thus, deposits of various kinds are now in process of forma- 
 tion in our existing seas, as, for example, in the Arctic Ocean, 
 the Atlantic, and the Pacific, and many of these deposits are 
 known to us by actual examination and observation with the 
 sounding-lead and dredge. But it is hardly necessary to add 
 that the animal remains contained in these deposits the 
 fossils of some future period instead of being identical, are 
 widely different from one another in their characters. 
 
 We have seen, then, that the entire stratified series is capable 
 of subdivision into a number of definite rock-groups or "forma- 
 tions," each possessing a peculiar and characteristic assem- 
 blage of fossils, representing the "life" of the "period" in 
 which the formation was deposited. We have still to inquire 
 shortly how it came to pass that two successive formations
 
 BREAKS IN THE GEOLOGICAL RECORD. 47 
 
 should thus be broadly distinguished by their life-forms, and 
 why they should not rather possess at any rate a majority of 
 identical fossils. It was originally supposed that this could be 
 explained by the hypothesis that the close of each formation 
 was accompanied by a general destruction of all the living 
 beings of the period, and that the commencement of each 
 new formation was signalised by the creation of a number of 
 brand-new organisms, destined to figure as the characteristic 
 fossils of the same. This theory, however, ignores the fact 
 that each formation as to which we have any sufficient 
 evidence contains a few, at least, of the life-forms which 
 existed in the preceding period; and it invokes forces and 
 processes of which we know nothing, and for the supposed 
 action of which we cannot account. The problem is an un- 
 deniably difficult one, and it will not be possible here to give 
 more than a mere outline of the modern views upon the sub- 
 ject. Without entering into the at present inscrutable question 
 as to the manner in which new life-forms are introduced upon 
 the earth, it may be stated that almost all modern geologists 
 hold that the living beings of any given formation are in the 
 main modified forms of others which have preceded them. It 
 is not believed that any general or universal destruction of 
 life took place at the termination of each geological period, or 
 that a general introduction of new forms took place at the 
 commencement of a new period. It is, on the contrary, 
 believed that the animals and plants of any given period are 
 for the most part (or exclusively) the lineal but modified 
 descendants of the animals and plants of the immediately pre- 
 ceding period, and that some of them, at any rate, are con- 
 tinued into the next succeeding period, either unchanged, or 
 so far altered as to appear as new species. To discuss these 
 views in detail would lead us altogether too far. but there is 
 one very obvious consideration which may advantageously 
 receive some attention. It is obvious, namely, that the great 
 discordance which is found to subsist between the animal 
 life of any given formation and that of the next succeeding 
 formation, and which no one denies, would be a fatal blow to 
 the views just alluded to, unless admitting of some satisfactory 
 explanation. Nor is this discordance one purely of life-forms, 
 for there is often a physical break in the successions of strata 
 as well. Let us therefore briefly consider how far these 
 interruptions and breaks in the geological and palasonto- 
 logical record can be accounted lor, and still allow us to 
 believe in some theory of continuity as opposed to the doc- 
 trine of intermittent and occasional action.
 
 48 PRINCIPLES OF PALEONTOLOGY. 
 
 In the first place, it is perfectly clear that if we admit the 
 conception above mentioned of a continuity of life from the 
 Laurentian period to the present day, we could never prove 
 our view to be correct, unless we could produce in evidence 
 fossil examples of all the kinds of animals and plants that 
 have lived and died during that period. In order to do this, 
 we should require, to begin with, to have access to an abso- 
 lutely unbroken and perfect succession of all the deposits 
 which have ever been laid down since the beginning. If, 
 however, we ask the physical geologist if he is in possession 
 of any such uninterrupted series, he will at once answer in the 
 negative. So far from the geological series being a perfect one, 
 it is interrupted by numerous gaps of unknown length, many 
 of which we can never expect to fill up. Nor are the proofs 
 of this far to seek. Apart from the facts that we have hitherto 
 examined only a limited portion of the dry land, that nearly 
 two-thirds of the entire area of the globe is inaccessible to 
 geological investigation in consequence of its being covered 
 by the sea, that many deposits can be shown to have been 
 more or less completely destroyed subsequent to their depo- 
 sition, and that there may be many areas in which living beings 
 exist where no rock is in process of formation, we have the broad 
 fact that rock-deposition only goes on to any extent in water, 
 and that the earth must have always consisted partly of dry 
 land and partly of water at any rate, so far as any period of 
 which we have geological knowledge is concerned. There 
 must, therefore, always have existed, at some part or another 
 of the earth's surface, areas where no deposition of rock was 
 going on, and the proof of this is to be found in the well- 
 known phenomenon of "unconformability? Whenever, namely, 
 deposition of sediment is continuously going on within the 
 limits of a single ocean, the beds which are laid down succeed 
 one another in uninterrupted and regular sequence. Such 
 beds are said to be " conformable," and there are many rock- 
 groups known where one may pass through fifteen or twenty 
 thousand feet of strata without a break indicating that the 
 beds had been deposited in an area which remained continu- 
 ously covered by the sea. On the other hand, we commonly 
 find that there is no such regular succession when we pass 
 from one great formation to another, but that, on the contrary, 
 the younger formation rests " unconformably," as it is called, 
 either upon the formation immediately preceding it in point of 
 time, or upon some still older one. The essential physical 
 feature of this unconformability is that the beds of the younger 
 formation rest upon a worn and eroded surface formed by the
 
 BREAKS IN THE GEOLOGICAL RECORD. 49 
 
 beds of the older series (fig. 18) ; and a moment's considera- 
 tion will show us what this indicates. It indicates, beyond 
 
 Fig. 18. Section showing strata of Tertiary age (a) resting upon a worn and eroded 
 surface of White Chalk (b), the stratification of which is marked by lines of flint. 
 
 the possibility of misconception, that there was an interval, 
 between the deposition of the older series and that of the 
 newer series of strata ; and that during this interval the older 
 beds were raised above the sea-level, so as to form dry land, 
 and -were subsequently depressed again beneath the waters, to 
 receive upon their worn and wasted upper surface the sedi- 
 ments of the later group. During the interval thus indicated, 
 the deposition of rock must of necessity have been proceeding 
 more or less actively in other areas. Every unconformity, 
 therefore, indicates that at the spot where it occurs, a more or 
 less extensive series of beds must be actually missing ; and 
 though we may sometimes be able, to point to these missing 
 strata in other areas, there yet remains a number of unconfor- 
 mities for which we cannot at present supply the deficiency 
 even in a partial manner. 
 
 It follows from the above that the serie> of stratified deposits 
 is to a greater or less extent irremediably imperfect ; and in 
 this imperfection we have one great cause why we can never 
 obtain a perfect series of all the animals and plants that have 
 lived upon the globe. Wherever one of these great physical 
 gaps occurs, we find, as we might expect, a corresponding 
 break in the series of life-forms. In other words, whenever we 
 find two formations to be unconformable, we shall always find 
 at the same time that there is a great difference in their fossils, 
 and that many of the fossils of the older formation do not sur- 
 vive into the newer, whilst many of those in the newer are not 
 known to occur in the older. The cause of this is, obviously,
 
 5O PRINCIPLES OF PALEONTOLOGY. 
 
 that the lapse of time, indicated by the unconformability, has 
 been sufficiently great to allow of the dying out or modifica- 
 tion of many of the older forms of life, and the introduction of 
 new ones by immigration. 
 
 Apart, however, altogether, from these great physical breaks 
 and their corresponding breaks in life, there are other reasons 
 why we can never become more than partially acquainted with 
 the former denizens of the globe. Foremost amongst these is 
 the fact that an enormous number of animals possess no hard 
 parts of the nature of a skeleton, and are therefore incapable, 
 under any ordinary circumstances, of leaving behind them any 
 traces of their existence. It is true that there are cases in 
 which animals in themselves completely soft-bodied are never- 
 theless able to leave marks by which their former presence can 
 be detected. Thus every geologist is familiar with the wind- 
 ing and twisting " trails " formed on the surface of the strata 
 by sea -worms; and the impressions left by the stranded 
 carcases of Jelly-fishes on the fine-grained lithographic slates 
 of Solenhofen supply us with an example of how a creature 
 which is little more than "organised sea -water" may still 
 make an abiding mark upon the sands of time. As a general 
 rule, however, animals which have no skeletons are incapable 
 of being preserved as fossils, and hence there must always 
 have been a vast number of different kinds of marine animals 
 of which we have absolutely no record whatever. Again, 
 almost all the fossiliferous rocks have been laid down in water; 
 and it is a necessary result of this that the great majority of 
 fossils are the remains of aquatic animals. The remains of 
 air-breathing animals, whether of the inhabitants of the land 
 or of the air itself, are comparatively rare as fossils, and the 
 record of the past existence of these is much more imperfect 
 than is the case with animals living in water. Moreover, the 
 fossiliferous deposits are not only almost exclusively aqueous 
 formations, but the great majority are marine, and only a com- 
 paratively small number have been formed by lakes and rivers. 
 It follows from the foregoing that the palaeontological record 
 is fullest and most complete so far as sea-animals are concerned, 
 though even here we find enormous gaps, owing to the absence 
 of hard structures in many great groups ; of animals inhabiting 
 fresh waters our knowledge is rendered still further incomplete 
 by the small proportion that fluviatile and lacustrine deposits 
 bear to marine ; whilst we have only a fragmentary acquaint- 
 ance with the air-breathing animals which inhabited the earth 
 during past ages. 
 
 Lastly, the imperfection of the palaeontological record, due
 
 BREAKS IN THE GEOLOGICAL RECORD. 51 
 
 to the causes above enumerated, is greatly aggravated, especi- 
 ally as regards the earlier portion of the earth's history, by the 
 fact that many rocks which contained fossils when deposited 
 have since been rendered barren of organic remains. The 
 principal cause of this common phenomenon is what is known 
 as " metamorphism " that is, the subjection of the rock to a 
 sufficient amount of heat to cause a rearrangement of its par- 
 ticles. When at all of a pronounced character, the result of 
 metamorphic action is invariably the obliteration of any fossils 
 which might have been originally present in the rock. Meta- 
 morphism may affect rocks of any age, though naturally more 
 prevalent in the older rocks, and to this cause must be set 
 down an irreparable loss of much fossil evidence. The most 
 striking example which is to be found of this is the great Lau- 
 rentian series, which comprises some 30,000 feet of highly- 
 metamorphosed sediments, but which, with one not wholly 
 undisputed exception, has as yet yielded no remains of living 
 beings, though there is strong evidence of the former existence 
 in it of fossils. 
 
 Upon the whole, then, we cannot doubt that the earth's 
 crust, so far as yet deciphered by us, presents us with but a 
 very imperfect record of the past. Whether the known and 
 admitted imperfections of the geological and palaeontological 
 records are sufficiently serious to account satisfactorily for the 
 deficiency of direct evidence recognisable in some modern 
 hypotheses, may be a matter of individual opinion. There 
 can, however, be little doubt that they are sufficiently extensive 
 to throw the balance of evidence decisively in favour of some 
 theory of continuity, as opposed to any theory of intermittent 
 and occasional action. The apparent breaks which divide the 
 great series of the stratified rocks into a number of isolated 
 formations, are not marks of mighty and general convulsions 
 of nature, but are simply indications of the imperfection of 
 our knowledge. Never, in all probability, shall we be able to 
 point to a complete series of deposits, or a complete succession 
 of life linking one great geological period to another. Never- 
 theless, we may well feel sure that such deposits and such an 
 unbroken succession must have existed at one time. We are 
 compelled to believe that nowhere in the long series of the 
 fossiliferous rocks has there been a total break, but that there 
 must have been a complete continuity of life, and a more or 
 less complete continuity of sedimentation, from the Laurentian 
 period to the present day. One generation hands on the 
 lamp of life to the next, and each system of rocks is the direct 
 offspring of those which preceded it in time. Though there
 
 52 PRINCIPLES OF PALAEONTOLOGY. 
 
 has not been continuity in any given area, still the geological 
 chain could never have been snapped at one point, and taken 
 up again at a totally different one. Thus we arrive at the 
 conviction that continuity is the fundamental law of geology, 
 as it is of the other sciences, and that the lines of demarca- 
 tion between the great formations are but gaps in our own 
 knowledge. 
 
 CHAPTER V. 
 
 CONCLUSIONS TO BE DRAWN FROM FOSSILS. 
 
 We have already seen that geologists have been led by the 
 study of fossils to the all-important generalisation that the vast 
 series of the Fossiliferous or Sedimentary Rocks may be 
 divided into a number of definite groups or " formations," 
 each of which is characterised by its organic remains. It may 
 simply be repeated here that these formations are not properly 
 and strictly characterised by the occurrence in them of any 
 one particular fossil. It may be that a formation contains 
 some particular fossil or fossils not occurring out of that 
 formation, and that in this way an observer may identify a 
 given group with tolerable certainty. It very often happens, 
 indeed, that some particular stratum, or sub-group of a series, 
 contains peculiar fossils, by which its existence may be deter- 
 mined in various localities. As before remarked, however, the 
 great formations are characterised properly by the association 
 of certain fossils, by the predominance of certain families or 
 orders, or by an assemblage of fossil remains representing the 
 " life " of the period in which the formation was deposited. 
 
 Fossils, then, enable us to determine the age of the deposits 
 in which they occur. Fossils furlher enable us to come to 
 very important conclusions as to the mode in which the fossil- 
 iferous bed was deposited, and thus as to the condition of the 
 particular district or region occupied by the fossiliferous bed 
 at the time of the formation of the latter. If, in the first 
 place, the bed contain the remains of animals such as now 
 inhabit rivers, we know that it is " fluviatile" in its origin, and 
 that it must at one time have either formed an actual river- 
 bed, or been deposited by the overflowing of an ancient 
 stream. Secondly, if the bed contain the remains of shell- 
 fish, minute crustaceans, or fish, such as now inhabit lakes,
 
 CONCLUSIONS TO BE DRAWN FROM FOSSILS. 53 
 
 we know that it is " lacustrine," and was deposited beneath 
 the waters of a former lake. Thirdly, if the bed contain the 
 remains of animals such as now people the ocean, we know 
 that it is " marine " in its origin, and that it is a fragment of 
 an old sea-bottom. 
 
 We can, however, often determine the conditions under 
 which a bed was deposited with greater accuracy than this. 
 If, for example, the fossils are of kinds resembling the marine 
 animals now inhabiting shallow waters, if they are accompanied 
 by the detached relics of terrestrial organisms, or if they are 
 partially rolled and broken, we may conclude that the fossil- 
 iferous deposit was laid down in a shallow sea, in the immediate 
 vicinity of a coast-line, or as an actual shore-deposit. If, again, 
 the remains are those of animals such as now live in the deeper 
 parts of the ocean, and there is a very sparing intermixture of 
 extraneous fossils (such as the bones of birds or quadrupeds, 
 or the remains of plants), we may presume that the deposit is 
 one of deep water. In other cases, we may find, scattered 
 through the rock, and still in their natural position, the valves 
 of shells such as we know at the present day as living buried 
 in the sand or mud of the sea-shore or of estuaries. In other 
 cases, the bed may obviously have been an ancient coral-reef, 
 or an accumulation of social shells, like Oysters. Lastly, if we 
 find the deposit to contain the remains of marine shells, but 
 that these are dwarfed of their fair proportions and distorted 
 in figure, we may conclude that it was laid down in a brackish 
 sea, such as the Baltic, in which the proper saltness was want- 
 ing, owing to its receiving an excessive supply of fresh water. 
 
 In the preceding, we have been dealing simply with the 
 remains of aquatic animals, and we have seen that certain con- 
 clusions can be accurately reached by an examination of these. 
 As regards the determination of the conditions of deposition 
 from the remains of aerial and terrestrial animals, or from 
 plants, there is not such an absolute certainty. The remains 
 of land-animals would, of course, occur in " sub-aerial " deposits 
 that is, in beds, like blown sand, accumulated upon the land. 
 Most of the remains of land-animals, however, are found in 
 deposits which have been laid down in water, and they owe 
 their present position to the fact that their former owners were 
 drowned in rivers or lakes, or carried out to sea by streams. 
 Birds, Flying Reptiles, and Flying Mammals might also simi- 
 larly find their way into aqueous deposits ; but it is to be re- 
 membered that many birds and mammals habitually spend a 
 great part of their time in the water, and that these might there- 
 fore be naturally expected to present themselves as fossils in
 
 54 
 
 PRINCIPLES OF PALAEONTOLOGY. 
 
 Sedimentary Rocks. Plants, again, even when undoubtedly 
 such as must have grown on land, do not prove that the bed 
 in which they occur was formed on land. Many of the remains 
 of plants known to us are extraneous to the bed in which they 
 are now found, having reached their present site by falling into 
 lakes or rivers, or being carried out to sea by floods or gales of 
 wind. There are, however, many cases in which plants have 
 undoubtedly grown on the very spot where we now find them. 
 Thus it is now generally admitted that the great coal-fields 
 of the Carboniferous age are the result of the growth in situ 
 of the plants which compose coal, and that these grew 
 
 on vast marshy or partially 
 
 submerged tracts of level 
 alluvial land. We have, 
 however, distinct evidence 
 of old land-surfaces, both in 
 the Coal-measures and in 
 other cases (as, for instance, 
 in the well-known "dirt- 
 bed" of the Purbeck series). 
 When, for example, we find 
 the erect stumps of trees 
 standing at right angles 
 to the surrounding strata, 
 we know that the surface 
 through which these send 
 their roots was at one time 
 the surface of the dry land, 
 or, in other words, was an 
 ancient soil (fig. 19). 
 
 In many cases fossils en- 
 able us to come to important 
 conclusions as to the climate 
 of the period in which they 
 lived, but only a few in- 
 stances of this can be here 
 adduced. As fossils in the majority of instances are the re- 
 mains of marine animals, it is mostly the temperature of the 
 sea which can alone be determined in this way; and it is import- 
 ant to remember that, owing to the existence of heated currents, 
 the marine climate of a given area does not necessarily imply a 
 correspondingly warm climate in the neighbouring land. Land- 
 climates can only be determined by the remains of land-ani- 
 mals or land-plants, and these are comparatively rare as fossils. 
 It is also important to remember that all conclusions on this 
 
 Fig. 19. Erect Tree containing Reptilian 
 remains. Coal-measures, Nova Scotia. (After 
 Dawson.)
 
 CONCLUSIONS TO BE DRAWN FROM FOSSILS. 55 
 
 head are really based upon the present distribution of animal 
 and vegetable life on the globe, and are therefore liable to be 
 vitiated by the following considerations : 
 
 a. Most fossils are extinct, and it is not certain that the 
 habits and requirements of any extinct animal were exactly 
 similar to those of its nearest living relative. 
 
 b. When we get very far back in time, we meet with groups 
 of organisms so unlike anything we know at the present day as 
 to render all conjectures as to climate founded upon their sup- 
 posed habits more or less uncertain and unsafe. 
 
 c. In the case of marine animals, we are as yet very far from 
 knowing the exact limits of distribution of many species within 
 our present seas ; so that conclusions drawn from living forms 
 as to extinct species are apt to prove incorrect. For instance, 
 it has recently been shown that many shells formerly believed 
 to be confined to the Arctic Seas have, by reason of the ex- 
 tension of Polar currents, a wide range to the south ; and this 
 has thrown doubt upon the conclusions drawn from fossil 
 shells as to the Arctic conditions under which certain beds 
 were supposed to have been deposited. 
 
 d. The distribution of animals at the present day is certainly 
 dependent upon other conditions beside climate alone ; and 
 the causes which now limit the range of given animals are 
 certainly such as belong to the existing order of things. But 
 the establishment of the present order of things does not date 
 back in many cases to the introduction of the present species 
 of animals. Even in the case, therefore, of existing species of 
 animals, it can often be shown that the past distribution of the 
 species was different formerly to what it is now, not necessarily 
 because the climate has changed, but because of the alteration 
 of other conditions essential to the life of the species or con- 
 ducing to its extension. 
 
 Still, we are in many cases able to draw completely reliable 
 conclusions as to the climate of a given geological period, by 
 an examination of the fossils belonging to that period. Among 
 the more striking examples of how the past climate of a region 
 may be deduced from the study of the organic remains con- 
 tained in its rocks, the following may be mentioned : It has 
 been shown that in Eocene times, or at the commencement 
 of the Tertiary period, the climate of what is now Western 
 Europe was of a tropical or sub-tropical character. Thus the 
 Eocene beds are found to contain the remains of shells such 
 as now inhabit tropical seas, as, for example, Cowries and 
 Volutes ; and with these are the fruits of palms, and the 
 remains of other tropical plants. It has been shown, again,
 
 56 PRINCIPLES OF PALEONTOLOGY. 
 
 that in Miocene times, or about the middle of the Tertiary 
 period, Central Europe was peopled with a luxuriant flora 
 resembling that of the warmer parts of the United States, and 
 leading to the conclusion that the mean annual temperature 
 must have been at least 30 hotter than it is at present. It 
 has been shown that, at the same time, Greenland, now buried 
 beneath a vast ice-shroud, was warm enough to support a large 
 number of trees, shrubs, and other plants, such as inhabit the 
 temperate regions of the globe. Lastly, it has been shown, 
 upon physical as well as palseontological evidence, that the 
 greater part of the North Temperate Zone, at a comparatively 
 recent geological period, has been visited with all the rigours 
 of an Arctic climate, resembling that of Greenland at the pre- 
 sent day. This is indicated by the occurrence of Arctic shells 
 .in the superficial deposits of this period, whilst the Musk-ox 
 and the Reindeer roamed far south of their present limits. 
 
 Lastly, it was from the study of fossils that geologists learnt 
 originally to comprehend a fact which may be regarded as of 
 cardinal importance in all modern geological theories and 
 speculations namely, that the crust of the earth is liable to 
 local elevations and subsidences. For long after the remains 
 of shells and other marine animals were for the first time ob- 
 served in the solid rocks forming the dry land, and at great 
 heights above the sea-level, attempts were made to explain this 
 almost unintelligible phenomenon upon the hypothesis that 
 the fossils in question were not really the objects they repre- 
 sented, but were in truth mere lusus natures, due to some 
 "plastic virtue latent in the earth." The common-sense of 
 scientific men, however, soon rejected this idea, and it was 
 agreed by universal consent that these bodies really were the 
 remains of animals which formerly lived in the sea. When 
 once this was admitted, the further steps were comparatively 
 easy, and at the present day no geological doctrine stands on 
 a firmer basis than that which teaches us that our present con- 
 tinents and islands, fixed and immovable as they appear, have 
 been repeatedly sunk beneath the ocean.
 
 THE BIOLOGICAL RELATIONS OF FOSSILS. 57 
 
 CHAPTER VI. 
 THE BIOLOGICAL RELATIONS OF FOSSILS, 
 
 Not only have fossils, as we have seen, a most important 
 bearing upon the sciences of Geology and Physical Geography, 
 but they have relations of the most complicated and weighty 
 character with the numerous problems connected with the 
 study of living beings, or in other words, with the science of 
 Biology. To such an extent is this the case, that no adequate 
 comprehension of Zoology and Botany, in their modern 
 form, is so much as possible without some acquaintance with 
 the types of animals and plants which have passed away. 
 There are also numerous speculative questions in the domain 
 of vital science, which, if soluble at all, can only hope to find 
 their key in researches carried out on extinct organisms. To 
 discuss fully the biological relations of fossils would, there- 
 fore, afford matter for a separate treatise ; and all that can be 
 done here is to indicate very cursorily the principal points to 
 which the attention of the palaeontological student ought to 
 be directed. 
 
 In the first place, the great majority of fossil animals and 
 plants are "extinct" that is to say, they belong to species 
 which are no longer in existence at the present day. So far, 
 however, from there being any truth in the old view that there 
 were periodic destructions of all the living beings in existence 
 upon the earth, followed by a corresponding number of new 
 creations of animals and plants, the actual facts of the case show 
 that the extinction of old forms and the introduction of new 
 forms have been processes constantly going on throughout the 
 whole of geological time. Every species seems to come into 
 being at a certain definite point of time, and to finally dis- 
 appear at another definite point ; though there are few in- 
 stances indeed, if there are any, in which our present know- 
 ledge would permit us safely to fix with precision the times of 
 entrance and exit. There are, moreover, marked differences 
 in the actual time during which different species remained in 
 existence, and therefore corresponding differences in their 
 " vertical range," or, in other words, in the actual amount and 
 thickness of strata through which they present themselves as 
 fossils. Some species are found to range through two or even 
 three formations, and a few have an even more extended life. 
 More commonly the species which begin in the commence-
 
 58 PRINCIPLES OF PALEONTOLOGY. 
 
 ment of a great formation die out at or before its close, whilst 
 those which are introduced for the first time near the middle 
 or end of the formation may either become extinct, or may 
 pass on into the next succeeding formation. As a general 
 rule, it is the animals which have the lowest and simplest 
 organisation that have the longest range in time, and the 
 additional possession of microscopic or minute dimensions 
 seems also to favour longevity. Thus some of the Forami- 
 nifera appear to have survived, with little or no perceptible 
 alteration, from the Silurian period to the present day ; whereas 
 large and highly-organised animals, though long-lived as indi- 
 viduals, rarely seem to live long specifically, and have, there- 
 fore, usually a restricted vertical range. Exceptions to this, 
 however, are occasionally to be found in some "persistent 
 types," which extend through a succession of geological 
 periods with very little modification. Thus the existing 
 Lampshells of the genus Lingula are little changed from the 
 Lingulce which swarmed in the Lower Silurian seas ; and the 
 existing Pearly Nautilus is the last descendant of a clan 
 nearly as ancient. On the other hand, some forms are singu- 
 larly restricted in their limits, and seem to have enjoyed a 
 comparatively brief lease of life. An example of this is to 
 be found in many of the Ammonites close allies of the Nau- 
 tilus which are often confined strictly to certain zones of 
 strata, in some cases of very insignificant thickness. 
 
 Of the causes of extinction amongst fossil animals and 
 plants, we know little or nothing. All we can say is, that the 
 attributes which constitute a species do not seem to be intrin- 
 sically endowed with permanence, any more than the attri- 
 butes which constitute an individual, though the former may 
 endure whilst many successive generations of the latter have 
 disappeared. Each species appears to have its own life- 
 period, its commencement, its culmination, and its gradual 
 decay ; and the life-periods of different species may be of very 
 different duration. 
 
 From what has been said above, it may be gathered that 
 our existing species of animals and plants are, for the most 
 part, quite of modern origin, using the term " modern " in its 
 geological acceptation. Measured by human standards, the 
 majority of existing animals (which are capable of being 
 preserved as fossils) are known to have a high antiquity; 
 and some of them can boast of a pedigree which even the 
 geologist may regard with respect. Not a few of our shell- 
 fish are known to have commenced their existence at some 
 point of the Tertiary period; one Lampshell (Terebratulina
 
 THE BIOLOGICAL RELATIONS OF FOSSILS. 59 
 
 caput-serpentis] is believed to have survived since the Chalk ; 
 and some of the Forarninifera date, at any rate, from the 
 Carboniferous period. We learn from this the additional 
 fact that our existing animals and plants do not constitute an 
 assemblage of organic forms which were introduced into the 
 world collectively and simultaneously, but that they com- 
 menced their existence at very different periods, some being 
 extremely old, whilst others may be regarded as compara- 
 tively recent animals. And this introduction of the existing 
 fauna and flora was a slow and gradual process, as shown 
 admirably by the study of the fossil shells of the Tertiary 
 period. Thus, in the earlier Tertiary period, we find about 
 95 per cent of the known fossil shells to be species that are 
 no longer in existence, the remaining 5 per cent being 
 forms which are known to live in our present seas. In the 
 middle of the Tertiary period we find many more recent 
 and still existing species of shells, and the extinct types are 
 much fewer in number ; and this gradual introduction of 
 forms now living goes on steadily, till, at the close of the Ter- 
 tiary period, the proportions with which we started may be 
 reversed, as many as 90 or 95 per cent of the fossil shells 
 being forms still alive, while not more than 5 per cent may 
 have disappeared. 
 
 All known animals at the present day may be divided into 
 some five or six primary divisions, which are known technically 
 as " sub -kingdoms? Each of these sub-kingdoms* may be 
 regarded as representing a certain type or plan of structure, 
 and all the animals comprised in each are merely modified forms 
 of this common type. Not only are all known living animals 
 thus reducible to some five or six fundamental plans of struc- 
 ture, but amongst the vast series of fossil forms no one has 
 yet been found however unlike any existing animal to 
 possess peculiarities which would entitle it to be placed in a 
 new sub-kingdom. All fossil animals, therefore, are capable 
 of being referred to one or other of the primary divisions of 
 the animal kingdom. Many fossil groups have no closely- 
 related group now in existence ; but in no case do we meet 
 with any grand structural type which has not survived to the 
 present day. 
 
 The old types of life differ in many respects from those now 
 upon the earth ; and the further back we pass in time, the 
 more marked does this divergence become. Thus, if we were 
 to compare the animals which lived in the Silurian seas with 
 
 * In the Appendix a brief definition is given of the sub-kingdoms, and 
 the chief divisions of each are enumerated.
 
 60 PRINCIPLES OF PALAEONTOLOGY. 
 
 those inhabiting our present oceans, we should in most in- 
 stances find differences so great as almost to place us in 
 another world. This divergence is the most marked in the 
 Palaeozoic forms of life, less so in those of the Mesozoic period, 
 and less still in the Tertiary period. Each successive formation 
 has therefore presented us with animals becoming gradually 
 more and more like those now in existence ; and though there 
 is an immense and striking difference between the Silurian 
 animals and those of to-day, this difference is greatly reduced 
 if \ve compare the Silurian fauna with the Devonian ; that 
 again with the Carboniferous ; and so on till we reach the 
 present. 
 
 It follows from the above that the animals of any given 
 formation are more like those of the next formation below, 
 and of the next formation above, than they are to any others ; 
 and this fact of itself is an almost inexplicable one, unless we 
 believe that the animals of any given formation are, in part at 
 any rate, the lineal descendants of the animals of the preced- 
 ing formation, and the progenitors, also in part at least, of the 
 animals of the succeeding formation. In fact, the palaeon- 
 tologist is so commonly confronted with the phenomenon of 
 closely-allied forms of animal life succeeding one another in 
 point of time, that he is compelled to believe that such forms 
 have been developed from some common ancestral type by 
 some process of "evolution." On the other hand, there are 
 many phenomena, such as the apparently sudden introduction 
 of new forms throughout all past time, and the common occur- 
 rence of wholly isolated types, which cannot be explained in 
 this way. Whilst it seems certain, therefore, that many of the 
 phenomena of the succession of animal life in past periods can 
 only be explained by some law of evolution, it seems at the 
 same time certain that there has always been some other 
 deeper and higher law at work, on the nature of which it 
 would be futile to speculate at present. 
 
 Not only do we find that the animals of each successive 
 formation become gradually more and more like those now 
 existing upon the globe, as we pass from the older rocks into 
 the newer, but we also find that there has been a gradual pro- 
 gression and development in the types of animal life which 
 characterise the geological ages. If we take the earliest-known 
 and oldest examples of any" given group of animals, it can 
 sometimes be shown that these primitive forms, though in 
 themselves highly organised, possessed certain characters such 
 as are now only seen in \heyottng of their existing representa- 
 tives. In technical language, the early forms of life in some
 
 THE BIOLOGICAL RELATIONS OF FOSSILS. 6 1 
 
 instances possess ''embryonic' 1 '' characters, though this does 
 not prevent them often attaining a size much more gigantic 
 than their nearest living relatives. Moreover, the ancient 
 forms of life are often what is called " comprehensive types " 
 that is to say, they possess characters in combination such 
 as we nowadays only find separately developed in different 
 groups of animals. Now, this permanent retention of embry- 
 onic characters and this "comprehensiveness" of structural 
 type are signs of what a zoologist considers to be a compara- 
 tively low grade of organisation ; and the prevalence of these 
 features in the earlier forms of animals is a very striking phe- 
 nomenon, though they are none the less perfectly organised so 
 far as their own type is concerned. As we pass upwards in 
 the geological scale, we find that these features gradually dis- 
 appear, higher and ever higher forms are introduced, and 
 (i specialisation " of type takes the place of the former com- 
 prehensiveness. We shall have occasion to notice many of 
 the facts on which these views are based at a later period, and 
 in connection with actual examples. In the meanwhile, it is 
 sufficient to state, as a widely-accepted generalisation of palae- 
 ontology, that there has been in the past a general progression 
 .of organic types, and that the appearance of the lower forms 
 of life has in the main preceded that of the higher forms in 
 point of time.
 
 PART II. 
 
 HISTORICAL PALEONTOLOGY.
 
 PART II. 
 
 CHAPTER VII. 
 
 THE LA URENTIAN AND HURONIAN PERIODS. 
 
 THE Laureutian Rocks constitute the base of the entire strati- 
 fied series, and are, therefore, the oldest sediments of which 
 we have as yet any knowledge. They are more largely and 
 more typically developed in North America, and especially in 
 Canada, than in any known part of the world, and they derive 
 their title from the range of hills which the old French geo- 
 graphers named the " Laurentides." These hills are com- 
 posed of Laurentian Rocks, and form the watershed tetween 
 the valley of the St Lawrence river on the one hand, and the 
 great plains which stretch northwards to Hudson Bay on the 
 other hand. The main area of these ancient deposits forms 
 a great belt of rugged and undulating country, which extends 
 from Labrador westwards to Lake Superior, and then bends 
 northwards towards the Arctic Sea. Throughout this extensive 
 area the Laurentian Rocks for the most part present themselves 
 in the form of low, rounded, ice-worn hills, which, if generally 
 wanting in actual sublimity, have a certain geological grandeur 
 from the fact that they "have endured the battles and the storms 
 of time longer than any other mountains" (Dawson). In some 
 places, however, the Laurentian Rocks produce scenery of the 
 most magnificent character, as in the great gorge cut through 
 them by the river Saguenay, where they rise at times into ver- 
 tical precipices 1500 feet in height. In the famous group of 
 the Adirondack mountains, also, in the state of New York, 
 they form elevations no less than 6000 feet above the level of 
 the sea. As a general rule, the character of the Laurentian 
 region is that of a rugged, rocky, rolling country, often densely
 
 66 HISTORICAL PALEONTOLOGY. 
 
 timbered, but rarely well fitted for agriculture, and chiefly 
 attractive to the hunter and the miner. 
 
 As regards its mineral characters, the Laurentian series is 
 composed throughout of metamorphic and highly crystalline 
 rocks, which are in a high degree crumpled, folded, and 
 faulted. By the late Sir William Logan the entire series was 
 divided into two great groups, the Lower Laurentian and the 
 Upper Laurentian, of which the latter rests unconformably 
 upon the truncated edges of the former, and is in turn uncon- 
 formably overlaid by strata of Huronian and Cambrian age 
 (fig. 20). 
 
 '^\\& Lower Laurentian series attains the enormous thickness of 
 
 Fig. 20. Diagrammatic section of the Laurentian Rocks in Lower Canada, a Lower 
 Laurentian ; b Upper Laurentian, resting unconformably upon the lower series ; c Cam- 
 brian strata (Potsdam Sandstone), resting unconformably on the Upper Laurrentian. 
 
 over 20,000 feet, and is composed mainly of great beds of gneiss, 
 altered sandstones (quartzites), mica-schist, hornblende-schist, 
 magnetic iron-ore, and haematite, together with masses of lime- 
 stone. The limestones are especially interesting, and have an 
 extraordinary development three principal beds being known, 
 of which one is not less than 1500 feet thick; the collective 
 thickness of the whole being about 3500 feet. 
 
 The Upper Laurentian series, as before said, reposes uncon- 
 formably upon the Lower Laurentian, and attains a thickness 
 of at least 10,000 feet. Like the preceding, it is wholly meta- 
 morphic, and is composed partly of masses of gneiss and quartz- 
 ite ; but it is especially distinguished by the possession of great 
 beds of felspathic rock, consisting principally of " Labrador 
 felspar." 
 
 Though typically developed in the great Canadian area 
 already spoken of, the Laurentian Rocks occur in other locali- 
 ties, both in America and in the Old World. In Britain, the 
 so-called " fundamental gneiss " of the Hebrides and of Suther- 
 landshire is probably of Lower Laurentian age, and the " hy- 
 persthene rocks " of the Isle of Skye may, with great proba- 
 bility, be regarded as referable to the Upper Laurentian. In 
 other localities in Great Britain (as in St David's, South 
 Wales ; the Malvern Hills ; and the North of Ireland) occur 
 ' ancient metamorphic deposits which also are probably refer- 
 able to the Laurentian series. The so-called " primitive gneiss" 
 of Norway appears to belong to the Laurentian, and the
 
 THE LAURENTIAN AND HURONIAN PERIODS. 6/ 
 
 ancient metamorphic rocks of Bohemia and Bavaria may be 
 regarded as being approximately of the same age. 
 
 By some geological writers the ancient and highly meta- 
 morphosed sediments of the Laurentian and the succeeding 
 Huronian series have been spoken of as the "Azoic rocks" 
 (Gr. a, without ; zoe, life) ; but even if we were wholly destitute 
 of any evidence of life during these periods, this name would be 
 objectionable upon theoretical grounds. If a general name be 
 needed, that of " Eozoic " (Gr. eos, dawn ; zoe, life), proposed 
 by Principal Dawson, is the most appropriate. Owing to their 
 metamorphic condition, geologists long despaired of ever de- 
 tecting any traces of life in the vast pile of strata which con- 
 stitute the Laurentian System. Even before any direct traces 
 were discovered, it was, however, pointed out that there were 
 good reasons for believing that the Laurentian seas had been 
 tenanted by an abundance of living beings. These reasons 
 are briefly as follows : (i) Firstly, the Laurentian series con- 
 sists, beyond question, of marine sediments which originally 
 differed in no essential respect from those which were subse- 
 quently laid down in the Cambrian or Silurian periods. (2) 
 In all formations later than the Laurentian, any limestones 
 which are present can be shown, with few exceptions, to be 
 organic rocks, and to be more or less largely made up of the 
 comminuted debris of marine or fresh-water animals. The 
 Laurentian limestones, in consequence of the metamorphism 
 to which they have been subjected, are so highly crystalline 
 (fig. 2 1 ) that the microscope fails to detect any organic struc- 
 ture in the rock, and no fos- 
 sils beyond those which will 
 be spoken of immediately have 
 as yet been discovered in 
 them. We know, however, of 
 numerous cases in which lime- 
 stones, of later age, and un- 
 doubtedly organic to begin 
 with, have been rendered so 
 intensely crystalline by meta- 
 morphic action that all traces 
 of organic structure have been 
 obliterated. We have there- 
 fore, by analogy, the strongest 
 possible ground for believing 
 that the vast beds of Lauren- 
 tian limestone have been ori- 
 ginally organic in their origin, 
 and primitively composed, in the main, of the calcareous skele- 
 
 Fig. 21. Section of Lower Laurentian 
 Limestone from Hull, Ottawa; enlarged 
 five diameters. The rock is very highly 
 crystalline, and contains mica and other 
 minerals. The irregular black masses in 
 it are graphite. (Original.)
 
 68 HISTORICAL PALAEONTOLOGY. 
 
 tons of marine animals. It would, in fact, be a matter of 
 great difficulty to account for the formation of these great cal- 
 careous masses on any other hypothesis. (3) The occurrence of 
 phosphate of lime in the Laurentian Rocks in great abundance, 
 and sometimes in the form of irregular beds, may very possibly 
 be connected with the former existence in the strata of the re- 
 mains of marine animals of whose skeleton this mineral is a con- 
 stituent. (4) The Laurentian Rocks contain a vast amount of 
 carbon in the form of black-lead or graphite. This mineral is 
 especially abundant in the limestones, occurring in regular beds, 
 in veins or strings, or disseminated through the body of the lime- 
 stone in the shape of crystals, scales, or irregular masses. The 
 amount of graphite in some parts of the Lower Laurentian is 
 so great that it has been calculated as equal to the quantity of 
 carbon present in an equal thickness of the Coal-measures. 
 The general source of solid carbon in the crust of the earth 
 is, however, plant-life ; and it seems impossible to account for 
 the Laurentian graphite, except upon the supposition that it 
 is metamorphosed vegetable matter. (5) Lastly, the great 
 beds of iron-ore (peroxide and magnetic oxide) which occur 
 in the Laurentian series interstratified with the other rocks, 
 point with great probability to the action of vegetable life; 
 since similar deposits in later formations can commonly be 
 shown to have been formed by the deoxidising power of vege- 
 table matter in a state of decay. 
 
 In the words of Principal Dawson, " any one of these rea- 
 sons might, in itself, be held insufficient to prove so great and, 
 at first sight, unlikely a conclusion as that of the existence of 
 abundant animal and vegetable life in the Laurentian; but the 
 concurrence of the whole in a series of deposits unquestion- 
 ably marine, forms a chain of evidence so powerful that it 
 might command belief even if no fragment of any organic or 
 living form or structure had ever been recognised in these an- 
 cient rocks." Of late years, however, there have been dis- 
 covered in the Laurentian Rocks certain bodies which are 
 believed to be truly the remains of animals, and of which by 
 far the most important is the structure known under the now 
 celebrated name of Eozob'n. If truly organic, a very special 
 and exceptional interest attaches itself to Eozoon, as being the 
 most ancient fossil animal of which we have any knowledge ; 
 but there are some who regard it really a peculiar form of 
 mineral structure, and a severe, protracted, and still unfinished 
 controversy has been carried on as to its nature. Into this 
 controversy it is wholly unnecessary to enter here ; and it will 
 be sufficient to briefly explain the structure of Eozoon, as eluci- 
 dated by the elaborate and masterly investigations of Car-
 
 THE LAURENTIAN AND HURONIAN PERIODS. 69 
 
 penter and Dawson, from the standpoint that it is a genuine 
 organism the balance of evidence up to this moment inclin- 
 ing decisively to this view. 
 
 The structure known as Eozoon is found in various localities 
 in the Lower Laurentian limestones of Canada, in the form of 
 isolated masses or spreading layers, which are composed of 
 thin alternating laminae, arranged more or less concentrically 
 (fig. 22). The laminae of these masses are usually of different 
 
 Fig. 22. Fragment of Eozoffn, of the natural size, showing alternate laminae 
 of loganite and dolomite. (After Dawson.) 
 
 colours and composition ; one series being white, and com- 
 posed of carbonate of lime whilst the laminae of the second 
 series alternate with the preceding, are green in colour, and 
 are found by chemical analysis to consist of some silicate, 
 generally serpentine or the . closely-related " loganite." In 
 some instances, however, all the laminae are calcareous, the 
 concentric arrangement still remaining visible in consequence 
 of the fact that the laminae are composed alternately of lighter 
 and darker coloured limestone. 
 
 When first discovered, the masses of Eozoon were supposed 
 to be of a mineral nature ; but their striking general resem- 
 blance to the undoubted fossils which will be subsequently 
 spoken of under the name of Stromatopora was recognised by 
 Sir William Logan, and specimens were submitted for minute 
 examination, first to Principal Dawson, and subsequently to 
 Dr W. B. Carpenter. After a careful microscopic examina- 
 tion, these two distinguished observers came to the conclusion 
 that Eozoon was truly organic, and in this opinion they were 
 afterwards corroborated by other high authorities (Mr W. K. 
 Parker, Profesor Rupert Jones, Mr H. B. Brady, Professor 
 Giimbel, &c.) Stated briefly, the structure of Eozoon, as ex- 
 hibited by the microscope, is as follows :
 
 HISTORICAL PALEONTOLOGY. 
 
 The concentrically-laminated mass of Eozoon is composed 
 of numerous calcareous layers, representing the original skele- 
 ton of the organism (fig. 23, b). These calcareous layers serve 
 
 to separate and de- 
 fine a series of cham- 
 bers arranged in suc- 
 cessive tiers, one 
 above the other (fig. 
 23, A, B, C) ; and 
 they are perforated 
 not only by passages 
 (fig. 23, c\ which 
 serve to place suc- 
 cessive tiers of cham- 
 bers in communica- 
 tion, but also by a 
 system of delicate 
 branching canals (fig. 
 23, d}. Moreover, 
 the central and prin- 
 cipal portion of each 
 calcareous layer, with 
 the ramified canal- 
 system just spoken 
 of, is bounded both above and below by a thin lamina which has 
 a structure of its own, and which may be regarded as the proper 
 shell-wall (fig. 23, a a). This proper wall forms the actual lin- 
 ing of the chambers, as well as the outer surface of the whole 
 mass ; and it is perforated with numerous fine vertical tubes 
 (fig. 24, a a), opening into the chambers and on to the sur- 
 face by corresponding fine pores. From the resemblance of 
 this tubulated layer to similar structures in the shell of the 
 Nummulite, it is often spoken of as the " Nummuline layer." 
 The chambers are sometimes piled up one above the other in 
 an irregular manner ; but they are more commonly arranged 
 in regular tiers, the separate chambers being marked off from 
 one another by projections of the wall in the form of parti- 
 tions, which are so far imperfect as to allow of a free communi- 
 cation between contiguous chambers. In the original condi- 
 tion of the organism, all these chambers, of course, must have 
 been filled with living matter; but they are found in the present 
 state of the fossil to be generally filled with some silicate, such 
 as serpentine, which not only fills the actual chambers, but has 
 also penetrated the minute tubes of the proper wall and the 
 branching canals of the intermediate skeleton. In some cases 
 
 - b 
 
 lagram ot a portion of Eozoon cut verli- 
 ^, Three tiers of chambers communicating 
 i one another by slightly constricted apertures : a a, 
 The true shell-wall, perforated by numerous delicate 
 tubes; b b, The main calcareous skeleton ("intermedi- 
 ate skeleton"); c, Passage of communication (" stolon- 
 passage ") from one tier of chambers to another ; d, Rami- 
 fying tubes in the calcareous skeleton. (After Car- 
 penter.) 
 
 Fig. 23. Diagram of ; 
 cally. A, B, C, Three tiers of chamber 
 withe
 
 THE LAURENTIAN AND HURONIAN PERIODS. 7 1 
 
 the chambers are simply filled svith crystalline carbonate of 
 lime. When the originally porous fossil has been permeated 
 
 Fi^. 24. Portion of one of- the calcareous layers of Eozoon, magnified 
 a a. The proper wall (" Nummuline layer") of one of the chambers, showing the fine ver- 
 tical tubuli with which it is penetrated, and which are slightly bent along the line a' a.', 
 c f> The intermediate skeleton, with numerous branched canals. The oblique lines are 
 the cleavage planes of the carbonate of lime, extending across both the intermediate 
 skeleton and tlie proper wall. (After Carpenter.) 
 
 by a silicate, it is possible to dissolve away the whole of the 
 calcareous skeleton by means of acids, leaving an accurate and 
 beautiful cast of the chambers and the tubes connected with 
 them in the insoluble silicate. 
 
 The above are the actual appearances presented by Eozoon 
 when examined microscopically, and it remains to see how 
 far they enable us to decide upon its true position in the 
 animal kingdom. Those who wish to study this interesting 
 subject in detail must consult the admirable memoirs by Dr 
 W. B. Carpenter and Principal Dawson : it will be enough 
 here to indicate the results which have been arrived at. The 
 only animals at the present day which possess a continuous 
 calcareous skeleton, perforated by pores and penetrated by 
 canals, are certain organisms belonging to the group of the 
 Foraminifcra. We have had occasion before to speak of these 
 animals, and as they are not conspicuous or commonly-known 
 forms of life, it may be well to say a few words as to the 
 structure of the living representatives of the group. The 
 Foraminifera are all inhabitants of the sea, and are mostly of 
 small or even microscopic dimensions. Their bodies are com-
 
 HISTORICAL PALEONTOLOGY. 
 
 posed of an apparently structureless animal substance of an 
 albuminous nature ("sarcode"), of a gelatinous consistence, 
 transparent, and exhibiting numerous minute granules or 
 rounded particles. The body-substance cannot be said in 
 itself to possess any definite form, except in so far as it may 
 be bounded by a shell ; but it has the power, wherever it may 
 be exposed, of emitting long thread-like filaments ("pseudo- 
 podia "), which interlace with one another to form a network 
 (fig. 25, ). These filaments can be thrown out at will, and 
 
 Fig. ._Th 
 ?moved by a \ 
 showing the shell su 
 
 onionina, one of the Foratninifera, after the shell has been 
 
 removed by a weak acid ; 6, Gromia, a single-chambered Foraminifer (after Schulue), 
 iiided by a network of filaments derived from the body substance. 
 
 to considerable distances, and can be.again retracted into the 
 soft mass of the general body-substance, and they are the 
 agents by which the animal obtains its food. The soft bodies 
 of the Foraminifera are protected by a shell, which is usually 
 calcareous, but may be composed of sand-grains cemented
 
 THE LAURENTIAN AND HURONIAN PERIODS. 73 
 
 together ; and it may consist of a single chamber (fig. 26, a), 
 or of many chambers arranged in different ways (fig. 26, b-f). 
 
 Fig 26. Shells of living Foraminifera. a, Orbnlina universa, in its perfect condi- 
 tion, showing the tubular spines which radiate from the surface of the shell ; b, Globi- 
 gerina bulloides, in its ordinary condition, the thin hollow spines which are attached to 
 the shell when perfect having been broken off; c, Textularia variabilis ; ti, Peneroplis 
 planatus; e, Rotalia conca merata ; /, Cristellaria subarcnatula. [Fig. a is after 
 Wyville Thomson ; the others are after Williamson. All the figures are greatly en- 
 larged.] 
 
 Sometimes the shell has but one large opening into it the 
 mouth : and then it is from this aperture that the animal pro- 
 trudes the delicate net of filaments with which it seeks its 
 food. In other cases the entire shell is perforated with 
 minute pores (fig. 26, e), through which the soft body-substance 
 gains the exterior, covering the whole shell with a gelatinous 
 film of animal matter, from which filaments can be emitted at 
 any point. When the shell consists of many chambers, all of 
 these are placed in direct communication with one another, 
 and the actual substance of the shell is often traversed by 
 minute canals -filled with living matter (e.g., in Calcarina and 
 Nummulina}. The shell, therefore, may be regarded, in such 
 cases, as a more or less completely porous calcareous structure,
 
 74 PRINCIPLES OF PALEONTOLOGY. 
 
 filled to its minutest internal recesses with the substance of the 
 living animal, and covered externally with a layer of the same 
 substance, giving off a network of interlacing filaments. 
 
 Such, in brief, is the structure of the living Foraminifera ; 
 and it is believed that in Eozoon we have an extinct example 
 of the same group, not only of special interest from its imme- 
 morial antiquity, but hardly less striking from its gigantic 
 dimensions. In its original condition, the entire chamber- 
 system of Eozoon is believed to have been filled with soft 
 structureless living matter, which passed from chamber to 
 chamber through the wide apertures connecting these cavities, 
 and from tier to tier by means of the tubuli in the shell-wall and 
 the branching canals in the intermediate skeleton. Through 
 the perforated shell-wall covering the outer surface the soft 
 body-substance flowed out, forming a gelatinous investment, 
 from every point of which radiated an interlacing net of deli- 
 cate filaments, providing nourishment for the entire colony. 
 In its present state, as before said, all the cavities originally 
 occupied by the body-substance have been filled with some 
 mineral substance, generally with one of the silicates of mag- 
 nesia; and it has been asserted that this fact militates strongly 
 against the organic nature of Eozoon, if not absolutely dis- 
 proving it. As a matter of fact, however as previously no- 
 ticed it is by no means very uncommon at the present day 
 to find the shells of living species of Foraminifera in which 
 all the cavities primitively occupied by the body-substance, 
 down to the minutest pores and canals, have been similarly 
 injected by some analogous silicate, such as glauconite. 
 
 Those, then, whose opinions on such a subject deservedly 
 carry the greatest weight, are decisively of opinion that we are 
 presented in the Eozoon of the Laurentian Rocks of Canada 
 with an ancient, colossal, and in some respects abnormal type 
 of the Foraminifera. In the words of Dr Carpenter, it is not 
 pretended that " the doctrine of the Foraminiferal nature of 
 Eozoon can be proved in the demonstrative sense ; " but it 
 may be affirmed " that the convergence of a number of separate 
 and independent probabilities, all accordant with that hypothesis, 
 while a separate explanation must be invented for each of 
 them on any other hypothesis, gives it that high probability 
 on which we rest in the ordinary affairs of life, in the verdicts 
 of juries, and in the interpretation of geological phenomena 
 generally." 
 
 It only remains to be added, that whilst Eozoon is by far 
 the most important organic body hitherto found in the Lauren- 
 tian, and has been here treated at proportionate length, other
 
 THE LAURENTIAN AND HURONIAN PERIODS. 75 
 
 traces of life have been detected, which may subsequently 
 prove of great interest and importance. Thus, Principal 
 Dawson has recently described under the name of Archceo- 
 sphccrince certain singular rounded bodies which he has dis- 
 covered in the Laurentian limestones, and which he believes 
 to be casts of the shells of Foraminifera possibly somewhat 
 allied to the existing Globigerincs. The same eminent palaeon- 
 tologist has also described undoubted worm -burrows from 
 rocks probably of Laurentian age. Further and more extend- 
 ed researches, we may reasonably hope, will probably bring 
 to light other actual remains of organisms in these ancient 
 deposits. 
 
 THE HURONIAN PERIOD. 
 
 The so-called Huronian Rocks, like the Laurentian, have 
 their typical development in Canada, and derive their name 
 from the fact that they occupy an extensive area on the borders 
 of Lake Huron. They are wholly metamorphic, and consist 
 principally of altered sandstones or quartzites, siliceous, fels- 
 pathic, or talcose slates, conglomerates, and limestones. They 
 are largely developed on the north shore of Lake Superior, 
 and give rise to a broken and hilly country, very like that 
 occupied by the Laurentians, with an abundance of timber, 
 but rarely with sufficient soil of good quality for agricultural 
 purposes. They are, however, largely intersected by mineral 
 veins, containing silver, gold, and other metals, and they will 
 ultimately doubtless yield a rich harvest to the miner. The 
 Huronian Rocks have been identified, with greater or less 
 certainty, in other parts of North America, and also in the 
 Old World. 
 
 The total thickness of the Huronian Rocks in Canada is 
 estimated as being not less than 18,000 feet, but there is con- 
 siderable doubt as to their precise geological position. In 
 their typical area they rest unconformably on the edges of 
 strata of Lower Laurentian age ; but they have never been seen 
 in direct contact with the Upper Laurentian, and their exact 
 relations to this series are therefore doubtful. It is thus open 
 to question whether the Huronian Rocks constitute a distinct 
 formation, to be intercalated in point of time between the 
 Laurentian and the Cambrian groups ; or whether, rather, they 
 should not be considered as the metamorphosed representa- 
 tives of the Lower Cambrian Rocks of other regions. 
 
 As regards the fossils of the Huronian Rocks, little can be 
 said. Some of the specimens of Eozobn Canadcnsevi\\\c\\ have
 
 76 HISTORICAL PALEONTOLOGY. 
 
 been discovered in Canada are thought to come from rocks 
 which are probably of Huronian age. In Bavaria, Dr Giimbel 
 has described a species of Eozoon under the name of Eozoon 
 Bavaricum, from certain metamorphic limestones which he 
 refers to the Huronian formation. Lastly, the late Mr Billings 
 described, from rocks in Newfoundland apparently referable to 
 the Huronian, certain problematical limpet-shaped fossils, to 
 which he gave the name of Aspidella. 
 
 LITERATURE. 
 
 Amongst the works and memoirs which the student may consult with 
 regard to the Laurentian and Huronian deposits may be mentioned the 
 following :* 
 
 (1) 'Report of Progress of the Geological Survey of Canada from its 
 
 Commencement to 1863,' pp. 38-49, and pp. 50-66. 
 
 (2) 'Manual of Geology.' Dana. 2d Ed. 1875. 
 
 (3) 'The Dawn of Life.' J. W. Dawson. 1876. 
 
 (4) " On the Occurrence of Organic Remains in the Laurentian Rocl<s 
 
 of Canada." Sir W. E. Logan. 'Quart. Journ. Geol. Soc.,' 
 xxi. 45-50. 
 
 (5) " On the Structure of Certain Organic Remains in the Laurentian 
 
 Limestones of Canada." J. W. Dawson. 'Quart. Journ. Geol. 
 Soc.,' xxi. 51-59. 
 
 (6) " Additional Note on the Structure and Affinities of Eozoon Cana- 
 
 dense." W. B. Carpenter. 'Quart. Journ. Geol. Soc.,' xxi. 
 59-66. 
 
 (7) " Supplemental Notes on the Structure and Affinities of Eozoon 
 
 Canadense. " W. B. Carpenter. 'Quart. Journ. Geol. Soc., 
 xxii. 219-228. 
 
 (8) " On the So-Called Eozoonal Rocks." King & Rowney. ' Quart. 
 
 Journ. Geol. Soc.,' xxii. 185-218. 
 ' Chemica 
 
 (9) ' Chemical and Geological Essays.' Sterry Hunt. 
 
 The above list only includes some of the more important memoirs which 
 may be consulted as to the geological and chemical features of the Lauren- 
 tian and Huronian Rocks, arid as to the true nature of Eozoon. Those 
 who are desirous of studying the later phases of the controversy with re- 
 gard to Eozoon must consult the papers of Carpenter, Carter, Dawson, 
 King & Rowney, Hahn, and others, in the ' Quart. Journ. of the Geological 
 Society,' the ' Proceedings of the Royal Irish Academy,' the 'Annals of Nat- 
 ural History,' the 'Geological Magazine,' &c. Dr Carpenter's ' Introduc- 
 tion to the Study of the Foraminifera ' should also be consulted. 
 
 * In this and in all subsequently following bibliographical lists, not only 
 is the selection of works and memoirs quoted necessarily extremely limited ; 
 but only such have, as a general rule, been chosen for mention as are easily 
 accessible to students who-are in the position of being able to refer to a 
 good library. Exceptions, however, are occasionally made to this rule, 
 in favour of memoirs or works of special historical interest. It is also un- 
 necessary to add that it has not been thought requisite to insert in these 
 lists the well-known handbooks of geological and palseontological science, 
 except in such instances as where they contain special information on 
 special points.
 
 THE CAMBRIAN PERIOD. 77 
 
 CHAPTER VIII. 
 THE CAMBRIAN PERIOD. 
 
 The traces of life in the Laurentian period, as we have seen, 
 are but scanty ; but the Cambrian Rocks so called from their 
 occurrence in North Wales and its borders (" Cambria") have 
 yielded numerous remains of animals and some dubious plants. 
 T"he Cambrian deposits have thus a special interest as being 
 the oldest rocks in which occur any number of well-preserved 
 and unquestionable organisms. We have here the remains of 
 the first fauna, or assemblage of animals, of which we have at 
 present knowledge. As regards their geographical distribu- 
 tion, the Cambrian Rocks have been recognised in many parts 
 of the world, but there is some question as to the precise limits 
 of the formation, and we may consider that their most typical 
 area is in South Wales, where they have been carefully worked 
 out, chiefly by Dr Henry Hicks. In this region, in the neigh- 
 bourhood of the promontory of St David's, the Cambrian Rocks 
 are largely developed, resting upon an ancient ridge of Pre- 
 Cambrian (Laurentian?) strata, and overlaid by the lowest 
 beds of the Lower Silurian. The subjoined sketch-section 
 (fig. 27) exhibits in a general manner the succession of strata 
 in this locality. 
 
 From this section it will be seen that the Cambrian 
 Rocks in Wales are divided in the first place into a lower and 
 an upper group. The Lower Cambrian is constituted at the 
 base by a great series of grits, sandstones, conglomerates, and 
 slates, which are known as the " Longmynd group," from their 
 vast development in the Longmynd Hills in Shropshire, and 
 which attain in North Wales a thickness of 8000 feet or more. 
 The Longmynd beds are succeeded by the so-called " Mene- 
 vian group," a series of sandstones, flags, and grits, about 600 
 feet in thickness, and containing a considerable number of 
 fossils. The Upper Cambrian series consists in its lower por- 
 tion of nearly 5000 feet of strata, principally shaly and slaty, 
 which are known as the " Lingula Flags," from the great 
 abundance in them of a shell referable-to the genus Lingula. 
 These are followed by 1000 feet of dark shales and flaggy 
 sandstones, which are known as the " Tremadoc slates," from 
 their occurrence near Tremadoc in North Wales ; and these 
 in turn are surmounted, apparently quite conformably, by the 
 basement beds of the Lower Silurian. 
 
 7 '
 
 HISTORICAL PALEONTOLOGY. 
 
 GENERALISED SECTION OF THE CAMBRIAN ROCKS IN WALES. 
 
 Fig. 27. 
 
 Arenig Group (Base of the 
 Lower Silurian). 
 
 Tremadoc Slates. 
 
 Upper Lingula Flags. 
 
 Middle Lingula Flags. 
 
 Lower Lingula Flags. 
 Menevian Group. 
 
 > Longmynd or Harlech Group. 
 
 Pre-Cambrian Rocks. 
 
 The above may be regarded as giving a typical series of the 
 Cambrian Rocks in a typical locality ; but strata of Cambrian 
 age are known in many other regions, of which it is only 
 possible here to allude to a few of the most important. In 
 Scandinavia occurs a well-developed series of Cambrian de- 
 posits, representing both the lower and upper parts of the
 
 THE CAMBRIAN PERIOD. 
 
 79 
 
 formation. In Bohemia, the Upper Cambrian, in particular, 
 is largely developed, and constitutes the so-called " Primordial 
 zone" of Barrande. Lastly, in North America, whilst the 
 Lower Cambrian is only imperfectly developed, or is repre- 
 sented by the Huronian, the Upper Cambrian formation has 
 a wide extension, containing fossils similar in character to the 
 analogous strata in Europe, and known as the " Potsdam Sand- 
 stone." The subjoined table shows the chief areas where Cam- 
 brian Rocks are developed, and their general equivalency : 
 
 TABULAR VIEW OF THE CAMBRIAN FORMATION. 
 
 Britain. 
 
 Europe. 
 
 America. 
 
 (a. Tremadoc Slates. 
 
 a. Primordial zone 
 
 a. Potsdam 
 
 
 of Bohemia. 
 
 Sandstone. 
 
 b. Lin?ula Flags. 
 
 b. Paradoxides 
 
 b. Acadian 
 
 
 Schists, Olenus 
 Schists, and Dict- 
 
 group of New 
 Brunswick. 
 
 
 yonema schists of 
 
 
 
 Sweden. 
 
 
 (a, Longmynd Beds. 
 
 a. Fucoidal Sand- 
 
 Huronian 
 
 
 stone of Sweden. 
 
 Formation ? 
 
 b. Llanberis Slates. 
 
 b. Eophyton Sand- 
 
 
 
 stone of Sweden. 
 
 
 c. Harlech Grits. 
 
 
 
 -Lower 1 ^ O i dhamia Slates 
 
 
 
 Cambrian. \ o f Ireland. 
 
 
 
 1 e. Conglomerates and 
 
 
 
 Sandstones of 
 
 
 
 Sutherlandshire ? 
 
 
 
 \f. Menevian Beds. 
 
 
 
 Like all the older Palaeozoic deposits, the Cambrian Rocks, 
 though by no means necessarily what would be called actually 
 " metamorphic," have been highly cleaved, and otherwise 
 altered from their original condition. Owing partly to their 
 indurated state, and partly to their great antiquity, they are 
 usually found in the heart of mountainous districts, which have 
 undergone great disturbance, and have been subjected to an 
 enormous amount of denudation. In some cases, as in the 
 Longmynd Hills in Shropshire, they form low rounded eleva- 
 tions, largely covered by pasture, and with few or no elements 
 of sublimity. In other cases, however, they rise into bold and 
 rugged mountains, girded by precipitous cliffs. Industrially, 
 the Cambrian Rocks are of interest, if only for the reason that 
 the celebrated Welsh slates of Llanberis are derived from 
 highly-cleaved beds of this age Taken as a whole, the Cam- 
 brian formation is essentially Composed of arenaceous and
 
 8O HISTORICAL PALAEONTOLOGY. 
 
 muddy sediments, the latter being sometimes red, but more 
 commonly nearly black in colour. It has often been supposed 
 that the Cambrians are a deep-sea deposit, and that we may 
 thus account for the few fossils contained in them ; but the 
 paucity of fossils is to a large extent imaginary, and some of 
 the Lower Cambrian beds of the Longmynd Hills would ap- 
 pear to have been laid down in shallow water, as they exhibit 
 rain-prints, sun-cracks, and ripple-marks incontrovertible evi- 
 dence of their having been a shore-deposit. The occurrence 
 of innumerable worm-tracks and burrows in many Cambrian 
 strata is also a proof of shallow-water conditions ; and the gen- 
 eral absence of limestones, coupled with the coarse mechani- 
 cal nature of many of the sediments of the Lower Cambrian, 
 may be taken as pointing in the same direction. 
 
 The life of the Cambrian, though not so rich as in the suc- 
 ceeding Silurian period, nevertheless consists of representa- 
 tives of most of the great classes of invertebrate animals. The 
 coarse sandy deposits of the formation, which abound more 
 particularly towards its lower part, naturally are to a large 
 extent barren of fossils ; but the muddy sediments, when not 
 too highly cleaved, and especially towards the summit of the 
 group, are replete with organic remains. This is also the case, in 
 many localities at any rate, with the finer beds of the Potsdam 
 Sandstone in America. Limestones are known to occur in 
 only a few areas (chiefly in America), and this may account for 
 the apparent total absence of corals. It is, however, interest- 
 ing to note that, with this exception, almost all the other lead- 
 ing groups of Invertebrates are known to have come into 
 existence during the Cambrian period. 
 
 Of the land - surfaces of the Cambrian period we know 
 nothing ; and there is, therefore, nothing surprising in the fact 
 that our acquaintance with the Cambrian vegetation is confined 
 to some marine plants or sea-weeds, often of a very obscure and 
 problematical nature. The "Fucoidal Sandstone" of Sweden, 
 and the " Potsdam Sandstone " of North America, have both 
 yielded numerous remains which have been regarded as mark- 
 ings left by sea-weeds or " Fucoids ; " but these are highly enig- 
 matical in their characters, and would, in many instances, seem 
 to be rather referable to the tracks and burrows of marine 
 worms. The first-mentioned of these formations has also 
 yielded the curious, furrowed and striated stems which have 
 been described as a kind of land-plant under the name of 
 Eophyton (fig. 28). It cannot be said, however, that the vege- 
 table origin of these singular bodies has been satisfactorily 
 proved. Lastly, there are found in certain green and purple
 
 THE CAMBRIAN PERIOD. 8l 
 
 beds of Lower Cambrian age at Bray Head, Wicklow, Ireland, 
 some very remarkable fossils, which are well known under the 
 
 Fig. 28. Fragment of Kapfiyton Lintteaiium, a supposed land-p'ant. Lower 
 Cambrian, Sweden, of the natural size. 
 
 name of Oldhamia, but the true nature of which is very doubtful. 
 The commonest form of Oldhamia (fig. 29) consists of a 
 thread-like stem or axis, from which spring at regular intervals 
 bundles of short filamentous branches in a fan-like manner. 
 In the locality where it occurs, the fronds of Oldhamia are very 
 abundant, and are spread over the surfaces of the strata in 
 tangled layers. That it is organic is certain, and that it is a 
 calcareous sea-weed is probable ; but it may possibly belong to 
 the sea-mosses (Polyzoa), or to the sea-firs (Sertularians). 
 
 Amongst the lower forms of animal life (Protozoa], we find 
 the Sponges represented by the curious bodies, composed of 
 netted fibres, to which the name of Protospcngia has been given 
 (fig. 32, a) ; and the comparatively gigantic, conical, or cylin-
 
 82 
 
 HISTORICAL PALAEONTOLOGY. 
 
 drical fossils termed Archceocyathus by Mr Billings are certainly 
 referable either to the Foraminifera or to the Sponges. The 
 almost total absence of lime- 
 stones in the formation may 
 be regarded as a sufficient ex- 
 planation of the fact that the 
 Foraminifera are not more 
 largely and unequivocally re- 
 presented ; though the exist- 
 ence of greensands in the 
 Cambrian beds of Wisconsin 
 
 Fig. 29. A portion of Oldhamiii ti'i- 
 tiqna, Lower Cambrian, Wick^ow, Ire- 
 land, of the natural size. (After Saltcr.) 
 
 and Tennessee may be taken 
 as an indication that this class 
 of animals was by no means 
 wholly wanting. The same 
 fact may explain the total ab- 
 sence of corals, so far as at 
 present known. 
 
 The group of the Echinoder- 
 mata (Sea- lilies, Sea-urchins, 
 and their allies) is represented 
 by a few forms, which are prin- 
 cipally of interest as being the earliest-known -examples of the 
 class. It is also worthy of note that these precursors of a 
 group which subsequently attains such geological importance, 
 are referable to no less than three distinct orders the Crinoids 
 or Sea-lilies, represented by a species of Dendrocrinus ; the 
 Cystideans by Protocystites ; and the Star-fishes by Palasterina 
 and some other forms. Only the last of these groups, how- 
 ever, appears to occur in the Lower Cambrian. 
 
 The Ringed-worms (Annelida), if rightly credited with all 
 the remains usually referred to them, appear to have swarmed 
 in the Cambrian seas. Being soft-bodied, we do not find the 
 actual worms themselves in the fossil condition, but we have, 
 nevertheless, abundant traces of their existence. In some 
 cases we find vertical burrows of greater or less depth, often 
 expanded towards their apertures, in which the worm must 
 have actually lived (fig. 30), as various species do at the pre- 
 sent day. In these cases, the tube must have been rendered 
 more or less permanent by receiving a coating of mucus, or 
 perhaps a genuine membranous secretion, from the body of 
 the animal, and it may be found quite empty, or occupied by 
 a cast of sand or mud. Of this nature are the burrows which 
 have been described under the names of Scolithus and Scoleco- 
 derma, and probably the Histiodenna of the Lower Cambrian
 
 THE CAMBRIAN PERIOD. 83 
 
 of Ireland. In other cases, as in Arenicolites (fig. 32, l>), the 
 worm seems to have inhabited a double burrow, shaped like 
 
 Fig. 30. Annelide-burrows (Sco/it/ins linearis), from the Potsdam Sandstone of 
 Canada, of the natural size. (After Billings.) 
 
 the letter U, and having two openings placed close together 
 on the surface of the stratum. Thousands of these twin- 
 burrows occur in some of the strata of the Longmynd, and it 
 is supposed that the worm used one opening to the burrow as 
 an aperture of entrance, and the other as one of exit. In other 
 cases, again, we find simply the meandering trails caused by 
 the worm dragging its body over the surface of the mud. 
 Markings of this kind are commoner in the Silurian Rocks, 
 and it is generally more or less doubtful whether they may 
 not have been caused by other marine animals, such as shell- 
 fish, whilst some of them have certainly nothing whatever to 
 do with the worms. Lastly, the Cambrian beds often show 
 twining cylindrical bodies, commonly more or less matted 
 together, and not confined to the surfaces of the strata, but 
 passing through them. These have often been regarded as 
 the remains of sea-weeds, but it is more probable that they 
 represent casts of the underground burrows of worms of simi- 
 lar habits to the common lob-worm (Arenicola) of the present 
 day. 
 
 The Articulate animals are numerously represented in the 
 Cambrian deposits, but exclusively by the class of Crustaceans. 
 Some of these are little double-shelled creatures, resembling 
 our living water-fleas (Ostracoda}. A few are larger forms, and 
 belong to the same group as the existing brine-shrimps and 
 fairy-shrimps {Phyllopoda). One of the most characteristic of
 
 84 HISTORICAL PALEONTOLOGY. 
 
 these is the Hymenocaris vermicanda of the Lingula Flags (fig. 
 32, d}. By far the larger number of the Cambrian Crustacea 
 belong, however, to the remarkable and wholly extinct group 
 of the Trilobites. These extraordinary -animals must have 
 literally swarmed in the seas of the later portion of this and 
 the whole of the succeeding period ; and they survived in 
 greatly diminished numbers till the earlier portion of the 
 Carboniferous period. They died out, however, wholly before 
 the close of the Palaeozoic epoch, and we have no Crusta- 
 ceans at the present day which can be considered as their 
 direct representatives. They have, however, relationships of 
 a more or less intimate character with the existing groups of 
 the Phyllopods, the King-crabs (Limulus), and the Isopods 
 (" Slaters," Wood-lice, &c.) Indeed, one member of the last- 
 mentioned order, namely, the Scrolls of the coasts of Patagonia, 
 has been regarded as the nearest living ally of the Trilobites. 
 Be this as it may, the Trilobites possessed a skeleton which, 
 though capable of undergoing almost endless variations, was 
 wonderfully constant in its pattern of structure, and we may 
 briefly describe here the chief features of this. 
 
 The upper surface of the body of a Trilobite was defended 
 " by a strong shell or " crust," partly horny and partly calcare- 
 ous in its composition. This shell (fig. 31) generally exhibits 
 a very distinct " trilobation " or division into three longitudinal 
 lobes, one central and two lateral. It also exhibits a more 
 important and more fundamental division into three transverse 
 portions, which are so loosely connected with one another as 
 very commonly to be found separate. The first and most 
 anterior of these divisions is a shield or buckler which covers 
 the head ; the second or middle portion is composed of mov- 
 able rings covering the trunk (" thorax ") ; and the third is a 
 shield which covers the tail or " abdomen." The head-shield 
 (fig. 31, e) is generally more or less semicircular in shape ; and 
 its central portion, covering the stomrcb of the animal, is usu- 
 ally strongly elevated, and generally marked by lateral furrows. 
 A little on each side of the head are placed the eyes, which 
 are generally crescentic in shape, and resemble the eyes of 
 insects and many existing Crustaceans in being "compound," 
 or made up of numerous simple eyes aggregated together. 
 So excellent is the state of preservation of many specimens of 
 Trilobites, that the numerous individual lenses of the eyes 
 have been uninjured, and as many as four hundred have been 
 counted in each eye of some forms. The eyes may be sup- 
 ported upon prominences, but they are never carried on mov- 
 able stalks (as they are in the existing lobsters and crabs) ; and
 
 THE CAMBRIAN PERIOD. 85 
 
 in some of the Cambrian Trilobites, such as the little Agnosti 
 (lig. 31 g), the animal was blind. The lateral portions of the 
 
 Fig. 31. Cambrian Trilobites: a, Paradorides Bohemicns, reduced in size; b, Ellifi- 
 socephalus Hoffi; c, Sao hirsTita; d, Conocoryphe Snttzeri (all the above, together with 
 fig. ?, are from the Upper Cambrian or "Primordial Zone" of Bohemia); e, Head-shield 
 of Dikellocephaltis Celticits, from the Lingula Flags of Wales ; /, Head-shield of Cono- 
 coryphe Mattheiui, from the Upper Cambrian (Acadian Group) of New Brunswick; g, 
 Agnostus rex, Bohemia ; h. Tail-shield of Dikellocephahts Minnesotensis, from the Upper 
 Cambrian (Potsdam Sandstone) of Minnesota. (After Barrande, Dawson, Salter, and 
 Dale Owen.) 
 
 head-shield are usually separated from the central portion by 
 a peculiar line of division (the so-called " facial suture ") on 
 each side ; but this is also wanting in some of the Cambrian 
 species. The backward angles of the head-shield, also, are 
 often prolonged into spines, which sometimes reach a great 
 length. Following the head-shield behind, we have a portion 
 of the body which is composed of movable segments or "body- 
 rings," and which is technically called the " thorax." Ordi- 
 narily, this region is strongly trilobed, and each ring consists of 
 a central convex portion, and of two flatter side-lobes. The 
 number of body-rings in the thorax is very variable (from two 
 to twenty-six), but is fixed for the adult forms of each group of 
 the Trilobites. The young forms have much fewer rings than 
 the full-grown ones ; and it is curious to find that the Cam-
 
 86 HISTORICAL PALEONTOLOGY. 
 
 brian Trilobites very commonly have either a great many rings 
 (as in Paradoxides, tig. 31, ), or else very few (as in Agnostus, 
 fig. 3 !,). In some instances, the body-rings do not seem to 
 have been so constructed as to allow of much movement, but 
 in other cases this region of the body is so flexible that the 
 animal possessed the power of rolling itself up completely, like 
 a hedgehog ; and many individuals have been permanently 
 preserved as fossils in this defensive condition. Finally, the 
 body of the Trilobite was completed by a tail-shield (techni- 
 cally termed the "pygidium"), which varies much in size and 
 form, and is composed of a greater or less number of rings, 
 similar to those which form the thorax, but immovably amalga- 
 mated with one another (fig. 31, //). 
 
 The under surface of the body in the Trilobites appears to 
 have been more or less entirely destitute of hard structures, 
 with the exception of a well-developed upper lip, in the form 
 of a plate attached to the inferior side of the head-shield in 
 front. There is no reason to doubt that the animal possessed 
 legs; but these structures seem to have resembled those of 
 many living Crustaceans in being quite soft and membranous. 
 This, at any rate, seems to have been generally the case ; 
 though structures which have been regarded as legs have been 
 detected on the under surface of one of the larger species of 
 Trilobites. There is also, at present, no direct evidence that 
 the Trilobites possessed the two pairs of jointed feelers ("an- 
 tennae") which are so characteristic of recent Crustaceans. 
 
 The Trilobites vary much in size, and the Cambrian forma- 
 tion presents examples of both the largest and the smallest 
 members of the order. Some of the young forms may be little 
 bigger than a millet-seed, and some adult examples of the 
 smaller species (such as Agnostus) may be only a few lines in 
 length ; whilst such giants of the order as Paradoxides and 
 Asaphus may reach a length of from one to two feet. Judging 
 from what we actually know as to the structure of the Trilo- 
 bites, and also from analogous recent forms, it would seem that 
 these ancient Crustaceans were mud-haunting creatures, deni- 
 zens of shallow seas, and affecting the soft silt of the bottom 
 rather than the clear water above. Whenever muddy sedi- 
 ments are found in the Cambrian and Silurian formations, 
 there we are tolerably sure to find Trilobites, though they are 
 by no means absolutely wanting in limestones. They appear 
 to have crawled about upon the sea-bottom, or burrowed in the 
 yielding mud, with the soft under surface directed downwards; 
 and it is probable that they really derived their nutriment from 
 the organic matter contained in the ooze amongst which they
 
 THE CAMBRIAN PERIOD. 87 
 
 lived. The vital organs seem to have occupied the central lobe 
 of the skeleton, by which they were protected ; and a series of 
 delicate leaf-like paddles, which probably served as respiratory 
 organs, would appear to have been carried on the under surface 
 of the thorax. That they had their enemies may be regarded 
 as certain ; \>ut we have no evidence that they were furnished 
 with any offensive weapons, or, indeed, with any means of 
 defence beyond their hard crust, and the power, possessed by 
 so many of them, of rolling themselves into a ball. An addi- 
 tional proof of the fact that they for the most part crawled 
 along the sea-bottom is found in the occurrence of tracks and 
 markings of various kinds, which can hardly be ascribed to 
 any other creatures with any show of probability. That this 
 is the true nature of some of the markings in question cannot 
 be doubted at all ; and in other cases no explanation so pro- 
 bable has yet been suggested. If, however, the tracks which 
 have been described from the Potsdam Sandstone of North 
 America under the name of Protichnites are really due to the 
 peregrinations of some Trilobite, they must have been pro- 
 duced by one of the largest examples of the order. 
 
 As already said, the Cambrian Rocks are very rich in the 
 remains of Trilobites. In the lowest beds of the series (Long- 
 mynd Rocks), representatives of some half-dozen genera have 
 now been detected, including the dwarf Agnosttts and the giant 
 Paradoxides. In the higher beds, the number both of genera 
 and species is largely increased ; and from the great compara- 
 tive abundance of individuals, the Trilobites have every right 
 to be considered as the most characteristic fossils of the Cam- 
 brian period, the more so as the Cambrian species belong to 
 peculiar types, which, for the most part, died out before the 
 commencement of the Silurian epoch. 
 
 All the remaining Cambrian fossils which demand any notice 
 here are members of one or other division of the great class 
 of the Mollusca, or " Shell-fish " properly so called. In the 
 Lower Cambrian Rocks the Lamp-shells (Brachiopoda) are the 
 principal or sole representatives of the class, and appear chiefly 
 in three interesting and important types namely, Lingiddla, 
 Distinct, and Obolella. Of these the last (fig. 32, /') is highly 
 characteristic of these ancient deposits ; whilst Discina is one 
 of those remarkable persistent types which, commencing at 
 this early period, has continued to be represented by varying 
 forms through all the intervening geological formations up to 
 the present day. Lingulclla (fig. 32, c], again, is closely allied 
 to the existing " Goose-bill " Lamp-shell (Lingula anatina), and 
 thus presents us with another example of an extremely long-
 
 88 
 
 HISTORICAL PALEONTOLOGY. 
 
 Jived type. The Lingulellce and their successors, the Lingulce, 
 are singular in possessing a shell which is of a horny texture, 
 and contains but a small proportion of calcareous matter. In 
 the Upper Cambrian Rocks, the Lingulellce become much more 
 abundant, the broad satchel - shaped species kjjown as L. 
 Davisii (fig. 32, e) being so abundant that one of the great 
 divisions of the Cambrian is termed the " Lingula Flags." 
 Here, also, we meet for the first time with examples of the 
 genus Orthis (fig. 32, f, k, 1} a characteristic Palaeozoic type of 
 
 Fig. 32. Cambrian Fossils: a, Protospoiigiafenestrata, Menevian Group; 6, At 
 colitesdidymus, Longmynd Group ; c, Lingiilella ferruginea, Longmynd and ] 
 nlarged ; d, Hymenocaris vermicanda, Lingula Flags; e, Lingulella Davisii, Lingula 
 
 Menevian, 
 
 Flags;/; Ortkis lenticularis, Lingula Flags; g, Theca David ii, Tremadoc Slates; A, 
 Modiolopsis Solvensis, Tremadoc Slates; i, Obolella sagittalis, interior of valve, Mene- 
 vian ; j, Exterior of the same ; k, Orthis Hicksii, Menevian ; /, Cast of the same ; /, 
 O.'enus micrurus, Lingula Flags. (Alter Salter, Hicks, and Davidson..) 
 
 the Brachiopods, which is destined to undergo a vast extension 
 in later ages. 
 
 Of the higher groups of the Mollusca the record is as yet 
 but scanty. In the Lower Cambrian, we have but the thin, 
 fragile, dagger -shaped shells of the free -swimming oceanic 
 Molluscs or "Winged-snails" (Pteropoda), of which the most 
 characteristic is the genus Theca (fig. 32,^). In the Upper 
 Cambrian, in addition to these, we have a few Univalves 
 (Gasteropoda), and, thanks to the researches of Dr Hicks, 
 quite a small assemblage of Bivalves (Lamdhbranchiatd), 
 though these are mostly of no great dimensions (fig. 32, h). 
 Of the chambered Cephalopoda (Cuttle-fishes and their allies),
 
 THE CAMBRIAN PERIOD. 
 
 8 9 
 
 
 we have but few traces, and these wholly confined to the higher 
 beds of the formation. We meet, however, with examples of 
 the wonderful genus OrtJioceras, with its 
 straight, partitioned shell, which we shall 
 find in an immense variety of forms in the 
 Silurian rocks. Lastly, it is worthy of 
 note that the lowest of all the groups of 
 the Mollusca namely, that of the Sea- 
 mats, Sea-mosses, and Lace-corals (Poly- 
 zoo] is only doubtfully known to have 
 any representatives in the Cambrian, 
 though undergoing a large and varied 
 development in the Silurian deposits. 
 
 An exception, however, may with much 
 probability be made to this statement in F ; g 33 ._ Fragment of 
 favour of the singular genus Dictyonema Dktymuntasociaie,c- 
 
 . r * . . . . , . . , , . . - siderably enlarged, show- 
 
 (ng. 33), WhlCU IS highly Characteristic Ot ing the horny branches, 
 
 the highest Cambrian beds (Tremadoc ^^^1^-?^* 
 Slates). This curious fossil occurs in the of ceils on each side. 
 form of fan-like or funnel-shaped expan- 
 sions, composed of slightly-diverging horny branches, which 
 are united in a net-like manner by numerous delicate cross- 
 bars, and exhibit a row of little cups or cells, in which the ani- 
 mals were contained, on each side. Dictyonema has generally 
 been referred to the Graptolites ; but it has a much greater 
 affinity with the plant-like Sea-firs (Sertnlarians) or the Sea- 
 mosses (Polyzoa), and the balance of evidence is perhaps in 
 favour of placing it with the latter. 
 
 LITERATURE. 
 
 The following are the more important and accessible works and memoirs 
 hich rr 
 gical rel; 
 
 which may be consulted in studying the stratigraphical and pakeontolo- 
 elations of the Cambrian Rocks : 
 
 (1) 'Siluria.' Sir Roderick Murchison. 5th ed., pp. 21-46. 
 
 (2) 'Synopsis of the Classification of the British Palaeozoic Rocks.' 
 
 Sedgwick. Introduction to the 3d Fasciculus of the 'Descrip- 
 tions of British Palaeozoic Fossils in the Woodwardian Museum,' 
 by F. M'Coy, pp. i-xcviii, 1855. 
 
 (3) ' Catalogue of the Cambrian and Silurian Fossils in the Geological 
 
 Museum of the University of Cambridge.' Salter. With a Pref- 
 ace by Prof. Sedgwick. 1873. 
 
 (4) 'Thesaurus Siluricus.' Bigsby. 1868. 
 
 (5) " History of the Names Cambrian and Silurian." Sterry Hunt. 
 
 'Geological Magazine.' 1873. 
 
 (6) 'Systeme Silurien du Centre de la Boheme.' Barrande. Vol. I. 
 
 (7) ' Report of Progress of the Geological Survey of Canada, from its 
 
 Commencement to 1863,' pp. 87-109.
 
 90 HISTORICAL PALAEONTOLOGY. 
 
 (8) 'Acadian Geology.' Dawson. Pp. 641-657. 
 
 (9) " Guide to the Geology of New York," Lincklaen ; and "Contribu- 
 
 tions to the Palaeontology of New York," James Hall. ' Four- 
 teenth Report on the State Cabinet.' 1861. 
 
 (10) ' Palaeozoic Fossils of Canada.' Billings. 1865. 
 
 (11) 'Manual of Geology.' Dana. Pp. 166-182. 2d ed. 1875. 
 
 (12) "Geology of North Wales," Ramsay; with Appendix on the 
 
 Fossils, Salter. 'Memoirs of the Geological Survey of Great 
 Britain,' vol. iii. 1 866. 
 
 (13) " On the Ancient Rocks of the St David's Promontory, South Wales, 
 
 and their Fossil Contents." Harkness and Hicks. 'Quart. 
 
 Journ. Geol. Soc.,' xxvii. 384-402. 1871. 
 n the Tre 
 
 (14) "On the Tremadoc Rocks in the Neighbourhood of St David's, 
 South Wales, and their Fossil Contents." Hicks. 'Quart. 
 Journ. Geol. Soc.,' xxix. 39-52. 1873. 
 
 In the above list, allusion has necessarily been omitted to numerous 
 works and memoirs on the Cambrian deposits of 'Sweden and Norway, 
 Central Europe, Russia, Spain, and various parts of North America, as 
 well as to a number of important papers on the British Cambrian strata by 
 various well-known observers. Amongst these latter may be mentioned 
 memoirs by Prof. Phillips, and Messrs Salter, Hicks, Belt, Plant, Horn- 
 fray, Ash, Holl, &c. 
 
 CHAPTER IX. 
 THE LOWER SILURIAN PERIOD. 
 
 The great system of deposits to which Sir Roderick Murchi- 
 son applied the name of * Silurian Rocks " reposes directly 
 upon the highest Cambrian beds, apparently without any 
 marked unconformity, though with a considerable change in 
 the nature of the fossils. The name "Silurian" was originally 
 proposed by the eminent geologist just alluded to for a great 
 series of strata lying below the Old Red Sandstone, and occu- 
 pying districts in Wales and its borders which were at one 
 time inhabited by the "Silures," a tribe of ancient Britons. 
 Deposits of a corresponding age are now known to be largely 
 developed in other parts of England, in Scotland, and in Ire- 
 land, in North America, in Australia, in India, in Bohemia, 
 Saxony, Bavaria, Russia, Sweden and Norway, Spain, and in 
 various other regions of less note. In some regions, as in the 
 neighbourhood of St Petersburg, the Silurian strata are found 
 not only to have preserved their original horizontally, but also 
 to have retained almost unaltered their primitive soft and inco- 
 herent nature. In other regions, as in Scandinavia and many
 
 THE LOWER SILURIAN PERIOD. 9! 
 
 parts of North America, similar strata, now consolidated into 
 shales, sandstones, and limestones, may be found resting with 
 a very slight inclination on still older sediments. In a great 
 many regions, however, the Silurian deposits are found to have 
 undergone more or less folding, crumpling, and dislocation, 
 accompanied by induration and " cleavage " of the finer and 
 softer sediments ; whilst in some regions, as in the Highlands 
 of Scotland, actual " metamorphism " has taken place. In 
 consequence of the above, Silurian districts usually present 
 the bold, rugged, and picturesque outlines which are char- 
 acteristic of the older "Primitive" rocks of the earth's crust in 
 general. In many instances, we find Silurian strata rising into 
 mountain-chains of great grandeur, and sublimity, exhibiting 
 the utmost diversity of which rock-scenery is capable, and de- 
 lighting the artist with endless changes of valley, lake, and 
 cliff. Such districts are little suitable for agriculture, though this 
 is often compensated for by the valuable mineral products con- 
 tained in the rocks. On the other hand, when the rocks are 
 tolerably soft and uniform in their nature, or when few disturb- 
 ances of the crust of the earth have taken place, we may find 
 Silurian areas to be covered with an abundant pasturage or to 
 be heavily timbered. 
 
 Under the head of "Silurian Rocks," Sir Roderick Murchi- 
 son included all the strata between the summit of the "Long- 
 mynd " beds and the Old Red Sandstone, and he divided these 
 into the two great groups of the Lower Silurian and Upper Silu- 
 rian. It is, however, now generally admitted that a considerable 
 portion of the basement beds of Murchison's Silurian series 
 must be transferred if only upon palasontological grounds to 
 the Upper Cambrian, as has here been done; and much contro- 
 versy has been carried on as to the proper nomenclature of the 
 Upper Silurian and of the remaining portion of Murchison's 
 Lower Silurian. Thus, some would confine the name "Silu- 
 rian" exclusively to the Upper Silurian, and would apply the 
 name of " Cambro-Silurian " to the Lower Silurian, or would 
 include all beds of the latter age in the " Cambrian " series of 
 Sedgwick. It is not necessary to enter into the merits of these 
 conflicting views. For our present purpose, it is sufficient to 
 recognise that there exist two great groups of rocks between 
 the highest Cambrian beds, as here defined, and the base of 
 the Devonian or Old Red Sandstone. These two great groups 
 are so closely allied to one another, both physically and palre- 
 ontologically, that many authorities have established a third 
 or intermediate group (the " Middle Silurian "), by which a pas-
 
 92 HISTORICAL PALAEONTOLOGY. 
 
 sage is made from one into the other. This method of pro- 
 cedure involves disadvantages which appear to outweigh its 
 advantages ; and the two groups in question are not only gen- 
 erally capable of very distinct stratigraphical separation, but at 
 the same time exhibit, together with the alliances above spoken 
 of, so many and such important palaeontological differences, 
 that it is best to consider them separately. We shall there- 
 fore follow this course in the present instance ; and pending 
 the final solution of the controversy as to Cambrian and Silu- 
 rian nomenclature, we shall distinguish these two groups of 
 strata as the " Lower Silurian " and the " Upper Silurian." 
 
 The Lower Silurian Rocks are known already to be devel- 
 oped in various regions; and though their general succession 
 in these areas is approximately the same, each area exhibits 
 peculiarities of its own, whilst the subdivisions of each are 
 known by special names. All, therefore, that can be attempted 
 here, is to select two typical areas such as Wales and North 
 America and to briefly consider the grouping and divisions 
 of the Lower Silurian in each. 
 
 In Wales, the line between the Cambrian and Lower Silurian 
 is somewhat ill-defined, arid is certainly not marked by any 
 strong unconformity. There are, however, grounds for accept- 
 ing the line proposed, for palseontological reasons, by Dr 
 Hicks, in accordance with which the Tremadoc Slates ("Lower 
 Tremadoc" of Salter) become the highest of the Cambrian 
 deposits of Britain. If we take this view, the Lower Silurian 
 rocks of Wales and adjoining districts are found to have the 
 following general succession from below upwards (fig. 34) : 
 
 1. The Arenig Group. This group derives its name from 
 the Arenig mountains, where it is extensively developed. It 
 consists of about 4000 feet of slates, shales, and flags, and is 
 divisible into a lower, middle, and upper division, of which the 
 former is often regarded as Cambrian under the name of 
 " Upper Tremadoc Slates." 
 
 2. The Llandeilo Group. The thickness of this group varies 
 from about 4000 to as much as 10,000 feet; but in this latter 
 case a great amount of the thickness is made up of volcanic 
 ashes and interbedded traps. The sedimentary beds of this 
 group are principally slates and flags, the latter occasionally 
 with calcareous bands ; and the whole series can be divided 
 into a lower, middle, and upper Llandeilo division, of which 
 the last is the most important. The name of " Llandeilo" is 
 derived from the town of the same name in Wales, where strata 
 of this age were described by Murchison.
 
 THE LOWER SILURIAN PERIOD. 93 
 
 3. The Caradoc or Bala Group. The alternative names of 
 this group are also of local origin, and are derived, the one 
 from Caer Caradoc in Shropshire, the other from Bala in Wales, 
 strata of this age occurring in both localities. The series is 
 divided into a lower and upper group, the latter chiefly com- 
 posed of shales and flags, and the former of sandstones and 
 shales, together with the important and interesting calcareous 
 band known as the " Bala Limestone." The thickness of the 
 entire series varies from 4000 to as much as 12,000 feet, ac- 
 cording as it contains more or less of interstratified igneous 
 rocks. 
 
 4. The Llandovery Group (Lower Llandovery of Murchison). 
 This series, as developed near the town of Llandovery, in 
 Caermarthenshire, consists of less than 1000 feet of conglom- 
 erates, sandstones, and shales. It is probable, however, that 
 the little calcareous band known as the " Hirnant Limestone," 
 together with certain pale-coloured slates which lie above the 
 Bala Limestone, though usually referred to the Caradoc series, 
 should in reality be regarded as belonging to the Llandovery 
 group. 
 
 The general succession of the Lower Silurian strata of Wales 
 and its borders, attaining a maximum thickness (along with 
 contemporaneous igneous matter) of nearly 30,000 feet, is 
 diagramatically represented in the annexed sketch-section 
 (fig- 34):- 
 
 [GENERALISED SECTION
 
 94 
 
 HISTORICAL PALEONTOLOGY. 
 
 GENERALISED SECTION OF THE LOWER SILURIAN ROCKS 
 OF WALES. 
 
 Fig- 34- 
 
 ( May Hill Sandstone (base 
 ( of Upper Silurian). 
 
 Llandovery Group. 
 
 Upper Bala. 
 
 Lower Bala. 
 
 Upper Llandeilo. 
 
 Middle Llandeilo. 
 
 Lower Llandeilo. 
 
 Upper Arenig. 
 
 . Middle Arenig. 
 
 Lower Arenig (Upper 
 Tremadoc Group). 
 
 Tremadoc Slates (Lower 
 Tremadoc Group). 
 
 In North America, both in the United States and in Can- 
 ada, the Silurian rocks are very largely developed, and may be
 
 THE LOWER SILURIAN PERIOD. 95 
 
 regarded as constituting an exceedingly full and typical series 
 of the deposits of this period. The chief groups of the Silurian 
 rocks of North America are as follows, beginning, as before,' 
 with the lowest strata, and proceeding upwards (fig. 35) : 
 
 1. Quebec Group. This group is typically developed in 
 the vicinity of Quebec, where it consists of about 5000 feet of 
 strata, chiefly variously - coloured shales, together with some 
 sandstones and a few calcareous bands. It contains a number 
 of peculiar Graptolites, by which it can be identified without 
 question with the Arenig group of Wales and the correspond- 
 ing Skiddaw Slates of the North of England. It is also to be 
 noted that numerous Trilobites of a distinct Cambrian fades 
 have been obtained in the limestones of the Quebec group, 
 near Quebec. These fossils, however, have been exclusively 
 obtained from the limestones of the group ; and as these lime- 
 stones are principally calcareous breccias or conglomerates, 
 there is room for believing that these primordial fossils are 
 really derived, in part at any rate, from fragments of an upper 
 Cambrian limestone. In the State of New York, the Grapto- 
 litic shales of Quebec are wanting ; and the base of the Silurian 
 is constituted by the so-called " Calciferous Sand-rock " and 
 " Chazy Limestone."* The first of these is essentially and 
 typically calcareous, and the second is a genuine limestone. 
 
 2. The Trenton Group. This is an essentially calcareous 
 group, the various limestones of which it is composed being 
 known as the " Bird's-eye," " Black River," and " Trenton " 
 Limestones, of which the last is the thickest and most import- 
 ant. The thickness of this group is variable, and the bands of 
 limestone in it are often separated by beds of shale. 
 
 3. The Cincinnati Group (Hudson River Formation t). 
 This group consists essentially of a lower series of shales, often 
 black in colour and highly charged with bituminous matter 
 (the " Utica Slates "), and of an upper series of shales, sand- 
 
 * The precise relations of the Quebec shales with Graptolites (Levis 
 Formation) to the Calciferous and Chazy beds are still obscure, though 
 there seems little doubt but that the Quebec Shales are superior to the 
 Calciferous Sand-rock. 
 
 t There is some difficulty about the precise nomenclature of this group. 
 It was originally called the "Hudson River Formation; " but this name 
 is inappropriate, as rocks of this age hardly touch anywhere the actual 
 Hudson River itself, the rocks so called formerly being now known to be 
 of more ancient date. There is also some want of propriety in the name of 
 "Cincinnati Group," since the rocks which are known under this name in 
 the vicinity of Cincinnati itself are the representatives of the Trenton 
 Limestone, Utica Slates, and the old Hudson River group, inseparably 
 united in what used to be called the "Blue Limestone Series."
 
 9 6 
 
 HISTORICAL PALEONTOLOGY. 
 
 stones, and limestones (the " Cincinnati" rocks proper). The 
 exact parallelism of the Trenton and Cincinnati groups with 
 the subdivisions of the Welsh Silurian series can hardly be 
 stated positively. Probably no precise equivalency exists; 
 but there can be no doubt but that the Trenton and Cincin- 
 nati groups correspond, as a whole, with the Llandeilo and 
 Caradoc groups of Britain. The subjoined diagrammatic 
 section (fig. 35) gives a general idea of the succession of the 
 Lower Silurian rocks of North America : 
 
 GENERALISED SECTION OF THE LOWER SILURIAN ROCKS 
 OF NORTH AMERICA. 
 
 Fig. 35- 
 
 Medina Sandstone (base of 
 Upper Silurian). 
 
 Cincinnati Group proper. 
 
 Ulica Slates. 
 -Trenton Limestone. 
 
 Black River Limestone. 
 
 Bird's-eye Limestone. 
 
 Chazy Limestone. 
 
 Quebec Shales (Levis Beds). 
 
 Calcifcrous Sand-rock. 
 Potsdam Sandstone.
 
 THE LOWER SILURIAN PERIOD. 
 
 97 
 
 Of the life of the Lower Silurian period we have record in a 
 vast number of fossils, showing that the seas of this period 
 were abundantly furnished- with living denizens. We have, 
 however, in the meanwhile, no knowledge of the land-surfaces 
 of the period. We have therefore no means of speculating 
 as to the nature of the terrestrial animals of this ancient age, 
 nor is anything known with certainty of any land-plants which 
 may have existed. The only relics of vegetation upon which 
 a positive opinion can be expressed belong to the obscure 
 group of the " Fucoids," and are supposed to be the remains 
 of sea-weeds. Some of the fossils usually placed under this 
 head are probably not of a vegetable nature at all, but others 
 
 Fig. 36. Licrophycits Ottaivciensis, a " Fucoid," from the Trentou Limestone 
 (.Lower Silurian) of Canada. (After Billings.) 
 
 ( n g- 36) appear to be unquestionable plants. The true affin- 
 ities of these, however, are extremely dubious. All that can 
 be said is, that remains which appear to be certainly vegetable,
 
 9 3 
 
 HISTORICAL PALAEONTOLOGY. 
 
 and which are most probably due to marine plants, have been 
 recognised nearly at the base of the Lower Silurian (Arenig), 
 and that they are found throughout the series whenever suitable 
 conditions recur. 
 
 The Protozoans appear to have flourished extensively in the 
 Lower Silurian seas, though to a large extent under forms 
 which are still little understood. We have here for the first 
 time the appearance of Foraminifera of the ordinary type one 
 of the most interesting observations in this connection being 
 that made by Ehrenberg, who showed that the Lower Silurian 
 sandstones of the neighbourhood of St Petersburg contained 
 casts in glauconite of Foraminiferous shells, some of which are 
 referable to the existing genera Rotalia and Textularia. True 
 Sponges, belonging to that section of the group in which the 
 skeleton is calcareous, are also not unknown, one of the most 
 characteristic genera being As- 
 tylospongia (fig. 37). In this 
 genus are included more or less 
 globular, often lobed sponges, 
 which are believed not to have 
 been attached toforeign bodies. 
 In the form here figured there 
 is a funnel-shaped cavity at the 
 summit; and the entire mass of 
 the sponge is perforated, as in 
 living examples, by a system 
 of canals which convey the 
 sea-water to all parts of the 
 organism. The canals by 
 which the sea-water gains en- 
 trance open on the exterior of 
 the sphere, and those by which 
 it again escapes from the sponge open into the cup-shaped 
 depression at the summit. 
 
 The most abundant, and at the same time the least under- 
 stood, of Lower Silurian Protozoans belong, however, to the 
 genera Slromatopora and Reccptacitlitcs, the structure of which 
 can merely be alluded to here. The specimens of Stromato- 
 pora (fig. 38) occur as hemispherical, pear-shaped, globular, or 
 irregular masses, often of very considerable size, and some- 
 times demonstrably attached to foreign bodies. In their struc- 
 ture these masses consist of numerous thin calcareous laminae, 
 usually arranged concentrically, and separated by narrow 
 interspaces. These interspaces are generally crossed by 
 numerous vertical calcareous pillars, giving the vertical section 
 
 Fig- 37- Astylospongia priemorsa, cut 
 vertically so as to exhibit the canal-system 
 in the interior. Lower Silurian, Tennessee. 
 (After Ferdinand Roemer.)
 
 THE LOWER SILURIAN PERIOD. 99 
 
 of the fossil a lattice-like appearance. There are also usually 
 minute pores in the concentric laminae, by which the successive 
 
 Fig. 38. A small and perfect specimen of Stromatopora. mgosa, of the natural 
 size, from the Trenton Limestone of Canada. (After Billings.) 
 
 interspaces are placed in communication ; and sometimes the 
 surface presents large rounded openings, which appear to corre- 
 spond with the water-canals of the Sponges. Upon the whole, 
 though presenting some curious affinities to the calcareous 
 Sponges, Stromatopora is perhaps more properly regarded as 
 a gigantic Foraminifer. If this view be correct, it is of special 
 interest as being probably the nearest ally of Eozoon, the 
 general appearance of the two being strikingly similar, though 
 their minute structure is not at all the same. Lastly, in the 
 fossils known as Receptaculites and Ischadites we are also pre- 
 sented with certain singular Lower Silurian Protozoans, which 
 may with great probability be regarded as gigantic Forami- 
 nifera. Their structure is very complex; but fragments are 
 easily recognised by the fact that the exterior is covered with 
 numerous rhomboidal calcareous plates, closely fitting together, 
 and arranged in peculiar intersecting curves, presenting very 
 much the appearance of the engine-turned case of a watch. 
 
 Passing next to the sub-kingdom of Ccelenterate animals 
 (Zoophytes, Corals, &c.), we find that this great group, almost 
 or wholly absent in the Cambrian, is represented in Lower
 
 IOO HISTORICAL PALAEONTOLOGY. 
 
 Silurian deposits by a great number of forms belonging on the 
 one hand to the true Corals, and on the other hand to the 
 singular family of the Graptolites. If we except certain plant- 
 like fossils which probably belong rather to the Sertularians 
 or the Polyzoans (e.g., Dictyonema, Dendrograptus, &c.), the 
 family of the Graptolites may be regarded as exclusively 
 Silurian in its distribution. Not only is this the case, but it 
 attained its maximum development almost upon its first ap- 
 pearance, in the Arenig Rocks ; and whilst represented by a 
 great variety of types in the Lower Silurian, it only exists in 
 the Upper Silurian in a much diminished form. The Grap- 
 tolites (Gr. grapho, I write ; lithos, stone) were so named by 
 Linnaeus, from the resemblance of some of them to written or 
 pencilled marks upon the stone, though the great naturalist him- 
 self did not believe them to be true fossils at all. They occur 
 as linear or leaf-like bodies, sometimes simple, sometimes com- 
 pound and branched ; and no doubt whatever can be enter- 
 tained as to their being the skeletons of composite organisms, 
 or colonies of semi-independent animals united together by 
 a common fleshy trunk, similar to what is observed in the 
 colonies of the existing Sea-firs (Sertularians). This fleshy- 
 trunk or common stem of the colony was protected by a deli- 
 cate horny sheath, and it gave origin to the little flower-like 
 " polypites," which constituted the active element of the whole 
 assemblage. These semi-independent beings were, in turn, 
 protected each by a little horny cup or cell, directly connected 
 with the common sheath below, and terminating above in an 
 opening through which the polypite could protrude its tentacled 
 head or could again withdraw itself for safety. The entire 
 skeleton, again, was usually, if not universally, supported by 
 a delicate horny rod or "axis," which appears to have been 
 hollow, and which often protrudes to a greater or less extent 
 beyond one or both of the extremities of the actual colony. 
 
 The above gives the elementary constitution of any Grapto- 
 ///<?, but there are considerable differences as to the manner in 
 which these elements are arranged and combined. In some 
 forms the common stem of the colony gives origin to but a 
 single row of cells on one side. If the common stem is a 
 simple, straight, or slightly-curved linear body, then we have 
 the simplest form of Graptolite known (the genus Monograptus)\ 
 and it is worthy of note that these simple types do not come 
 into existence till comparatively late (Llandeilo), and last 
 nearly to the very close of the Upper Silurian. In other 
 cases, whilst there is still but a single row of cells, the colony 
 may consist of two of these simple stems springing from a
 
 THE LOWER SILURIAN PERIOD. 
 
 101 
 
 common point, as in the so-called " twin Graptolites " (Didy- 
 mograptus, fig. 40). This type is entirely confined to the earlier 
 
 portion of the Lower Silu- 
 rian period (Arenig arid 
 Llandeilo). In other cases, 
 again, there may be four 
 of such stems springing 
 from a central point ( Tet- 
 ragraptus). Lastly, there 
 are numerous complex 
 forms (such as Dichograp- 
 tus, Loganograptus, &c.) in 
 which there are eight or 
 more of these simple bran- 
 ches, all arising from a 
 common centre (fig. 39), 
 which is sometimes fur- 
 nished with a singular 
 horny disc. These com- 
 plicated branching forms, 
 as well as the Tftragrapti, 
 are characteristic of the 
 horizon of the Arenig 
 group. Similar forms, of- 
 ten specifically identical, 
 
 Fig. 39. Dichflgrafitrts octobrachiattis, a branched, "unicellular" Graptolite from 
 the'Slciddaw and Quebec Groups (Arenig}. (After Hall.) 
 
 are found at this horizon in Wales, in the great series of the 
 Skiddaw Slates of the north of England, in the Quebec group 
 in Canada, in equivalent beds in Sweden, and in certain gold- 
 bearing slates of the same age in Victoria in Australia. 
 
 In another great group of Graptolites (including the genera 
 Diplograptus, Dicranograpfus, Cltniacograptus^c.} the common 
 stem of the colony gives origin, over part or the whole of its 
 length, to two rows of cells, one on each side (fig. 41). These 
 double-celled " Graptolites are highly characteristic of the 
 Lower Silurian deposits ; and, with an exception more appa-
 
 102 
 
 HISTORICAL PALEONTOLOGY. 
 
 rent than real in Bohemia, they are exclusively confined to 
 strata of Lower Silurian age, and are not known to occur in 
 
 Fig. 40. Central portion of the colony of Didyttirgraptiis divaricatus, Upper 
 Llandeilo, Dumfriesshire. (Original.) 
 
 the Upper Silurian. Lastly, there is a group of Graptolites 
 (Phyllograptus, fig. 42) in which the colony is leaf-like in form, 
 
 m 
 
 Fig. 41. Example 
 pristis, showing variations in the appen- 
 dages at the base. Upper Llandeilo, 
 Dumfriesshire. (Original.) 
 
 Fig. 42. Group of individuals of Phyllo- 
 graphts typns, from the Quebec group of 
 Canada. (After Hall.) One of the four rows 
 of cells is hidden on the under surface. 
 
 and is composed of fjur rows of cells springing in a cross-like
 
 THE LOWER SILURIAN PERIOD. 103 
 
 manner from the common stem. These forms are highly char- 
 acteristic of the Arenig group. 
 
 The Graptolites are usually found in dark-coloured, often 
 black shales, which sometimes contain so much carbon as to 
 become " anthracitic." They may be simply carbonaceous; 
 but they are more commonly converted into iron-pyrites, when 
 they glitter with the brilliant lustre of silver as they lie scattered 
 on the surface of the rock, fully deserving in their metallic 
 tracery the name of "written stones." They constitute one 
 of the most important groups of Silurian fossils, and are of the 
 greatest value in determining the precise stratigraphical posi- 
 tion of the beds in which they occur. They present, however, 
 special difficulties in their study ; and it is still a moot point as 
 to their precise position in the zoological scale. The balance 
 of evidence is in favour of regarding them as an ancient and 
 peculiar group of the Sea-firs (Hydroid Zoophytes), but some 
 regard them as belonging rather to the Sea-mosses (Poly zoo). 
 Under any circumstances, they cannot be directly compared 
 either with the ordinary Sea-firs or the ordinary Sea-mosses ; 
 for these two groups consist of fixed organisms, whereas the 
 Graptolites were certainly free - floating creatures, living at 
 large in the open sea. The only Hydroid Zoophytes or Poly- 
 zoans which have a similar free mode of existence, have either 
 no skeleton at all, or have hard structures quite unlike the 
 horny sheaths of the Graptolites. 
 
 The second great group of Ccelenterate animals (Actinozod) 
 is represented in the Lower Silurian rocks by numerous 
 Corals. These, for obvious reasons, are much more abundant 
 in regions where the Lower Silurian series is largely calcareous 
 (as in North America) than in districts like Wales, where 
 limestones are very feebly developed. The Lower Silurian 
 Corals, though the first of their class, and presenting certain 
 peculiarities, may be regarded as essentially similar in nature 
 to existing Corals. These, as is well known, are the calcareous 
 skeletons of animals the so - called " Coral - Zoophytes " 
 closely allied to the common Sea-anemones in structure and 
 habit. A simple coral (fig. 43) consists of a calcareous cup 
 embedded in the soft tissues of the flower-like polype, and hav- 
 ing at its summit a more or less deep depression (the " calice ") 
 in which the digestive organs are contained. The space within 
 the coral is divided into compartments by numerous vertical 
 calcareous plates (the "septa"), which spring from the inside 
 of the wall of the cup, and of which some generally reach the 
 centre. Compound corals, again (fig. 44), consist of a greater 
 or less number of structures similar in structure to the above,
 
 IO4 
 
 HISTORICAL PALEONTOLOGY. 
 
 but united together in different ways into a common mass. 
 Simple corals, therefore, are the skeletons of single and inde- 
 
 Fig. 43. Zaphrentis Siokcsi. a simple Fig. 44. Upper surface of a mass of 
 
 "cup-coral," Upper Silurian, Canada. (After Strcjitbcc/es pentagonus, Upper Silurian, 
 Billings.) Canada. (After Billings.) 
 
 pendent polypes ; whilst compound corals are the skeletons of 
 assemblages or colonies of similar polypes, living united with 
 one another as an organic community. 
 
 In the general details of their structure, the Lower Silurian 
 Corals do not differ from the ordinaiy Corals of the present 
 day. The latter, however, have the vertical calcareous plates 
 of the coral (" septa ") arranged in multiples of six or five ; 
 whereas the former have these structures arranged in multiples 
 of four, and often showing a cross-like disposition. For this 
 reason, the common Lower Silurian Corals are separated to 
 form a distinct group under the name of Rugose Corals or 
 Rugosa. They are further distinguished by the fact that the 
 cavity of the coral (" visceral chamber ") is usually subdivided 
 by more or less numerous horizontal calcareous plates or 
 partitions, which divide the coral into so many tiers or storeys, 
 and which are known as the "tabulae" (fig. 45). 
 
 In addition to the Rugose Corals, the Lower Silurian rocks 
 contain a number of curious compound corals, the tubes 
 of which have either no septa at all or merely rudimentary 
 ones, but which have the transverse partitions or " tabulae " 
 very highly developed. These are known as the Tabulate 
 Corals ; and recent researches on some of their existing allies 
 (such as Hdicpora} have shown that they are really allied to
 
 THE LOWER SILURIAN PERIOD. IO5 
 
 the modern Sea-pens, Organ-pipe Corals, and Red Coral, 
 rather than to the typical stony Corals. Amongst the charac- 
 
 Fig. 45. Columnaria alveolate, a Rugose compound coral, with imperfect septa, but 
 having the corallites partitioned off into storeys by " tabulae." Lower Silurian, Canada. 
 (After Billings.) 
 
 teristic Rugose Corals of the Lower Silurian maybe mentioned 
 species belonging to the genera Coliimnaria, Favistella, Strep- 
 telasma, and Zaphrentis ; whilst amongst the " Tabulate " 
 Corals, the principal forms belong to the genera Chcetetes, 
 Halysites (the Chain-coral), Constellaria, and Heliolites. These 
 groups of the Corals, however, attain a greater development 
 at a later period, and they will be noticed more particularly 
 hereafter. 
 
 Passing on to higher animals, we find that the class of the 
 Echinoderinata is represented by example^ of the Star-fishes 
 (Asteroidea), the Sea-lilies (Crinoidea), and the peculiar extinct 
 group of the Cystideans (Cystoidea), with one or two of the 
 Brittle-stars ( Ophiuroidea) the Sea-urchins (Echinoidea) being 
 still wanting. The Crinoids, though in some places extremely 
 numerous, have not the varied development that they possess 
 in the Upper Silurian, in connection with which their structure 
 will be more fully spoken of. In the meanwhile, it is sufficient 
 to note that many of the calcareous deposits of the Lower 
 Silurian are strictly entitled to the name of " Crinoidal lime- 
 stones/' being composed in great part of the detached joints, 
 and plates, and broken stems, of these beautiful but fragile 
 organisms (see fig. 12). Allied to the Crinoids are the singular 
 creatures which are known as Cystideans (fig. 46). These are 
 generally composed of a globular or ovate body (the " calyx "), 
 supported upon a short stalk (the " column ") ; by which the 
 organism was usually attached to some foreign body. The 
 body was enclosed by closely-fitting calcareous plates, accu-
 
 io6 
 
 HISTORICAL PALEONTOLOGY. 
 
 rately jointed together ; and the stem was made up of numerous 
 distinct pieces or joints, flexibly united to each other by mem- 
 
 Fig. 46. Group of Cystideans. A, Caryocrinns ornatus pper ua 
 B, Pleiirocystites squfimosus, showing two short "arms," Lower Silurian, Canada; C, 
 Psendocrinns bifasciatus, Upper Silurian, England ; D, Lejxuiocrinns GMtanii, Upper 
 Silurian, America. (After Hall, Billings, and Salter.) 
 
 brane. The chief distinction which strikes one in comparing 
 the Cystideans with the Crinoids is, that the latter are always 
 furnished, as will be subsequently seen, with a beautiful crown 
 of branched and feathery appendages, springing from the sum- 
 mit of the calyx, and which are composed of innumerable 
 calcareous plates or joints, and are known as the "arms." In 
 the Cystideans, on the other hand, there are either no " arms " 
 at all, or merely short, unbranched, rudimentary arms. The 
 Cystideans are principally, and indeed nearly exclusively, 
 Silurian fossils ; and though occurring in the Upper Silurian 
 in no small numbers, they are pre-eminently characteristic of 
 the Llandeilo-Caradoc period of Lower Silurian time. They 
 commenced their existence, so far as known, in the Upper 
 Cambrian ; and though examples are not absolutely unknown 
 
 * The genus Caryocrinus is sometimes regarded as properly belonging 
 to the Crinoids, but there seem to be good reasons for rather considering 
 it as an abnormal form of Cystidean.
 
 THE LOWER SILURIAN PERIOD. 
 
 107 
 
 in later periods, they are pre-eminently characteristic of the 
 earlier portion of the Palaeozoic epoch. 
 
 The Ringed Worms (Annelides) are abundantly represented 
 in the Lower Silurian, but principally by tracks and burrows 
 similar in essential respects to those which occur so commonly 
 in the Cambrian formation, and calling for no special com- 
 ment. Much more important are the Articulate animals, rep- 
 resented, as heretofore, wholly by the remains of the aquatic 
 
 Fig. 47. Lower Silurian Crustaceans, a, Asa/thus tyranntts, Upper Llandeilo; />, 
 Ogygia Bnchii, Upper Llandeilo ; c, Trimidens conccntricus, Caradoc ; if, Carypcaris 
 H 'ris/iiii, Arenig (Skicldaw Slates) ; e, Beyrichia compUcata, natural size and enlarged. 
 Upper Llandeilo and Caradoc;/, Ptimitia stranmlata. Caradoc: , Head-shield of 
 Calymene Blumenbachii, var. brevicapitata, Caradoc ; h, Head-shield of Triarthnts 
 Becki (Utica Slates), United States ; i, Shield of Lefierditia Canadensis, var. Josef h- 
 ifina, of the natural size, Trenton Limestone, Canada ; /, The same, viewed from the 
 front. (After Salter, M'Coy, Rupert Jones, and Dana.) 
 
 group of the Crustaceans. Amongst these are numerous little 
 bivalved forms such as species Q{ Primitia (fig. 47, /), Bey-
 
 108 HISTORICAL PALEONTOLOGY. 
 
 richia (fig. 47, e), and Leperditia (fig. 47, /and _/). Most of 
 these are very small, varying from the size of a pin's head up 
 to that of a hemp seed ; but they are sometimes as large as 
 a small bean (fig. 47, /), and they are commonly found in 
 myriads together in the rock. As before said, they belong to 
 the same great group as the living Water-fleas (Ostracoda). 
 Besides these, we find the pod-shaped head-shields of the 
 shrimp-like Phyllopods such as Caryocaris (fig. 47, d) and 
 Ceratiocaris. More important, however, than any of these are 
 the Trilobites, which may be considered as attaining their maxi- 
 mum development in the Lower Silurian. The huge Paradoxides 
 of the Cambrian have .now disappeared, and with them almost 
 all the principal and characteristic " primordial " genera, save 
 Olenus and Agnostus. In their place we have a great number 
 of new forms some of them, like the great Asaphus tyrannus 
 of the Upper Llandeilo (fig. 47, ), attaining a length of a foot 
 or more, and thus hardly yielding in the matter of size to their 
 ancient rivals. Almost every subdivision of the Lower Silurian 
 series has its own special and characteristic species of Trilo- 
 bites ; and the study of these is therefore of great importance 
 to the geologist. A few widely-dispersed and characteristic 
 species have been here figured (fig. 47) ; and the following 
 may be considered as the principal Lower Silurian genera 
 Asaphus, Ogygia, Cheirurus, Ampyx, Catymeiie, Trinucleus, 
 Lichas, Illcenus, sEglina, Harpes, Remopknrides, Phacops, 
 Acidaspis, and Honialonotus, a few of them passing upwards 
 under new forms into the Upper Silurian. 
 
 Coming next to the Mollusca, we find the group of the Sea- 
 mosses and Sea-mats (Polyzoa) represented now by quite a 
 number of forms. Amongst these are examples of the true 
 Lace-corals (Retepora and Fenestella), with their netted fan-like 
 or funnel-shaped fronds ; and along with these are numerous 
 delicate encrusting forms, which grew parasitically attached to 
 shells and corals (Hippothoa, Alecto, &c.) ; but perhaps the 
 most characteristic forms belong to the genus Ptilodidya (figs. 
 48 and 49). In this group the frond is flattened, with thin 
 striated edges, sometimes sword-like or scimitar-shaped, but 
 often more or less branched ; and it consists of two layers of 
 cells, separated by a delicate membrane, and opening upon 
 opposite sides. Each of these little chambers or " cells " was 
 originally tenanted by a minute animal, and the whole thus 
 constituted a compound organism or colony. 
 
 The Lamp-shells or Brachiopods are so numerous, and pre- 
 sent such varied types, both in this and the succeeding period 
 of the Upper Silurian, that the name of " Age of Brachiopods"
 
 THE LOWER SILURIAN PERIOD. 
 
 109 
 
 has with justice been applied to the Silurian period as a whole. 
 It would be impossible here to enter into details as to the 
 
 Fig. 48. Ptilodictya falciformis. a, 
 Small specimen of the natural size ; b, 
 Cross-section, showing the shape of the 
 frond ; c, Portion of the surface, enlarged. 
 Trenton Limestone and Cincinnati Group, 
 America. (Original.) 
 
 Fig. 49.-A, Ptilodictya acnta ; B, Ptil- 
 odictya Schafferi. a, Fragment, of the 
 natural size ; b, Portion, enlarged to show 
 the cells. Cincinnati Group of Ohio and 
 Canada. (Original.) 
 
 many different forms of Brachiopods which present themselves 
 in the Lower Silurian deposits ; but we may select the three 
 genera Orthis, Strophomena, and Leptcena for illustration, as 
 being specially characteristic of this period, though not exclu- 
 
 Fig. 50. Lower Silurian Brachiopods. a and a', Orthis h'forata, Llandeilo-Caradoc, 
 Britain and America: b, Orthis Jlabelhiium. Caradoc, Britain : c. Orthis sitbqnadraia, 
 Cincinnati Group, America : c', Interior of the dorsal valve of the same; d, Stropho- 
 mena deltoidea, Llandeilo-Caradoc, Britain and America. (After Meek, Hall, and 
 Salter.) 
 
 sively confined to it. The numerous shells which belong to 
 the extensive and cosmopolitan genus Orthis (fig. 50, a, b, c,
 
 no 
 
 HISTORICAL PALEONTOLOGY. 
 
 and fig. 51, c and </), are usually more or less transversely- 
 oblong or subquadrate, the two valves (as more or less in all 
 
 Fig. 51. Lower Silurian Brachioppds. a, Strophomena alternnta, Cincinnati Group, 
 America ; b. Strophomena filitexta, Trenton and Cincinnati Groups, America ; c, Orthis 
 testudinaria, Caradoc, Kurope, and America ; d, d ', Orthis plicatella, Cincinnati 
 Group, America ; e, ^. e", Leptcena sericea, Llandeilo and Caradoc, Europe and Ame- 
 rica. (After Meek, Hall, and the Author.) 
 
 the Brachiopods) of unequal sizes, generally more or less con- 
 vex, and marked with radiating ribs or lines. The valves of 
 the shell are united to one another by teeth and sockets, and 
 there is a straight hinge-line. The beaks are also separated 
 by a distinct space (" hinge-area "), formed in part by each 
 valve, which is perforated by a triangular opening, through 
 which, in the living condition, passed a muscular cord attach- 
 ing the shell to some foreign object. The genus Strophomena 
 (fig. 50, d, and 51, a and />) is very like Orthis in general char- 
 acter ; but the shell is usually much flatter, one or other valve 
 often being concave, the hinge -line is longer, and the aperture 
 for the emission of the stalk of attachment is partially closed 
 by a calcareous plate. In Leptana, again (fig. 51, e), the shell 
 is like Strophomena in many respects, but generally compara- 
 tively longer, often completely semicircular, and having one 
 valve convex and the other valve concave. Amongst other 
 genera of Brachiopods which are largely represented in the 
 Lower Silurian rocks may be mentioned Lingula, Crania, 
 Discina, Trematis, Siphonotreta, Acrotrda, RhyncJionella, and 
 Athyris ; but none of these can claim the importance to which 
 the three previously-mentioned groups are entitled. 
 
 The remaining Lower Silurian groups of Mollusca can be 
 but briefly glanced at here. The Bivalves (Lamdlibranchiata) 
 find numerous representatives, belonging to such genera as
 
 THE LOWER SILURIAN PERIOD. 
 
 Ill 
 
 Modiolopsis, Ctenodonta, Orthonota, Palcearca, Lyrodesma, Am- 
 bonychia, and Cleidophorus. The Univalves (Gasteropoda) are 
 also very numerous, the two most important genera being 
 Murchisonia (fig. 52) and Pleurotomaria. In both these groups 
 the outer lip of the shell is notched ; but the shell 
 in the former is elongated and turreted, whilst in 
 the latter it is depressed. The curious oceanic 
 Univalves known as the Heteropods are also very 
 abundant, the principal forms belonging to Bel- 
 lerophon and Madurca. In the former (fig. 53) 
 there is a symmetrical convoluted shell, like that 
 of the Pearly Nautilus in shape, but without any 
 internal partitions, and having the aperture of- 
 ten expanded and notched behind. The species 
 of Madurea (fig. 54) are found both in North 
 America and in Scotland, and are exclusively 
 confined to the Lower Silurian period, so far 
 as known. They have the shell coiled into a 
 flat spiral, the mouth being furnished with a 
 very curious, thick, and solid lid or "opercu- 
 lum." The Lower Silurian Pteropods, or "Wing- 
 ed Snails," are numerous, and belong principally 
 to the genera Theca, Conularia, and Tentaculites, 
 the last-mentioned of these often being extremely abundant in 
 certain strata. 
 
 Lastly, the Lower Silurian Rocks have yielded a vast number 
 
 Fig. 52. Mur- 
 cliisonia gracilis, 
 Trenton Lime- 
 stone, America. 
 (After Billings.) 
 
 it views of Rellero/>hon Argo, Trenton Limestone, Canada. 
 (After Billings.) 
 
 of chambered shells, referable to animals which belong to the 
 same great division as the Cuttle-fishes (the Cephalopoda), and 
 of which the Pearly Nautilus is the only living representative at 
 the present day. In this group of Cephalopods the animal 
 possesses a well-developed external shell, which is divided 
 into chambers by shelly partitions ("septa"). The animal 
 lives in the last-formed and largest chamber of the shell, to
 
 112 HISTORICAL PALEONTOLOGY. 
 
 which it is organically connected by muscular attachments. 
 The head is furnished with long muscular processes or "arms/' 
 
 Fig. 54. Different views of Maclnrea crenulata, Quel>ec Group, Newfoundland. 
 (After Billings.) 
 
 and can be protruded from the mouth of the shell at will, or 
 again withdrawn within it. We learn, also, from the Pearly 
 Nautilus, that these animals must have possessed two pairs of 
 breathing organs or " gills ; " hence all these forms are grouped 
 together under the name of the " Tetrabranchiate " Cephalo- 
 pods (Gr. tetra, four; bragchia, gill). On the other hand, the 
 ordinary Cuttle-fishes and Calamaries either possess an internal 
 skeleton, or if they have an external shell, it is not chambered ; 
 their " arms " are furnished with powerful organs of adhesion 
 in ths form of suckers ; and they possess only a single pair of 
 gills. For this last reason they are termed the " Dibranchiate " 
 Cephalopods (Gr. dis, twice ; bragc/iia, gill). No trace of the 
 true Cuttle-fishes has yet been found in Lower Silurian deposits; 
 but the Tetrabranchiate group is represented by a great num- 
 ber of forms, sometimes of great size. The principal Lower 
 Silurian genus is the well-known and widely-distributed Ortho- 
 ceras (fig. 55). The shell in this genus agrees with that of the 
 existing Pearly Nautilus, in consisting of numerous chambers 
 separated by shelly partitions (or septa), the latter being per- 
 forated by a tube which runs the whole length of the shell 
 after the last chamber, and is known as the " siphuncle " (fig. 
 56, s). The last chamber formed is the largest, and in it the 
 animal lives. The chambers behind this are apparently filled 
 with some gas secreted by the animal itself; and these are sup- 
 posed to act as a kind of float, enabling the creature to move 
 with ease under the weight of its shell. The various air- 
 chambers, though the siphuncle passes through them, have no 
 direct connection with one another ; and it is believed that the 
 animal has the power of slightly altering its specific gravity, 
 and thus of rising or sinking in the water by driving additional 
 fluid into the siphuncle or partially emptying it. The Ortho-
 
 THE LOWER SILURIAN PERIOD. 113 
 
 ceras further agrees with the Pearly Nautilus in the fact that 
 the partitions or septa separating the different air-chambers are 
 
 Fig. 55. Fragment of OrtJwcerascrebri- Fig. 56. Restoration of Orthoceras, 
 
 septum, Cincinnati Group, North America, the shell being supposed to bedivided ver- 
 
 of the natural size. The lower figure is a tically, and only its upper part being 
 
 section showing the air-chambers, and the shown, a. Arms ; f, Muscular tube 
 
 form and position of the siphuncle. (After ("funnel") by which water is expelled 
 
 Billings) from the mantle-chamber; c, Air-cham- 
 bers ; s, Siphuncle. 
 
 simple and smooth, concave in front and convex behind, and 
 devoid of the elaborate lobation which they exhibit in the 
 Ammonites ; whilst the siphuncle pierces the septa either in 
 the centre or near it. In the Nautilus, however, the shell is 
 coiled into a flat spiral ; whereas in Orthoceras the shell is a 
 straight, longer or shorter cone, tapering behind, and gradu- 
 ally expanding towards its mouth in front. The chief objec- 
 tions to the belief that the animal of the Orthoceras was essen- 
 tially like that of the Pearly Nautilus are the comparatively 
 small size of the body-chamber, the often contracted aperture 
 of the mouth, and the enormous size of some specimens of 
 
 * This illustration is taken from a rough sketch made by the author 
 many years ago, but he is unable to say from what original source it was 
 copied.
 
 114 HISTORICAL PALEONTOLOGY. 
 
 the shell. Thus, some Orthocerata have been discovered 
 measuring ten or twelve feet in length, with a diameter of a 
 foot at the larger extremity. These colossal dimensions cer- 
 tainly make it difficult to imagine that the comparatively small 
 body-chamber could have held an animal large enough to move 
 a load so ponderous as its own shell. To some, this difficulty 
 has appeared so great that they prefer to believe that the 
 Orthoceras did not live in its shell at all, but that its shell was 
 an internal skeleton similar to what we shall find to exist in 
 many of the true Cuttle-fishes. There is something to be said 
 in favour of this view, but it would compel us to believe in the 
 existence in Lower Silurian times of Cuttle-fishes fully equal 
 in size to the giant "Kraken" of fable. It need only be 
 added in this connection that the Lower .Silurian rocks have 
 yielded the remains of many other Tetrabranchiate Cephalo- 
 pods besides Orthoceras. Some of these belong to Cyrtoceras, 
 which only differs from Orthoceras in the bow-shaped form of 
 the shell ; others belong to Phragmoceras, Lituites, &c. ; and, 
 lastly, we have true Nautili, with their spiral shells, closely 
 resembling the exjsting Pearly Nautilus. 
 
 Whilst all the sub-kingdoms of the Invertebrate animals are 
 represented in the Lower Silurian rocks, no traces of Verte- 
 brate animals have ever been discovered in these ancient 
 deposits, unless the so-called " Conodonts " found by Pander 
 in vast numbers in strata of this age * in Russia should prove 
 to be really of this nature. These problematical bodies are of 
 microscopic size, and have the form of minute, conical, tooth- 
 shaped spines, with sharp edges, and hollow at the base. 
 Their original discoverer regarded them as the horny teeth' 
 of fishes allied to the Lampreys ; but Owen came to the con- 
 clusion that they probably belonged to Invertebrates. The 
 recent investigation of a vast number of similar but slightly 
 larger bodies, of very various forms, in the Carboniferous rocks 
 of Ohio, has led Professor Newberry to the conclusion that 
 these singular fossils really are, as Pander thought, the teeth of 
 Cyclostomatous fishes. The whole of this difficult question 
 has thus been reopened, and we may yet have to record the 
 first advent of Vertebrate animals in the Lower Silurian. 
 
 * According to Pander, the "Conodonts" are found not only in the 
 Lower Silurian beds, but also in the " Ungulite Grit " (Upper Cambrian), 
 as well as in the Devonian and Carboniferous deposits of Russia. Should 
 the Conodonts prove to be truly the remains of fishes, we should thus have 
 to transfer the first appearance of Vertebrates to, at any rate, as early a 
 period as the Upper Cambrian.
 
 THE UPPER SILURIAN PERIOD. 115 
 
 CHAPTER X. 
 THE UPPER SILURIAN PERIOD. 
 
 Having now treated of the Lower Silurian period at consider- 
 able length, it will not be necessary to discuss the succeeding 
 group of the Upper Silurian in the same detail the more so, 
 as with a general change of species the Upper Silurian animals 
 belong for the most part to the same great types as those which 
 distinguish the Lower Silurian. As compared, also, as regards 
 the total bulk of strata concerned, the thickness of the Upper 
 Silurian is generally very much below that of the Lower Silurian, 
 indicating that they represent a proportionately shorter period 
 of time. In considering the general succession of the Upper 
 Silurian beds, we shall, as before, select Wales and America as 
 being two regions where these deposits are typically developed. 
 
 In Wales and its borders the general succession of the 
 Upper Silurian rocks may be taken to be as follows, in ascend- 
 ing order (fig. 57): 
 
 (1) The base of the Upper Silurian series is constituted by 
 a series of arenaceous beds, to which the name of " May Hill 
 Sandstone " was applied by Sedgwick. These are succeeded 
 by a series of greenish grey or pale-grey slates (" Tarannon 
 Shales "), sometimes of great thickness ; and these two groups 
 of beds together form what may be termed the "-May Hill 
 Group" (Upper Llandovery of Murchison). Though not very 
 extensively developed in Britain, this zone is one very well 
 marked by its fossils ; and it corresponds with the " Clinton 
 Group" of North America, in which similar fossils occur. In 
 South Wales this group is clearly unconformable to the highest 
 member of the subjacent Lower Silurian (the Llandovery group); 
 and there is reason to believe that a similar, though less con- 
 spicuous, physical break occurs very generally between the 
 base of the Upper and the summit of the Lower Silurian. 
 
 (2) The Wenlock Group succeeds the May Hill group, and 
 constitutes the middle member of the Upper Silurian. At its 
 base it may have an irregular limestone ("Woolhope Lime- 
 stone"), and its summit may be formed by a similar but thicker 
 calcareous deposit ("Wenlock Limestone"); but the bulk of the 
 group is made up of the argillaceous and shaly strata known as 
 the " Wenlock Shale." In North Wales the Wenlock group is 
 represented by a great accumulation of flaggy and gritty strata 
 (the "Denbighshire Flags and Grits"), and similar beds (the
 
 Il6 HISTORICAL PALEONTOLOGY. 
 
 " Coniston Flags " and " Coniston Grits ") take the same place 
 in the north of England. 
 
 (3) The Ludlow Group is the highest member of the Upper 
 Silurian, and consists typically of a lower arenaceous and shaly 
 series (the "Lower Ludlow Rock") a middle calcareous 
 member (the " Aymestry Limestone"), and an upper shaly and 
 sandy series (the " Upper Ludlow Rock" and " Downton Sand- 
 stone "). At the summit, or close to the summit, of the Upper 
 Ludlow, is a singular stratum only a few inches thick (vary- 
 ing from an inch to a foot), which contains numerous remains 
 of crustaceans and fishes, and is well known under the name 
 of the "bone-bed." Finally, the Upper Ludlow rock graduates 
 invariably into a series of red sandy deposits, which, when of 
 a flaggy character, are known locally as the "Tile-stones." 
 These beds are probably to be regarded as the highest member 
 of the Upper Silurian ; but they are sometimes looked upon as 
 passage-beds into the Old Red Sandstone, or as the base of 
 this formation. It is, in fact, apparently impossible to draw 
 any actual line of demarcation between the Upper Silurian and 
 the overlying deposits of the Devonian or Old Red Sandstone 
 series. Both in Britain and in America the Lower Devonian 
 beds repose with perfect conformity upon the highest Silurian 
 beds, and the two formations appear to pass into one another 
 by a gradual and imperceptible transition. 
 
 The Upper Silurian strata of Britain vary from perhaps 
 3000 or 4000 feet in thickness up to 8000 or io,oco feet. In 
 North America the corresponding series, though also variable, 
 is generally of much smaller thickness, and maybe under 1000 
 feet. The general succession of the Upper Silurian deposits 
 of North America is as follows : 
 
 (1) Medina Sandstone. This constitutes the base of the 
 Upper Silurian, and consists of sandy strata, singularly devoid 
 of life, and passing below in some localities into a conglo- 
 merate (" Oneida Conglomerate "), which is stated to contain 
 pebbles derived from the older beds, and which would thus 
 indicate an unconformity between the Upper and Lower 
 Silurian. 
 
 (2) Clinton Group. Above the Medina sandstone are 
 beds of sandstone and shale, sometimes with calcareous bands, 
 which constitute what is known as the " Clinton Group." The 
 Medina and Clinton groups are undoubtedly the equivalent of 
 the " May Hill Group " of Britain, as shown by the identity of 
 their fossils.
 
 THE UPPER SILURIAN PERIOD. 
 
 117 
 
 GENERALISED SECTION OF THE UPPER SILURIAN STRATA 
 OF WALES AND SHROPSHIRE. 
 
 Fig- 57- 
 
 -I 
 
 J Base of Old Red Sand- 
 
 ( stone. 
 
 Tile-stones. 
 
 Upper Ludlow Rock. 
 
 Aymestry Limestone. 
 
 Lower Ludlow Rock. 
 
 j__J! I Wenlock Limestone. 
 
 Wenlock Shale (Denbigh- 
 shire Flags and Grits of 
 North Wales). 
 
 Woolhope Limestone. 
 
 Tarannon Shales. 
 May Hill Sandstone. 
 
 Llandovery Rocks. 
 
 (3) Niagara Group. This group consists typically of a 
 series of argillaceous beds (" Niagara Shale ") capped by 
 limestones ("Niagara Limestone"); and the name of the 
 group is derived from the fact that it is over limestones of this 
 age that the Niagara river is precipitated to form the great 
 Falls. In places the Niagara group is wholly calcareous, 
 and it is continued upwards into a series of marls and sand- 
 stones, with beds of salt and masses of gypsum (the " Salina 
 Group "), or into a series of magnesian limestones (" Guelpli 
 Limestones"). The Niagara group, as a whole, corresponds 
 unequivocally with the Wenlock group of Britain. 
 
 (4) Lower Helderberg Group. The Upper Silurian period 
 in North America was terminated by the deposition of a series 
 of calcareous beds, which derive the name of " Lower Helder- 
 berg" from the Helderberg mountains, south of Albany, and
 
 Il8 HISTORICAL PALAEONTOLOGY. 
 
 which are divided into several zones, capable of recognition by 
 their fossils, and known by local names (Tentaculite Lime- 
 stone, Water-lime, Lower Pentamerus Limestone, Delthyris 
 Shaly Limestone, and Upper Pentamerus Limestone). As a 
 whole, this series may be regarded as the equivalent of the 
 Ludlow group of Britain, though it is difficult to establish any 
 precise parallelism. The summit of the Lower Helderberg 
 group is constituted by a coarse-grained sandstone (the " Oris- 
 kany Sandstone "), replete with organic remains, which have 
 to a large extent a Silurian fades. Opinions differ as to whether 
 this sandstone is to be regarded as the highest bed of the Upper 
 Silurian or the base of the Devonian. We thus see that in 
 America, as in Britain, no other line than an artificial one can be 
 drawn between the Upper Silurian and the overlying Devonian. 
 
 As regards the life of the Upper Silurian period, we have, as 
 before, a number of so-called "Fucoids," the true vegetable 
 nature of which is in many instances beyond doubt. In addi- 
 tion to these, however, we meet for the first time, in deposits 
 of this age, with the remains of genuine land-plants, though 
 our knowledge of these is still too scanty to enable us to con- 
 struct any detailed picture of the terrestrial vegetation of the 
 period. Some of these remains indicate the existence of the 
 remarkable genus Lepidodendron a genus which played a part 
 of great importance in the forests of the Devonian and Carbon- 
 iferous periods, and which may be regarded as a gigantic and 
 extinct type of the Club-mosses (Lycopodiacea). Near the 
 summit of the Ludlow formation in Britain there have also 
 been found beds charged with numerous small globular bodies, 
 which Dr Hooker has shown to be the seed-vessels or " spor- 
 angia " of Club-mosses. Principal Dawson further states that 
 he has seen in the same formation fragments of wood with the 
 structure of the singular Devonian Conifer known as Proto- 
 taxites. Lastly, the same distinguished observer has described 
 from the Upper Silurian of North America the remains of the 
 singular land-plants belonging to the genus Psilophyton, which 
 will be referred to at greater length hereafter. 
 
 The marine life of the Upper Silurian is in the main con- 
 stituted by types of animals similar to those characterising the 
 Lower Silurian, though for the most part belonging to different 
 species. The Protozoans are represented principally by Stro- 
 matopora and Ischaditcs, along with a number of undoubted 
 sponges (such as Amphispongia, Astrceospongia, Astylospongia, 
 and Palceomanoii). ' 
 
 Amongst the Ccelenterates, we find the old group of Grap- 
 tolites now verging on extinction. Individuals still remain
 
 THE UPPER SILURIAN PERIOD. 
 
 lip 
 
 numerous, but the variety of generic and specific types has 
 now become greatly reduced. All the branching and complex 
 forms of the Arenig, the twin-Grap- 
 tolites and Dicranograpti of the 
 Llandeilo, and the double-celled 
 Diplograpti and Climacograpti of 
 the Bala group, have now disap- 
 peared. In their place we have 
 the singular Retiolites, with its curi- 
 ously-reticulated skeleton; and seve- 
 ral species of the single-celled genus 
 Monographis, of which a character- 
 istic species (M. priodori) is here 
 figured. If we remove from this 
 group the plant-like Dictyonewce, 
 which are still present, and which 
 survive into the Devonian, no 
 known species of Graptolite has 
 hitherto been detected in strata 
 higher in geological position than 
 the Ludlow. This, therefore, pre- 
 sents us with the first instance we 
 have as yet met with of the total 
 disappearance and extinction of a 
 great and important series of or- 
 ganic forms. 
 
 The Corals are very numerously 
 represented in the -Upper Silurian 
 rocks, some of the limestones (such 
 as the Wenlock Limestone) being 
 often largely composed of the skeletons of these animals. 
 Almost all the known forms of this period belong to the 
 two great divisions of the Rugose and Tabulate corals, the 
 former being represented by species of Zaphrentis, Omphyma, 
 Cystiphyllum, Strombodes, Acenndaria, CyathopJiylluin, &c. ; 
 whilst the latter belong principally to the genera Favositcs, 
 Chcetetcs, Halysites, Syringopora, Hcliolites, and Plasinopora. 
 Amongst the Rugosa, the first appearance of the great and 
 important genus Cyathophylhim, so characteristic of the Palae- 
 ozoic period, is to be noted ; and amongst the Tabulata 
 we have similarly the first appearance, in force at any rate, 
 of the widely-spread genus Favosites the " Honeycomb- 
 corals." The "Chain- corals" (Halysites], figured below (fig. 59), 
 are also very common examples of the Tabulate corals during 
 this period, though they occur likewise in the Lower Silurian. 
 
 Fig. 58. A, Monograptus prio- 
 don, slightly enlarged. B, Frag- 
 ment of the same viewed from 
 behind. C, Fragment of the same 
 viewed in front, showing the mouths 
 of the cellules. D, Cross-section 
 of the same. From the Wenlock 
 Group (Coniston Flags of the North 
 of England). (Original.)
 
 12O 
 
 HISTORICAL PALEONTOLOGY. 
 
 Amongst the Echinodermata, all those orders which have 
 hard parts capable of ready preservation are more or less 
 
 Fig. 59. a, Halysites catennlaria, small variety, of the natural size ; 6, Fragment of 
 a large variety of the same, of the natural size; c, Fragment of limestone with tie tubes 
 of Halysites agglomerata, of the natural size ; d, Vertical section of two tubes of the 
 same, showing the tabulae, enlarged. Niagara Limestone (Wenlock), Canada. (Original.) 
 
 largely represented. We have no trace of the Holothurians 
 or Sea-cucumbers ; but this is not surprising, as the record of 
 the past is throughout almost silent as to the former existence 
 of these soft-bodied creatures, the scattered plates and spicules 
 in their skin offering a very uncertain chance of preservation 
 in the fossil condition. The Sea-urchins (Echinoids) are said 
 to be represented by examples of the old genus Pal&chinus. 
 The Star-fishes (Asteroids) and the Brittle- stars (Ophiimnds) 
 are, comparatively speaking, largely represented , the former 
 by species of Palasterina (fig. 60), Pal&aster (fig. 60), Paltzo- 
 coma (fig. 60), Petraster, Glyptaster, and Lepidasler and the 
 latter by species of Protaster (fig. 61), Pal&odiscus, Acroura, 
 and Eudadia. The singular Cystideans, or " Globe Crinoids," 
 with their globular or ovate, tesselated bodies (fig. 46, A, C, D,), 
 are also not uncommon in the Upper Silurian ; and if they do 
 not become finally extinct here, they certainly survive the close 
 of this period by but a very bi'ief time. By far the most im- 
 portant, however, of the Upper Silurian Echinoderms, are the 
 Sea-lilies or Crinoids. The limestones of this period are often 
 largely composed of the fragmentary columns and detached
 
 THE UPPER SILURIAN PERIOD. 121 
 
 plates of these creatures, and some of them (such as the Wen- 
 lock Limestone of Dudley) have yielded perhaps the most 
 
 Fig. 60. Upper Silurian Star-fishes, i, Pa'asterina. primmia, Lower Ludlow ; 2, 
 ''atceaster Ruthveni, Lower Ludlow ; 3, Palieocoma Colvini, Lower Ludlow. (After 
 alter.) 
 
 exquisitely-preserved examples of this group with which we 
 are as yet acquainted. However varied in their forms, these 
 
 Fig. 61. A, Protester Sedgwickii, showing- the disc and bases of the arms; E, Por- 
 tion of an arm, greatly enlarged. Lower Ludlow. (After Salter.) 
 
 beautiful organisms consist of a globular, ovate, or pear-shaped 
 body (the " calyx "), supported upon a longer or shorter 
 jointed stem (or " column "). The body is covered externally 
 with an armour of closely-fitting calcareous plates (fig. 62), and 
 its upper surface is protected by similar but smaller plates 
 more loosely connected by a leathery integument. From the 
 upper surface of the body, round its margin, springs a series 
 of longer or shorter flexible processes, composed of innu- 
 merable calcareous joints or pieces, movably united with one
 
 122 
 
 HISTORICAL PAL/EONTOLOGY. 
 
 another. The arms are typically five in number; but they 
 generally subdivide at least once, sometimes twice, and they 
 
 Fig 62. Upper Silurian Crinoids. a, Calyx and arms of Eucalyptocrinns polydacty- 
 s, Wenlock Limestone ; 6, Ichthyocrimis ' ' "' 
 
 tubarculatus, Wenlock Li 
 
 t'&vis, Niagara Limestone, America ; 
 . (After M'Coy and Hall.) 
 
 are furnished with similar but more slender lateral branches 
 or " pinnules," thus giving rise to a crown of delicate feathery 
 plumes. The " column " is the stem by which the animal is 
 attached permanently to the bottom of the sea ; and it is com- 
 posed of numerous separate plates, so jointed together that 
 whilst the amount of movement between any two pieces must 
 be very limited, the entire column acquires more or less flexi- 
 bility, allowing the organism as a whole to wave backwards and 
 forwards on its stalk. Into the exquisite minutia of structure 
 by which the innumerable parts entering into the composition 
 of a single Crinoid are adapted for their proper purposes in 
 the economy of the animal, it is impossible to enter here. No 
 period, as before said, has yielded examples of greater beauty 
 than the Upper Silurian, the principal genera represented 
 being Cyathocrinus, Platycrinus, Marsupiocrinus, Taxocrinus, 
 Eucalyptocrinus, Ichthyocrinus, Mariacrinus, Periechocrinus, 
 Glyptocrinus, Crotalocrinus, and Edriocrinus. 
 
 The tracks and burrows of Annelides are as abundant in 
 the Upper Silurian strata as in older deposits, and have just 
 as commonly been regarded as plants. The most abundant 
 forms are the cylindrical, twisted bodies (Planolites), which are
 
 THE UPPER SILURIAN PERIOD. 
 
 123 
 
 so frequently found on the surfaces of sandy beds, and which 
 have been described as the stems of sea-weeds. These fossils 
 (fig. 63), however, can be nothing more, in most cases, than 
 
 Fig. (>$. PlanoUtes vulgar! s, the filled-up bum 
 Upper Silurian (Clinton Group), Ca 
 
 ida. (Original.) 
 
 the filled-up burrows of marine worms resembling the living 
 Lob-worms. There are also various remains which belong to 
 the group of the tube-inhabiting Annelides (Titbico!a). Of 
 this nature are the tubes of Serpulites and Cornnlites, and the 
 little spiral discs of Spirorbis Leivisii. 
 
 Amongst the Articulates, we still meet only with the remains 
 of Crustaceans. Besides the little bivalved Ostracoda which 
 here are occasionally found of the size of beans and various 
 Phyllopods of different kinds, we have an abundance of Trilo- 
 bites. These last-mentioned ancient types, however, are now 
 beginning to show signs of decadence ; and though still indi- 
 vidually numerous, there is a great diminution in the number 
 of generic types. Many of the old genera, which flourished 
 so abundantly in Lower Silurian seas, have now died out; 
 and the group is represented chiefly by species of Cheinirus, 
 Encrinurus, Harpes, Proetus, Ltchas, Acidaspis, Illanus, Caly- 
 tnene, Homalonotus, and Phacops the last of these, one of the
 
 I2 4 
 
 HISTORICAL PALAEONTOLOGY. 
 
 highest and most beautiful of the groups of Trilobites, attaining 
 here its maximum of development. In the annexed illustra- 
 tion (fig. 64) some of the characteristic Upper Silurian Trilo- 
 
 Fig. 64. Upper Silurian Trilobites. a, Ckeirjints linmcronatus, Wenlock and Cara- 
 doc ; b, Phacops hngicandalns, Wenlock, Britain, and America ; c, Pluicops Dmuningiie, 
 Wenlock and Ludlow ; d, Harpes ungula, Upper Silurian, Bohemia. (After Salter 
 and Barrande.) 
 
 bites are represented all, however, belonging to genera which 
 have their commencement in the Lower Silurian period. In 
 addition to the above, the Ludlow rocks of Britain and the 
 Lower Helderberg beds of North America have yielded the 
 remains of certain singular Crustaceans belonging to the 
 extinct order of the Eurypterida. Some of these wonderful 
 forms are not remarkable for their size ; but others, such as 
 Pterygotus Anglicus (fig. 65), attain a length of six feet or more, 
 and may fairly be considered as the giants of their class. The 
 Eurypterids are most nearly allied to the existing King-crabs 
 (.Limuli), and have the anterior end of the body covered with 
 a great head-shield, carrying two pairs of eyes, the one simple 
 and the other compound. The feelers are converted into 
 pincers, whilst the last pair of limbs have their bases covered 
 with spiny teeth so as to act as jaws, and are flattened and 
 widened out towards their extremities so as to officiate as 
 swimming-paddles. The hinder extremity of the body is com- 
 posed of thirteen rings, which have no legs attached to them ; 
 and the last segment of the tail is either a flattened plate or a
 
 THE UPPER SILURIAN PERIOD. 
 
 125 
 
 narrow, sword-shaped spine. Fragments of the skeleton are 
 easily recognised by the peculiar scale-like markings with 
 which the surface is adorned, and 
 which look not at all unlike the 
 scales of a fish. The most fam- 
 ous locality for these great Crus- 
 taceans is Lesmahagow, in Lan- 
 arkshire, where many different 
 species have been found. The 
 true King-crabs (Liinuli) of exist- 
 ing seas also appear to have been 
 represented by at least one form 
 {Neolimulus) in the Upper Silu- 
 rian. 
 
 Coining to the Mollusca, we 
 note the occurrence of the same 
 great groups as in the Lower 
 Silurian. Amongst the Sea- 
 mosses {Polyzod), we have the 
 ancient Lace - corals (Fenestella 
 and Retepora), with the nearly- 
 allied Gfawonome, and species of 
 Ptilodictya (fig. 66) ; whilst many 
 forms often referred here may 
 probably have to be transferred 
 to the Corals, just as some so- 
 called Corals will ultimately be 
 removed to the present group. 
 
 The Brachiopods continued 
 to flourish during the Upper 
 Silurian period in immense num- 
 bers and under a greatly in- 
 creased variety of forms. The three prominent Lower 
 Silurian genera Orihis, Strophomena, and Lepttzna are still 
 well represented, though they have lost their former pre- 
 eminence. Amongst the numerous types which have now 
 come upon the scene for the first time, or which have now a 
 special development, are Spirifera and Pentamerus. In the 
 first of these (fig. 69, b, c), one of the valves of the shell (the 
 dorsal) is furnished in its interior with a pair of great calca- 
 reous spires, which served for the support of the long and 
 fringed fleshy processes or " arms " which were attached to the 
 sides of the mouth.* In the genus Pentamerus (fig. 70) the 
 
 * In all the Lamp-shells the mouth is provided with two long fleshy 
 organs, which carry delicate filaments on their sides, and which are 
 10 
 
 Fig. 65. Pttrygot* 
 ewed from the under 
 n size, and restored, c < 
 antennae), terminating 
 ~aws ; o o, Eyes ; m in, Three pairs of 
 ointed limbs, with pointed extremi- 
 ics ; it 11, Swimming-paddles, the bases 
 
 of which are spiny and act as jaws. 
 
 Upper Silurian, Lanarkshire. (After 
 
 Henry Woodward.)
 
 126 
 
 HISTORICAL PALAEONTOLOGY. 
 
 shell is curiously subdivided in its interior by calcareous 
 plates. The Pentameri commenced their existence at the very 
 
 n 
 
 Fig. 66. Upper Silurian Polyzoa. i, Fan-shaped frond of Rhinopora verrticosa', in, 
 Portion of the surface of the same, enlarged ; 2 and za, Phienopora eiisiforniis, of the 
 natural size and enlarged ; 3 and yt, Hclopora frugilis, of the natural size and en- 
 larged ; 4 and 4^, Ptiladictya raripora, of the natural size and enlarged. The speci- 
 mens are all from the Clinton Formation (May Hill Group) of Canada. (Original.) 
 
 close of the Lower Silurian (Llandovery), and survived to the 
 close of the Upper Silurian ; but they are specially character- 
 istic of the May Hill and Wenlock groups, both in Britain 
 and in other regions. One species, Pentamerus galeatus, is 
 common to Sweden, Britain, and America. Amongst the 
 remaining Upper Silurian Brachiopods are the extraordinary 
 
 usually coiled into a spiral. These organs are known as the "arms," 
 and it is from their presence that the name of " Brachiopoda " is derived 
 (Gr. brachion, arm ; podes, feet). In some cases the arms are merely coiled 
 away within the shell, without any support ; but in other cases they are 
 carried upon a more or less elaborate shelly loop, often spoken of as the 
 "carriage-spring apparatus." In the Spirifirs, and in other ancient 
 genera, this apparatus is coiled up into a complicated spiral (fig. 67). It 
 
 Fig. f>i.Spirifera hysterics. The right-hand 
 dorsal valve, with the calcareous spires for 
 
 is these "arms," with or without the supporting loops or spires, which 
 serve as one of the special characters distinguishing the Brachiopods from 
 the true Bivalves (Lamcllibranchiatd).
 
 THE UPPER SILURIAN PERIOD. 
 
 127 
 
 Trimerellids ; the old and at the same time modern Lingulce, 
 Discince, and Crania ; together with many species of Atrypa 
 
 fig. 68. Upper Silurian Brachiopods. a a', Leptoccelia plano-convexa, Clinton 
 Group, America; b b' , Rkynchonella neglecta, Clinton Group, America ; c , Rkynchonella 
 cnncata, Niagara Group, America, and Wenlock Group, Britain; d d', Orthis elegan- 
 tuta, Llandeilo to Ludlow, America and Europe; e e , A try fa. hemispherica, Clinton 
 Group, America, and IJandovery and May Hill Groups, Britain ;//', Atrypa congesta, 
 Clinton Group, America ; g g 1 , Orthis Davidsoni, Clinton Group, America. (After Hall, 
 Billings, and the Author.) 
 
 (fig. 68, e), Leptocalia (fig. 68, a), Rhynchoiiella (fig. 68, /;, c) t 
 Meristella (fig. 69, a, ,f], Athyris^ Reizia, Cuonetes, &c. 
 
 Fig. 69. a, n! Meristella intermedia, Niagara Group, America; b, Spirifera Niagar- 
 ensis, Niagara Group, America; c c , Spirijcra crispn, May Hill to Ludlow, Britain, and 
 Niagara Group, America ; d, Stroflwtnena (Streptorhynchris) subplana, Niagara Group, 
 
 /, Meristella cylindrica. 
 
 America ; e, Meristella namfortni*. N 
 Niagara Group, America. (After Hall 
 
 Group, Amer 
 illings, and the At 
 
 The higher groups of the Mollusca are also largely repre- 
 sented in the Upper Silurian. Apart from some singular types,
 
 128 
 
 HISTORICAL PALAEONTOLOGY. 
 
 such as the huge and thick-shelled Megalomi of the American 
 Wenlock formation, the Bivalves (Lamcllibrancluata) present 
 
 Fig. ^.-Pentamenis Knightii. Wenlock and Ludlow. The right-hand 
 figure shows the internal partitions of the shell. 
 
 little of special interest ; for though sufficiently numerous, they 
 are rarely well preserved, and their true affinities are often un- 
 certain. Amongst the most characteristic genera of this period 
 may be mentioned Cardiola (fig. 71, A and C) and Pterinea (fig. 
 
 Fig. 71. Upper Silurian Bivalves. A, Cardiola intemifita, W'enlocU and Ludlow; 
 B, Pterinea subfalcata, Wenlock ; C, Cardiola fibrosa, Ludlow. (After Salter and 
 M'Coy.) 
 
 71, B), though the latter survives to a much later date. The 
 Univalves {Gasteropoda) are very numerous, and a few charac- 
 teristic forms are here figured (fig. 72). Of these, no genus 
 is perhaps more characteristic than Euomphalus (fig. 72, &), 
 with its flat discoidal shell, coiled up into an oblique spiral, 
 and deeply hollowed out on one side ; but examples of this 
 group are both of older and of more modern date. Another 
 very extensive genus, especially in America, is Platyceras (fig. 
 
 72, a and/), with its thin fragile shell often hardly coiled up 
 at all its minute spire, and its widely-expanded, often sinuated 
 mouth. The British Acroculitz should probably be placed 
 here, and the group has with reason been regarded as allied 
 to the Violet-snails (lanthina) of the open Atlantic. The
 
 THE UPPER SILURIAN PERIOD. 
 
 I2 9 
 
 species of Platyostoma (fig. 72, K) also belong to the same 
 family ; and the entire group is continued throughout the 
 Devonian into the Carboniferous. Amongst other well-known 
 Upper Silurian Gasteropods are species of the genera Holopea 
 
 Fig. 72. Upper Silurian Gasteropods. a, Platyceras ventricosum, Lower He'der- 
 berg, America ; b, Euomphalus discors, Wenlock, Britain ; c, Holopella. obsoleta, Lud- 
 low, Britain ; d, Platyschisma helicites. Upper Ludlow, Britain ; e, Holopella gracilior, 
 Wenlock, Britain;/, Platyceras mnltisinttatum, Lower Helderberg, America; g, Holo- 
 pea. subconica, Lower Helderberg, America; h, h', Platyostoma. Niagarense, Niagara 
 Group, America. (After Hall, M'Coy, and Salter.) 
 
 (fig. 72, g), Holopella (fig. 72, c), Platyschisna (fig. 72, d\ 
 Cydonema, Pleurotomaria, Murchisonia, Trochoncma, &c. The 
 oceanic Univalves (Heteropods) are rep- 
 resented mainly by species of Bellero- 
 phon ; and the Winged Snails, or Ptcro- 
 pods, can still boast of the gigantic Thecce 
 and Comtlarice, which characterise yet 
 older deposits. The commonest genus 
 of Ptcropoda, however, is Te?itaailites (fig. 
 73), which clearly belongs here, though 
 it has commonly been regarded as the 
 tube of an Annelide. The shell in this 
 group is a conical tube, usually adorned 
 with prominent transverse rings, and 
 often with finer transverse or longitudi- 
 nal striae as well ; and many beds of the 
 Upper Silurian exhibit myriads of such tubes scattered promis- 
 cuously over their surfaces.
 
 1 3 o 
 
 HISTORICAL PALAEONTOLOGY. 
 
 The last and highest group of the Mollusca that of the 
 Cephalopoda is still represented only by Tetrabranchiate 
 forms; but the abundance and variety of these is almost 
 beyond belief. Many hundreds of different species are known, 
 chiefly belonging to the straight Orthoceratites, but the slightly- 
 curved Cyrtoceras is only little less common. There are also 
 numerous forms of the genera Phragmoccras, Ascoceras, Gyro- 
 cer'as, Lituites, and Nautilus. Here, also, are the first-known 
 species of the genus Goniatites a group which attains con- 
 siderable importance in later deposits, and which is to be 
 regarded as the precursor of the Ammonites of the Secondary 
 period. 
 
 Finally, we find ourselves for the first time called upon to 
 consider the remains of undoubted vertebrate animals, in the 
 form of Fishes. The oldest of these remains, so far as yet 
 known, are found in the Lower Ludlow rocks, and they con- 
 sist of the bony head-shields or bucklers 
 of certain singular armoured fishes belong- 
 ing to the group of the Ganoids, repre- 
 sented at the present day by the Stur- 
 geons, the Gar-pikes of North America, 
 and a few other less familiar forms. The 
 principal Upper Silurian genus of these is 
 Picraspis, and the annexed illustration (fig. 
 74) will give some idea of the extraordi- 
 nary form of the shield covering the head 
 in these ancient fishes. The remarkable 
 stratum near the top of the Ludlow for- 
 mation known as the " bone-bed " has 
 also yielded the remains of shark-like 
 fishes. Some of these, for which the name 
 of Onchus has been proposed, are in the form of com- 
 pressed, slightly-curved spines (fig. 75, A), which would appear 
 
 Fig. 74. Head-shield 
 of Pteraspis Banks ii. 
 l.udl 
 
 rocks. 
 Murchison.) 
 
 (After 
 
 Fig. 75. A, Spine of Onckns tennistrlatvs ; B, Shagreen-scales of Thelodus. "Both 
 from the " bone-bed " of the Upper Ludlow rocks. (After Murchison.) 
 
 to be of the nature of the strong defensive spines implanted 
 in front of certain of -the fins in many living fishes. Besides 
 these, have been found fragments of prickly skin or shagreen 
 (Sphagodus), along with minute cushion-shaped bodies ( Thelo-
 
 THE UPPER SILURIAN PERIOD. 131 
 
 dus, fig. 75, B), which are doubtless the bony scales of some 
 fish resembling the modern Dog-fishes. As the above mentioned 
 remains belong to two distinct, and at the same time highly- 
 organised, groups of the fishes, it is hardly likely that we are 
 really presented here with the first examples of this great class. 
 On the contrary, whether the so-called "Conodonts" should 
 prove to be the teeth of fishes or not, we are justified in ex- 
 pecting that unequivocal remains of this group of animals will 
 still be found in the Lower Silurian. It is interesting, also, to 
 note that the first appearance of fishes the lowest class of 
 vertebrate animals so far as known to us at present, does not 
 take place until after all the great sub-kingdoms of invertebrates 
 have been long in existence ; and there is no reason for think- 
 ing that future discoveries will materially affect the relative 
 order of succession thus indicated. 
 
 LITERATURE. 
 
 From the vast and daily-increasing mass of Silurian literature, it is im- 
 possible to do more than select a small number of works which have a 
 classical and historical interest to the English-speaking geologist, or which 
 embody researches on special groups of Silurian animals anything like an 
 enumeration of all the works and papers on this subject being wholly out 
 of the question. Apart, therefore, from numerous and in many cases 
 extremely important memoirs, by various well-known observers, both at 
 home and abroad, the following are some of the more weighty works to 
 which the student may refer in investigating the physical characters and 
 succession of the Silurian strata and their fossil contents : 
 
 (1) ' Siluria.' Sir Roderick Murchison. 
 
 (2) 'Geology of Russia in Europe.' Murchison (with M. de Verneuil 
 
 and Count von Keyserling). 
 
 (3) ' Bassin Silurien de Boheme Centrale.' Barrande. 
 
 (4) ' Introduction to the Catalogue of British Palaeozoic Fossils in the 
 
 Woodwardian Museum of Cambridge.' Sedgwick. 
 
 (5) ' Die Urwelt Russlands.' Eicflwald. 
 
 (6) ' Report on the Geology of Londonderry, Tyrone,' &c. Portlock. 
 
 (7) "Geology of North Wales" 'Mem. Geol. Survey of Great Britain,' 
 
 vol. iii. Ramsay. 
 
 (8) ' Geology of Canada,' 1863, Sir W. E. Logan ; and the ' Reports of 
 
 Progress of the Geological Survey ' since 1863. 
 
 (9) 'Memoirs of the Geological Survey of Great Britain.' 
 
 (10) ' Reports of the Geological Surveys of the States of New York, 
 
 Illinois, Ohio, Iowa, Michigan, Vermont, Wisconsin, Minne- 
 sota,' &c. By Emmons, Hall, Worthen, Meek, New berry, 
 Orton, Winchell, Dale Owen, &c. 
 
 (11) 'Thesaurus Siluricus.' Bigsby. 
 
 (12) 'British Palaeozoic Fossils.' M'Coy. 
 
 (13) ' Synopsis of the Silurian Fossils of Ireland,' M'Coy. 
 
 (14) " Appendix to the Geology of North Wales" 'Mem. Geol. Survey,' 
 
 vol. iii. Sailer.
 
 132 HISTORICAL PALAEONTOLOGY. 
 
 (15) 'Catalogue of the Cambrian and Silurian Fossils in the Woodward- 
 
 ian Museum of Cambridge. ' Salter. 
 
 (16) 'Characteristic British Fossils.' Baily. 
 
 (17) ' Catalogue of British Fossils.' Morris. 
 
 (18) ' Palaeozoic Fossils of Canada.' Billings. 
 
 (19) ' Decades of the Geological Survey of Canada.' Billings, Salter, 
 
 Rupert Jones. 
 
 (20) ' Decades of the Geological Survey of Great Britain.' Salter, Edward 
 
 Forbes. 
 
 (21) ' Paleontology of New York,' vols. i.-iii. Hall. 
 
 (22) ' Palaeontology of Illinois.' Meek and Worthen. 
 
 (23) 'Palaeontology of Ohio.' Meek, Hall, Whitfield, Nicholson. 
 
 (24) ' Silurian Fauna of West Tennessee ' (Silurische Fauna des West- 
 
 lichen Tennessee). Ferdinand Roemer. 
 
 (25) ' Reports on the State Cabinet of New York.' Hall. 
 
 (26) ' Lethaea Geognostica.' Bronn. 
 
 (27) ' Index Paleeontologicus.' Bronn. 
 
 (28) ' Lethaea Rossica.' Eichwald. 
 
 (29) ' Lethaea Suecica.' Hisinger. 
 
 (30) ' Palaeontologica Suecica. ' Angelin. 
 
 (31) ' Petrefacta Germaniae. ' Goldfuss. 
 
 (32) ' Versteinerungen der Grauwacken- Formation in Sachsen.' Geinitz. 
 
 (33) 'Organisation of Trilobites ' (Ray Society). Burmeister. 
 
 (34) ' Monograph of the British Trilobites' (Palaeontographical Society). 
 
 Salter. 
 
 (35) ' Monograph of the British Merostomata' (Palaeontographical Society). 
 
 Henry Woodward. 
 
 (36) Monograph of British Brachiopoda ' (Palaeontographical Society). 
 
 Thomas Davidson. 
 
 (37) ' Graptolites of the Quebec Group.' James Hall. 
 
 (38) 'Monograph of the British Graptolitidae.' Nicholson. 
 
 (39) ' Monographs on the Trilobites. Pteropods, Cephalopods, Grapto- 
 
 lites,' &c. Extracted from the ' Systeme Silurien du Centre de 
 la Boheme.' Barrande. 
 
 (40) ' Polypiers Fossiles des Terrains Paleozoiques,' and 'Monograph of 
 
 the British Corals' (Palaeontographical Society). Milne Ed- 
 wards and Jules Haime. 
 
 CHAPTER XI. 
 
 THE DEVONIAN AND OLD RED SANDSTONE 
 PERIOD. 
 
 Between the summit of the Ludlow formation and the strata 
 which are universally admitted to belong to the Carboniferous
 
 DEVONIAN AND OLD RED PERIOD. 133 
 
 series is a great system of deposits, to which the name of " Old 
 Red Sandstone" was originally applied, to distinguish them 
 from certain arenaceous strata which lie above the coal (" New 
 Red Sandstone"). The Old Red Sandstone, properly so 
 called, was originally described and investigated as occurring 
 in Scotland and in South Wales and its borders ; and similar 
 strata occur in the south of Ireland. Subsequently it was 
 discovered that sediments of a different mineral nature, and 
 containing different organic remains, intervened between the 
 Silurian and the Carboniferous rocks on the continent of Eu- 
 rope, and strata with similar palaeontological characters to these 
 were found occupying a considerable area in Devonshire. The 
 name of " Devonian " was applied to these deposits ; and this 
 title, by common usage, has come to be regarded as synony- 
 mous with the name of " Old Red Sandstone." Lastly, a 
 magnificent series of deposits, containing marine fossils, and 
 undoubtedly equivalent to the true " Devonian " of Devon- 
 shire, Rhenish Prussia, Belgium, and France, is found to inter- 
 vene in North America between the summit of the Silurian 
 and the base of the Carboniferous rocks. 
 
 Much difficulty has been felt in correlating the true " Devon- 
 ian Rocks " with the typical " Old Red Sandstone" this diffi- 
 culty arising from the fact that though both formations are 
 fossiliferous, the peculiar fossils of each have only been rarely 
 and partially found associated together. The characteristic 
 crustaceans and many of the characteristic fishes of the Old 
 Red are wanting in the Devonian ; whilst the corals and 
 marine shells of the latter do not occur in the former. It is 
 impossible here to enter into any discussion as to the merits 
 of the controversy to which this difficulty has given origin. 
 No one, however, can doubt the importance and reality of the 
 Devonian series as an independent system of rocks to be in- 
 tercalated in point of time between the Silurian and the Car- 
 boniferous. The want of agreement, both lithologically and 
 palseontologieally, between the Devonian and the Old Red, 
 can be explained by supposing that these two formations, 
 though wholly or in great part contemporaneous, and therefore 
 strict equivalents, represent deposits in two different geographi- 
 cal areas, laid down under different conditions. On this view, 
 the typical Devonian rocks of Europe, Britain, and North 
 America are the deep-sea deposits of the Devonian period, or, 
 at any rate, are genuine marine sediments formed far from 
 land. On the other hand, the " Old Red Sandstone " of 
 Britain and the corresponding "Gaspe Croup" of Eastern
 
 134 HISTORICAL PALAEONTOLOGY. 
 
 Canada represent the shallow-water shore-deposits of the same 
 period. In fact, the former of these last - mentioned de- 
 posits contains no -fossils which can be asserted positively 
 to be marine (unless the Eurypterids be considered so) ; and 
 it is even conceivable that it represents the sediments of an 
 inland sea. Accepting this explanation in the meanwhile, 
 we may very briefly consider the general succession of the 
 deposits of this period in Scotland, in Devonshire, and in 
 North America. 
 
 In Scotland the " Old Red " forms a great series of arena- 
 ceous and conglomeratic strata, attaining a thickness of many 
 thousands of feet, and divisible into three groups. Of these, 
 the Lower Old Red Sandstone reposes with perfect conform- 
 ity upon the highest beds of the Upper Silurian, the two for- 
 mations being almost inseparably united by an intermediate 
 series of " passage-beds." In mineral nature this group con- 
 sists principally of massive conglomerates, sandstones, shales, 
 and concretionary limestones ; and its fossils consist chiefly of 
 large crustaceans belonging to the family of the Eurypterids, 
 fishes, and plants. The Middle Old Red Sandstone consists of 
 flagstones, bituminous shales, and conglomerates, sometimes 
 with irregular calcareous bands ; and its fossils are principally 
 fishes and plants. It may be wholly wanting, when the Upper 
 Old Red seems to repose unconformably upon the lower divi- 
 sion of the series. The Upper Old Red Sandstone consists of 
 conglomerates and grits, along with a great series of red and 
 yellow sandstones the fossils, as before, being fishes and re- 
 mains of plants. The Upper Old Red graduates upwards 
 conformably into the Carboniferous series. 
 
 The Devonian rocks of Devonshire are likewise divisible 
 into a lower, middle, and upper division. The Lower 
 Devonian or Lynton Group consists of red and purple sand- 
 stones, with marine fossils, corresponding to the "Spirifer 
 Sandstein " of Germany, and to the arenaceous deposits (Scho- 
 harie and Cauda-Galli Grits) at the base of the American 
 Devonian. The Middle Devonian or Ilfracombe Group consists 
 of sandstones and flags, with calcareous slates and crystalline 
 limestones, containing many corals. It corresponds with the 
 great " Eifel Limestone " of the Continent, and, in a general 
 way, with the Corniferous Limestone and Hamilton group of 
 North America. The Upper Devonian or Pi/ton Group, lastly, 
 consists of sandstones and calcareous shales which correspond 
 with the "Clymenia Limestone" and "Cypridina Shales" of 
 the Continent, and with the Chemting and Portage groups of
 
 DEVONIAN AND OLD RED PERIOD. 135 
 
 North America. It seems quite possible, also, that the so- 
 called " Carboniferous Slates " of Ireland correspond with 
 this group, and that the former would be more properly re- 
 garded as forming the summit of the Devonian than the 
 base of the Carboniferous. 
 
 In no country in the world, probably, is there a finer 
 or more complete exposition of the strata intervening be- 
 tween the Silurian and Carboniferous deposits than in the 
 United States. The following are the main subdivisions 
 of the Devonian rocks in the State of New York, where 
 the series may be regarded as being typically developed 
 (fig- 67): 
 
 (1) Cauda-Galli Grit and Schoharie Grit. Considering the 
 " Oriskany Sandstone " as the summit of the Upper Silurian, 
 the base of the Devonian is constituted by the arenaceous 
 deposits known by the above names, which rest quite conform- 
 ably upon the Silurian, and which represent the Lower 
 Devonian of Devonshire. The Cauda-Galli Grit is so called 
 from the abundance of a peculiar spiral fossil (Spirophyton 
 cauda-Galli], which is of common occurrence in the Carbon- 
 iferous rocks of Britain, and is supposed to be the remains 
 of a sea-weed. 
 
 (2) The Corniferous or Upper Held erb erg Limestone. A 
 series of limestones usually charged with considerable quan- 
 tities of siliceous matter in the shape of hornstone or chert 
 (Lat. cornu, horn). The thickness of this group rarely exceeds 
 300 feet ; but it is replete with fossils, more especially with 
 the remains of corals. The Corniferous Limestone is the 
 equivalent of the coral-bearing limestones of the Middle De- 
 vonian of Devonshire and the great " Eifel Limestone" of 
 Germany. 
 
 (3) The Hamilton Group consisting of shales at the base 
 (" Marcellus shales ") ; flags, shales, and impure limestones 
 ("Hamilton beds") in the middle ; and again a series of shales 
 ("Genesee Slates") at the top. The thickness of this group 
 varies from 200 to. 1200 feet, and it is richly charged with 
 marine fossils. 
 
 (4) The Portage Group. A great series of shales, flags, and 
 shaly sandstones, with few fossils. 
 
 (5) The Chemung Group. Another great series of sand- 
 stones and shales, but with many fossils. The Portage and 
 Chemung groups may be regarded as corresponding with the 
 Upper Devonian cf Devonshire. The Chemung beds are 
 succeeded by a great series of red sandstones and shales the
 
 136 HISTORICAL PALEONTOLOGY. 
 
 " Catskill Group" which pass conformably upwards into the 
 Carboniferous, and which may perhaps be regarded as the 
 equivalent of the great sandstones of the Upper Old Red in 
 Scotland. 
 
 Throughout the entire series of Devonian deposits in North 
 America no unconformability or physical break of any kind 
 has hitherto been detected ; nor is there any marked interrup- 
 tion to the current of life, though each subdivision of the series 
 has its own fossils. No completely natural line can thus be 
 indicated, dividing the Devonian in this region from the Silu- 
 rian on the one hand, and the Carboniferous on the other 
 hand. At the same time, there is the most ample evidence, 
 both stratigraphical and palaeontological, as to the complete 
 independence of the American Devonian series as a distinct 
 life-system between the older Silurian and the later Carbon- 
 iferous. The subjoined section (fig. 76) shows diagrammati- 
 cally the general succession of the Devonian rocks of North 
 America. 
 
 As regards the life of the Devonian period, we are now 
 acquainted with a large and abundant terrestrial flora this 
 being the first time that we have met with a land vegetation 
 capable of reconstruction in any fulness. By the researches 
 of Gceppert, Unger, Dawson, Carruthers, and other botanists, 
 a knowledge has been acquired of a large number of Devonian 
 plants, only a few of which can be noticed here. As might 
 have been anticipated, the greater number of the vegetable 
 remains of this period have been obtained from such shallow- 
 water deposits as the Old Red Sandstone proper and the Gaspe 
 series of North America, and few traces of plant-life occur in 
 the strictly marine sediments. Apart from numerous remains, 
 mostly of a problematical nature, referred to the comprehensive 
 group of the Sea-weeds, a large number of Ferns have now 
 been recognised, some being of the ordinary plant-like type 
 (Pecopteris, Neuropteris, Aleihopteris, Sphenoptcris, &c.), whilst 
 others belong to the gigantic group of the " Tree - ferns " 
 (Psaronius, Caulopteris, &c.) Besides these there is an abun- 
 dant development of the singular extinct types of the Lepido- 
 dendroids, the Sigillarioids, and the Calamites, all of which 
 attained their maximum in the Carboniferous. Of these, the 
 Lepidodendra may be regarded as gigantic, tree-like Club-mosses 
 (LycopodiacecE] ; the Calamites are equally gigantic Horse-tails 
 (Equisetacecz) ; and the Sigillarioids, equally huge in size, in 
 some respects hold a position intermediate between the Club- 
 mosses and the Pines (Conifers). The Devonian rocks have
 
 DEVONIAN AND OLD RED PERIOD. 
 
 GENERALISED SECTION OF THE DEVONIAN ROCKS OF 
 NORTH AMERICA. 
 
 Fig. 76. 
 
 li 
 
 Catskill Group. 
 
 Chemung Group. 
 Portage Group. 
 
 Hamilton Group. 
 
 Corniferous Limestone. 
 
 Schoharie Grit. 
 Cauda-Galli Grit. 
 Oriskany Sandstone. 
 
 Lower Helderberg. 
 
 also yielded traces of many other plants (such as Annularia, 
 Asterophyllites, Cardiocarpon, &c.), which acquire a greater pre- 
 dominance in the Carboniferous period, and which will be 
 spoken of in discussing the structure of the plants of the Coal- 
 measures. Upon the whole, the one plant which may be con- 
 sidered as specially characteristic of the Devonian (though not 
 confined to this series) is the Psilophyton (fig. 77) of Dr Daw- 
 son. These singular plants have slender branching stems, 
 with sparse needle-shaped leaves, the young stems being at 
 first coiled up, crosier-fashion, like the young fronds of ferns, 
 whilst the old branches carry numerous spore-cases. The
 
 138 
 
 HISTORICAL PALAEONTOLOGY. 
 
 stems and branches seem to have attained a height of two or 
 three feet; and they sprang from prostrate "root-stocks " or 
 creeping stems. Upon the whole, 
 Principal Dawson is disposed to 
 regard Psilophyton as a "general- 
 ised type" of plants intermediate 
 between the Ferns and the Club- 
 mosses. Lastly, the Devonian de- 
 posits have yielded the remains of 
 the first actual trees with which we 
 are as yet acquainted. About the 
 nature of some of these (Ormoxylon 
 and Dadoxylori) no doubt can be 
 entertained, since their trunks not 
 only show the concentric rings of 
 growth characteristic of exogen- 
 ous trees in general, but their 
 woody tissue exhibits under the 
 microscope the " discs " which are 
 characteristic of the wood of the 
 Pines and Firs (see fig. 2). The 
 singular genus Prototaxites, how- 
 ever, which occurs in an older por- 
 tion of the Devonian series than 
 the above, is not in an absolutely 
 unchallenged position. By Prin- 
 cipal Dawson it is regarded as the 
 trunk of an ancient Conifer the 
 most ancient known ; but Mr 
 CarYuthers regards it as more pro- 
 bably the stem of a gigantic sea- 
 weed. The trunks of Prototaxites 
 (fig. 78, A) vary from one to three 
 feet in diameter, and exhibit con- 
 centric rings of growth ; but its 
 woody fibres have not hitherto 
 been clearly demonstrated to pos- 
 sess difcs. Before leaving, the 
 
 Devonian vegetation, it may be mentioned that the hornstone 
 or chert so abundant in the Cornifcrous limestone of North 
 America has been shown to contain the remains of various 
 microscopic plants (Diatoms and Desmids). We find also in 
 the same siliceous material the singular spherical bodies, with 
 radiating spines, which occur so abundantly in the chalk flints, 
 and which are termed Xanthidia. These may be regarded 
 
 Fig- 77 Restoration of Psilo- 
 phyton prince f>s Devonian, Can- 
 ada. (After Dawson.)
 
 DEVONIAN AXU OLD RED PERIOD. 
 
 139 
 
 as probably the spore-cases of the minute plants known as 
 Desmidia. 
 
 Fig. 78. A, Trunk of Prototaxites Log-am', eighteen inches in diameter, as seen in the 
 cliff near 1,'Anse Brehaut, Gaspe ; B, Two wood-cells showing spiral fibres and obscure 
 pores, highly magnified. Lower Devonian, Cauada. (After Dawson ) 
 
 The Devonian Protozoans have still to be fully investigat- 
 ed. True Sponges (such as Astraospongia, Sphcerospongia, 
 &c.) are not unknown; but by far the commonest repre- 
 sentatives of this sub-kingdom in the Devonian strata are 
 Stromatopora and its allies. These singular organisms (fig. 
 79) are not only very abundant in some of the Devonian lime- 
 stones both in the Old World and the New but they often 
 attain very large dimensions. However much they may differ 
 in minor details, the general structure of these bodies is that 
 of numerous, concentrically-arranged, thin, calcareous laminae, 
 separated by narrow interspaces, which in turn are crossed by 
 numerous delicate vertical pillars, giving the whole mass a 
 cellular structure, and dividing it into innumerable minute 
 quadrangular compartments. Many of the Devonian Stromato- 
 por<z also exhibit on their surface the rounded openings of 
 canals, which can hardly have served any other purpose than 
 that of permitting the sea-water to gain ready access to every 
 part of the organism. 
 
 No true Graptolitcs have ever been detected in strata of
 
 140 HISTORICAL PALEONTOLOGY. 
 
 Devonian age ; and the whole of this group has become ex- 
 tinguished unless \ve refer here the still surviving Dictyonemx. 
 
 Fig. 79. a, Part of the under surface of Stromatopora. tubercnlata, showing the 
 wrinkled basement membrane and the openings of water-canals, of the natural size; b, 
 Portion of the upper surface of the same, enlarged; c, Vertical section of a fragment, mag- 
 nified to show the internal structure. Corniferous Limestone, Canada. (Original.) 
 
 The Ccelenterates, however, are represented by a vast nu,mber 
 of Corals, of beautiful forms and very varied types. The 
 marbles of Devonshire, the Devonian limestones of the Eifel 
 and of France, and the calcareous strata of the Corniferous 
 and Hamilton groups of America, are often replete with the 
 skeletons of these organisms so much so as to sometimes 
 entitle the rock to be considered as representing an ancient 
 coral-reef. In some instances the Corals have preserved their 
 primitive calcareous composition ; and if they are embedded 
 in soft shales, they may weather out of the rock in almost all 
 their original perfection. In other cases, as in the marbles of 
 Devonshire, the matrix is so compact and crystalline that the" 
 included corals can only be satisfactorily studied by means of 
 polished sections. In other cases, again, the corals have been 
 more or less completely converted into flint, as in the Cornifer- 
 ous limestone of North America. When this is the case, they 
 often come, by the action of the weather, to stand out from
 
 DEVONIAN AND OLD RED PERIOD. 
 
 141 
 
 the enclosing rock in the boldest relief, exhibiting to the ob- 
 server the most minute details of their organisation. As before, 
 
 Fig. %\.Zat>hrentjs corm'cula, of the 
 natural size. Devonian, America. (Ori- 
 ginal.) 
 
 Fig. Ho. Cystipkyllum vesiculostttii, 
 showing a succession of cups produced by 
 budding from the original coral. Of the 
 natural size. Devonian, America and 
 Europe. (Original.) 
 
 Fig. %v.Helio/>Jiylhim exigiiunt, view 
 ed from in front and behind. Of the natu- 
 ral size. Devonian, Canada. (Original.) 
 
 the principal representatives of the Corals are still referable to 
 the groups of the Rugosa and Tabulata. Amongst the Rugose 
 group we find a vast number of simple " cup-corals," generally 
 known by the quarrymen as '' horns," from their shape. Of 
 il
 
 142 HISTORICAL PALEONTOLOGY. 
 
 the many forms of these, the species of Cyathophyllum, Helio- 
 phyllum (fig. 82), Zaphrentis (fig. 81), and Cystiphyllum (tig. 80), 
 are perhaps those most abundantly represented none of these 
 genera, however, except Heliophyllum, being peculiar to the 
 Devonian period. There are also numerous compound Ru- 
 gose corals, such as species of Eridophyllum, Diphyphyl- 
 lum, Syringopora, Phillipsastrtza, and some of the forms of 
 Cyathophyllum and Crepidophyllum (fig. 83). Some of these 
 compound corals attain a very large size, and form of them- 
 
 Fig. 83. Portion of a mass of Crepidophyllum A rchinci, of the natural size. 
 Hamilton formation, Canada. (After Billings.) 
 
 selves regular beds, which have an analogy, at any rate, with 
 existing coral-reefs, though there are grounds for believing that 
 these ancient types differed from the modern reef-builders in 
 being inhabitants of deep water. The " Tabulate Corals " are 
 hardly less abundant in the Devonian rocks than the Rugosa ; 
 and being invariably compound, they hardly yield to the latter 
 in the dimensions of the aggregations which they sometimes 
 form. 
 
 The commonest, and at the same time the largest, of these 
 are the " honeycomb corals," forming the genus Favosites 
 (figs. 84, 85), which derive both their vernacular and their 
 technical names from their great likeness to masses of petrified 
 honeycomb. The most abundant species are Favosites Goth- 
 landica and F. hemispherica, both here figured, which form 
 masses sometimes not less than two or three feet in diameter. 
 Whilst Favosites has acquired a popular name by its honey- 
 combed appearance, the resemblance of Michelinia to a fossil-
 
 DEVONIAN AND OLD RED PERIOD. 143 
 
 ised wasp's nest with the comb exposed is hardly less strik- 
 ing, and has earned for it a similar recognition from the 
 
 Fig. 84. Portion of a mass of Fayo- Fig. 85. Fragment of Favcsites hemi- 
 
 sites Gotlilatidica, of the natural size. spherica, of the natural size. Upper Silu- 
 
 Upper Silurian and Devonian of Europe rian and Devonian of America. (After 
 
 and America. (Original.) Billings.) 
 
 non-scientific public. In addition to these, there are numer- 
 ous branching or plant-like Tabulate Corals, often of the most 
 graceful form, which are distinctive of the Devonian in all 
 parts of the world. 
 
 The Echinoderms of the Devonian period call for little 
 special notice. Many of the Devonian limestones are "crin- 
 oidal;" and the Crinoids are the most abundant and widely- 
 distributed representatives of their class in the deposits of 
 this period. 
 
 The Cystideans, with doubtful exceptions, have not been 
 recognised in the Devonian ; and their place is taken by the 
 allied group of the " Pentremites," which will be further spoken 
 of as occurring in the Carboniferous rocks. On the other hand, 
 the Star-fishes, Brittle-stars, and Sea-urchins are all continued 
 by types more or less closely allied to those of the preceding 
 Upper Silurian. 
 
 Of the remains of Ringed-worms (Annelides), the most numer- 
 ous and the most interesting are the calcareous envelopes of 
 some small tube-inhabiting species. No one who has visited 
 the seaside can have failed to notice the little spiral tubes of 
 the existing Spirorbis growing attached to shells, or covering 
 the fronds of the commoner Sea weeds (especially Fucus ser- 
 ratus}. These tubes are inhabited by a small Annelida, and 
 structures of a similar character occur not uncommonly from 
 the Upper Silurian upwards. In the Devonian rocks, Spir- 
 orbis is an extremely common fossil, growing in hundreds 
 attached to the outer surface of corals and shells, and appearing
 
 144 
 
 HISTORICAL PALEONTOLOGY. 
 
 &, 
 
 Fig. 87. 
 
 uphatodes, natural 
 
 and enlarged, Devonian, Europe and America; 
 t, Spircrbis Arkonensis, of the natural size and 
 enlarged ; c, The same, with the tube twisted in 
 
 :ction. Devonian, America. (Ori- 
 
 in many specific forms (figs. 86 and 87) ; but almost all the 
 known examples are of small size, and are liable to escape a 
 
 cursory examination. 
 
 The Crustaceans of 
 the Devonian are prin- 
 cipally Eurypterids and 
 Trilobites. Some of the 
 former attain gigantic 
 dimensions, and the 
 quarrymen in the Scotch 
 Old Red give them the 
 name of " seraphim/' 
 from their singular 
 scale -like ornamenta- 
 tion. The Trilobites, 
 though still sufficiently 
 abundant in some local- 
 ities, have undergone a 
 yet further diminution 
 since the close of the 
 Upper Silurian. In both 
 America and Europe 
 quite a number of gen- 
 eric types have survived from the Silurian, but few or no new 
 ones make their appearance during this period in either the Old 
 
 the reverse di: 
 ginal.) 
 
 Fig. . a , prors la.rns, enarge, pper 
 Silurian, America ; c, Spirorbls spinulijcra, of the 
 natural size and enlarged, Devonian, Canada. (Af- 
 ter Hall and the Author.) 
 
 Fig. 88. Devonian Trilobites ft, Phacops latifrons, Devonian of Britain, the Conti- 
 nent of Europe, and South America ; b, Homalonotns armatus, Europe ; c, Phacops 
 (Trimcrocephalns) la-vis, Europe; if, Head-shield of Phacops (fortloctea) ^nimilains, 
 Europe. (After Salter and Burmeister.) 
 
 World or the New. The species, however, are distinct ; and the
 
 DEVONIAN AND OLD RED PERIOD. 145 
 
 principal forms belong to the genera Phacops (fig. 88, a, c, */), 
 Hotnalonotus (fig. 88, &}, Proetus, and Bronteus. The species 
 figured above under the name of Phacops latifrons (fig. 88, a}, 
 has an almost world-wide distribution, being found in the 
 Devonian of Britain, Belgium, France, Germany, Russia, Spain, 
 and South America ; whilst its place is taken in North Ame- 
 rica by the closely-allied Phacops rana. In addition to the 
 Trilobites, the Devonian deposits have yielded the remains of 
 a number of the minute Ostracoda, such as Entomis (" Cypri- 
 dina "), Leperditia, &c., which sometimes occur in vast num- 
 bers, as in the so-called " Cypridina Slates " of the German 
 Devonian. There are also a few forms of Phyllopods (Es- 
 theria). Taken as a whole, the Crustacean fauna of the 
 Devonian period presents many alliances with that of the 
 Upper Silurian, but has only slight relationships with that of 
 the Lower Carboniferous. 
 
 Besides Crustaceans, we meet here for the first time with 
 the remains of air-breatJiing Articulates, in the shape of Insects. 
 So far, these have only been obtained from the Devonian 
 rocks of North America, and they indicate the existence of at 
 least four generic types, all more or less allied to the existing 
 May-flies (EpJicmeridce). One of these interesting primitive 
 insects, namely, Platephemera antiqua (fig. 89), appears to have 
 measured five inches in ex- 
 panse of wing; and another 
 (Xenoneura antiquoruni) has 
 attached to its wing the re- 
 mains of a " stridulating- 
 organ " similar to that pos- 
 sessed by the modern Grass- 
 hoppers the instrument, as 
 Principal Dawson remarks, 
 of " the first music of living 
 things that Geology as yet 
 reveals to us." 
 
 Amongst the Mollusca, the Devonian rocks have yielded a 
 great number of the remains of Sea-mosses (Polyzoa). Some 
 of these belong to the ancient type Ptilodidya, which seems to 
 disappear here, or to the allied ClatJiropora (fig. 90), with its 
 fenestrated and reticulated fronds. We meet also with the 
 graceful and delicate stems of Ceriopora (fig. 91). 
 
 The majority of the Devonian Polyzoa belong, however, to 
 the great and important Palaeozoic group of the Lace-corals 
 (Fcnestdla, figs. 92 and 94, Retepora, fig. 93, Polypora, and 
 their allies). In all these forms there is a horny skeleton, of a
 
 146 
 
 HISTORICAL PALEONTOLOGY. 
 
 fan-like or funnel-shaped form, which grew attached by its 
 base to some foreign body. The frond consists of slightly- 
 
 Fig. 90. Fragment of Clathrofiora intertexta, of the 
 natura) size and enlarged. Devonian, Canada. (Original.) 
 
 Fig. 91. Fragment of 
 Ceriopora. Hamiitonensis, of 
 the natural size and enlarg- 
 ed. Devonian, Canada. (Ori- 
 ginal.) 
 
 diverging or nearly parallel branches, which are either united 
 by delicate cross-bars, or which bend alternately from side to 
 side, and become directly united with one another at short 
 intervals in either case giving origin to numerous oval or 
 
 3. Fragment of Retcpora 
 of the natural size and 
 Devonian, Canada. (Ori- 
 
 F ! g. 92. Fragment of Ft 
 the natural ' 
 
 esteUa 
 
 of the natural size and enlarged. 
 Canada. (Original.) 
 
 Devonian, 
 
 Fig. 94. Fragment of Fenestella 
 cribwa, of the natural size and enlarg- 
 ed. Devonian, Canada. (Original.) 
 
 oblong perforations, which communicate to the whole plant- 
 like colony a characteristic netted and lace-like appearance. 
 On one of its surfaces sometimes the internal, sometimes the 
 external the frond carries a number of minute chambers or
 
 DEVONIAN AND OLD RED PERIOD. 147 
 
 "cells," which are generally borne in rows on the branches, 
 and of which each originally contained a minute animal. 
 
 The Brachiopods still continue to be represented in great 
 force through all the Devonian deposits, though not occurring 
 in the true Old Red Sandstone. Besides such old types as 
 On 'his, Strophoinena, Lingula, Athyris, and Rhynchonella, we 
 find some entirely new ones ; whilst various types which only 
 commenced their existence in the Upper Silurian, now under- 
 go a great expansion and development. This last is especially 
 the case with the two families of the Spirifcrida and the Pro- 
 ductidce. The Spirifers, in particular, are especially character- 
 istic of the Devonian, both in the Old and New Worlds some 
 of the most typical forms, such as Spirifera mucronata (fig. 96), 
 having the shell " winged," or with the lateral angles prolonged 
 
 - . 
 
 scnlfiiilis. Devonian, Ca- Fig. &.Sf*rifera mucronatn. Devonian, America, 
 
 nada. (After Billings.) (After Killings.) 
 
 to such an extent as to have earned for them the popular name 
 of " fossil-butterflies." The closely-allied Spirifera disjuncta 
 occurs in Britain, France, Spain, Belgium, Germany, Russia, 
 and China. The family of the Productidcz commenced to exist 
 in the Upper Silurian, in the genus Chonetes ; and we shall 
 heieafter find it culminating in the Carboniferous in many 
 forms of the great genus Producta * itself. In the Devonian 
 period, there is an intermediate state of things, the genus 
 Chonetes being continued in new and varied types, and the 
 Carboniferous Products being represented by many forms of 
 the allied gronp Productella. Amongst other well-known De- 
 vonian Brachiopods may be mentioned the two long-lived and 
 persistent types Atrypa relicularis (fig. 97) and Strophomcna 
 rhomboidalis (fig. 98). The former of these commences in the 
 Upper Silurian, but is more abundantly developed in the De- 
 vonian, having a geographical range that is nothing less than 
 world-wide; whilst the latter commences in the Lower Silurian, 
 
 * The name of this genus is often written Productus, just as Spirifera 
 is often given in the masculine gender as Spirifer (the name originally given 
 to it). The masculine termination to these names is, however, grammati- 
 cally incorrect, as the feminine noun cochlea (shell) is in these cases under- 
 stood.
 
 148 
 
 HISTORICAL PALEONTOLOGY. 
 
 and, with an almost equally cosmopolitan range, survives into 
 the Carboniferous period. 
 
 Fig. 97. Atrypa reticularis. Upper Silurian and Devonian of Europe 
 and America. (After Billings.) 
 
 The Bivalves (Lamellibranchiatci) of the Devonian call for 
 no special comment, the genera Pterinea and Megalodon being, 
 
 Fig. 98. Strophomena rhomboidalis. Lower Silurian, Upper Silurian, and 
 Devonian of Europe and America. 
 
 perhaps, the most noticeable. The Univalves (Gasteropods], 
 also, need not be discussed in detail, though many interesting 
 forms of this group are known. The type most abundantly 
 represented, especially in America, is Platyceras (fig. 99), 
 
 comprising thin, wide - 
 mouthed shells, probably 
 most nearly allied to the 
 existing "Bonnet-limpets," 
 and sometimes attaining 
 very considerable dimen- 
 sions. We may also note 
 the continuance of the 
 6 genus Euomphalus, with 
 
 Fig. 99. Different views of Platyceras du- its discoidal Spiral shell. 
 ii'c;:nn, of the natural size. Devonian, Canada. A , rr . , j 
 
 (Original.) Amongst the Heteropods, 
 
 the survival of BdleropJwn 
 
 is to be recorded ; and in the " Winged-snails," or Pteropods, we 
 find new forms of the old genera Tentaculites and Conularia
 
 DEVONIAN AND OLD RED PERIOD. 
 
 149 
 
 (fig. 100). The latter, with its fragile, conical, and often beauti- 
 fully ornamented shell, is especially noticeable. 
 
 The remains of Cephalopoda are far from uncommon in the 
 Devonian deposits, all the known forms 
 being still Tetrabranchiate. Besides the 
 ancient types Orthoceras and Cyrtoceras, 
 we have now a predominance of the 
 spirally-coiled chambered shells of Goni- 
 atites and Clymenia. In the former of 
 these the shell is shaped like that of the 
 Nautilus ; but the partitions between the 
 chambers (" septa ") are more or less 
 lobed, folded, or angulated, and the 
 " siphuncle" runs along the back or con- 
 vex side of the shell these being char- 
 acters which approximate Goniatites to 
 the true Ammonites of the later rocks. 
 In Clymenia, on the other hand, whilst 
 the shell (fig. 101) is coiled into a flat 
 spiral, and the partitions or septa are 
 simple or only slightly lobed, there is still 
 this difference, as compared with the Nautilus ^ that the tube of 
 the siphuncle is placed on the inner or concave side of the 
 
 Fig. \oo.-Connlaria or- 
 nata, of the natural size. 
 Devonian, Europe. 
 
 j. 
 
 Fig. 101. Clymenia Sedgwickii. Devonian, Europe. 
 
 shell. The species of Clymenia are exclusively Devonian in
 
 150 HISTORICAL PALAEONTOLOGY. 
 
 their range ; and some of the limestones of this period in 
 Germany are so richly charged with fossils of this genus as to 
 have received the name of " Clymenien-kalk." 
 
 The sub-kingdom of the Vertebrates is still represented by 
 Fishes only ; but these are so abundant, and belong to such 
 varied types, that the Devonian period has been appropriately 
 called the " Age of Fishes." Amongst the existing fishes there 
 are three great groups which are of special geological import- 
 ance, as being more or less extensively represented in past time. 
 These groups are : (i) The Bony Fishes (Teleostei}, comprising 
 most existing fishes, in which the skeleton is more or less com- 
 pletely converted into bone ; the tail is symmetrically lobed or 
 divided into equal moieties ; and the scales are usually thin, 
 horny, flexible plates, which overlap one another to a greater 
 or less extent. (2) The Ganoid Fishes (Gatwidei), comprising 
 the modem Gar-pikes, Sturgeons, &c., in which the skeleton 
 usually more or less completely retains its primitive soft and 
 cartilaginous condition ; the tail is generally markedly unsym- 
 metrical, being divided into two unequal lobes ; and the scales 
 (when present) have the form of plates of bone, usually cov- 
 ered by a layer of shining enamel. These scales may overlap ; 
 or they may be rhomboidal plates, placed edge to edge in 
 oblique rows ; or they have the form of large-sized bony plates, 
 which are commonly united in the region of the head to form 
 a regular buckler. (3) The Placoid Fishes, or Elasmobranchii, 
 comprising the Sharks, Rays, and Chimtera of the present day, 
 in which the skeleton is cartilaginous; the tail is unsymmetri- 
 cally lobed ; and the scales have the form of detached bony 
 plates of variable size, scattered in the integument. 
 
 It is to the two last of these groups that the Devonian fishes 
 belong, and they are more specially referable to the Ganoids. 
 The order of the Ganoid fishes at the present day comprises 
 but some seven or eight genera, the species of which princi- 
 pally or exclusively inhabit fresh waters, and all of which are 
 confined to the northern hemisphere. As compared, there- 
 fore, with the Bony fishes, which constitute the great majority 
 of existing forms, the Ganoids form but an extremely small and 
 limited group. It was far otherwise, however, in Devonian 
 times. At this period, the bony fishes are not known to have 
 come into existence at all, and the Ganoids held almost undis- 
 puted possession of the waters. To what extent the Devonian 
 Ganoids were confined to fresh waters remains yet to be proved ; 
 and that many of them lived in the sea is certain. It was 
 formerly supposed that the Old Red Sandstone of Scotland 
 and Ireland, with its abundant fish-remains, might perhaps be 
 a fresh-water deposit, since the habitat of its fishes is uncer-
 
 DEVONIAN AND OLD RED PERIOD. 151 
 
 tain, and it contains no indubitable marine fossils. It has 
 been now shown, however, that the marine Devonian strata of 
 Devonshire and the continent of Europe contain some of the 
 most characteristic of the Old Red Sandstone fishes of Scot- 
 land ; whilst the undoubted marine deposit of the Corniferous 
 limestone of North America contains numerous shark-like and 
 Ganoid fishes, including such a characteristic Old Red genus 
 as Coccosteus. There can be little doubt, therefore, but that the 
 majority of the Devonian fishes were truly marine in their habits, 
 though it is probable that many of them lived in shallow water, 
 in the immediate neighbourhood of the shore, or in estuaries. 
 The Devonian Ganoids belong to a number of groups; and 
 
 Fig. 102. Fishes of the Devonian rocks of America, a. Diagram of the jaws and teeth 
 of Dinichthys Hertzeri, viewed from the front, and greatly reduced ; b, Diagram of the 
 skull of MacropetalichthysSulli-vanti, reduced in size ; c, A portion of the enair.elled sur- 
 face of the skull of the same, magnified ; d, One of the scales of Onyclwdns sigmoides, of 
 the natural size ; e, One of the front teeth of the lower jaw of the same, of the natural size \f, 
 Kin-spine of Machceracanthus major, a shark-like fish, reduced in size. (After New berry.) 
 
 it is only possible to notice a few of the most important forms 
 here. The modern group of the Sturgeons is represented,
 
 152 HISTORICAL PALEONTOLOGY. 
 
 more or less remotely, by a few Devonian fishes such as As- 
 tcrosteus ; and the great Macropetalichthys of the Corniferous 
 limestone of North America is believed by Newberry to belong 
 to this group. In this fish (fig. 102, b) the skull was of large 
 size, its outer surface being covered with a- tuberculated en- 
 amel ; and, as in the existing Sturgeons, the mouth seems to 
 have been wholly destitute of teeth. Somewhat allied, also, to 
 the Sturgeons, is a singular group of armoured fishes, which is 
 highly characteristic of the Devonian of Britain and Europe, 
 and less so of that of America. In these curious forms the 
 head and front extremity of the body were protected by a 
 buckler composed of large enamelled plates, more or less 
 firmly united to one another ; whilst the hinder end of the body 
 was naked, or was protected with small scales. Some forms of 
 this group such as Pteraspis and Coccosteus date from the 
 Upper Silurian ; but they attain their maximum in the Devo- 
 nian, and none of them are known to pass upwards into the 
 overlying Carboniferous rocks. Amongst the most character- 
 istic forms of this group may be mentioned Cephalaspis (fig. 
 103) and Pterichthys (fig. 104). In the former of these the 
 
 Lyellii. Old Red Sandstone, Scotland. (After Page.) 
 
 head-shield is of a crescentic shape, having its hinder angles 
 produced backwards into long " horns," giving it the shape of 
 a " saddler's knife." No teeth have been discovered ; but the 
 bod/ was covered with small ganoid scales, and there was an 
 unsymmetrical tail-fin. In Pterichthys which, like the preced- 
 ing, was first brought to light by the labours of Hugh Miller - 
 the whole of the head and the front part of the body were de- 
 fended by a buckler of firmly-united enamelled plates, whilst 
 the rest of the body was covered with small scales. The form 
 of the "pectoral fins" was quite unique these having the 
 shape of two long, curved spines, somewhat like wings, covered 
 by finely-tuberculated ganoid plates. All the preceding forms
 
 DEVONIAN AND OLD RED PERIOD. 153 
 
 of this group are of small size ; but few fishes, living or extinct, 
 could rival the proportions of the great Dinichthys, referred to 
 
 Fig. -iot,.Pterichthys cornutus. Old Red Sandstone, Scotland. (After Agassiz.) 
 
 this family by Newberry. In this huge fish (fig. 102, a) the 
 head alone is over three feet in length, and the body is sup- 
 posed to have been twenty-five or thirty feet long. The head 
 was protected by a massive cuirass of bony plates firmly articu- 
 lated together, but the hinder end of the body seems to have 
 been simply enveloped in a leathery skin. The teeth are of 
 the most formidable description, consisting in both jaws of 
 serrated dental plates behind, and 'in front of enormous coni- 
 cal tusks (fig. 102, a). Though immensely larger, the teeth of 
 Dinichthys present a curious resemblance to those of the exist- 
 ing Mud-fishes (Lepidosiren). 
 
 In another great group of Devonian Ganoids, we meet with 
 fishes more or less closely allied to the living Polypteri (fig. 
 105) of the Nile and Senegal. In this group (fig. 106) the 
 pectoral fins consist of a central scaly lobe carrying the fin- 
 rays on both sides, the scales being sometimes rounded and 
 overlapping (fig. 106), or more commonly rhomboidal and 
 placed edge to edge (fig. 105, A). Numerous forms of these 
 " Fringe-finned " Ganoids occur in the Devonian strata, such 
 as HoloptycJiius, Glyptolczmus, Osfcolcpis, Phaneropleuron , &c. 
 To this group is also to be ascribed the huge Onychodus (fig. 
 102, d and e), with its large, rounded, overlapping scales, an 
 inch in diameter, and its powerful pointed teeth. It is to be 
 remembered, however, that some of these "Fringe-finned" 
 Ganoids are probably referable to the small but singular group 
 of the " Mud-fishes" (Dipnoi), represented at the present day 
 by the singular Lepidosircn of South America and Africa, and 
 the Ceratodus of the rivers of Queensland. 
 
 Leaving the Ganoid fishes, it still remains to be noticed that 
 the Devonian deposits have yielded the remains of a number 
 of fishes more or less closely allied to the existing Sharks,
 
 54 
 
 HISTORICAL PALEONTOLOGY. 
 
 Rays, and ChimcsriR (the Elasmobranchii). The majority of 
 the forms here alluded to are allied not to the true Sharks and 
 
 Fig. 105. A, Po'.ypterns, a recent Ganoid fish ; B, Osteolef-is, a Devonian Ganoid ; 
 a a, Pectoral fins, showi.ig the fin-rays arranged round a central lobe. 
 
 Dog-fishes, but to the more peaceable " Port Jackson Sharks," 
 with their blunt teeth, adapted for crushing the shells of Mol- 
 luscs. The collective name of " Cestracionts " is applied to 
 these; and we have evidence of their past existence in the 
 
 Fig. \<&.Ho:optych, 
 
 mis, restored. Old Red Sandstone, Scotland. 
 A, Scale of the same. 
 
 Devonian seas both by their teeth, and by the defensive spines 
 which were implanted in front of a greater or less number of 
 the fins. These are bony spines, often variously grooved, 
 serrated, or ornamented, with hollow bases, implanted in the 
 integument, and capable of being erected or depressed at will.
 
 DEVONIAN AND OLD RED PERIOD. 155 
 
 Many of these " fin-spines " have been preserved to us in the 
 fossil condition, and the Devonian rocks have yielded examples 
 belonging to many genera. As some of the true Sharks and 
 Dog-fishes, some of the Ganoids, and even some Bony Fishes, 
 possess similar defences, it is often a matter of some uncer- 
 tainty to what group a given spine is to be referred. One of 
 these spines, belonging to the genus Machceracanthus, from the 
 Devonian rocks of America, has been figured in a previous 
 illustration (fig. 102, f). 
 
 In conclusion, a very few words may be said as to the 
 validity of the Devonian series as an independent system of 
 rocks, preserving in its successive strata the record of an 
 independent system of life. Some high authorities have been 
 inclined to the view that the Devonian formation has in nature 
 no actual existence, but that it is made up partly of beds 
 which should be referred to the summit of the Upper Silurian, 
 and partly of beds which properly belong to the base of the 
 Carboniferous. This view seems to have been arrived at in 
 consequence of a too exclusive study of the Devonian series 
 of the British Isles, where the physical succession is not wholly 
 clear, and where there is a striking discrepancy between the 
 organic remains of those two members of the series which are 
 known as the "Old Red Sandstone" and the "Devonian" 
 rocks proper. This discrepancy, however, is not complete; 
 and, as we have seen, can be readily explained on the sup- 
 position that the one group of rocks presents us with the 
 shallow water and littoral deposits of the period, while in the 
 other we are introduced to the deep-sea accumulations of the 
 same period. Nor can the problem at issue be solved by an 
 appeal to the phenomena of the British area alone, be the 
 testimony of these what it may. As a matter of fact, there is 
 at present no sufficient ground for believing that there is any 
 irreconcilable discordance between the succession of rocks 
 and of life in Britain during the period which elapsed between 
 the deposition of the Upper Ludlow and the formation of the 
 Carboniferous Limestone, and the order of the same phe- 
 nomena during the same period in other regions. Some of 
 the Devonian types of life, as is the case with all great forma- 
 tions, have descended unchanged from older types ; others 
 pass upwards unchanged to the succeeding period : but the 
 fauna and flora of the Devonian period are, as a whole, quite 
 distinct from those of the preceding Silurian or the succeeding 
 Carboniferous ; and they correspond to an equally distinct 
 rock-system, which in point of time holds an intermediate 
 position between the two great groups just mentioned. As
 
 156 HISTORICAL PALEONTOLOGY. 
 
 before remarked, this conclusion may be regarded as suffi- 
 ciently proved even by the phenomena of the British area ; 
 but it may be said to be rendered a certainty by the study of 
 the Devonian deposits of the continent of Europe or, still 
 more, by the investigation of the vast, for the most part un- 
 interrupted and continuous series of sediments which com- 
 menced to be laid down in North America at the beginning of 
 the Upper Silurian, and did not cease till, at any rate, the close 
 of the Carboniferous. 
 
 LITERATURE. 
 
 The following list comprises the more important works and memoirs to 
 which the student of Devonian rocks and fossils may refer : 
 
 (1) ' Siluria.' Sir Roderick Murchison. 
 
 (2) ' Geology of Russia in Europe.' Murchison (together with De 
 
 Verneuil and Count von Keyserling). 
 
 (3) "Classification of the Older Rocks of De von and Cornwall" ' Proc. 
 
 Geol. Soc.,' vol. iii., 1839. Sedgvvick and Murchison. 
 
 (4) " On the Physical Structure of Devonshire ;" and on the " Classifi- 
 
 cation of the Older Stratified Rocks of Devonshire and Cornwall " 
 'Trans. Geol. Soc.,' vol. v., 1840. Sedgwick and Murchison. 
 
 (5) " On the Distribution and Classification of the Older or Pa'seozoic 
 
 Rocks of North Germany and Belgium" 'Geol. Trans., *2d ser. , 
 vol. vi., 1842. Sedgwick and Murchison. 
 
 (6) ' Report on the Geology of Cornwall, Devon, and West Somerset.' 
 
 De la Beche. 
 
 (7) 'Memoirs of the Geological Survey of Ireland and Scotland.' 
 
 Jukes and Geikie. 
 
 (8) " On the Carboniferous Slate (or Devonian Rocks) and the Old 
 
 Red Sandstone of South Ireland and North Devon" 'Quart. 
 Journ. Geol. Soc.,' vol. xxii. Jukes. 
 
 (9) " On the Physical Structure of West Somerset and North Devon ; " 
 
 and on the " Palaeontological Value of Devonian Fossils" 'Quart. 
 Journ. Geol. Soc.,' vol. iii. Etheridge. 
 
 (10) "On the Connection of the Lower, Middle, and Upper Old Red 
 
 Sandstone of Scotland" 'Trans. Edin. Geol. Soc.,' vol. i. part ii. 
 Powrie. 
 
 (11) 'The Old Red Sandstone,' 'The Testimony of the Rocks,' and 
 
 ' Footprints of the Creator.' Hugh Miller. 
 
 (12) " Report on the 4th Geological District" 'Geology of New York,' 
 
 vol. iv. James Hall. 
 
 (13) 'Geology of Canada,' 1863. Sir W. E. Logan. 
 
 (14) ' Acadian Geology. ' Dawson. 
 
 (15) ' Manual of Geology.' Dana. 
 
 (ib) 'Geological Survey of Ohio,' vol. i. 
 
 (17) 'Geological Survey of Illinois,' vol. i. 
 
 (18) 'Palaeozoic Fossils of Cornwall, Devon, and West Somerset.' 
 
 Phillips. 
 
 (19) ' Recherches sur les Poissons Fossiles.' Agassiz. 
 
 (20) ' Poissons de 1' Old Red.' Agassiz. 
 
 (21) " On the Classification of Devonian Fishes'* 'Mem. Geol. Survey 
 
 of Great Britain,' Decace X. Huxley.
 
 THE CARBONIFEROUS PERIOD. 157 
 
 (22) 'Monograph of the Fishes of the Old Red Sandstone of Britain* 
 
 (Palaeontographical Society). Powrie and Lankester. 
 
 (23) ' Fishes of the Devonian System, Palaeontology of Ohio.' New- 
 
 berry. 
 
 (24) ' Monograph of British Trifobites ' (Palaeontographical Society). 
 
 Saher. 
 
 (25) ' Monograph of British Merostomata ' (Palaeontographical Society). 
 
 Henry Woodward. 
 
 (26) ' Monograph of British Brachiopoda ' (Palaeontographical Society). 
 
 Davidson. 
 
 (27) 'Monograph of British Fossil Corals' (Palaeontographical Society). 
 
 Milne-Edwards and Haime. 
 
 (28) ' Polypiers Foss. des Terrains Paleozoiques.' Milne-Edwards 
 
 and Jules Haime. 
 
 (29) " Devonian Fossils of Canada West " ' Canadian Journal,' new ser., 
 
 vols. iv.-vi. Billings. 
 
 (30) 'Palaeontology of New York,' vol. iv. James Hall. 
 
 (31) 'Thirteenth, Fifteenth, and Twenty-third Annual Reports on the 
 
 State Cabinet.' James Hall. 
 
 (32) ' Palaeozoic Fossils of Canada,' vol. ii. Billings. 
 
 (33) 'Reports on the Palaeontology of the Province of Ontario for 1874 
 
 and 1875.' Nicholson. 
 
 (34) " The Fossil Plants of the Devonian and Upper Silurian Formations 
 
 of Canada" ' Geol. Survey of Canada. ' Dawson. 
 
 (35) ' Petrefacta Germaniae.' Goldfuss. 
 
 (36) ' Versteinerungen der Grauwacken-formation.' &c. Geinitz. 
 
 (37) ' Beitrag zur Palaeonlologie des Thuringer- \Valdes.' Richter and 
 
 Unger. 
 
 (38) ' Ueber die Placodermen der Devonischen System.' Pander. 
 
 (39) 'Die Gattungen der Fossilen Pflanzen.' Greppert. 
 
 (40) ' Genera et Species Plantarum Fossilium.' Unger. 
 
 CHAPTER XII. 
 THE CARBONIFEROUS PERIOD. 
 
 Overlying the Devonian formation is the great and import- 
 ant series of the Carboniferous Rocks, so called because workable 
 beds of coal are more commonly and more largely developed 
 in this formation than in any other. Workable coal-seams, 
 however, occur in various other formations (Jurassic, Cretace- 
 ous, Tertiary), so that coal is not an exclusively Carboniferous 
 product ; whilst even in the Coal-measures themselves the coal 
 bears but a very small proportion to the total thickness of 
 strata, occurring only in comparatively thin beds intercalated 
 in a great series of sandstones, shales, and other genuine 
 aqueous sediments, 
 li
 
 158 HISTORICAL PALEONTOLOGY. 
 
 Stratigraphically, the Carboniferous rocks usually repose 
 conformably upon the highest Devonian beds, so that the line 
 of demarcation between the Carboniferous and Devonian for- 
 mations is principally a palaeontological one, founded on the 
 observed differences in the fossils of the two groups. On the 
 other hand, the close of the Carboniferous period seems to 
 have been generally, though not universally, signalised by 
 movements of the crust of the earth, so that the succeeding 
 Permian beds oflen lie unconformably upon the Carboniferous 
 sediments. 
 
 Strata of Carboniferous age have been discovered in almost 
 every large land-area which has been sufficiently investigated ; 
 but they are especially largely developed in Britain, in various 
 parts of the continent of Europe, and in North America. 
 Their general composition, however, is, comparatively speak- 
 ing, so uniform, that it will suffice to take a comprehensive 
 view of the formation without considering any one area in 
 detail, though in each region the subdivisions of the formation 
 are known by distinctive local names. Taking such a com- 
 prehensive view, it is found that the Carboniferous series is 
 generally divisible into a Lower and essentially calcareous 
 group (the " Sub-Carboniferous " or " Carboniferous Lime- 
 stone"); a Middle and principally arenaceous group (the 
 " Millstone Grit"); and an Upper group, of alternating shales 
 and sandstones, with workable seams of coal (the " Coal- 
 measures "). 
 
 I. The Carboniferous, Sub- Carboniferous, or Mountain Lime- 
 stone Series constitutes the general base of the Carboniferous 
 system. As typically developed in Britain, the Carboniferous 
 Limestone is essentially a calcareous formation, sometimes 
 consisting of a mass of nearly pure limestone from 1000 to 
 2000 feet in thickness, or at other times of successive great 
 beds of limestone with subordinate sandstones and shales. 
 In the north of England the base of the series consists of 
 pebbly conglomerates and coarse sandstones ; and in Scot- 
 land generally, the group is composed of massive sandstones 
 with a comparatively feeble development of the calcareous 
 element. In Ireland, again, the base of the Carboniferous 
 Limestone is usually considered to be formed by a locally- 
 developed group of grits and shales (the " Coomhola Grits " 
 and " Carboniferous Slate "), which attain the thickness of 
 about 5000 feet, and contain an intermixture of Devonian 
 with Carboniferous types of fossils. Seeing that the Devonian 
 formation is generally conformable to the Carboniferous, we 
 need feel no surprise at this intermixture of forms ; nor does it
 
 THE CARBONIFEROUS PERIOD. 159 
 
 appear to be of great moment whether these strata be referred 
 to the former or to the latter series. Perhaps the most satis- 
 factory course is to regard the Coomhola Grits and Carbon- 
 iferous Slates as "passage-beds" between the Devonian and 
 Carboniferous ; but any view that may be taken as to the 
 position of these beds, really leaves unaffected the integrity 
 of the Devonian series as a distinct life-system, which, on the 
 whole, is more closely allied to the Silurian than to the Car- 
 boniferous. In North America, lastly, the Sub-Carboniferous 
 series is never purely calcareous, though in the interior of the 
 continent it becomes mainly so. In other regions, however, 
 it consists principally of shales and sandstones, with subor- 
 dinate beds of limestone, and sometimes with thin beds of 
 coal or deposits of clay-ironstone. 
 
 II. The Millstone Grit. The highest beds of the Carbon- 
 iferous Limestone series are succeeded, generally with perfect 
 conformity, by a scries of arenaceous beds, usually known as 
 the Millstone Grit. As typically developed in Britain, this 
 group consists of hard quartzose sandstones, often so large- 
 grained and coarse in texture as to properly constitute fine 
 conglomerates. In other cases there are regular conglomer- 
 ates, sometimes with shales, limestones, and thin beds of coal 
 the thickness of the whole series, when well developed, varying 
 from 1000 to 5000 feet. In North America, the Millstone 
 Grit rarely reaches 1000 feet in thickness; and, like its Brit- 
 ish equivalent, consists of coarse sandstones and grits, some- 
 times with regular conglomerates. Whilst the Carboniferous 
 Limestone was undoubtedly deposited in a tranquil ocean 
 of considerable depth, the coarse mechanical sediments of 
 the Millstone Grit indicate the progressive shallowing of 
 the Carboniferous seas, and the consequent supervention 
 of shore-conditions. 
 
 III. The Coal-meastires. The Coal-measures properly so 
 called rest conformably upon the Millstone Grit, and usually 
 consist of a vast series of sandstones, shales, grits, and coals, 
 sometimes with beds of limestone, attaining in some regions a 
 total thickness of from 7000 to nearly 14,000 feet. Beds of 
 workable coal are by no means unknown in some areas in the 
 inferior group of the Sub-Carboniferous; but the general state- 
 ment is true, that coal is mostly obtained from the true Coal- 
 measures the largest known, and at present most produc- 
 tive coal-fields of the world being in Great Britain, North 
 America, and Belgium. Wherever they are found, with 
 limited exceptions, the Coal - measures present a singular 
 general uniformity of mineral composition. They consist,
 
 160 HISTORICAL PAL/EONTOLOGY. 
 
 namely, of an indefinite alternation of beds of sandstone, 
 shale, and coal, sometimes with bands of clay-ironstone or beds 
 of limestone, repeated in no constant order, but sometimes 
 attaining the enormous aggregate thickness of 14,000 feet, or 
 little short of 3 miles. The beds of coal differ in number and 
 thickness in different areas, but they seldom or never exceed 
 one-fiftieth part of the total bulk of the formation in thickness. 
 The characters of the coal itself, and the way in which the 
 coal-beds were deposited, will be briefly alluded to in speaking 
 of the vegetable life of the period. In Britain, and in the Old 
 World generally, the Coal-measures are composed partly of 
 genuine terrestrial deposits such as the coal and partly of 
 sediments accumulated in the fresh or brackish waters of vast 
 lagoons, estuaries, and marshes. The fossils of the Coal- 
 measures in these regions are therefore necessarily the remains 
 either of terrestrial plants and animals, or of such forms of 
 life as inhabit fresh or brackish waters, the occurrence of strata 
 with marine fossils being quite a local and occasional phe- 
 nomenon. In various parts of North America, on the other 
 hand, the Coal-measures, in addition to sandstones, shales, 
 coal-seams, and bands of clay-ironstone, commonly include 
 beds of limestone, charged with marine remains, and indicating 
 marine conditions. The subjoined section (fig. 107) gives, in 
 a generalised form, the succession of the Carboniferous strata 
 in such a British area as the north of England, where the series 
 is developed in a typical form. 
 
 As regards the life of the Carboniferous period, we naturally 
 find, as has been previously noticed, great differences in dif- 
 ferent parts of the entire series, corresponding to the different 
 mode of origin of the beds. Speaking generally, the Lower 
 Carboniferous (or the Sub-Carboniferous) is characterised by 
 the remains of marine animals ; whilst the Upper Carbon- 
 iferous (or Coal-measures) is characterised by the remains 
 of plants and terrestrial animals. In all those cases, how- 
 ever, in which marine beds are found in the series of the 
 Coal-measures, as is common in America, then we find that the 
 fossils agree in their general characters with those of the older 
 marine deposits of the period. 
 
 Owing to the fact that coal is simply compressed and other- 
 wise altered vegetable matter, and that it is of the highest 
 economic value to man, the Coal-measures have been more 
 thoroughly explored than any other group of strata of equiva- 
 lent thickness in the entire geological series. Hence we have 
 already a very extensive acquaintance with the plants of the 
 Carboniferous period ; and our knowledge on this subject is
 
 THE CARBONIFEROUS PERIOD. 
 
 161 
 
 daily undergoing increase. It is not to be supposed, however, 
 that the remains of plants are found solely in the Coal- 
 
 GENERALISED SECTION OF THE CARBONIFEROUS STRATA 
 OF THE NORTH OF ENGLAND. 
 
 Fig. 107. 
 
 li 
 
 wU 
 
 8 
 
 Permian (New Red Sand- 
 stone). 
 
 - Coal-measures. 
 
 Millstone Grit. 
 
 Yoredale Series. 
 
 Scar-Limestone Series. 
 
 Basement Beds (Conglom- 
 erates and Sandstones). 
 
 measures ; for though most abundant towards the summit, 
 they are found in less numbers in all parts of the series. 
 Wherever found, they belong to the same great types of vege-
 
 l62 HISTORICAL PALEONTOLOGY. 
 
 tation ; but, before reviewing these, a few words must be said 
 as to the origin and mode of formation of coal. 
 
 The coal - beds, as before mentioned, occur interstratified 
 with shales, sandstones, and sometimes limestones ; and there 
 may, within the limits of a single coal-field, be as many as 80 
 or too of such beds, placed one above the other at different 
 levels, and varying in thickness from a few inches up to 20 or 
 30 feet. As a general rule, each bed of coal rests upon a bed 
 of shale or clay, which is termed the "under-clay," and in 
 which are found numerous roots of plants ; whilst the strata 
 immediately on the top of the coal may be shaly or sandy, 
 but in either case are generally charged with the leaves and 
 stems of plants, and often have upright trunks passing vertically 
 through them. When we add to this that the coal itself is, 
 chemically, nearly wholly composed of carbon, and that its 
 microscopic structure shows it to be composed almost entirely 
 of fragments of steins, leaves, bark, seeds, and vegetable debris 
 derived from land-plants, we are readily enabled to understand 
 how the coal was formed. The "under -clay" immediately 
 beneath the coal-bed represents an old land-surface some- 
 times, perhaps, the bottom of a swamp or marsh, covered 
 with a luxuriant vegetation ; the coal bed itself represents the 
 slow accumulation, through long periods, of the leaves, seeds, 
 fruits, stems, and fallen trunks of this vegetation, now hardened 
 and compressed into a fraction of its original bulk by the pres- 
 sure of the superincumbent rocks ; and the strata of sand or 
 shale above the coal-bed the so-called ".roof" of the coal 
 represent sediments quietly deposited as the land, after a long 
 period of repose, commenced to sink beneath the sea. On 
 this view, the rank and long-continued vegetation which gave 
 rise to each coal-bed was ultimately terminated by a slow 
 depression of the surface on which the plants grew. The 
 land-surface then became covered by the water, and aqueous 
 sediments were accumulated to a greater or less thickness upon 
 the dense mass of decaying vegetation below, enveloping any 
 trunks of trees which might still be in an erect position, and 
 preserving between their layers the leaves and branches of 
 plants brought down from the neighbouring land by streams, 
 or blown into the water by the wind. Finally, there set in a 
 slow movement of elevation, the old land again reappeared 
 above the water; a new and equally luxuriant vegetation 
 flourished upon the new land-surface ; and another coal-bed 
 was accumulated, to be preserved ultimately in a similar 
 fashion. Some few beds of coal may have been formed by 
 drifted vegetable matter brought down into the ocean by rivers,
 
 THE CARBONIFEROUS PERIOD. 163 
 
 and deposited directly on the bottom of the sea ; but in the 
 majority of cases the coal is undeniably the result of the slow 
 growth and decay of plants in situ ; and as the plants of the 
 coal are not marine plants, it is necessary to adopt some such 
 theory as the above to account for the formation of coal- 
 seams. By this theory, as is obvious, we are compelled to 
 suppose that the vast alluvial and marshy flats upon which the 
 coal-plants grew were liable to constantly-recurring oscillations 
 of level, the successive land-surfaces represented by the suc- 
 cessive coal-beds of any coal-field being thus successively 
 buried beneath accumulations of mud or sand. We have no 
 need, however, to suppose that these oscillations affected large 
 areas at the same time ; and geology teaches us that local 
 elevations and depressions of the land have been matters of 
 constant occurrence throughout the whole of past time. 
 
 All the varieties of coal (bituminous coal, anthracite, cannel- 
 coal, &c.) show a more or less distinct "lamination" that is 
 to say, they are more or less obviously composed of successive 
 thin layers, differing slightly in colour and texture. All the 
 varieties of coal, also, consist chemically of carbon, with vary- 
 ing proportions of certain gaseous constituents and a small 
 amount of incombustible mineral or " ash." By cutting thin 
 and transparent slices of coal, we are further enabled, by 
 means of the microscope, to ascertain precisely not only that 
 the carbon of the coal is derived from vegetables, but also, in 
 many cases, what kinds of plants, and what parts of these, enter 
 into the formation of coal. When examined in this way, all 
 coals are found to consist more or less entirely of vegetable 
 matter; but there is considerable difference in different coals as 
 to the exact nature of this. By Professor Huxley it has been 
 shown that many of the English coals consist largely of ac- 
 cumulations of rounded discoidal sacs or bags, which are 
 unquestionably the seed-vessels or " spore-cases " of certain of 
 the commoner coal-plants (such as the Lepidodendra). The 
 best bituminous coals seem to be most largely composed of 
 these spore-cases ; whilst inferior kinds possess a progressively 
 increasing amount of the dull carbonaceous substance which is 
 known as " mineral charcoal," and which is undoubtedly com- 
 posed of " the stems and leaves of plants reduced to little 
 more than their carbon." On the other hand, Principal Daw- 
 son finds that the American coals only occasionally exhibit 
 spore-cases to any extent, but consist principally of the cells, 
 vessels, and fibres of the bark, integumentary coverings, and 
 woody portions of the Carboniferous plants. 
 
 The number of plants already known to have existed during
 
 1 64 HISTORICAL PALAEONTOLOGY. 
 
 the Carboniferous period is so great, that nothing more can be 
 done here than to notice briefly the typical and characteristic 
 groups of these such as the Ferns, the Catamites, the Lepido- 
 dendroids, the Sigillarioids, and the Conifers. 
 
 In accordance with M. Brongniart's generalisation, that 
 the Palaeozoic period is, botanically speaking, the "Age of 
 Acrogens," we find the Carboniferous plants to be still mainly 
 referable to the Flowerless or " Cryptogamous " division of the 
 vegetable kingdom. The flowering or " Phanerogamous " 
 plants, which form the bulk of our existing vegetation, are hardly 
 known, with certainty, to have existed at all in the Carbon- 
 iferous era, except as represented by trees related to the existing 
 
 Fig. i<&.Odontopteris SMothchnii. Carboniferous, Europe and North America. 
 
 Pines and Firs, and possibly by the Cycads or "false palms."* 
 Amongst the " Cryptogams," there is no more striking or 
 beautiful group of Carboniferous plants than the Ferns. .Re- 
 mains of these are found all through the Carboniferous, but in 
 exceptional numbers in the Coal-measures, and include both 
 herbaceous forms like the majority of existing species, and 
 arborescent forms resembling the living Tree-ferns of New 
 Zealand. Amongst the latter, together with some new types, 
 are examples of the genera Psaronius and Caulopteris, both of 
 
 * Whilst the vegetation of the Coal-period was mainly a terrestrial one, 
 aquatic plants are not unknown. Sea-weeds (such as the Spirophyton 
 cauda-Galli] are common in some of the marine strata ; whilst coal, 
 according to the researches of the Abbe Castracane, is asserted commonly 
 to contain the siliceous envelopes of Diatoms.
 
 THE CARBONIFEROUS PERIOD. 
 
 165 
 
 which date from the Devonian. The simply herbaceous ferns 
 are extremely numerous, and belong to such widely-distributed 
 
 Fig. 109. Ca'amites can 
 
 cfformis . Carboniferous Rocks, Europe and 
 North America. 
 
 and largely-represented genera as Neuropteris, Odontopteris (fig. 
 
 1 08), Alethopteris, Pccopteris, Sphenopteris, Hymenophyllites, &c. 
 
 The fossils known as Catamites (fig. 109) are very common
 
 1 66 HISTORICAL PALEONTOLOGY. 
 
 in the Carboniferous deposits, and have given occasion to an 
 abundance of research and speculation. They present them- 
 selves as prostrate and flattened striated stems, or as similar 
 uncompressed stems growing in an erect position, and some- 
 times attaining a length of twenty feet or more. Externally, the 
 stems are longitudinally ribbed, with transverse joints at regular 
 intervals, these joints giving origin to a whorl of branchlets, 
 which may or may not give origin to similar whorls of smaller 
 branchlets still. The stems, further, were hollow, with trans- 
 verse partitions at the joints, and having neither true wood nor 
 bark, but only a thin external fibrous shell. There can be little 
 doubt but that the Calamites are properly regarded as colossal 
 representatives of the little Horse-tails (Equisetacece) of the 
 present day. They agree with these not only in the general 
 details of their organisation, but also" in the fact that the fruit 
 was a species of cone, bearing " spore-cases " under scales. 
 According to Principal Dawson, the Calamites " grew in dense 
 brakes on the sandy and muddy flats, subject to inundation, 
 or perhaps even in water ; and they had the power of budding 
 out from the base of the stem, so as to form clumps of plants, 
 and also of securing their. foothold by numerous cord-like roots 
 proceeding from various heights on the lower part of the 
 stem." 
 
 The Lepidodendroids, represented mainly by the genus 
 Lepidodendron itself (fig. no), were large tree-like plants, 
 which attain their maximum in the Carboniferous period, but 
 which appear to commence in the Upper Silurian, are well 
 represented in the Devonian, and survive in a diminished form 
 into the Permian. The trunks of the larger species of Lepido- 
 dendron at times reach a length of fifty feet and upwards, giv- 
 ing off branches in a regular bifurcating manner. The bark 
 is marked with numerous rhombic or oval scars, arranged in 
 quincunx order, and indicating the points where the long, 
 needle-shaped leaves were formerly attached. The fruit con- 
 sisted of cones or spikes, carried at the ends of the branches, 
 and consisting of a central axis surrounded by overlapping 
 scales, each of which supports a " spore-case " or seed-vessel. 
 These cones have commonly been described under the name 
 of Lepidostrobi, In the structure of the trunk there is nothing 
 comparable to what is found in existing trees, there being 
 a thick bark surrounding a zone principally composed of 
 "scalariform" vessels, this in turn enclosing a large central pith. 
 In their general appearance the Lepidodendra bring to mind 
 the existing Araucarian Pines ; but they are true " Crypto- 
 gams," and are to be regarded as a gigantic extinct type of the
 
 THE CARBONIFEROUS PERIOD. 
 
 i6 7 
 
 modern Club-mosses (Lycopodiarca). They are amongst the 
 commonest and most characteristic of the Carboniferous 
 
 Fig. ito.- LefidntJendron Sternhergii, Carboniferous, F.urope. The central figure 
 represents a portion ot tue trunk with its branches, much reduced in size. The right- 
 hand figure is a portion of a branch with the leaves partially attached to it ; and the left- 
 hand figure represents the end of a branch bearing a cone of fructification. 
 
 plants; and the majority of the "spore-cases" so commonly 
 found in the coal appear to have been derived from the cones 
 of Lepidodendroids.
 
 1 68 
 
 HISTORICAL PALEONTOLOGY. 
 
 The so-called Sigillarioids, represented mainly by Sigillaria 
 itself (fig. in), were no less abundant and characteristic of the 
 Carboniferous forests than the Lepidodendra. They commence 
 their existence, so far as known, in the Devonian period, but 
 they attain their maximum in the Carboniferous ; and unlike 
 the Lepidodendroids they are not known to occur in the 
 Permian period. They are comparatively gigantic in size, 
 often attaining a height of from thirty to fifty feet or more ; 
 but though abundant and well preserved, great divergence of 
 opinion prevails as to their true affinities. The name of Sigil- 
 larioids (Lat. sigilla, little seals or images) is derived from the 
 fact that the bark is marked with seal-like impressions or leaf- 
 scars (fig. in). 
 
 Externally, the trunks ok Sigillaria present .strong longitudinal 
 ridges, with vertical alternating rows of oval leaf scars indicating 
 
 Fig. in. Fragment of the external surface of Sigillaria Grosser!, showing the ribs and 
 leaf-scars. The left-hand figure represents a small portion enlarged. Carboniferous, 
 Kurope. 
 
 the points where the leaves were originally attached. The trunk 
 was furnished with a large central pith, a thick outer bark, and 
 an intermediate woody zone, composed, according to Dawson, 
 partly of the disc-bearing fibres so characteristic of Conifers ; 
 but, according to Carruthers, entirely made up of the " scalari- 
 form " vessels characteristic of Cryptogams. The size of the 
 pith was very great, and the bark seems to have been the most 
 durable portion of the trunk. Thus we have evidence that 
 in many cases the stumps and " stools " of Sigillarice, standing
 
 THE CARBONIFEROUS PERIOD. 
 
 I6 9 
 
 upright in the old Carboniferous swamps, were completely 
 hollowed out by internal decay, till nothing but an exterior 
 shell of bark was left. Often these hollow stumps became 
 ultimately filled up with sediment, sometimes enclosing the 
 remains of galley-worms, land- snails, or Amphibians, which 
 formerly found in the cavity of the trunk a congenial home ; 
 and from the sandstone or shale now filling such trunks some 
 of the most interesting fossils of the Coal-period have been 
 obtained. There is little certainty as to either the leaves or 
 fruits of Sigillaria, and there is equally little certainty as to the 
 true botanical position of these plants. By Principal Dawson 
 they are regarded as being probably flowering plants allied to 
 the existing " false palms" or " Cycads ;" but the high author- 
 ity of Mr Carruthers is to be quoted in support of the belief 
 that they are Cryptogamic, and most nearly allied to the Club- 
 mosses. 
 
 Leaving the botanical position of Sigillaria thus undecided, 
 we find that it is now almost universally conceded that the 
 fossils originally described under the name of Stigmaria are 
 the roots of Sigillaria, the actual connection between the two 
 having been in numerous instances demonstrated in an unmis- 
 takable manner. The Stigmaria (fig. 112) ordinarily present 
 themselves in the form of long, compressed or rounded frag- 
 
 12. Stigma 
 
 Carboniferous. 
 
 ments, the external surface of which is covered with rounded 
 pits or shallow tubercles, each of which has a little pit or de- 
 pression in its centre. From each of these pits there proceeds, 
 in perfect examples, a long cylindrical rootlet ; but in many 
 cases these have altogether disappeared. In their internal 
 structure, Stigmaria exhibits a central pith surrounded by a 
 sheath of scalariform vessels, the whole enclosed in a cellular 
 envelope. The Stigtnarice are generally found ramifying in
 
 I/O HISTORICAL PALEONTOLOGY. 
 
 the "under clay," which forms the floor of a bed of coal, and 
 which represents the ancient soil upon which the SigiHaHtegr&vr. 
 The Lepidodendroids and Sigillarioids, though the first were 
 certainly, and the second possibly, Cryptogamic or flowerless 
 plants, must have constituted the main mass of the forests of 
 the Coal period; but we are not .without evidence of the exist- 
 ence at the same time of genuine " trees," in the technical 
 sense of this term namely, flowering plants with large woody 
 steins. So far as is certainly known, all the true trees of the 
 Carboniferous formation were Conifers, allied to the existing 
 Pines and Firs. They are recognised by the great size and 
 concentric woody rings of their prostrate, rarely erect trunks, 
 and by the presence of disc-bearing fibres in their wood, as 
 demonstrated by the microscope; and the principal genera 
 which have been recognised are Dadoxylon, Palczoxylon, 
 Araucarioxylon, and Pittites. Their fruit is not known with 
 absolute certainty, unless it be represented, as often conjectured, 
 by Trigonocarpon (fig. 113). The fruits known under this 
 name are nut-like, often of consider- 
 able size, and commonly three- or six- 
 angled. They probably originally pos- 
 sessed a fleshy envelope; and if truly 
 referable to the Conifers, they would 
 indicate that these ancient evergreens 
 produced berries instead of cones, 
 and thus resembled the modern Yews 
 rather than the Pines. It seems, 
 further, that the great group of the 
 Cycads, which are nearly allied to the Conifers, and which 
 attained such a striking prominence in the Secondary period, 
 probably commenced its existence during the Coal period ; 
 but these anticipatory forms are comparatively few in number, 
 and for the most part of somewhat dubious affinities. 
 
 CHAPTER XIII. 
 
 THE CARBONIFEROUS PERIOD Continued. 
 ANIMAL LIFE OF THE CARBONIFEROUS. 
 
 We have seen that there exists a great difference as to the 
 mode of origin of the Carboniferous sediments, some being 
 purely marine, whilst others are terrestrial; and others, again,
 
 THE CARBONIFEROUS PERIOD. I/ 1 
 
 have been formed in inland swamps and morasses, or in brack- 
 ish-water lagoons, creeks, or estuaries. A corresponding dif- 
 ference exists necessarily in the animal remains of these de- 
 posits, and in many regions this difference is extremely well 
 marked and striking. The great marine limestones which 
 characterise the lower portion of the Carboniferous series in 
 Britain, Europe, and the eastern portion of America, and the 
 calcareous beds which are found high up in the Carboniferous 
 in the western States of America, may, and do, often contain 
 the remains of drifted plants ; but they are essentially charac- 
 terised by marine fossils; and, moreover, they can be demon- 
 strated by the microscope to be almost wholly composed of 
 the remains of animals which formerly inhabited the ocean. 
 On the other hand, the animal remains of the beds accompany- 
 ing the coal are typically the remains of air-breathing, terres- 
 trial, amphibious, or. aerial animals, together with those which 
 inhabit fresh or brackish waters. Marine fossils may be found 
 in the Coal-measures, but they are invariably confined to spe- 
 cial horizons in the strata, and they indicate temporary depres- 
 sions of the land beneath the sea. Whilst the distinction here 
 mentioned is one which cannot fail to strike the observer, it is 
 convenient to consider the animal life of the Carboniferous as 
 a whole : and it is simply necessary, in so doing, to remember 
 that the marine fossils are in general derived from the inferior 
 portion of the system; whilst the air-breathing, fresh-water, and 
 brackish-water forms are almost exclusively derived from the 
 superior portion of the same. 
 
 The Carboniferous Protozoans consist mainly of Foramini- 
 fcra and Sponges. The latter are still very insufficiently known, 
 but the former are very abundant, and belong to very varied 
 types. Thin slices of the limestones of the period, when ex- 
 amined by the microscope, very commonly exhibit the shells 
 of Foraminifera in greater or less plenty. Some limestones, 
 indeed, are made up of little else than these minute and elegant 
 shells, often belonging to types, such as the Textularians and 
 Rotalians, differing little or not at all from those now in exist- 
 ence. This is the case, for example, with the Carboniferous 
 Limestone of Spergen Hill in Indiana (fig. 114), which is 
 almost wholly made up of the spiral shells of a species of 
 Endothyra. In the same way, though to a less extent, the 
 black Carboniferous marbles of Ireland, and the similar mar- 
 bles of Yorkshire, the limestones of the west of England and 
 of Derbyshire, and the great " Scar Limestones " of the north 
 of England, contain great numbers of Foraminiferous shells; 
 whilst similar organisms commonly occur in the shale-beds
 
 HISTORICAL PALEONTOLOGY. 
 
 Fig. 114. Transparent slice of Carbon- 
 iferous Limestone, from Spergen Hill, In- 
 diana, U.S., showing numerous shells of 
 Endotkyra (Rotalia), Baileyi slightly en- 
 larged. (Original.) 
 
 associated with the limestones throughout the Lower Carbon- 
 iferous series. One of the most interesting of the British Car- 
 boniferous forms is the Sac- 
 cammina of Mr Henry Brady, 
 which is sometimes present in 
 considerable numbers in the 
 limestones of Northumberland, 
 Cumberland, and the west 
 of Scotland, and which is con- 
 spicuous for the comparatively 
 large size of its spheroidal or 
 pear - shaped shell (reaching 
 from an eighth to a fifth of an 
 inch in size). More widely dis- 
 tributed are the generally spin- 
 dle-shaped shells of Fusulina 
 (fig. 115), which occur in vast 
 numbers in the Carboniferous 
 Limestone of Russia, Arme- 
 nia, the Southern Alps, and 
 Spain, similar forms occurring in equal profusion in the higher 
 limestones which are found in the Coal-measures of the United 
 
 States, in Ohio, Illinois, 
 Indiana, Missouri, &c. Mr 
 Henry Brady, lastly, has 
 shown that we have in the 
 Nummulina pristina of the 
 Carboniferous Limestone of 
 Namur a genuine Numnni- 
 
 lite, precursor of the great and important family of the Tertiary 
 Nummulites. 
 
 The sub-kingdom of the Ccehnterates, so far as certainly 
 known, is represented only by Corals;* but the remains of 
 these are so abundant in many of the limestones of the Car- 
 boniferous formation as to constitute a feature little or not at 
 all less conspicuous than that afforded by the Crinoids. As is 
 the case in the preceding period, the Corals belong, almost 
 exclusively, to the groups of the JRugosa and Tabulata; and 
 there is a general and striking resemblance and relationship 
 between the coral-fauna of the Devonian as a whole, and that 
 
 Fig. 115. Fiisiilina cyUudrica, Carbon- 
 iferous Limestone, Russia. 
 
 * A singular fossil has been described by Professor Martin Duncan and 
 Mr Jenkins from the Carboniferous rocks under the name of Pal&ocoryne, 
 and has been referred to the Hydroid Zoophytes (Corynidd]. Doubt, 
 however, has been thrown by other observers on the correctness of this 
 reference.
 
 THE CARBONIFEROUS PERIOD. 1 73 
 
 of the Carboniferous. Nevertheless, there is an equally decid- 
 ed and striking amount of difference between these successive 
 faunas, due to the fact that the great majority of the Carbon- 
 iferous species are new ; whilst some of the most characteristic 
 Devonian genera have nearly or quite disappeared, and several 
 new genera now make their appearance for the first time. 
 Thus, the characteristic Devonian types Heliophyllum, Pachy- 
 phyllum, Chonophyllum, Acervularia, SpongepJiyllum, Smit/iia, 
 Endophyllum, and Cystiphyllum, have now disappeared; and 
 the great masses of Favosites which are such a striking feature in 
 the Devonian limestones, are represented but by one or two 
 degenerate and puny successors. On the other hand, we meet 
 in the Carboniferous rocks not only with entirely new genera 
 such as Axophyllum, Lophophyllum, and Londsdaleia but we 
 have an enormous expansion of certain types which had just 
 begun to exist in the preceding period. This is especially 
 well seen in the case of the genus Lithostrotion (fig. 116, b}, 
 which more than any other may be considered as the predo- 
 minant Carboniferous group of Corals. All the species of 
 Lithostrotion are compound, consisting either of bundles of 
 loosely-approximated cylindrical stems, or of similar "coral- 
 lites" closely aggregated together into astraeiform colonies, and 
 rendered polygonal by mutual pressure. This genus has a 
 historical interest, as having been noticed as early as in the 
 year 1699 by Edward Lhwyd; and it is geologically important 
 from its wide distribution in the Carboniferous rocks of both 
 the Old and New Worlds. Many species are known, and whole 
 beds of limestone are often found to be composed of little else 
 than the skeletons of these ancient corals, still standing upright 
 as they grew. Hardly less characteristic of the Carboniferous 
 than the above is the great group of simple " cup-corals," of 
 which Clisiophyllum is the central type. Amongst types which 
 commenced in the Silurian and Devonian, but which are still 
 well represented here, may be mentioned Syringopora (fig. 116, 
 e), with its colonies of delicate cylindrical tubes united at in- 
 tervals by cross-bars; Zaphrentis (fig. 116, d\ with its cup- 
 shaped skeleton and the well-marked depression (or "fossula") 
 on one side of the calice ; Ampkxus (fig. 116, c\ with its 
 cylindrical, often irregularly swollen coral and short septa ; 
 Cyathophyllum (fig. 1 1 6, a), sometimes simple, sometimes form- 
 ing great masses of star-like corallites ; and Chcefetes, with its 
 branched stems, and its minute, "tabulate" tubes (fig. u6,/). 
 The above, together with other and hardly less characteristic 
 forms, combine to constitute a coral-fauna which is not only in 
 itself perfectly distinctive, but which is of especial interest, 
 13
 
 174 
 
 HISTORICAL PALAEONTOLOGY. 
 
 from the fact that almost all the varied types of which it is 
 composed disappeared utterly before the close of the Carbon- 
 
 Fig. 116. Corals of the Carboniferous Limestone, a. Cyathophyllum paracida, show- 
 ing young corallites budded forth from the disc of the old one ; a', One of the corallites 
 of the same, seen in cross-section ; b, Fragment of a mass of Lithostrotion irregulars ; 
 V, One of the corallites of the same, divided transversely ; c. Portion of the simple cylin- 
 drical coral of Amplexus coralloidesl c*, Transverse section of the same species; d t 
 Zaphrentis vermicnlaris, showing the depression or " fossula " on one side of the cup ; 
 e. Fragment of a mass of Syringopora ramnlosa; f, Fragment of Cluztetes tiunidiis; /', 
 Portion of the surface of the same, enlarged. From the Carboniferous Limestone of 
 Britain and Belgium. (After Thomson, De Koninck, Milne-Edwards and Haime, and 
 the Author.) 
 
 iferous period. In the first marine sediments of a calcareous 
 nature which succeeded to the Coal-measures (the magnesian 
 limestones of the Permian), the great group of the Rugose 
 corals, which flourished so largely throughout the Silurian, De- 
 vonian, and Carboniferous periods, is found to have all but
 
 THE CARBONIFEROUS PERIOD. 
 
 175 
 
 disappeared, and it. is never again represented save sporadi- 
 cally and by isolated forms. 
 
 Amongst the Ec/iirwderms, by far the most important forms 
 are the Sea-lilies and the Sea-urchins the former from their 
 great abundance, and the latter from their singular structure ; 
 but the little group of the " Pentremites " also requires to be 
 noticed. The Sea-lilies are so abundant in the Carboniferous 
 rocks, that it has been proposed to call the earlier portion of 
 the period the " Age of Crinoids." Vast masses of the lime- 
 stones of the period are " crinoidal," being more or less ex- 
 tensively composed of the broken columns, and detached plates 
 and joints of Sea-lilies, whilst perfect " heads " may be exceed- 
 ingly rare and difficult to procure. In North America the re- 
 mains of Crinoids are even more abundant at this horizon than 
 in Britain, and the specimens found seem to be commonly 
 more perfect. The commonest of the Carboniferous Crinoids 
 belong to the genera Cyathocrinus, Actinocrinus, Platycrinus, 
 
 Fig. 117. Platycrinns tricontadactylns, Lower Carboniferous. The left-hand figure 
 shows the calyx, arms, and upper part of the stem ; and the figure next this shows the sur- 
 face of one of the joints of the column. The right-hand figure shows the proboscis. (After 
 M'Coy.) 
 
 (fig. 117), PoteHocrimis, Zeacrinus, and Forbesiocrinus. Closely 
 allied to the Crinoids, or forming a kind of transition between
 
 1/6 HISTORICAL PALEONTOLOGY. 
 
 these and the Cystideans, is the little group of the " Pentre- 
 mites," or Blastoids (fig. 118). This group is first known to 
 
 Fig. 118. A, Pentremites pyriformis, side-view of the body ("calyx") ; B, The same 
 viewed from below, showing the arrangement of the plates ; C, Body of Pentremites 
 conoideus, viewed from above. Carboniferous. 
 
 have commenced its existence in the Upper Silurian, and it 
 increased considerably in numbers in the Devonian ; but it 
 was in the seas of the Carboniferous period that it attained its 
 maximum, and no certain representative of the family has been 
 detected in any later deposits. The " Pentremites " resemble 
 the Crinoids in having a cup-shaped body (fig. 118, A) enclosed 
 by closely-fitting calcareous plates, and supported on a short 
 stem or " column," composed of numerous calcareous pieces 
 flexibly articulated together. They differ from the Crinoids, 
 however, in the fact that the upper surface of the body does 
 not support the crown of branched feathery " arms," which are 
 so characteristic of the latter. On the contrary, the summit of 
 the cup is closed up in the fashion of a flower-bud, whence the 
 technical name of Blastoidea applied to the group (Gr. blastos, 
 a bud; eidos, form). From the top of the cup radiate five broad, 
 transversely-striated areas (fig. 118, C), each with a longitudi- 
 nal groove down its middle; and along each side of each of
 
 THE CARBONIFEROUS PERIOD. 1 77 
 
 these grooves there seems to have been attached a row of 
 short jointed calcareous filaments or " pinnules." 
 
 A few Star-fishes and Brittle-stars are known to occur in the 
 Carboniferous rocks ; but the only other Echinoderms of this 
 period which need be noticed are the Sea-urchins (Echinoids). 
 Detached plates and spines of these are far from rare in the 
 Carboniferous deposits ; but anything like perfect specimens 
 are exceedingly scarce. The Carboniferous Sea-urchins agree 
 with those of the present day in having the body enclosed in 
 a shell, formed by an enormous number of calcareous plates 
 articulated together. The shell may be regarded as, typically, 
 nearly spherical in shape, with the mouth in the centre of the 
 base, and the excretory opening or vent at its summit. In both 
 the ancient forms and the recent ones, the plates of the shell 
 
 Fig. 119. Paltzchiniis ellipticus, one of the Carboniferous Sea-urchins. The left- 
 .nd figure shows one of the "ambulacral areas " enlarged, exhibiting the perforated 
 ites. The right-1 and figure exhibits a single plate from one of the " inter-ambulacral 
 eas." (After M 'Coy.) 
 
 h 
 
 plat 
 
 areas." (Aft 
 
 are arranged in ten zones which generally radiate from the 
 summit to the centre of the base. In five of these zones 
 termed the " ambulacral areas " the plates are perforated by 
 minute apertures or " pores," through which the animal can 
 protrude the little water-tubes (" tube-feet") by which its loco- 
 motion is carried on. In the other five zones the so-called 
 " inter-ambulacral areas " the plates are of larger size, and 
 are not perforated by any apertures. In all the modern Sea- 
 urchins each of these ten zones, whether perforate or imper- 
 forate, is composed of two rows of plates ; and there are thus 
 twenty rows of plates in all. In the Palaeozoic Sea-urchins, on 
 the other hand, the " ambulacral areas "are often like those 
 of recent forms, in consisting of two rows of perforated plates 
 (fig. 119); but the "inter-ambulacral areas "are always quite
 
 178 HISTORICAL PALAEONTOLOGY. 
 
 peculiar in consisting each of three, four, five, or more rows of 
 large imperforate plates, whilst there are sometimes four or ten 
 rows of plates in the " ambulacral areas " also : so that there 
 are many more than twenty rows of plates in the entire shell. 
 Some of the Palaeozoic Sea-urchins, also, exhibit a very pecu- 
 liar singularity of structure which is only known to exist in a 
 very few recently-discovered modern forms (viz., Calveria and 
 Phortnosoma). The plates of the inter - ambulacral areas, 
 namely, overlap one another in an imbricating manner, so as 
 to communicate a certain amount of flexibility to the shell ; 
 whereas in the ordinary living forms these plates are firmly 
 articulated together by their edges, and the shell forms a rigid 
 immovable box. The Carboniferous Sea-urchins which ex- 
 hibit this extraordinary peculiarity belong to the genera Lepi- 
 dechinus and Lepidesthes, and it seems tolerably certain that 
 a similar flexibility of the shell existed to a less degree in 
 the much more abundant genus Archceoddaris. The Carbon- 
 iferous Sea-urchins, like the modern ones, possessed movable 
 spines of greater or less length, articulated to the exterior of 
 the shell ; and these structures are of very common occur- 
 rence in a detached condition. The most abundant genera 
 are Archceoddaris and Palcechinus ; but the characteristic 
 American forms belong principally to Melonitcs, Oligoporus, 
 and Lepidechinus. 
 
 Amongst the Annelides it is only necessary to notice the little 
 spiral tubes of Spirorbis Carbonarius (fig. 120), which are 
 
 Fig. 120. Spirorbls (Microconchus) Carbonarins, of the natural size, attached to a fossil 
 plant, and magnified. Carboniferous .Britain and North America. (After Dawson.) 
 
 commonly found attached to the leaves or stems of the Coal- 
 plants. This fact shows that though the modern species of 
 Spirorbis are inhabitants of the sea, these old representatives 
 of the genus must have been capable of living in the brackish 
 waters of lagoons and estuaries. 
 
 The Crustaceans of the Carboniferous rocks are numerous,
 
 THE CARBONIFEROUS PERIOD. 
 
 1/9 
 
 and belong partly to structural types with which we are already 
 familiar, and partly to higher groups which come into existence 
 here for the first time. The gigantic Eurypterids of the Upper 
 Silurian and Devonian are but feebly represented, and make 
 their final exit here from the scene of life. Their place, how- 
 ever, is taken by peculiar forms belonging to the allied group 
 of the Xiphosura, represented at the present day by the King- 
 crabs or " Horse-shoe Crabs " (Limulus}. Characteristic forms 
 of this group appear in the Coal-measures both of Europe and 
 America ; and though constituting three distinct genera (Prest- 
 wichia, Belinurus, and Euproops), they are all nearly related 
 to one another. The best known of them, perhaps, is the 
 Prestwichia rotundata of Coal brook dale, here figured (fig. 121^ 
 The ancient and for- 
 merly powerful order 
 of the Trilobites also 
 undergoes its final ex- 
 tinction here, not sur- 
 viving the deposition 
 of the Carboniferous 
 Limestone series in Eu- 
 rope, but extending its 
 range in America into 
 the Coal-measures. All 
 the known Carbonifer- 
 ous forms are small in 
 size and degraded in 
 point of structure, and 
 they are referable to 
 but three genera (Phil- 
 lipsia, Griffithides, and 
 Brachymetopiis], be- 
 longing to a single fa- 
 mily. The Phillipsia seminifera here figured (fig. 122, a) is a 
 characteristic species in the Old World. The Water -fleas 
 (Ostracoaa) are extremely abundant in the Carboniferous rocks, 
 whole strata being often made up of little else than the little 
 bivalved shells of these Crustaceans. Many of them are ex- 
 tremely small, averaging about the size of a millet-seed ; but a 
 few forms, such as Entomoconchus Scouleri (fig. 1 2 2, r), may attain 
 a length of from one to three quarters of an inch. The old 
 group of the Phyllopods is likewise still represented in some 
 abundance, partly by tailed forms of a shrimp-like appearance, 
 such as Dithyrocaris (fig. 122, </), and partly by the curious 
 striated Estherice and their allies, which present a curious 
 
 Fig. \i.\.Prestiv : cJiia 
 Crustacean. Coal-measur 
 Woodward.) 
 
 rotundata, a Limnloid 
 :s, Britain. (After Henry
 
 i So 
 
 HISTORICAL PALEONTOLOGY. 
 
 resemblance to the true Bivalve Molluscs (fig. 122,$). Lastly, 
 we meet for the first time in the Carboniferous rocks with the 
 remains of the highest of all the groups of Crustaceans name- 
 ly, the so-called " Decapods," in which there are five pairs of 
 walking-limbs, and the hinder end of the body ("abdomen") 
 is composed of separate rings, whilst the anterior end is cov- 
 ered by a head-shield or " carapace." All the Carboniferous 
 Decapods hitherto discovered resemble the existing Lobsters, 
 
 \\ \ 
 
 Fig. 122. Crustaceans of the Carboniferous Rocks, a, Phillipsia. semiir/era, of the 
 natural size Mountain Limestone, Europe ; b, One valve of the shell of Estheria tenella, 
 of the natural size and enlarged Coal-measures, Europe ; c, Bivalved shell of Entoino- 
 cynchns Scouleri, of the natural size Mountain Limestone, Europe ; d, Dlthyrocaris 
 Scouleri, reduced in size Mountain Limestone, Ireland ; e, Pala-ocaris typits, slightly 
 enlarged Coal-measures, North America \ f, Anthreipaheinon gracilis, of the natural 
 size Coal-measures, North America. (After De Koninck, M'Coy, Rupert Jones, and 
 Meek and Worthen.) 
 
 Prawns, and Shrimps (the Macrura], in having a long and well- 
 developed abdomen terminated by an expanded tail-fin. The 
 Palceocaris typus (fig. 122, e) and the AntJirapalcemon gracilis 
 (fig. 122, f), from the Coal-measures of Illinois, are two of the 
 best understood and most perfectly preserved of the few known 
 representatives of the " Long-tailed " Decapods in the Car- 
 boniferous series. The group of the Crabs or "Short-tailed"
 
 THE CARBONIFEROUS PERIOD. 
 
 181 
 
 Decapods (Brachyura), in which the abdomen is short, not 
 terminated by a tail-fin, and tucked away out of sight beneath 
 the body, is at present not known to be represented at all in 
 the Carboniferous deposits. 
 
 In addition to the water-inhabiting group of the Crustaceans, 
 we find the articulate animals to be represented by members 
 belonging to the air-breathing classes of the Arachnida, Myria- 
 poda, and Insecta. The remains of these, as might have been 
 expected, are not known to occur in the marine limestones of 
 the Carboniferous series, but are exclusively found in beds asso- 
 ciated with the Coal, which have been deposited in lagoons, 
 estuaries, or marshes, in the immediate vicinity of the land, and 
 which actually represent an old land-surface. The Arachnids 
 are at present the oldest known of their class, and are repre- 
 sented both by true Spiders and Scorpions. Remains of the 
 latter (fig. 123) have been found both in the Old and New 
 
 Fig. 123. Cycloplithali) 
 
 ~ senior. A fossil Scorpion from the Coal-measures 
 of Bohemia. 
 
 Worlds, and indicate the existence in the Carboniferous period 
 of Scorpions differing but very little from existing forms. The 
 group of the Myriapoda, including the recent Centipedes and 
 Galley-worms, is likewise represented in the Carboniferous strata,
 
 182 
 
 HISTORICAL PALEONTOLOGY. 
 
 but by forms in many respects very unlike any that are known 
 to exist at the present day. The most interesting of these 
 were obtained by Principal Dawson, along with the bones of 
 Amphibians and the shells of Land-snails, in the sediment filling 
 the hollow trunks of Stgillaria, and they belong to the genera 
 Xylobius (fig. 124) and Archiulus. Lastly, the true insects are 
 
 Fig. 124. Xylobiiis Sigillarite, a Carboniferous Myriapod. a, A specimen, of the 
 natural size ; b, Anterior portion of the same, enlarged ; c, Posterior portion, enlarged. 
 From the Coal-measures of Nova Scotia. (After Dawson.) 
 
 represented by various forms of Beetles (Coleoptera), Orthoptera 
 (such as Cockroaches), and Neuropterous insects resembling 
 those which we have seen to have existed towards the close of 
 
 Fig. 125. Haplophlebhim Earnest, a Carboniferous insect, from the Coal-measures 
 of Nova Scotia. (After Dawson.) 
 
 the Devonian period. One of the most remarkable of the 
 latter is a huge May-fly (Haplophlebium Barnesi, fig. 125), with
 
 THE CARBONIFEROUS PERIOD. 
 
 183 
 
 netted wings attaining an expanse of fully seven inches, and 
 therefore much exceeding any existing Ephemerid in point 
 of size. 
 
 The lower groups of the Mollusca are abundantly represented 
 in the marine strata of the Carboniferous series by Polyzoans 
 
 Fig. 126. Carboniferous Polyzoa. a, Fragment of Polyfiora dendroides, of the natural 
 size, Ireland ; a' Small portion of the same, enlarged to show the cells ; b, Glaucotwnie 
 pnlcherrima, a fragment, of the natural size, Ireland; f. Portion of the same, enlarged; 
 c, The central screw-like axis of Archimedes IVortheni, of the natural size Carboniferous, 
 America ; c 1 , Portion of the exterior of the frond of the same, enlarged ; c". Portion of 
 the interior of the frond of the same showing the mouths of the cells, enlarged. (After 
 M 'Coy and Hall.) 
 
 and Brachiopods. Amongst the former, although a variety of 
 other types are known, the majority still belong to the old 
 group of the " Lace-corals " (Fenestellidcz), some of the charac- 
 teristic forms of which are here figured (fig. 126). The graceful
 
 1 84 HISTORICAL PALEONTOLOGY. 
 
 netted fronds of Feneste/la, Retepora, and Polypora (fig. 126, a) 
 are highly characteristic, as are the slender toothed branches 
 of Glauconome (fig. 126, b}. A more singular form, however, is 
 the curious Archimedes (fig. 126, <;), which is so characteristic 
 of the Carboniferous formation of North America. In this re- 
 markable type, the colony consists of a succession of funnel- 
 shaped fronds, essentially similar to Fencstella in their structure, 
 springing in a continuous spiral from a strong screw-like vertical 
 axis. The outside of the fronds is simply striated ; but the 
 branches exhibit on the interior the mouths of the little cells 
 in which the semi-independent beings composing the colony 
 originally lived. 
 
 The Brachiopods are extremely abundant, and for the most 
 part belong to types which are exclusively or principally 
 Palaeozoic in their range. The old genera Strophomena, Ortkis 
 (fig. 127, c\ At/iyris(fig. 127, e), Rhynchonella (fig. 127, g\ and 
 Spirifera (fig. 127, h\ are still well represented the latter, in 
 particular, existing under numerous specific forms, conspicuous 
 by their abundance and sometimes by their size. Along with 
 these ancient groups, we have representatives for the fin t time 
 in any plenty of the great genus Terebratula (fig. 127, d\ 
 which underwent a great expansion during later periods, and 
 still exists at the present day. The most characteristic Car- 
 boniferous Brachiopods, however, belong to the family of the 
 Productida, of which the principal genus is Producia itself. 
 This family commenced its existence in the Upper Silurian 
 with the genus Chonetes, distinguished by its spinose hinge- 
 margin. This genus lived through the Devonian, and flourished 
 in the Carboniferous (fig. I27,/). The genus Producta itself, 
 represented in the Devonian by the nearly allied Productella, 
 appeared first in the Carboniferous, at any rate in force, and 
 survived into the Permian ; but no member of this extensive 
 family has yet been shown to have over-lived the Palaeozoic 
 period. The Products of the Carboniferous are not only ex- 
 ceedingly abundant, but they have in many instances a most 
 extensive geographical range, and some species attain what 
 may fairly be considered gigantic dimensions. The shell (fig. 
 127, a and /;) is generally more or less semicircular, with a 
 straight hinge-margin, and having its lateral angles produced 
 into larger or smaller ears (hence its generic name "cochlea 
 producta"}. One valve (the ventral) is usually strongly convex, 
 whilst the other (the dorsal) is flat or concave, the surface of 
 both being adorned with radiating ribs, and with hollow 
 tubular spines, often of great length. The valves are not 
 locked together by teeth, and there is no sign in the fully-
 
 THE CARBONIFEROUS PERIOD. 
 
 I8 5 
 
 grown shell of an opening in or between the valves for the 
 emission of a muscular stalk for the attachment of the shell to 
 foreign objects. It is probable, therefore, that the Products, 
 unlike the ordinary Lamp-shells, lived an independent exist- 
 ence, their long spines apparently serving to anchor them 
 firmly in the mud or ooze of the sea-bottom ; but Mr Robert 
 Etheridge, jun., has recently shown that in one species the 
 
 Fig. 127. Carboniferous Brachiopoda. a, Producta. semireticulata, showing the 
 slightly concave dorsal valve ; a' Side view of the same, showing the convex ventral 
 valve; b, Prodncta longispina; c, Orthis resupinatn ; d, Terebratula hastati; i; 
 Athyris subtitita;/, Chonetes Hardrensis ; g, Rhynchpnella plenrodon; h, Spir : fera 
 trigoiialis. Most of these forms are widely distributed in the Carboniferous Limestone 
 of Britain, Europe, America, &c. All the figures are of the natural size. (After David- 
 son, De Koninck, and Meek.) 
 
 spines were actually employed as organs of adhesion, whereby 
 the shell was permanently attached to some extraneous object, 
 such as the stem of a Crinoid. The two species here figured 
 are interesting for their extraordinarily extensive geographical 
 range Producta semireticulata (fig. 127, a) being found in the 
 Carboniferous rocks of Britain, the continent of Europe, 
 Central Asia, China, India, Australia, Spitzbergen, and North
 
 1 86 
 
 HISTORICAL PALEONTOLOGY. 
 
 and South America; whilst P. longispina (fig. 127, b) has a 
 distribution little if at all less wide. 
 
 The higher Mollusca are abundantly represented in the 
 Carboniferous rocks by Bivalves (Lamellibranchs), Univalves 
 (Gasteropoda), Winged - snails (Pteropoda), and Cephalopods. 
 Amongst the Bivalves we may note the great abundance of 
 Scallops (Aviculopecten and other allied forms), together with 
 numerous other types some of ancient origin, others repre- 
 sented here for the first time. Amongst the Gasteropods, we 
 find the characteristically Palaeozoic genera Macrocheilus and 
 Loxonema, the almost exclusively Palaeozoic Euomphalus, and 
 the persistent genus Pleurotomaria ; whilst the free-swimming 
 Univalves (Heteropodd) are represented by Bellerophon an&Porcel- 
 lia, and the Pteropoda by the old genus Comdaria. With regard 
 to the Carboniferous Univalves, it is also of interest to note here 
 the first appearance of true air-breathing or terrestrial Molluscs, 
 as discovered by Dawson and Bradley in the Coal-measures of 
 Nova Scotia and Illinois. Some of these ( Conul'us priscus) are 
 true Land-snails, resembling the existing Zottites ;. whilst others 
 (Pupa vetusta,^. 128) appear to be generically inseparable 
 from the " Chrysalis-shells " 
 (Pupa) of the present day. 
 All the known forms three 
 in number are of small size., 
 and appear to have been local 
 in their distribution or in their 
 preservation. More import- 
 ant, however, than any of the 
 preceding, are the Cephalo- 
 poda, represented, as before, 
 exclusively by the chambered 
 shells of the Tetrabranchiates. 
 The older and simpler type of 
 these, with simple plain septa, 
 and mostly a central siphuncle, 
 is represented by the straight 
 conical shells of the ancient 
 genus Orthoceras, and the bow- 
 shaped shells of the equally 
 ancient Cyrtoceras some of 
 the former attaining a great size. 
 The spirally-curved discoidal 
 shells of the persistent genus Naictilus are also not unknown, 
 and some of these likewise exhibit very considerable dimen- 
 sions. Lastly, the more complex family of the Ammonitidce, 
 
 i (D;ndropnpa)vetnsta. 
 aii fr 
 
 Fig. ii 
 
 a Carboniferous La.id-snaii from the Coal 
 measures of Nova Scotia, a, The shell, of 
 the natural siza ; b, The same, magnified ; 
 c, Apex of the shell, enlarged ; d, Portion 
 of the surface, enlarged. (After Dawson.)
 
 THE CARBONIFEROUS PERIOD. 187 
 
 with lobed or angulated septa, and a dorsally-placed siphuncle 
 (situated on the convex side of the curved shells), now for the 
 first time commences to acquire a considerable prominence. 
 The principal representative of this group is the genus Gonia- 
 tites (fig. 129), which commenced its existence in the Upper 
 Silurian, is well represented in the De- 
 vonian, and attains its maximum here. 
 In this genus, the shell is spirally 
 curved, the septa are strongly lobed 
 or angulated, though not elaborately 
 frilled as in the Ammonites, and the 
 siphuncle is dorsal. In addition to 
 Goniatites, the shells of true Ammon- 
 ites, so characteristic of the Secondary 
 period, have been described by Dr 
 Waagen as occurring in the Carbon- 
 iferous rocks of India- 
 
 Fig. 129. Goniatites (Aganides) Joss*?. Carboniferous Limestone. 
 
 Coming finally to the Vertebrata, we have in the first place 
 to very briefly consider the Carboniferous fishes. These are 
 numerous ; but, with the exception of the still dubious " Cono- 
 donts," belong wholly to the groups of the Ganoids and the 
 Placoids (including under the former head remains which per- 
 haps are truly referable to the group of the Dipnoi or Mud- 
 fishes). Amongst the Ganoids, the singular buckler-headed 
 fishes of the Upper Silurian and Devonian ( Cephalaspida) have
 
 1 88 HISTORICAL PALEONTOLOGY. 
 
 apparently disappeared ; and the principal types of the Car- 
 boniferous belong to the groups respectively represented at 
 the present day by the Gar pike (Lepidosteus) of the North 
 American lakes, and the Polyptcrus of the rivers of Africa. Of 
 the former, the genera Palcewiiscus and Amblyptcrus (fig. 130), 
 
 croptenis. Carboniferous. 
 
 with their small rhomboidal and enamelled scales, and their 
 strongly unsymmetrical tails, are perhaps the most abundant. 
 Of the latter, the most important are species belonging to 
 the genera Megalichthys and Rhizodus, comprising large fishes, 
 with rhomboidal scales, unsymmetrical (" heterocercal ") tails, 
 and powerful conical teeth. These fishes are sometimes said 
 to be " sauroid," from their presenting some Reptilian features 
 in their organisation, and they must have been the scourges 
 of the Carboniferous seas. The remains of Placoid fishes in 
 the Carboniferous strata are very numerous, but consist wholly 
 of teeth and fin-spines, referable to forms more or less closely 
 allied to our existing Port Jackson Sharks, Dog-fishes, and 
 Ravs. The teeth are of very various shapes and sizes, some 
 with sharp, cutting edges (Petalodus, Cladodus, &c.) ; others in 
 the form of broad crushing plates, adapted, like the teeth of the 
 existing Port Jackson Shark (Cestracion Philippi), for breaking 
 down the hard shells of Molluscs and Crustaceans. Amongst 
 the many kinds of these latter, the teeth of Psammodus and 
 Cochliodiis (fig. 131) may be mentioned as specially charac- 
 teristic. The fin-spines are mostly similar to those so common 
 in the Devonian deposits, consisting of hollow defensive spines 
 implanted in front of the pectoral or other fins, usually slightly 
 curved, often superficially ribbed or sculptured, and not un- 
 commonly serrated or toothed. The genera Cte?iacanthus, 
 Gyracanthus, HomacantJms, &c., have been founded for the 
 reception of these defensive weapons, some of which indicate 
 fishes of great size and predaceous habits.
 
 THE CARBONIFEROUS PERIOD. 189 
 
 In the Devonian rocks we meet with no other remains of 
 Vertebrated animals save fishes only; but the Carboniferous 
 deposits have yielded re- 
 mains of the higher group 
 of the Amphibians. This 
 class, comprising our ex- 
 isting Frogs, Toads, and 
 Newts, stands to some ex- 
 tent in a position midway 
 betsveen the class of the 
 fishes and that of the true 
 reptiles, being distinguished 
 from the latter by the fact Fig . I3I ._ Teet hof CccM**, amtortu*. 
 
 that itS members invariably Carboniferous Limestone, Britain. 
 
 possess gills in their early 
 
 condition, if not throughout life; whilst they are separated from 
 the former by always possessing true lungs when adult, and 
 by the fact that the limbs (when present at all) are never in 
 the form of fins. The Amphibians, therefore, are all water- 
 breathers when young, and have respiratory organs adapted 
 for an aquatic mode of life ; whereas, when grown up, they 
 develop lungs, and with these the capacity for breathing air 
 directly. Some of them, like the Frogs and Newts, lose their 
 gills altogether on attaining the adult condition ; but others, 
 such as the living Proteus and Menobranchus, retain their gills 
 even after acquiring their lungs, and are thus fitted indiffer- 
 ently for an aquatic or terrestrial existence. The name of 
 " Amphibia," though applied to the whole class, is thus not 
 precisely appropriate except to these last-mentioned forms 
 (Gr. amphi, both; bios, life). The Amphibians also differ 
 amongst themselves according as to whether they keep per- 
 manently the long tail which they all possess when young (as 
 do the Newts and Salamanders), or lose this appendage when 
 grown up (as do the Frogs and Toads). Most of them have 
 naked skins, but a few living and many extinct forms have 
 hard structures in the shape of scales developed in the integu- 
 ment. All of them have well-ossified skeletons, though some 
 fossil types are partially deficient in this respect ; and all of 
 them which possess limbs at all have these appendages sup- 
 ported by bones essentially similar to those found in the limbs 
 of the higher Vertebrates. All the Carboniferous Amphibians 
 belong to a group which has now wholly passed away namely, 
 that of the Labyrinthodonts. In the marine strata which form 
 the base of the Carboniferous series these creatures have only 
 been recognised by their curious hand- shaped footprints, similar 
 14
 
 190 
 
 HISTORICAL PALEONTOLOGY. 
 
 in character to those which occur in theTriassic rocks, and which 
 will be subsequently spoken of under the name of Cheirotherium. 
 In the Coal-measures of Britain, the continent of Europe, and 
 North America, however, many bones of these animals have 
 been found, and we are now tolerably well acquainted with a 
 considerable number of forms. All of them seem to have be- 
 longed to the division of Amphibians in which the long tail 
 of the young is permanently retained ; and there is evidence 
 that some of them kept the gills also throughout life. The 
 skull is of the characteristic Amphibian type (fig. 132, a), with 
 
 Fig. 132. a, Upper surface of the skull of Anthracosaurus Rnsselli, one-sixth of the 
 natural size ; b. Part of one of the teeth cut across, and highly magnified to show the 
 characteristic labyrinthine structure ; c. One of the integumentary shields or scales, one- 
 half of the natural size. Coal-measures, Northumberland. (After Atthey.) 
 
 two occipital condyles, and having its surface singularly pitted 
 and sculptured ; and the vertebrae are hollowed out at both 
 ends. The lower surface of the body was defended by an 
 armour of singular integumentary shields or scales (fig. 132, c); 
 and an extremely characteristic feature (from which the entire 
 group derives its name) is, that the walls of the teeth are deeply 
 folded, so as to give rise to an extraordinary " labyrinthine " 
 pattern when they are cut across (fig. 132, b}. Many of the 
 Carboniferous Labyrinthodonts are of no great size, some of
 
 THE CARBONIFEROUS PERIOD. 191 
 
 them very small, but others attain comparatively gigantic 
 dimensions, though all fall short in this respect of the huge 
 examples of this group which occur in the Trias. One of the 
 largest, and at the same time most characteristic, forms of the 
 Carboniferous series, is the genus Anthracosaurus, the skull of 
 which is here figured. 
 
 No remains of true Reptiles, Birds, or Quadrupeds have as 
 yet been certainly detected in the Carboniferous deposits in 
 any part of the world. It should, however, be mentioned, 
 that Professor Marsh, one of the highest authorities on the 
 subject, has described from the Coal-forrnation of Nova Scotia 
 certain vertebrae which he believes to have belonged to a 
 marine reptile (Eosa/urus Acadianus), allied to the great 
 Ichthyosauri of the Lias. Up to this time no confirmation 
 of this determination has been obtained by the discovery of 
 other and more unquestionable remains, and it therefore 
 remains doubtful whether these bones of Eosaurus may not 
 really belong to large Labyrinthodonts. 
 
 LITERATURE. 
 
 The following list contains some of the more important of the original 
 sources of information to which the student of Carboniferous rocks and 
 fossils may refer : 
 
 (1) 'Geology of Yorkshire,' vol. ii. ; 'The Mountain Limestone Dis- 
 
 trict.' John Phillips. 
 
 (2) ' Siluria.' Sir Roderick Murchison. 
 
 (3) ' Memoirs of the Geological Survey of Great Britain and Ireland.' 
 
 (4) 'Geological Report on Londonderry,' &c. Portlock. 
 
 (5) ' Acadian Geology.' Dawson. 
 
 (6) 'Geology of Iowa,' vol. i. James Hall. 
 
 (7) ' Reports of the Geological Survey of Illinois ' (Geology and Palae- 
 
 ontology). Meek, Worthen, &c. 
 
 (8) ' Reports of the Geological Survey of Ohio ' (Geology and Palaeon- 
 
 tology). Newberry, Cope, Meek, Hall, &c. 
 
 (9) ' Description des Animaux fossiles qui se trouvent dans le Terrain 
 
 Carbonifere de la Belgique,' 1843 ; with subsequent monographs 
 on the genera Productus and Clionetes, on Crinoids, on Corals, 
 &.c. De Koninck. 
 
 (10) ' Synopsis of the Carboniferous Fossils of Ireland.' M'Coy. 
 
 (11) ' British Palteozoic Fossils.' M'Coy. 
 
 (12) ' Figures of Characteristic British Fossils.' Baily. 
 
 (13) ' Catalogue of British Fossils.' Morris. 
 
 (14) ' Monograph of the Carboniferous Brachiopoda of Britain ' (Palaeon- 
 
 tographical Society). Davidson. 
 
 (15) ' Monograph of the British Carboniferous Corals ' (Paloeontographical 
 
 Society). Milne-Edwards and Haime. 
 
 (16) ' Monograph of the Carboniferous Bivalve Entomostraca of Britain ' 
 
 (Palaeontographical Society). Rupert Jones, Kirkby, and George 
 S. Brady.
 
 192 HISTORICAL PALEONTOLOGY. 
 
 (17) ' Monograph of the Carboniferous Foraminifera of Britain ' (Palaeon- 
 
 tographical Society). H. B. Brady. 
 
 (18) "On the Carboniferous Fossils of the West of Scotland" 'Trans. 
 
 Geol. Soc.,' of Glasgow, vol. iii., Supplement. Young and 
 Armstrong. 
 
 (19) ' Poissons Fossiles.' Agassiz. 
 
 (20) "Report on the Labyrinthodonts of the Coal-measures" 'British 
 
 Association Report,' 1873. L. C. Miall. 
 
 (21) 'Introduction to the Study of Palseontological Botany.' John 
 
 Huttbn Balfour. 
 
 (22) 'Traitede Paleontologie Vegetale. ' Schimper. 
 
 (23) ' Fossil Flora.' Lindley and Hutton. 
 
 (24) ' Histoire des Vegetaux Fossiles.' Brongniart. 
 
 (25) ' On Calamites and Calamodendron ' (Monographs of the Palseonto- 
 
 graphical Society). Binney. 
 
 (26) ' On the Structure of Fossil Plants found in the Carboniferous 
 
 Strata' (Palaeontographical Society). Binney. 
 
 Also numerous memoirs by Huxley, Davidson, Martin Duncan, Profes- 
 sor Young, John Young, R. Etheridge, jun., Baily, Carruthers, Dawson, 
 Binney, Williamson, Hooker, Jukes, Geikie, Rupert Jones, Salter, and 
 many other British and foreign observers. 
 
 CHAPTER XIV. 
 THE PERMIAN PERIOD. 
 
 The Permian formation closes the long series of the Palaso- 
 zoic deposits, and may in some respects be considered as a 
 kind of appendix to the Carboniferous system, to which it can- 
 not be compared in importance, either as regards the actual 
 bulk of its sediments or the interest and variety of its life- 
 record. Consisting, as it does, largely of red rocks sand- 
 stones and marls for the most part singularly destitute of 
 organic remains, the Permian rocks have been regarded as a 
 lacustrine or fluviatile deposit; but the presence of well-devel- 
 oped limestones with indubitable marine remains entirely 
 negatives this view. It is, -however, not improbable that we 
 are presented in the Permian formation, as known to us at 
 present, with a series of sediments laid down in inland seas of 
 great extent, due to the subsidence over large areas of the 
 vast land-surfaces of the Coal-measures. This view, at any 
 rate, would explain some of the more puzzling physical char- 
 acters of the formation, and would not be definitely negatived 
 by any of its fossils. 
 
 A large portion of the Permian series, as already remarked, 
 consists of sandstones and marls, deeply reddened by peroxide
 
 THE PERMIAN PERIOD. 193 
 
 of iron, and often accompanied by beds of gypsum or deposits 
 of salt. In strata of this nature few or no fossils are found ; 
 but their shallow-water origin is sufficiently proved by the 
 presence of the footprints of terrestrial animals, accompanied 
 in some cases by well-defined "ripple-marks." Along with 
 these are occasionally found massive breccias, holding larger 
 or smaller blocks derived from the older formations; and these 
 have been supposed to represent an old " boulder-clay," and 
 thus to indicate the prevalence of an arctic climate. Beds of 
 this nature must also have been deposited in shallow water. 
 In all regions, however, where the Permian formation is well 
 developed, one of its most characteristic members is a Mag- 
 nesian limestone, often highly and fantastically concretionary, 
 but containing numerous remains of genuine marine animals, 
 and clearly indicating that it was deposited beneath a mod- 
 erate depth of salt water. 
 
 It is not necessary to consider here whether this formation 
 can be retained as a distinct division of the geological series. 
 The name of Permian was given to it by Sir Roderick Murchi- 
 son, from the province of Perm in Russia, where rocks of this 
 age are extensively developed. Formerly these rocks were 
 grouped with the succeeding formation of the Trias under the 
 common name of " New Red Sandstone." This name was 
 given them because they contain a good deal of red sandstone, 
 and because they are superior to the Carboniferous rocks, 
 while the Old Red Sandstone is inferior. Nowadays, how- 
 ever, the term "New Red Sandstone" is rarely employed, 
 unless it be for red sandstones and associated rocks, which 
 are seen to overlie the Coal-measures, but which contain no 
 fossils by which their exact age may be made out. Under 
 these circumstances, it is sometimes convenient to employ the 
 term " New Red Sandstone." The New Red, however, of the 
 older geologists, is now broken up into the two formations of 
 the Permian and Triassic rocks the former being usually con- 
 sidered as the top of the Palaeozoic series, and the latter con- 
 stituting the base of the Mesozoic. 
 
 In many instances, the Permian rocks are seen to repose 
 unconformably upon the underlying Carboniferous, from which 
 they can in addition be readily separated by their lithological 
 characters. In other instances, however, the Coal-measures 
 terminate upwards in red rocks, not distinguishable by their 
 mineral characters from the Permian ; and in other cases no 
 physical discordance between the Carboniferous and Per- 
 mian strata can be detected. As a general rule, also, the 
 Permian rocks appear to pass upwards conformably into the
 
 194 HISTORICAL PALAEONTOLOGY. 
 
 Trias. The division, therefore, between the Permian and Tri- 
 assic rocks, and consequently between the Palaeozoic and Me- 
 sozoic series, is not founded upon any conspicuous or universal 
 physical break, but upon the difference in life which is ob- 
 served in comparing the marine animals of the Carboniferous 
 and Permian with those of the Trias. It is to be observed, how- 
 ever, that this difference can be solely due to the fact that the 
 Magnesian Limestone of the Permian series presents us with 
 only a small, and not a typical, portion of the marine deposits 
 which must have been accumulated in some area at present 
 unknown to us during the period which elapsed between the 
 formation of the great marine limestones of the Lower Carbon- 
 iferous and the open-sea and likewise calcareous sediments of 
 the Middle Trias. 
 
 The Permian rocks exhibit their most typical features in 
 Russia and Germany, though they are very well developed in 
 parts of Britain, and they occur in North America. When 
 well developed, they exhibit three main divisions : a lower set 
 of sandstones, a middle group, generally calcareous, and an 
 upper series of sandstones, constituting respectively the Lower, 
 Middle, and Upper Permians. 
 
 In Russia, Germany, and Britain, the Permian rocks con- 
 sist of the following members : 
 
 1. The Lower Permians, consisting mainly of a great series 
 of sandstones, of different colours, but usually red. The base 
 of this series is often constituted by massive breccias with 
 included fragments of the older rocks, upon which they may 
 happen to repose ; and similar breccias sometimes occur in 
 the upper portion of the series as well. The thickness of this 
 group varies a good deal, but may amount to 3000 or 4000 
 feet. 
 
 2. The Middle Permians, consisting, in their typical de- 
 velopment, of laminated marls, or " marl-slate," surmounted 
 by beds of magnesian limestone (the "Zechstein " of the Ger- 
 man geologists). Sometimes the limestones are degenerate or 
 wholly deficient, and the series may consist of sandy shales 
 and gypsiferous clays. The magnesian limestone, however, of 
 the Middle Permians is, as a rule, so well marked a feature 
 that it was long spoken of as the Magnesian Limestone. 
 
 3. The Upper Permians, consisting of a series of sandstones 
 and shales, or of red or mottled marls, often gypsiferous, and 
 sometimes including beds of limestone. 
 
 In North America, the Permian rocks appear to be confined 
 to the region west of the Mississippi, being especially well de- 
 veloped in Kansas. Their exact limits have not as yet been
 
 THE PERMIAN PERIOD. 
 
 195 
 
 made out, and their total thickness is not more than a few 
 hundred feet. They consist of sandstones, conglomerates, 
 limestones, marls, and beds of gypsum. 
 
 The following diagrammatic section shows the general 
 sequence of the Permian deposits in the north of England, 
 where the series is extensively developed (fig. 133): 
 
 GENERALISED SECTION OF THE PERMIAN ROCKS 
 IN THE NORTH OF ENGLAND. 
 
 Fig. 133- 
 
 ( Upper Red Sandstones 
 and Marls. 
 
 Magnesian Limestone. 
 
 Marl Slate. 
 
 Lower Red Sandstones 
 and Breccias. 
 
 Coal-measures. 
 
 The record of the life of the Permian period is but a scanty 
 one, owing doubtless to the special peculiarities of such of the
 
 196 HISTORICAL PALEONTOLOGY. 
 
 deposits of this age with which we are as yet acquainted. Red 
 rocks are, as a general rule, more or less completely unfossil- 
 iferous, and sediments of this nature are highly characteristic of 
 the Permian. Similarly, magnesian limestones are rarely as 
 highly charged with organic remains as is the case with normal 
 calcareous deposits, especially when they have been subjected 
 to concretionary action, as is observable to such a marked ex- 
 tent in the Permian limestones. Nevertheless, much interest 
 is attached to the organic remains, as marking a kind of transi- . 
 tion-period between the Palaeozoic and Mesozoic epochs. 
 
 The plants of the Permian period, as a whole, have a dis- 
 tinctly Palaeozoic aspect, and are far more nearly allied to those 
 of the Coal-measures than they are to those of the earlier 
 Secondary rocks ; though the Permian species are mostly dis- 
 tinct from the Carboniferous, and there are some new genera. 
 Thus, we find species of Lepidodcndron, Calamites, Eguisetites, 
 Asterophyllites, Annularia, and other highly characteristic 
 Carboniferous genera. On the other hand, the Sigillarioids of 
 the Coal seem to have finally disappeared at the close of the 
 Carboniferous period. Ferns are abundant in the Permian 
 rocks, and belong for the most part to the well-known Carbon- 
 iferous genera Alethopteris, Neuropteris, Sphenopteris, and Pccop- 
 teris. There are also Tree-ferns referable to the ancient genus 
 Psaronius. The Conifers of the Permian period are numerous, 
 and belong in part to Carboniferous genera. A characteristic 
 genus, however, is Walchia (fig. 134), distinguished by its lax 
 
 Fig. 134. Walchia plniformis, from the Permian of Saxony. 
 a, Branch ; b, Twig. (After Gutbier.) 
 
 short leaves. This genus, though not exclusively Permian, is 
 mainly so, the best-known species being the IV. piniformis. 
 Here, also, we meet with Conifers which produce true cones, 
 and which differ, therefore, in an important degree from the
 
 THE PERMIAN PERIOD. 1 97 
 
 Taxoid Conifers of the Coal-measures. Besides Walchia, a 
 characteristic form of these is the Ullmania selaginoides, which 
 occurs in the Magnesian Limestone of Durham, the Middle 
 Permian of Westmorland, and the " Kupfer-schiefer " of Ger- 
 many. The group of the Cycads, which we shall subsequently 
 find to be so characteristic of the vegetation of the Secondary 
 period, is, on the other hand, only doubtfully represented in 
 the Permian deposits by the singular genus Nceggerathia. 
 
 The Protozoans Q{ the Permian rocks are few in number, and 
 for the most part imperfectly known. A few Foraminifrra have 
 been obtained from the Magnesian Limestone of England, 
 and the same formation has yielded some ill -understood 
 Sponges. It does not seem, however, altogether impossible 
 that some of the singular " concretions " of this formation may 
 ultimately prove to have an organic structure, though others 
 would appear to be clearly of purely inorganic origin. From 
 the Permian of Saxony, Professor Geinitz has described two 
 species of Spongillopsis, which he believes to be most nearly 
 allied to the existing fresh-water Sponges (Spongilla). This 
 observation has an interest as bearing upon the mode of de- 
 position and origin of the Permian sediments. 
 
 The Cxlentcrates are represented in the Permian by but a 
 few Corals. These belong partly to the Tabulate, and partly 
 to the Rugose division ; but the latter great group, so abun- 
 dantly represented in Silurian, Devonian, and Carboniferous 
 seas, is now extraordinarily reduced in numbers, the British 
 strata of this age yielding only_ species of the single genus 
 Polyccelia. So far, therefore, as at present known, all the 
 characteristic genera of the Rugose Corals of the Carboniferous 
 had become extinct before the deposition of the limestones of 
 the Middle Permian. 
 
 The Echinodcrms are represented by a few Crinoids, and by a 
 Sea-urchin belonging to the genus Eocidaris. The latter genus 
 is nearly allied to the Archtzocidaris of the Carboniferous, so 
 that this Permian form belongs to a characteristically Palaeozoic 
 type. 
 
 A few Annelides (Spirorbis, Vermilia, &c.) have been de- 
 scribed, but are of no special importance. Amongst the 
 Crustaceans, however, we have to note the total absence of 
 the great Palaeozoic group of the Trilobites ; whilst the little 
 Ostracoda and Phyllopods still continue to be represented. 
 We have als.o to note the first appearance here of the ' % Short- 
 tailed " Decapods or Crabs (Brac/iyura), the highest of all the 
 groups of Crustacea, in the person of Hcmitrochiscus parado&us> 
 an extremely minute Crab from the Permian of Germany.
 
 198 HISTORICAL PALEONTOLOGY. 
 
 Amongst the Mollusca, the remains of Polyzoa may fairly be 
 said to be amongst the most abundant of all the fossils of the 
 Permian formation. The principal forms of these are the 
 fronds of the Lace-corals {Fenestella, Retepora, and Synodadia)\ 
 which are very abundant in the Magnesian Limestone of the 
 north of England, and belong to various highly characteristic 
 species (such as Fenestella retiformis, Retepora Ehrenbergi, and 
 Synodadia virgulacea). The Brachiopoda are also represented 
 in moderate numbers in the Permian. Along with species of 
 the persistent genera Discina, Crania, and Lingula, we still 
 meet with representatives of the old groups Spirifera, Athyris, 
 and Streptorhynchus ; and the Carboniferous Products yet 
 survive under well-marked and characteristic types, though in 
 much-diminished numbers. The species of Brachiopods here 
 figured (fig. 135) are characteristic of the Magnesian Limestone 
 in Britain and of the corresponding strata on the Continent. 
 
 Fig- 135 Brachiopods of the Permian formation, a, Producta horrida', b, Lingula 
 Credneri; c, Terebratula elongata; a? and e, Camarophoria. globulina, (After King.) 
 
 Upon the whole, the most characteristic Permian Brachiopods 
 belong to the genera Producta, Strophalosia, and Camaro- 
 phoria. 
 
 The Bivalves (Lamellibranchiatd) have a tolerably varied 
 development in the Permian rocks; but nearly all the old 
 types, except some of those which occur in the Carboniferous, 
 have now disappeared. The principal Permian Bivalves 
 belong to the groups of the Pearl Oysters (Aviculidce) and the 
 Trigoniada, represented by genera such as Bakewellia and 
 Schizodtis ; the true Mussels (Mytilid<z\ represented by species 
 which have been referred to Mytilns itself; and the Arks 
 (Arcada), represented by species of the genera Area (fig. 136) 
 and Byssoarca. The first and last of these three families have 
 a very ancient origin; but the family of the Trigoniada, though
 
 THE PERMIAN PERIOD. 
 
 199 
 
 feebly represented at the present day, is one which attained its 
 maximum development in the Mesozoic period. 
 
 The Univalves (Gasteropoda} are rare, and do not demand 
 special notice. It may be ob- 
 served, however, that the Palaeo- 
 zoi u genera Euomphahis, Mur- 
 chisonia, Loxonema, and Macro- 
 chtilus are still in existence, to- 
 gether with the persistent genus 
 Pleurotomaria. Pteropods of the 
 old genera Theca and Conula- 
 ria have been discovered; but 
 the first of these characteristi- 
 cally Palaeozoic types finally 
 
 dies out here, and the second F ; g . i 3 6.-/im /,*** Permian, 
 only survives but a short time 
 
 longer. Lastly, a few Cephalopods have been found, still wholly 
 referable to the Tetrabranchiate group, and belonging to the old 
 genera Orthoceras and Cyrtoceras and the long-lived Nautilus. 
 
 Amongst Vertebrates, we meet in the Permian period not 
 only with the remains of Fishes and Amphibians, but also, for 
 the first time, with true Reptiles. The Fishes are mainly 
 Ganoids, though there are also -emains of a few Cestraciont 
 
 Fig. 137 Platysomus zibbosns, a "heterocercal" Ga 
 Middle Permian of Russia. 
 
 Sharks. Not only are the Ganoids still the predominant group 
 of Fishes, but all the known forms possess the unsymmetrical 
 ("heterocercal") tail which is so characteristic of the Palaeozoic 
 Ganoids. Most of the remains of the Permian Fishes have 
 been obtained from the " Marl-slate " of Durham and the 
 corresponding " Kupfer-schiefer " of Germany, on the horizon
 
 200 HISTORICAL PALEONTOLOGY. 
 
 of the Middle Permian ; and the principal genera of the 
 Ganoids are Pal&oniscus and Platysomus (fig. 137). 
 
 The Amphibians of the Permian period belong principally 
 to the order of the Labyrinthodonts, which commenced to be 
 represented in the Carboniferous, and has a large development 
 in the Trias. Under the name, however, of Pal&osircn Bcinerti, 
 Professor Geinitz has described an Amphibian from the Lower 
 Permian of Germany, which he believes to be most nearly 
 allied to the existing " Mud-eel " (Siren lacertina) of North 
 America, and therefore to be related to the Newts and Sala- 
 manders (Urodela). 
 
 Finally, we meet in the Permian deposits with the first un- 
 doubted remains of true Reptiles. These are distinguished, as 
 a class, from the Amphibians, by the fact that they are air- 
 breathers throughout the whole of their life, and therefore are 
 at no time provided with gills; whilst they are exempt from 
 that metamorphosis which all the Amphibia undergo in early 
 life, consequent upon their transition from an aquatic to a 
 more or less purely aerial mode of respiration. Their skel- 
 eton is well ossified ; they usually have horny or bony plates, 
 singly or in combination, developed in the skin; and their 
 limbs (when present) are never either in the form of fins or 
 wings, though sometimes capable of acting in either of these 
 capacities, and liable to great modifications of form and struc- 
 ture. Though there can be no doubt whatever as to the occur- 
 rence"of genuine Reptiles in deposits of unquestionable Per- 
 mian age, there is still uncertainty as to the precise number 
 of types which may have existed at this period. This uncer- 
 tainty arises partly from the difficulty of deciding in all cases 
 whether a given bone be truely Labyrinthodont or Reptilian, 
 ' but more especially from the confusion which exists at pres- 
 ent between the Permian and the overlying Triassic deposits. 
 Thus there are various deposits in different regions which 
 have yielded the remains of Reptiles, and which cannot in 
 the meanwhile be definitely referred either to the Permian 
 series or to the Trias by clear stratigraphical or palaeonto- 
 logical evidence. All that can be done in such cases is to be 
 guided by the characters of the Reptiles themselves, and to 
 judge by their affinities to remains from known Triassic or Per- 
 mian rocks to which of these formations the beds containing 
 them should be referred ; but it is obvious that this method 
 of procedure is seriously liable to lead to error. In accor- 
 dance, however, with this, the only available mode of deter- 
 mination in some cases, the remains of Thecodontosaurus and 
 Palceosaurus discovered in the dolomitic conglomerates near
 
 THE PERMIAN PERIOD. 
 
 201 
 
 Bristol will be considered as Triassic, thus leaving Protoro- 
 saurus * as the principal and most important representative of 
 
 Fig. -i-gProtorosaimtsSpeneri, Middle Permian, 
 
 (After Von Meyer.) [Copied from Dana.] 
 
 reduced in size. 
 
 the Permian Reptiles.t The type-species of the genus Pro- 
 torosaurus is the P. Speneri (fig. 138) of the "Kupfer-schiefer" of 
 
 * Though commonly spelt as above, it is probable that the name of this 
 Lizard was really intended to have been Proterosaurus from the Greek 
 proteros, first ; and saura, lizard : and this spelling is followed by many 
 writers. 
 
 t In an extremely able paper upon the subject (Quart. Journ. Geol. 
 Soc., vol. xxvi.), Mr Etheridge has shown that there are good physical 
 grounds for regarding the dolomitic conglomerate of Bristol as of Triassic 
 age, and as probably corresponding in time with the Muschelkalk of the 
 Continent.
 
 2O2 HISTORICAL PALEONTOLOGY. 
 
 Thuringia, but other allied species have been detected in the 
 Middle Permian of Germany and the north of England. This 
 Reptile attained a length of from three to four feet ; and it has 
 been generally referred to the group of the Lizards (Lacertilia], 
 to which it is most nearly allied in its general structure, at the 
 same time that it differs from all existing members of this group 
 in the fact that its numerous conical and pointed -teeth were 
 implanted in distinct sockets in the jaws this being a Croco- 
 dilian character. In other respects, however, Protorosaurus 
 approximates closely to the living Monitors ( Varanidce) ; and 
 the fact that the bodies of the vertebrae are slightly cupped or 
 hollowed out at the ends would lead to the belief that the 
 animal was aquatic in its habits. At the same time, the 
 structure of the hind-limbs and their bony supports proves 
 clearly that it must have also possessed the power of progres- 
 sion upon the land. Various other Reptilian bones have been 
 described from the Permian formation, of which some are pro- 
 bably really referable to Labyrintliodonts, whilst others are 
 regarded by Professor Owen as referable to the order of the 
 " Theriodonts," in which the teeth are implanted in sockets, 
 and resemble those of carnivorous quadrupeds in consisting 
 of three groups in each jaw (namely, incisors, canines, and 
 molars). Lastly, in red sandstones of Permian age in Dum- 
 friesshire have been discovered the tracks of what would ap- 
 pear to have been Chelonians (Tortoises and Turtles); but it 
 would not be safe to accept this conclusion as certain upon the 
 evidence of footprints alone. The Chelichnus Duncani, how- 
 ever, described by Sir William Jardine in his magnificent work 
 on the ' Ichnology of Annandale,' bears a great resemblance 
 to the track of a Turtle. 
 
 No remains of Birds or Quadrupeds have hitherto been 
 detected in deposits of Permian age. 
 
 LITERATURE. 
 
 The following works may be consulted by the student with regard to the 
 Permian formation and its fossils : 
 
 (1) "On the Geological Relations and Internal Structure of the Magne- 
 
 sian Limestone and the Lower Portions of the New Red Sand- 
 stone Series, &c." 'Trans. Geol. Soc.,' ser. 2, vol. iii. Sedg- 
 wick. 
 
 (2) 'The Geology of Russia in Europe.' Murchison, De Verneuil, and 
 
 Von Keyserling. 
 
 (3) 'Siluria.' Murchison. 
 
 (4) ' Permische System in Sachsen.' Geinitz and Gutbier. 
 
 (5) 'Die Versteinerungen des Deutschen Zechsteingebirges.' Geinitz. 
 
 (6) 'Die Animalischen Ueberreste der Dyas.' Geinitz.
 
 THE TRIASSIC PERIOD. 203 
 
 (7) 'Monograph of the Permian Fossils of England' (Palaeontographical 
 
 Society). King. 
 
 (8) 'Monograph of the Permian Brachiopoda of Britain' (Palaeonto- 
 
 graphical Society). Davidson. 
 
 (9) "On the Permian Rocks of the North- West of England and their 
 
 Extension into Scotland" 'Quart. Journ. Geol. Soc.,' vol. xx. 
 Murchison and Harkness. 
 
 (10) 'Catalogue of the Fossils of the Permian System of the Counties of 
 
 Northumberland and Durham.' Howse. 
 (n) 'Petrefacta Germanize.' Goldfuss. 
 
 (12) 'Beitrage zur Petrefaktenkunde.' Miinster. 
 
 (13) 'Ein Beitrag zur Palasontologie des Deutschen Zechsteingebirges. ' 
 
 Von Schauroth. 
 
 (14) ' Saurier aus dem Kupfer-schiefer der Zechstein-formation.' Von 
 
 Meyer. 
 
 (15) 'Manual of Palaeontology.' Owen. 
 
 (16) 'Recherches sur les Poissons Fossiles.' Agassiz. 
 
 (17) ' Ichnology of Annandale. ' Sir William Jardine. 
 
 (18) 'Die Fossile Flora der Permischen Formation.' Gceppert. 
 
 (19) 'Genera et Species Plantarum Fossilium.' Unger. 
 
 (20) " On the Red Rocks of England of older Date than the Trias" 
 
 'Quart. Journ. Geol. Soc.,' vol. xxvii. Ramsay. 
 
 CHAPTER XV. 
 
 THE TRIASSIC PERIOD. 
 
 We come now to the consideration of the great Mesozoic, or 
 Secondary series of formations, consisting, in ascending order, 
 of the Triassic, Jurassic, and Cretaceous systems. The Trias- 
 sic group forms the base of the Mesozoic series, and corre- 
 sponds with the higher portion of the New Red Sandstone of 
 the older geologists. Like the Permian rocks, and as implied 
 by its name, the Trias admits of a subdivision into three 
 groups a Lower, Middle, and Upper Trias. Of these sub- 
 divisions the middle one is wanting in Britain ; and all have 
 received German names, being more largely and typically de- 
 veloped in Germany than in any other country. Thus, the 
 Lower Trias is known as the Bunter Sandstein ; the Middle 
 Trias is called the Muschdkalk ; and the Upper Trias is known 
 as the Keuper. 
 
 I. The lowest division of the Trias is known as the Bunter 
 Sandstein (the Gres bigarre of the French), from the generally 
 variegated colours of the beds which compose it (German, 
 bunt, variegated). The Bunter Sandstein of the continent of 
 Europe consists of red and white sandstones, with red clays,
 
 2O4 HISTORICAL PALEONTOLOGY. 
 
 and thin limestones, the whole attaining a thickness of about 
 1500 feet. The term "marl" is very generally employed to 
 designate the clays of the Lower and Upper Trias ; but the 
 term is inappropriate, as they may contain no lime, and are 
 therefore not always genuine marls. In Britain the Bunter 
 Sandstein consists of red and mottled sandstones, with uncon- 
 solidated conglomerates, or " pebble-beds," the whole having 
 a thickness of 1000 to 2000 feet. The Bunter Sandstein, as 
 a rule, is very barren of fossils. 
 
 II. The Middle Trias is not developed in Britain, but it 
 is largely developed in Germany, where it constitutes what is 
 known as the Muschdkalk (Germ. Muschcl, mussel ; kalk, lime- 
 stone), from the abundance of fossil shells which it contains. 
 The Muschelkalk (the Calcaire coquillier of the French) consists 
 of compact grey or yellowish limestones, sometimes dolomitic, 
 and including occasional beds of gypsum and rock-salt. 
 
 III. The Upper Trias, or Kenpcr (the Marms irisees of the 
 French), as it is generally called, occurs in England ; but is 
 not so well developed as it is in Germany. In Britain, the 
 Keuper is 1000 feet or more in thickness, and consists of white 
 and brown sandstones, with red marls, the whole topped by 
 red clays with rock-salt and gypsum. 
 
 The Keuper in Britain is extremely unfossiliferous ; but it 
 passes upwards with perfect conformity into a very remarkable 
 group of beds, at one time classed with the Lias, and now 
 known under the names of the Penarth beds (from Penarth, in 
 Glamorganshire), the Rhoetic beds (from the Rhaetic Alps), or 
 the Avicula contorta beds (from the occurrence in them of 
 great numbers of this peculiar Bivalve). These singular beds 
 have been variously regarded as the highest beds of the Trias, 
 or the lowest beds of the Lias, or as an intermediate group. 
 The phenomena observed on the Continent, however, render 
 it best to consider them as Triassic, as they certainly agree 
 with the so-called Upper St Cassian or Kossen beds which 
 form the top of the Trias in the Austrian Alps. 
 
 The Penarth beds occur in Glamorganshire, Gloucestershire, 
 Warwickshire, Staffordshire, and the north of Ireland; and 
 they generally consist of a small thickness of grey marls, white 
 limestones, and black shales, surmounted conformably by the 
 lowest beds of the Lias. The most characteristic fossils which 
 they contain are the three Bivalves Cardium Rhceticum, Avicula 
 contorta, and Pecten Valoniensis ; but they have yielded many 
 other fossils, amongst which the most important are the re- 
 mains of Fishes and small Mammals (Microlestes\ 
 
 In the Austrian Alps the Trias terminates upwards in r.n
 
 THE TRIASSIC PERIOD. 
 
 205 
 
 extraordinary series of fossiliferous beds, replete with marine 
 fossils. Sir Charles Lyell gives the following table of these 
 remarkable deposits : 
 
 Strata belcnv the Lias in the Austrian Alps, in descending order. 
 
 I. Koessen beds. 
 
 (Synonyms, Upper St 
 Escher 
 
 Cassian beds of 
 and Merian.) 
 
 2. Dachstein beds. 
 
 3. Hallstadt beds 
 
 (or St Cassian). 
 
 4. A. Guttenstein beds. 
 B. Werfen beds, base of 
 
 Upper Trias ? 
 Lower Trias of some 
 geologists. 
 
 Grey and black limestone, with calcareous 
 marls having a thickness of about 50 
 feet. Among the fossils, Brachiopoda 
 very numerous ; some few species com- 
 mon to the genuine Lias ; many pecu- 
 liar. Avictda contorta, Pecten Valo- 
 niensis, Cardium Rh&ticum, Avicula 
 inccquivalvis, Spirifer Miinsteri, Dav. 
 Strata containing the above fossils al- 
 ternate with the .Dachstein beds, lying 
 next below. 
 
 White or greyish limestone, often in beds 
 three or four feet thick. Total thick- 
 ness of the formation above 2000 feet. 
 Upper part fossiliferous, with some 
 strata composed of corals (Lithoden- 
 dron.) Lower portion without fossils. 
 Among the characteristic shells are He- 
 micardium Wnlfeni, Megalodon triqtieter, 
 and other large bivalves. 
 
 Red, pink, or white marbles, from 800 to 
 1000 feet in thickness, containing more 
 than 800 species of marine fossils, for 
 the most part mollusca. Many species 
 of Orthoceras. True Ammonites, besides 
 Ceratites and Goniatites, Belemnites (rare), 
 Porcellia, Pleurotomaria, Trochtis, Mono- 
 tis salinaria, &c. 
 
 A. Black and grey lime- 
 stone 150 feet thick, al- 
 ternating with the un- 
 derlying Werfen beds. 
 
 B. Red and green shale 
 and sandstone, with 
 salt and gypsum. 
 
 Among the fossils 
 are Ceratites 
 caaianut, My- 
 acites fassaen- 
 si's, Naticella 
 costata, &c. 
 
 In the United States, rocks of Triassic age occur in several 
 areas between the Appalachians and the Atlantic seaboard ; 
 but they show no such triple division as in Germany, and their 
 exact place in the system is uncertain. The rocks of these 
 areas consist of red sandstones, sometimes shaly or conglomer- 
 atic, occasionally with beds of impure limestone. Other more 
 extensive areas where Triassic rocks appear at the surface, are 
 found west of the Mississippi, on the slopes of the Rocky Moun- 
 tains, where the beds consist of sandstones and gypsiferous 
 15
 
 206 
 
 HISTORICAL PALEONTOLOGY. 
 
 marls. The American Trias is chiefly remarkable for having 
 yielded the remains of a small Marsupial (Dromatheriiini), and 
 numerous footprints, which have generally been referred to 
 Birds (Brontozoum}, along .with the tracks of undoubted Rep- 
 tiles (Otozoum, Anisopus, &c.) 
 
 The subjoined section (fig. 139) expresses, in a diagram- 
 matic manner, the general sequence of the Triassic rocks when 
 fully developed, as, for example, in the Bavarian Alps : 
 
 GENERALISED SECTION OF THE TRIASSIC ROCKS OF 
 CENTRAL EUROPE. 
 
 Fig. 139- 
 
 I 
 
 IL It II II I! II ti_ 
 
 I' .. II I! II 
 
 il I II II 
 
 " " I' 
 
 Upper Keuper (Kossen or 
 Rhcetic beds, and Uach- 
 stein beds). 
 
 Middle Keuper (Hallstaclt 
 or St Cassian beds). 
 
 i Lower Keuper (Keuper 
 Sandstones proper). 
 
 Muschelkalk. 
 
 Bunter Sandstein. (Gutten- 
 stein and W erf en beds ?) 
 
 With regard to the life of the Triassic period, we have to
 
 THE TRIASSIC PERIOD. 2O/ 
 
 notice a difference as concerns the different members of the 
 group similar to that which has been already mentioned in 
 connection with the Permian formation. The arenaceous 
 deposits of the series, namely, resemble those of the Permian, 
 not only in being commonly red or variegated in their colour, 
 but also in their conspicuous paucity of organic remains. 
 They for the most part are either wholly unfossiliferous, or 
 they contain the remains of plants or the bones of reptiles, 
 such as may easily have been drifted from some neighbouring 
 shore. The few fossils which may be considered as properly 
 belonging to these deposits are chiefly Crustaceans (Estheria) 
 or Fishes, which may well have lived in the waters of estuaries 
 or vast inland seas. We may therefore conclude, with con- 
 siderable probability, that the barren sandy and marly accumu- 
 lations of the Bunter Sanclstein and Lower Keuper were not 
 laid down in an open sea, but are probably brackish-water 
 deposits, formed in estuaries or land-locked bodies of salt 
 water. This at any rate would appear to be the case as regards 
 these members of the series as developed in Britain and in 
 their typical areas on the continent of Europe ; and the origin 
 of most of the North American Trias would appear to be 
 much the same. Whether this view be correct or not, it is 
 certain that the beds in question were laid down in shallow 
 water, and in the immediate vicinity of land, as shown by the 
 numerous drifted plants which they contain and the common 
 occurrence in them of the footprints of air-breathing animals 
 (Birds, Reptiles, and Amphibians). On the other hand, the 
 middle and highest members of the Trias are largely calca- 
 reous, and are replete with the remains of undoubted marine 
 animals. There cannot, therefore, be the smallest doubt but 
 that the Muschelkalk and the Rhastic or Kossen beds were 
 slowly accumulated in an open sea, of at least a moderate 
 depth ; and they have preserved for ns a very considerable 
 selection from the marine fauna of the Triassic period. 
 
 The plants of the Trias are, on the whole, as distinctively 
 Mesozoic in their aspect as those of the Permian are Palaeo- 
 zoic. In spite, therefore, of the great difficulty which is ex- 
 perienced in effecting a satisfactory stratigraphical separation 
 between the Permian and the Trias, we have in this fact a 
 proof that the two formations were divided by an interval of 
 time sufficient to allow of enormous changes in the terrestrial 
 vegetation of the world. The Lcpidodcndroia's, Astcrophyllites, 
 and AnniilaricE, of the Coal and Permian formations, have now 
 apparently wholly disappeared : and the Triassic flora consists 
 mainly of Ferns, Cycads, and Conifers, of which only the two
 
 208 
 
 HISTORICAL PALEONTOLOGY. 
 
 last need special notice. The Cycads (fig. 140) are true exo- 
 genous plants, which in general form and habit ot growth pre- 
 
 Fig. 1^0,Zamia spiralis, a living Cycad. Australia. 
 
 sent considerable resemblance to young Palms, but which in 
 reality are most nearly related to the Pines and Firs (Coniferce). 
 The trunk is unbranched, often much shortened, and bears a 
 crown of feathery pinnate fronds. The leaves are usually 
 "circinate" they unroll in expanding, like the fronds of 
 ferns. The seeds are not protected by a seed-vessel, but are 
 borne upon the edge of altered leaves, or are carried on the 
 scales of a cone. All the living species of Cycads are natives 
 of warm countries, such as South America, the West Indies, 
 Japan, Australia, Southern Asia, and South Africa. The 
 remains of Cycads, as we have seen, are not known to occur 
 in the Coal formation, or only to a very limited extent towards 
 its close ; nor are they known with certainty as occurring in 
 Permian deposits. In the Triassic period, however, the re- 
 mains of Cycads belonging to such genera as Pterophylluin 
 (fig. 141, b), Zamites, and Podozamites (fig. 141, c), are suffi- 
 ciently abundant to constitute quite a marked feature in the 
 vegetation ; and they continue to be abundantly represented 
 throughout the whole Mesozoic series. The name "Age of 
 Cycads," as applied to the Secondary epoch, is therefore, 
 from a botanical point of view, an extremely appropriate one. 
 The Conifers of the Trias are not uncommon, the principal 
 form being Voltzia (fig. 141, a\ which possesses some peculiar 
 characters, but would appear to be most nearly related to the 
 recent Cypresses. 
 
 As regards the Invertebrate animals of the Trias, our know- 
 ledge is still principally derived from the calcareous beds 
 which constitute the centre of. the system (the Muschelkalk)
 
 THE TRIASSIC PERIOD. 209 
 
 on the continent of Europe, and from the St Cassian and 
 Rhaetic beds still higher in the series; whilst some of the 
 
 Fig. 141. Triassic Conifers and Cycads. a, Voltzia (Schizoneura) heterophylla, por- 
 tion of a branch, Europe and America ; b, Part of the frond of Pterophyltum Jageri, 
 Europe ; c, Part of the frond of Podozamites lanceolatus, America. 
 
 Triassic strata of California and Nevada have likewise yielded 
 numerous remains of marine Invertebrates. The Protozoans 
 are represented by Foraminifera and Sponges, and the Coelcn- 
 terates by a small number of Corals ; but these require no 
 special notice. It may be mentioned, however, that the great 
 Palaeozoic group of the Ritgose corals has no known repre- 
 sentative here, its place being taken by corals of Secondary 
 type (such as Montlivaltia, Synastrcea, &c.) 
 
 The Echinodenns are represented principally by Crinoids, 
 the remains of which are extremely abundant in some of the 
 limestones. The best -known species is the famous " Lily- 
 Encrinite " (Encrinus liliifonnis, fig. 142), which is character-
 
 210 
 
 HISTORICAL PALEONTOLOGY. 
 
 istic of the Muschelkalk. In this beautiful species, the flower- 
 like head is supported upon a rounded stem, the joints of 
 which are elaborately articulated with one 
 another; and the fringed arms are com- 
 posed each of a double series of alter- 
 nating calcareous pieces. The Palaeozoic 
 Urchins, with their supernumerary rows of 
 plates, the Cystideans, and the Pentremites 
 have finally disappeared ; but both Star- 
 fishes and Brittle-stars continue to be rep- 
 resented. One of the latter namely, the 
 AspiduraloncataQi Goldfuss (tig. 143) 16 
 
 Fig. 143. Asfc'rfitra Joricata, a Triassic Ophiuroid. 
 Muschelkalk, Germany. 
 
 highly characteristic of the Muschelkalk. 
 
 The remains of Articulate Animals are 
 not very abundant in the Trias, if we except 
 the bivalved cases of the little Water-fleas 
 (Osfracoda), which are occasionally very 
 plentiful. There are also many species 
 of the horny, concentrically-striated valves 
 of the Estherice (see fig. 122, &), which 
 might easily be taken for small Bivalve 
 Molluscs. The " Long-tailed " Decapods, 
 of the type of the Lobster, are not with- 
 out examples, but they become much more 
 numerous in the succeeding Jurassic pe- 
 riod. Remains of insects have also been discovered. 
 
 Amongst the Mollusca we have to note the disappearance, 
 amongst the lower groups, of many characteristic Palaeozoic 
 types. Amongst the Polyzoans, the characteristic " Lace- 
 corals," Fenestdla, Rctepora* Synocladia, Polypora, &c., have 
 
 * The genus Rctepora is really a recent one, represented by living forms ; 
 and the so-called Rctepora; of the Palceozoic rocks should properly receive 
 another name (Phyllopora}, as being of a different nature. The name 
 Retepora has been here retained for these old forms simply in accordance 
 with genera! usage. 
 
 Fig. 142. Head and 
 upper part of the column 
 of Encriuus HHiformis. 
 The lower figure shows 
 the articulating surface 
 of one of the joints of the 
 column. Muschelkalk, 
 Germany.
 
 THE TRIASSIC PERIOD. 
 
 211 
 
 become apparently extinct. The same is true of many of the 
 ancient types of Brachiopods, and conspicuously so of the 
 great family of the Product idee, which played such an important 
 part in the seas of the Carboniferous and Permian periods. 
 
 Bivalves (Lamellibranchiata) and Univalves (Gasteropoda) 
 are well represented in the marine beds of the Trias, and 
 some of the former are particularly characteristic either of the 
 formation as a whole or of minor subdivisions of it. A few of 
 these characteristic species are figured in the accompanying 
 illustration (fig. 144). Bivalve shells of the genera Daonella 
 (fig. 144, a) and Halobia (Monotis) are very abundant, and are 
 
 Fig. 144. Triassic Lamellibranchs. a, Daonella (Halobia) Lammelli; 
 Valoniensis; c, Myophoria liueata ; d, Cardium Rhceticum; e, Avicnla 
 /, Avicula socMis? 
 
 Pecten 
 torta ; 
 
 found in the Triassic strata of almost all regions. These 
 groups belong to the family of the Pearl-oysters (Aytculidat), 
 and are singular from the striking resemblance borne by some 
 of their included forms to the Strophomcntz amongst the Lamp- 
 shells, though, of course, no real relation exists between the 
 two. The little Pearl-oyster, Avicnla socialh (fig. 144, /), is 
 found throughout the greater part of the Triassic series, and is 
 especially abundant in the Muschelkalk. The genus Myo- 
 phoria (fig. 144, c), belonging to the Trigoniadce, and related 
 therefore to the Permian Schizodus, is characteristically Trias- 
 sic, many species of the genus being known in deposits of this 
 age. Lastly, the so-called "Rhastic" or " Kossen" beds are
 
 212 
 
 HISTORICAL PALAEONTOLOGY. 
 
 characterised by the occurrence in them of the Scallop, Pccten 
 Valoniensis (fig. 144, b}; the small Cockle, Cardium Rhczticum 
 (fig. 144, d); and the curiously-twisted Pearl-oyster, Avicula 
 contorta (fig. 144, e) this last Bivalve being so abundant that 
 the strata in question are often spoken of as the " Avicula 
 contorta beds." 
 
 Passing over the groups of the Heteropods and Pteropods, 
 we have to notice the Cephalopoda, which are represented in 
 the Trias not only by the chambered shells of Tetrabranchiates, 
 but also, for the first time, by the internal skeletons of Dibran- 
 chiate forms. The Trias, therefore, marks the first recognised 
 appearance of true Cuttle-fishes. All the known examples of 
 these belong to the great Mesozoic group of the Belemnitidce ; 
 and as this family is much more largely developed in the suc- 
 ceeding Jurassic period, the consideration of its characters 
 will be deferred till that formation is treated of. Amongst the 
 chambered Cephalopods we find quite a number of the Palae- 
 ozoic Orthoceratitcs, some of them of considerable size, along 
 with the ancient Cyttoceras and Goniatites ; and these old types, 
 singularly enough, occur in the higher portion of the Trias 
 (St Cassian beds), but have, for some unexplained reason, not 
 yet been recognised in the lower and equally fossiliferous 
 formation of the Muschelkalk. Along with these we meet for 
 the first time with true Ammonites, which fill such an extensive 
 
 place in the Jurassic 
 seas, and which will 
 be spoken of here- 
 after. The form, how- 
 ever, which is most 
 characteristic of the 
 Trias is Ceratites (fig. 
 145). In this genus 
 the shell is curved into 
 a flat spiral, the volu- 
 tions of which are in 
 contact ; and it further 
 agrees with both 6*0- 
 niatitesand. Ammonites 
 in the fact that the 
 septa or partitions be- 
 tween the air-cham- 
 bers are not simple and plain (as in the Nautilus and its allies), 
 but are folded and bent as they approach the outer wall of the 
 shell. In the Goniatite these foldings of the septa are of a simply 
 lobed or angulated nature, and in the Ammonite they are ex- 
 
 Fig. 145- -c. 
 
 and from behind. 
 
 Muschelkalk.
 
 THE TRIASSIC PERIOD. 
 
 213 
 
 tremely complex ; whilst in the Ceratite there is an inter- 
 mediate state of things, the special feature of which is, that 
 those foldings which are turned towards the mouth of the 
 shell are merely rounded, whereas those which are turned 
 away from the mouth are characteristically toothed. The 
 genus Ceratites, though principally Triassic, has recently been 
 recognised in strata of Carboniferous age in India. 
 
 From the foregoing it will be gathered that one of the most 
 important points in connection with the Triassic Mollusca is 
 the remarkable intermixture of Palaeozoic and Mesozoic types 
 which they exhibit. It is to be remembered, also, that this 
 intermixture has hitherto been recognised, not in the Middle 
 Triassic limestones of the Muschelkalk, in which as the 
 oldest Triassic beds with marine fossils we should naturally 
 expect to find it, but in the St Cassian beds, the age of which 
 is considerably later than that of the Muschelkalk. The 
 intermingling of old and new types of Shell-fish in the Upper 
 Trias is well brought out in the annexed table, given by Sir 
 Charles Lyell in his 'Student's Elements of Geology' (some 
 of the less important forms in the table being omitted here) : 
 
 GENERA OF FOSSIL MOLLUSCA IN THE ST CASSIAN 
 
 AND HALLSTADT BEDS. 
 
 Common to Older Rocks. 
 
 Characteristic of Triassic 
 Rocks. 
 
 Common to Newer Rocks. 
 
 Orthoceras. 
 
 Ceratites. 
 
 Ammonites. 
 
 Bactrites. 
 
 Cochloceras. 
 
 Chemnitzia. 
 
 Macrocheilus. 
 
 Rhabdoceras. 
 
 Cerithium. 
 
 Loxonema. 
 
 Aulacoceras. 
 
 Monodonta. 
 
 Holopella. 
 
 Naticella. 
 
 Sphcera. 
 
 Murchisonia. 
 
 Platystoma. 
 
 Cardita. 
 
 Porcellia. 
 Athyris. 
 
 Halobia. 
 Hornesia. 
 
 Myoconcha. 
 Hinnites. 
 
 Retzia. 
 
 Koninckia. 
 
 Monotis. 
 
 Cyrtina. 
 
 Scoliostoma. 
 
 Plicatula. 
 
 Euomphalus. 
 
 Myophoria. 
 (The last two are princi- 
 
 Pachyrisma. 
 Thecidium. 
 
 
 pally but not exclus- 
 
 
 
 ively Triassic. ) 
 
 
 Thus, to emphasise the more important points alone, the Trias 
 has yielded, amongst the Gasteropods, the characteristically 
 Palaeozoic Loxonema, Holopella, Murchisonia, Euomphalus, and 
 Porcellia, along with typically Triassic forms like Platystoma 
 and Scoliostoma, and the great modern groups Chemnitzia and 
 Cerithium. Amongst the Bivalves we find the Palaeozoic 
 Megct/odon side by side with the Triassic Halobia and Myo- 
 pJwria, these being associated with the Carditcz, Hinnites, 
 Plicatulce, and Trigonice of later deposits. The Brachiopods
 
 214 HISTORICAL PALEONTOLOGY. 
 
 exhibit the Palaeozoic Athyris, Retzia, and Cyrtina, with the 
 Triassic Koninckia and the modern Thecidium. Finally, it is 
 here that the ancient genera Orthoceras, Cyrtoceras, and Gonia- 
 tites make their last appearance upon the scene of life, the 
 place of the last of these being taken by the more complex 
 and almost exclusively Triassic Ceratites ; whilst the still more 
 complex genus Ammonites first appears here in force, and is 
 never again wanting till we reach the close of the Mesozoic 
 period. The first representatives of the great Secondary 
 family of the Belemnitcs are also recorded from this horizon. 
 
 Amongst the Vertebrate Animals of the Trias, the Fishes are 
 represented by numerous forms belonging to the Ganoids and 
 the Placoids. The Ganoids of the period are still all provided 
 with unsymmetrical (" heterocercal ") tails, and belong prin- 
 cipally to such genera as Palceoniscus and Catopterus. The 
 remains of Placoids are in the form of teeth and spines, the 
 two principal genera being the two important Secondary 
 groups Acrodus and Hybodus. Very nearly at the summit 
 of the Trias in England, in the Rhaetic series, is a singular 
 stratum, which is well known as the " bone-bed," from the 
 number of fish-remains which it contains. More interesting, 
 however, than the above, are the curious palate-teeth of the 
 Trias, upon which Agassiz founded the genus Ceratodus. The 
 teeth of Ceratodus (fig. 146) are singular flattened plates, 
 
 Fig. 146. a, Dental plate of Ceratodus serratns, Keuper; b, Dental plate of 
 Ceratodus altus, Keuper. (After Agassiz.) 
 
 composed of spongy bone beneath, covered superficially with 
 a layer of enamel. Each plate is approximately triangular, 
 one margin (which we now know to be the outer one) being 
 prolonged into prongs or conical prominences, whilst the 
 surface is more or less regularly undulated. Until recently, 
 though the master-mind of Agassiz recognised that these 
 singular bodies were undoubtedly the teeth of fishes, we were 
 entirely ignorant as to their precise relation to the animal, or 
 as to the exact affinities of the fish thus armed. Lately, how- 
 ever, there has been discovered in the rivers of Queensland 
 (Australia) a living species of Ceratodus (C. Fosteri, fig. 147),
 
 THE TRIASSIC PERIOD. 215 
 
 with teeth precisely similar to those of its Triassic predecessor; 
 and we thus have become acquainted with the use of these 
 
 Fig 147. Ceratodus Fasten', the Australian Mud-fish, reduced in size. 
 
 structures and the manner in which they were implanted in 
 the mouth. The palate carries two of these plates, with their 
 longer straight sides turned towards each other, their sharply- 
 sinuated sides turned outwards, and their short straight sides 
 or bases directed backwards. Two similar plates in the lower 
 jaw correspond to the upper, their undulated surfaces fitting 
 exactly to those of the opposite teeth. There are also two 
 sharp-edged front teeth, which are placed in the front of the 
 mouth in the upper jaw; but these have not been recognised 
 in the fossil specimens. The living Ceratodus feeds on vege- 
 table matters, which are taken up or torn off from plants by 
 the sharp front teeth, and then partially crushed between the 
 undulated surfaces of the back teeth (Giinther) ; and there 
 need be little doubt but that the Triassic Ceratodi followed 
 a similar mode of existence. From the study of the living 
 Ceralodits, it is certain that the genus belongs to the same 
 group as the existing Mud-fishes (Dipnoi) ; and we therefore 
 learn that this, the highest, group of the entire class of Fishes 
 existed in Triassic times under forms little or not at all differ- 
 ent from species now alive ; whilst it has become, probable 
 that the order can be traced back into the Devonian period. 
 
 The Amphibians of the Trias all belong to the old order of 
 the Labyrinthodonts, and some of them are remarkable for 
 their gigantic dimensions. They were first known by their 
 footprints, which were found to occur plentifully in the Tri- 
 assic sandstones of Britain and the continent of Europe, and 
 which consisted of a double series of alternately-placed pairs 
 of hand-shaped impressions, the hinder print of each pair being 
 much larger than the one in front (fig. 148). So like were these 
 impressions to the shape of the human hand, that the at that 
 time unknown animal which produced them was at once chris- 
 tened Cheirotherium, or " Hand-beast." Further discoveries, 
 however, soon showed that the footprints of Cheirotherium 
 were really produced by species of Amphibians which, like the 
 existing Frogs, possessed hind-feet of a much larger size than
 
 216 
 
 HISTORICAL PALEONTOLOGY. 
 
 the fore-feet, and to which the 
 name of Labyrinthodonts was ap- 
 plied in consequence of the 
 complex microscopic structure of 
 the teeth (fig. 149). In the essen- 
 tial details of their structure, the 
 Triassic Labyrinthodonts did not 
 differ materially from their pre- 
 decessors in the Coal-measures 
 and Permian rocks. They pos- 
 sessed the same frog-like skulls 
 (fig. 150), with a lizard-like body, 
 a long tail, and comparatively 
 feeble limbs. The hind - limbs 
 were stronger and longer than 
 the fore - limbs, and the lower 
 
 IT*, 
 
 \ 
 
 Fig. 148. Footprints of a Labyrinthodont (Ckeirotherium), from the Triassic Sand- 
 stones of Hessberg, near Hildburghausen, Germany, reduced one-eighth. The lower 
 figure shows a slab, with several prints, and traversed by reticulated sun-cracks : the 
 upper figure shows the impression of one of the hind-feet, one-half of the natural size, 
 (.-ifter Sickler.)
 
 THE TRIASSIC PERIOD. 217 
 
 surface of the body was protected by an armour of bony plates. 
 Some of the Triassic Labyrinthodonts must have attained 
 dimensions utterly unapproached amongst existing Amphibians, 
 the skull of Labyrinthodon Jageri (fig. 150) being upwards of 
 
 
 Fig. 149. Section of the tooth of Lafyrlnthodon 
 Mastodoitsaurus) Jcegeri, showing the microscopic 
 structure. Greatly enlarged. Trias. 
 
 Fig. 130. a, Skull of La- 
 lyrinthodon jeegeri, much 
 reduced in size ; 6, Tooth 
 of the same. Trias, Wurt- 
 temberg. 
 
 three feet in length and two feet in breadth. Restorations of 
 some of these extraordinary creatures have been attempted in 
 the guise of colossal Frogs ; but they must in reality have more 
 closely resembled huge Newts. 
 
 Remains of Reptiles are very abundant in Triassic deposits, 
 and belong to very varied types. The most marked feature, 
 in fact, connected with the Vertebrate fauna of the Trias, and 
 of the Secondary rocks in general, is the great abundance of 
 Reptilian life. Hence the Secondary period is often spoken 
 of as the "Age of Reptiles." Many of the Triassic reptiles 
 depart widely in their structure from any with which we are 
 acquainted as existing on the earth at the present day, and it is 
 only possible here to briefly note some of the more important 
 of these ancient forms. Amongst the group of the Lizards 
 {Lacertilia), represented by Protorosaurus in the older Permian 
 strata, three types more or less certainly referable to this order 
 may be mentioned. One of these is a small reptile which 
 was found many years ago in sandstones near Elgin, in Scot- 
 land, and which excited special interest at the time in conse- 
 quence of the fact that the strata in question were believed to 
 belong to the Old Red Sandstone formation. It is, however,
 
 2l8 HISTORICAL PALAEONTOLOGY. 
 
 now certain that the Elgin sandstones which contain Tderpcton 
 /ginense, as this reptile is termed, are really to be regarded as 
 of Triassic age. By Professor Huxley, Telerpeton is regarded 
 as a Lizard, which cannot be considered as " in any sense 
 a less perfectly - organised creature than the Gecko, whose 
 swift and noiseless run over walls and ceilings surprises the 
 traveller in climates warmer than our own." The "Elgin Sand- 
 stones " have also yielded another Lizard, which was originally 
 described by Professor Huxley under the name of Hyperoda- 
 pedon, the remains of the same genus having been subsequently 
 discovered in Triassic strata in India and South Africa. The 
 Lizards of this group must therefore have at one time enjoyed 
 a very wide distribution over the globe ; and the living Spheno- 
 don of New Zealand is believed by Professor Huxley to be the 
 nearest living ally of this family. The Hyperodapedon of the 
 Elgin Sandstones was about six feet in length, with limbs 
 adapted for terrestrial progression, but with the bodies of the 
 vertebrae slightly biconcave, and having two rows of palatal, 
 teeth, which become worn down to the bone in old age. 
 Lastly, the curious Rhynchosaurus of the Trias is also referred, 
 by the eminent comparative anatomist above mentioned, to the 
 order of the Lizards. In this singular reptile (fig. 151) the skull 
 is somewhat bird-like, and the 
 jaws appear to have been desti- 
 tute of teeth, and to have been 
 encased in a hcrny sheath like 
 the beak of a Turtle or a Bird. 
 It is possible, however, that the 
 palate was furnished with teeth. 
 The S ro P of the Crocodiles 
 and Alligators (Crocodilia), dis- 
 tinguished by the fact that the teeth are implanted in dis- 
 tinct sockets and the skin more or less extensively provided 
 with bony plates, is represented in the Triassic rocks by the 
 Stagonolepis of the Elgin Sandstones. 'The so-called " Theco- 
 dont " reptiles (such as Belodon, Thecodontosaurus, and Palceo- 
 saunes, fig. 152, c, d, e) are also nearly related to the Croco- 
 diles, though it is doubtful if they should be absolutely referred 
 to this group. In these reptiles, the teeth are implanted in 
 distinct sockets in the jaws, their crowns being more or less 
 compressed and pointed, " with trenchant and finely serrate 
 margins " (Owen). The bodies of the vertebrae are hollowed 
 out at both ends, but the limbs appear to be adapted for pro- 
 gression on the land. The genus Belodon (fig. 152, c] is 
 known to occur in the Keuper of Germany and in America;
 
 THE TRIASSIC PERIOD. 
 
 2I 9 
 
 and Palceosaurus (fig. 153, e) has also been found in the Trias 
 of the same region. Teeth of the latter, however, are found, 
 along with remains of Thecodontosaurus (fig. 153, d\ in a 
 singular magnesian conglomerate near Bristol, which was 
 originally believed to be of Permian age, but which appears 
 to be undoubtedly Triassic. 
 
 Fig. 152. Triassic Reptiles, a, Skull of Nothosaunts miralnlis, reduced in size Mus- 
 chelkalk, Germany ; b, Tooth of Simosaurns Gaillnrdoti, of the natural size Muschel- 
 kalk, Germany ; c, Tooth of Belodon Carotinerisis'l'rias, America ; d, Tooth of Theco- 
 dontosanriis antiquus, slightly enlarged Britain; e, Tooth of Palaosaurus platyodon, of 
 the natural size Britain. 
 
 The Trias has also yielded the remains of the great marine 
 reptiles which are often spoken of collectively as the " Enalio- 
 saurians" or " Sea-lizards," and which will be more particularly 
 spoken of in treating of the Jurassic period, of which they are 
 more especially characteristic. In all these reptiles the limbs 
 are flattened out, the digits being enclosed in a continuous 
 skin, thus forming powerful swimming-paddles, resembling the 
 "flippers" of the Whales and Dolphins both in their general 
 structure and in function. The tail is also long, and adapted 
 to act as a swimming-organ ; and there can be no doubt but 
 that these extraordinary and often colossal reptiles frequented 
 the sea, and only occasionally came to the land. The Triassic 
 Enaliosaurs belong to a group of which the later genus 
 Plesiosaurus is the type (the Sauropterygia). One of the best 
 known of the Triassic genera is Nothosaurus (fig. 152, a), in 
 which the neck was long and bird-like, the jaws being im- 
 mensely elongated, and carrying numerous powerful conical 
 teeth implanted in distinct sockets. The teeth in Stmosaunts 
 (152, b] are of a similar nature ; but the orbits are of enormous 
 size, indicating eyes of corresponding dimensions, and perhaps 
 pointing to the nocturnal'habits of the animal. In the singular
 
 220 HISTORICAL PALEONTOLOGY. 
 
 Placodits, again, the teeth are in distinct sockets, but resemble 
 those of many fishes in being rounded and obtuse (fig. 153), 
 forming broad crushing plates 
 adapted for the comminu- 
 tion of shell-fish. There is a 
 row of these teeth all round 
 the upper jaw proper, and a 
 double series on the palate, 
 but the lower jaw has only a 
 single row of teeth. Placodus 
 is found in the Muschelkalk, 
 and the characters of its den- 
 tal apparatus indicate that 
 it was much more peaceful 
 
 chelkalk, Germany. CiatCS the NotllOSaur and Sl- 
 
 The Triassic rocks of South Africa and India have yielded 
 the remains of some extraordinary Reptiles, which have been 
 placed by Professor Owen in a separate order under the name 
 of Anomodontia. The two principal genera of this group are 
 Dicynodon and Oudenodon, both of which appear to have been 
 large Reptiles, with well-developed limbs, organised for pro- 
 gression upon the dry land. In Oudenodon (fig. 154, B) the 
 jaws seem to have been wholly destitute of teeth, and must 
 have been encased in a horny sheath, similar to that with 
 which we are familiar in the beak of a Turtle. In Dicynodon 
 (fig. 154, A), on the other hand, the front of the upper jaw 
 and the whole of the lower jaw were destitute of teeth, and 
 the front of the mouth mujt have constituted a kind of beak; 
 but the upper jaw possessed on each side a single huge conical 
 tusk, which is directed downwards, and must have continued 
 to grow during the life of the animal. 
 
 It may be mentioned that the above-mentioned Triassic 
 sandstones of South Africa have recently yielded to the re- 
 searches of Professor Owen a new and unexpected type of 
 Reptile, which exhibits some of the structural peculiarities 
 which we have been accustomed to regard as characteristic 
 of the Carnivorous quadrupeds. The Reptile in question has 
 been named Cynodraco, and it is looked upon by its distin- 
 guished discoverer as the type of a new order, to which he has 
 given the name of Theriodontia. The teeth of this singular 
 form agree with those of the Carnivorous quadrupeds in con- 
 sisting of three distinct groups namely, front teeth or incisors, 
 eye teeth or canines, and back teeth or molars. The canines
 
 THE TRIASSIC PERIOD. 
 
 221 
 
 also are long and pointed, very much compressed, and having 
 their lateral margins finely serrated, thus presenting a singular 
 
 Fig. IS4.-TH 
 one of the 
 beak-like j 
 
 .Triassic Anomodont Reptiles. A, Skull of Dtcynodon laceriiceps, 
 great maxillary tusks; B, Skull of Oudenodon Bainii, showing the t 
 jaws. From the Trias of South Africa. (After Owen.) 
 
 showing, 
 
 toothless, 
 
 resemblance to the teeth of the extinct " Sabre-toothed Tiger" 
 (Machairodus}. The bone of the upper arm (humerus) further 
 shows some remarkable resemblances to the same bone in the 
 Carnivorous Mammals. As has been previously noticed, Pro- 
 fessor Owen is of opinion that some of the Reptilian remains 
 of the Permian deposits will also be found to belong to this 
 group of the "Theriodonts." 
 
 Lastly, we find in the Triassic rocks the remains of Reptiles 
 belonging to the great Mesozoic order of the Dcinosaiifia. 
 This order attains its maximum at a later period, and will be 
 spoken of when the Jurassic and Cretaceous deposits come to 
 be considered. The chief interest of the Triassic Reptiles of 
 this group .irises from the fact that they are known by their 
 footprints as well as by their bones ; and a question has arisen 
 whether the supposed footprints of birds which occur in the 
 Trias have not really been produced by Deinosaurs. This 
 leads us, therefore, to speak at the same time as to the evi- 
 dence which we have of the existence of the class of Birds 
 during the Triassic period. No actual bones of any bird have 
 1C
 
 222 HISTORICAL PALEONTOLOGY. 
 
 as yet been detected in any Triassic deposit : but we have 
 tolerably clear evidence of their existence at this time in the 
 form of footprints. The impressions in question are found in 
 considerable numbers in certain red sandstones' of the age of 
 the Trias in the valley of the Connecticut River, in the United 
 States. They vary much in size, and have evidently been 
 produced by many different animals walking over long 
 stretches of estuarine mud and sand exposed at low water. 
 The footprints now under consideration form a double series 
 of single prints, and therefore, beyond all question, are the 
 tracks of a biped that is, of an animal which walked upon 
 two legs. No living animals, save Man and the Birds, walk 
 habitually on two legs ; and there is, therefore, a prima facie 
 presumption that the authors of these prints were Birds. 
 Moreover, each impression consists of the marks of three toes 
 turned forwards (tig. 155), and therefore are precisely such as 
 
 
 Fig. 155. Supposed footprint of a Bird, from the Triassic Sandstones of the Con- 
 necticut River. The slab shows also numerous " rain-prints." 
 
 might be produced by Wading or Cursorial Birds. Further, 
 the impressions of the toes show exactly the same numerical 
 progression in the number of the joints as is observable in 
 living Birds that is to say, the inneimost of the three toes 
 consists of three joints, the middle one of four, and the outer 
 one of five joints. Taking this evidence collectively, it would 
 have seemed, until lately, quite certain that these tracks could 
 only have been formed by Birds. It has, however, been 
 shown that the Deinosaurian Reptiles possess, in some cases 
 at any rate, some singularly bird -like characters, amongst
 
 THE TRIASSIC PERIOD. 223 
 
 which is the fact that the animal possessed the power of 
 walking, temporarily at least, on its hind-legs, which were 
 much longer and stronger than the fore - limbs, and which 
 were sometimes furnished with no more than three toes. 
 As the bones and teeth of Deinosaurs have been found in 
 the Triassic deposits of North America, it may be regarded as 
 certain that some of the bipedal tracks originally ascribed to 
 Birds must have really been produced by these Reptiles. It 
 seems at the same time almost a certainty that others of the 
 three-toed impressions of the Connecticut sandstones were in 
 truth produced by Birds, since it is doubtful if the bipedal 
 mode of progression was more than an occasional thing 
 amongst the Deinosaurs, and the greater number of the 
 many known tracks exhibit no impressions of fore - feet. 
 Upon the whole, therefore, we may, with much probability, 
 conclude that the great class of Birds (Avcs] was in existence 
 in the Triassic period. If this be so, not only must there 
 have been quite a number of different forms, but some of 
 them must have been of very large size. Thus the largest 
 footprints hitherto discovered in the Connecticut sandstones 
 are 22 inches long and 12 inches wide, with a proportionate 
 length of stride. These measurements indicate a foot four 
 times as large as that of the African Ostrich ; and the animal 
 which produced them whether a Bird or a Deinosaur must 
 have been of colossal dimensions. 
 
 Finally, the Trias completes the tale of the great classes of 
 the Vertebrate sub-kingdom by presenting us with remains of 
 the first known of the true Quadrupeds or Mammalia. These 
 are at present only known by their teeth, or, in one instance, 
 by one of the halves of the lower jaw ; and these indicate 
 minute Quadrupeds, which present greater affinities with the 
 little Banded Ant-eater (Myrmecobius fasciatns, fig. 158) of 
 Australia than with any other living form. If this conjecture 
 
 Fig. i57--. Molar 
 Micro 'estes aiitiyttus, 
 fied ; l>. Crown of tin 
 Fig. 156. Lower jaw of Drotnatheriiitti sylvcstre. magnified still further. Trias, 
 
 Trias, North Carolina. (After Emmons ) Germany. 
 
 be correct, these ancient Mammals belonged to the order of 
 the Marsupials or Pouched Quadrupeds (Marsupialia\ which
 
 224 HISTORICAL PALAEONTOLOGY. 
 
 are now exclusively confined to the Australian province, South 
 America, and the southern portion of North America. In 
 
 Fig. 158. The Banded Ant-eater (Myrmecobius fasciatns) of Australia. 
 
 the Old World, the only known Triassic Mammals belong to 
 the genus Microlestes, and to the probably identical Hypsi- 
 prymnopsis of Professor Boyd Dawkins. The teeth of Micro- 
 lestes (fig. 157) were originally discovered by Plieninger in 
 1847 in the "bone-bed" which is characteristic of the sum- 
 mit of the Rh?etic series both in Britain and on the continent 
 of Europe ; and the known remains indicate two species. In 
 Britain, teeth of Microlestes have been discovered by Mr 
 Charles Moore in deposits of Upper Triassic age, filling a 
 fissure in the Carboniferous limestone near Frome, in Somer- 
 setshire ; and a molar tooth of Hypsiprymnopsis was found by 
 Professor Boyd Dawkins in Rhaetic marls below the " bone- 
 bed " at Watchet, also in Somersetshire. In North America, 
 lastly, there has been found in strata of Triassic age one of 
 the branches of the lower jaw of a small Mammal, which has 
 been described under the name of Dromatherinm sylvestre 
 (fig. 156). The fossil exhibits ten small molars placed side 
 by side, one canine, and three incisors, separated by small 
 intervals, and it indicates a small insectivorous animal, pro- 
 bably most nearly related to the existing MyrmecobL'.s. 
 
 LITERATURE. 
 
 The following list comprises a few of the more important sources of 
 information as to the Triassic strata and their fossil contents : 
 
 (1) ' Geology of Oxford and the Valley of the Thames.' Phillips. 
 
 (2) 'Memoirs of the Geological Survey of Great Britain and Ireland.' 
 
 (3) ' Report on the Geology of Londonderry,' &c. Portlock.
 
 THE TRIASSIC PERIOD. 22$ 
 
 (4) "On the Zone of Avicula contorta," &c. 'Quart. Journ. Geol. 
 
 Soc.,' vol. xvi., 1860. Dr Thomas Wright. 
 
 (5) "On the Zones of the Lower Lias and the Avicula contorta Zone" 
 
 ' Quart. Journ. Geol. Soc.,' vol. xvii., 1861. Charles Moore. 
 
 (6) "On Abnormal Conditions of Secondary Deposits," &c. 'Quart. 
 
 Journ. Geol. Soc.,' vol. xxiii., 1876-77. Charles Moore. 
 
 (7) ' Geognostische Beschreibung des Bayerischen Alpengebirges.' 
 
 Giimbel. 
 
 (8) ' Lethsea Rossica.' Pander. 
 
 (9) ' Lethaea Geognostica. ' Bronn. 
 
 (10) ' Petrefacta Germanise.' Goldfuss. 
 
 (11) ' Petrefaktenkunde.' Quenstedt. 
 
 (12) 'Monograph of the Fossil Estherire' (Palteontographical Society). 
 
 Rupert Jones. 
 
 (13) " P'ossil Remains of Three Distinct Saurian Animals, recently dis- 
 
 covered in the Magnesian Conglomerate near Bristol" ' Trans. 
 Geol. Soc.,' ser. 2, vol. v., 1840. Riley and Stutchbury. 
 
 (14) 'Die Saurier des Muschekalkes.' Von Meyer. 
 
 (15) ' Beit rage zur Palaeontologie Wiirttembergs. ' Von Meyer and 
 
 Plieninger. 
 
 (16) ' Manual of Palaeontology.' Owen. 
 
 (17) 'Odontography.' Owen. 
 
 fl8) ' Report on Fossil Reptiles ' (British Association, 1841). Owen. 
 
 (19) " On Dicynodon '' 'Trans. Geol. Soc., 'vol. iii., 1845. Owen. 
 
 (20) ' Descriptive Catalogue of Fossil Reptilia and Fishes in the Museum 
 
 of the Royal College of Surgeons, England.' Owen. 
 
 (21) " On Species of Labyrinthodon from Warwickshire " ' Trans. Geol. 
 
 Soc.,' ser. 2, vol. vi. Owen. 
 
 (22) "On a Carnivorous Reptile" (Cynodraco major), &c. 'Quart. 
 
 Journ. Geol. Soc.,' vol. xxxii., 1876. O 
 "On Evidences 
 
 (23) "On Evidences of Theriodonts in Permian Deposits," &c. 'Quart. 
 
 Journ. Geol. Soc.,' vol. xxxii., 1876. Owen. 
 
 (24) "On the Stagonolepis Robertson!," &c. 'Quart. Journ. Geol. 
 
 Soc.,' vol. xv., 1859. Huxley. 
 
 (25) "On a New Specimen of Telerpeton Elginense " 'Quart. Journ. 
 
 Geol. Soc.,' vol. xxiii., 1866. Huxley. 
 
 (26) "On Hyperodapedon " 'Quart. Journ. Geol. Soc.,' vol. xxv., 
 
 1869. Huxley. 
 
 (27) "On the Affinities between the Deinosaurian Reptiles and Birds" 
 
 'Quart. Journ. Geol. Soc.,' vol. xxvi., 1870. Huxley. 
 
 (28) "On the Classification of the Deinosauria," &c. ' Quart. Journ. 
 
 Geol. Soc.,' vol. xxvi., 1870. Huxley. 
 
 (29) " Palaeontologica Indica " ' Memoirs of the Geol. Survey of India. ' 
 
 (30) "On the Geological Position and Geographical Distribution of the 
 
 Dolomitic Conglomerate of the Bristol Area" 'Quart. Journ. 
 Geol. Soc.,' vol. xxvi., 1870. R. Etheridge, sen. 
 
 (31) " Remains of Labyrinthodonta from the Keuper Sand-tone of War- 
 
 wick " 'Quart. Journ. Geol. Soc.,' vol. xxx., 1874. Miall. 
 
 (32) 'Manual of Geology.' Dana. 
 
 (33) 'Synopsis of Extinct Batrachia and Reptilia of North America.' 
 
 Cope. 
 
 (34) 'Fossil Footmarks.' Hitchcock. 
 
 (35) 'Ichnology of New England.' Hitchcock. 
 
 (36) 'Traite de'Paleontologie Vegetale.' Schimper. 
 
 (37) ' Histoire des Vegetaux Fossiles. ' Brongniart. 
 
 (38) ' Monographic der Fossilen Coniferen.' Goeppert.
 
 226 HISTORICAL PALEONTOLOGY. 
 
 CHAPTER XVI. 
 THE JURASSIC PERIOD. 
 
 Resting upon the Trias, with perfect conformity, and with 
 an almost undeterminable junction, we have the great series of 
 deposits which are known as the Oolitic Rocks, from the com- 
 mon occurrence in them of oolitic limestones, or as the Juras- 
 sic Rocks, from their being largely developed in the mountain- 
 range of the Jura, on the western borders of Switzerland. 
 Sediments of this series occupy extensive areas in Great Britain, 
 on the continent of Europe, and in India. In North America, 
 limestones and marls of this age have been detected in " the 
 Black Hills, the Laramie range, and other eastern ridges of the 
 Rocky Mountains ; also over the Pacific slope, in the Uintah, 
 Wahsatch, and Humboldt Mountains, and in the Sierra Ne- 
 vada " (Dana) ; but in these regions their extent is still un- 
 known, and their precise subdivisions have not been deter- 
 mined. Strata belonging to the Jurassic period are also known 
 to occur in South America, in Australia, and in the Arctic 
 zone. When fully developed, the Jurassic series is capable of 
 subdivision into a number of minor groups, of which some are 
 clearly distinguished by their mineral characters, whilst others 
 are separated with equal certainty by the differences of the 
 fossils that they contain. It will be sufficient for our present 
 purpose, without entering into the more minute subdivisions 
 of the series, to give here a very brief and general account 
 of the main sub-groups of the Jurassic rocks, as developed in 
 Britain the arrangement of the Jura- formation of the continent 
 of Europe agreeing in the main with that of England. 
 
 I. THE LIAS. The base of the Jurassic series of Britain 
 is formed by the great calcareo - argillaceous deposit of the 
 "Lias," which usually rests conformably and almost inseparably 
 upon the Rhaetic beds (the so-called "White Lias"), and 
 passes up, generally conformably, into the calcareous sand- 
 stones of the Inferior Oolite. The Lias is divisible into the 
 three principal groups of the Lower, Middle, and Upper Lias, 
 as under, and these in turn contain many well-marked "zones;" 
 so that the Lias has some claims to be considered as an inde- 
 pendent formation, equivalent to all the remaining Oolitic 
 rocks. The Lower Lias (Terrain Sinemurien of D'Orbigny) 
 sometimes attains a thickness of as much as 600 feet, and con- 
 sists of a great series of blukh or greyish laminated clays,
 
 THE JURASSIC PERIOD. 22/ 
 
 alternating with thin bands of blue or grey limestone the 
 whole, when seen in quarries or cliffs from a little distance, 
 assuming a characteristically striped and banded appearance. 
 By means of particular species of Ammonites, taken along with 
 other fossils which are confined to particular zones, the Lower 
 Lias may be subdivided into several well-marked horizons. 
 The Middle Lias, or Marlstone Scries (Terrain Liasien of 
 D'Orbigny), may reach a thickness of 200 feet, and consists of 
 sands, arenaceous marls, and argillaceous limestones, sometimes 
 with ferruginous beds. The Upper Lias ( Terrain Toarcien of 
 D'Orbigny) attains a thickness of 300 feet, and consists princi- 
 pally of shales below, passing upwards into arenaceous strata. 
 
 II. THE LOWER OOLITES. Above the Lias comes a com- 
 plex series of partly arenaceous and argillaceous, but prin- 
 cipally calcareous strata, of which the following are the more 
 important groups : a, The Inferior Oolite (Terrain Bajodcn 
 of D'Orbigny), consisting of more than 200 feet of oolitic 
 limestones, sometimes more or less sandy ; b, The Fuller s 
 Earth, a series of shales, clays, and marls, about 120 feet in 
 thickness; c, The Great Oolite or Bat/i Oolite (Terrain Bath- 
 onien of D'Orbigny), consisting principally of oolitic lime- 
 stones, and attaining a thickness of about 130 feet. The well- 
 known " Stonesfield Slates " belong to this horizon ; and the 
 locally developed " Bradford Clay," " Cornbrash," and " For- 
 est-marble " may be regarded as constituting the summit of 
 this group. 
 
 III. THE MIDDLE OOLITES. The central portion of the 
 Jurassic series of Britain is formed by a great argillaceous de- 
 posit, capped by calcareous strata, as follows : a, The Oxford 
 Clay (Terrain Callovien and Terrain Oxfordien of D'Orbigny), 
 consisting of dark-coloured laminated clays, sometimes reach- 
 ing a thickness of 700 feet, and in places having its lower por- 
 tion developed into a hard calcareous sandstone (" Kelloway 
 Rock"); b, The Coral-Rag (Terrain Cora/lien of D'Orbigny, 
 "Nerinean Limestone" of the Jura, " Diceras Limestone" of 
 the Alps), consisting, when typically developed, of a central 
 mass of oolitic limestone, underlaid and surmounted by cal- 
 careous grits. 
 
 IV. THE UPPER OOLITES. a, The base of the Upper 
 Oolites of Britain is constituted by a great thickness (600 leet 
 or more) of laminated, sometimes carbonaceous or bituminous 
 clays, which are known as the Kimmeridge Clay (Terrain Kim- 
 meridgien of D'Orbigny); b, The Portland Beds (Terrain Port- 
 landien of D'Orbigny) succeed the Kimmeridge clay, and con- 
 sist inferiorly of sandv beds surmounted by oolitic limestones
 
 228 HISTORICAL PALEONTOLOGY. 
 
 ("Portland Stone"), the whole series attaining a thickness of 
 150 feet or more, and containing marine fossils; c, The Pur- 
 beck Beds are apparently peculiar to Great Britain, where they 
 form the summit of the entire Oolitic series, attaining a total 
 thickness of- from 150 to 200 feet. The Purbeck beds consist 
 of arenaceous, argillaceous, and calcareous .strata, which can 
 be shown by their fossils to consist of a most remarkable alter- 
 nation of fresh-water, brackish-water, and purely marine sedi- 
 ments, together with old land-surfaces, or vegetable soils, which 
 contain the upright stems of trees, and are locally known as 
 "Dirt-beds." 
 
 One of the most important of the Jurassic deposits of the 
 continent of Europe, which is believed to be on the horizon 
 of the Coral-rag or of the lower part of the Upper Oolites, is 
 the " Solenhofen Slate" of Bavaria, an exceedingly fine-grained 
 limestone, which is largely used in lithography, and is cele- 
 brated for the number and beauty of its organic remains, and 
 especially for those of Vertebrate animals. 
 
 The subjoined sketch-section (fig. 159) exhibits in a dia- 
 grammatic form the general succession of the Jurassic rocks of 
 Britain. 
 
 Regarded as a whole, the Jurassic formation is essentially 
 marine ; and though remains of drifted plants, and of insects 
 and other air-breathing animals, are not uncommon, the fossils 
 of the formation are in the main marine. In the Purbeck 
 series of Britain, anticipatory of the great river-deposit of the 
 Wealden, there are fresh- water, brackish-water, and even terres- 
 trial strata, indicating that the floor of the Oolitic ocean was 
 undergoing upheaval, and that the marine conditions which 
 had formerly prevailed were nearly at an end. In places 
 also, as in Yorkshire and Sutherlandshire, are found actual 
 beds of coal : but the great bulk of the formation is an indu- 
 bitable sea-deposit; and its limestones, oolitic as they com- 
 monly are, nevertheless are composed largely of the commin- 
 uted skeletons of marine animals. Owing to the enormous 
 number and variety of the organic remains which have been 
 yielded by the richly fossiliferous strata of the Oolitic series, 
 it will not be possible here to do more than to give an outline- 
 sketch of the principal forms of life which characterise the 
 Jurassic period as a whole. It is to be remembered, however, 
 that every minor group of the Jurassic formation has its own 
 peculiar fossils, and that by the labours of such eminent ob- 
 servers as Quenstedt, Oppel, D'Orbigny, Wright, De la Beche, 
 Tate, and others, the- entire series of Jurassic sediments admits 
 of a more complete and more elaborate subdivision into zones
 
 THE JURASSIC PERIOD. 
 
 229 
 
 characterised by special life-forms than has as yet been found 
 practicable in the case of any other rock-series. 
 
 GENERALISED SECTION OF THE JURASSIC ROCKS 
 OF ENGLAND. 
 
 Fig. 159- 
 
 Purbeck Beds. 
 
 Portland Beds. 
 
 -Kimmeridge Clay. 
 
 Coral-Rag. 
 
 -Oxford Clay. 
 
 Cornbrash and Forest-marble. 
 
 Great Oolite. 
 
 Fuller's Earth. 
 
 Inferior Oolite. 
 
 -Upper Lias. 
 
 ( Middle Lias (Marlstone 
 
 | series). 
 
 Lower Lias. 
 
 ( Rhsetic Marls (" White 
 \ Lias"). 
 
 The plants of the Jurassic period consist principally of 
 Ferns, Cycads, and Conifers agreeing in this respect, there-
 
 230 HISTORICAL PALAEONTOLOGY. 
 
 fore, with those of the preceding Triassic formation. The 
 Ferns are very abundant, and belong partly to old and partly 
 to new genera. The Cycads are also very abundant, and, on 
 the whole, constitute the most marked feature of the Jurassic 
 vegetation, many genera of this group being known (Ptero- 
 phyllum, Otozamitcs, Zamites, Crossozamia, Williamsonia, Buck- 
 landia, &c.) The so-called "dirt-bed" of the Purbeck series 
 consists of an ancien soil, in which stand erect the trunks of 
 Conifers and the silicified stools of Cycads of the genus Mantel- 
 lia (fig. 1 60). The Conifercz of the Jurassic are represented by 
 
 Fig. \do.ManteUi(i (Cycadeoidea) nte^aJophylla, a Cycad from the Purbeck 
 " dirt-bed." Upper Oolites, England. 
 
 various forms more or less nearly allied to the existing Arau- 
 caricE ; and these are known not only by their stems or 
 branches, but also in some cases by their cones. We meet, 
 also, with the remains of undoubted Endogenous plants, the 
 most important of which are the fruits of forms allied to the 
 existing Screw-pines (Pandanece), such as Podocarya and Kaida- 
 carpum. So far, however, no remains of Palms have been 
 found ; nor are we acquainted with any Jurassic plants which 
 could be certainly referred to the great " Angiospermous " 
 group of the Exogens, including the majority of our ordinary 
 plants and trees. 
 
 Amongst animals, the Protozoans are well represented in 
 the Jurassic deposits by numerous Foraminifers and Sponges ; 
 as are the Ccelentcrates by numerous Corals. Remains 
 of these last-mentioned organisms are extremely abundant 
 in some of the limestones of the formation, such as the 
 ." Coral- rag" and the Great Oolite ; and the former of these 
 may fairly be considered as an ancient "reef." The Rugost 
 Corals have not hitherto been detected in the Jurassic rocks ; 
 and the " Tabulate Corals" so-called, are represented only by 
 examples of the modern genus Millepora. With this excep-
 
 THE JURASSIC PERIOD. 23 1 
 
 tion, all the Jurassic Corals belong to th-e great group which 
 predominates in recent seas (Zoatitharia sderodermata); and 
 the majority belong to the important reef-building family of 
 the "Star-corals" (Astrceidce}. The form here figured (Thecos- 
 milia annular is, fig. 161) is one of the characteristic species 
 of the Coral-rag. 
 
 Fig. 161. Thecosmilia annularis. Coral-rag, England. 
 
 The Echinoderms are very numerous and abundant fossils 
 in the Jurassic series, and are represented by Sea-lilies, Sea- 
 urchins, Star-fishes, and Brittle-stars. The Crinoids are still 
 common, and some of the limestones of the series are largely 
 composed of the debris of these organisms. Most of the 
 Jurassic forms resemble those with which we are already 
 familiar, in having the body permanently attached to some 
 'foreign object by means of a longer or shorter jointed stalk 
 or " column." One of the most characteristic Jurassic genera 
 of these ' stalked" Crinoids (though not exclusively confined 
 to this period) is Pentacrinns (fig. 162). In this genus, the 
 column is five-sided, with whorls of " side-arms ; " and the arms 
 are long, slender, and branched. The genus is represented 
 at the present day by the beautiful " Medusa-head Pentacrin- 
 ite " {Pentacrinus caput-medusce]. Another characteristic Oolitic 
 .genus \&Apiocrinus, comprising the so-called "Pear Encrinites." 
 In this group the column is long and rounded, with a dilated 
 base, and having its uppermost joints expanded so as to form, 
 with the cup itself, a pear-shaped mass, from the summit of 
 which spring the comparatively short arms. Besides the
 
 2 3 2 
 
 HISTORICAL PALAEONTOLOGY. 
 
 "slalked" Crinoids, the Jurassic rocks have yielded the re- 
 mains of the higher group of the " free " Crinoids, such as 
 
 
 Fie 162 Pnttacrinus fascicnlosus, Lias. The left-hand figure shows a few of the 
 ioints of the column ; the middle figure shows the arms, and the summit of the column 
 with its side-arms; and the right-hand figure shows the articulating surface of one of the 
 column-joints. 
 
 Saccosoma. These forms resemble the existing "Feather- 
 stars" (Comatitla) in being attached when young to some
 
 THE JURASSIC PERIOD. 233 
 
 foreign body by means of a jointed stem, from which they 
 detach themselves when fully grown to lead an independent 
 existence. In this later stage of their life, therefore, they 
 closely resemble the Brittle-stars in appearance. True Star- 
 fishes (Asteroids] and Brittle-stars (Ophiuroids) are abundant 
 in the Jurassic rocks, and the Sea-urchins {iLchinoids) are so 
 numerous and so well preserved as to constitute quite a marked 
 feature of some beds of the series. All the Oolitic urchins 
 agree with the modern EcJunoids in having the shell composed 
 of no more than twenty rows of plates. Many different genera 
 are known, and a characteristic species of the Middle Oolites 
 (Hemicidaris crenularis, fig. 163) is here figured. 
 
 Fig. 163. Hsmicidat 
 
 spines we 
 
 Passing over the Annclides, which, though not uncommon, 
 are of little special interest, we come to the Articulates, which 
 also require little notice. Amongst the Crustaceans^ whilst the 
 little Water-fleas (Ostracoda) are still abundant, the most mark- 
 ed feature is the predominance which is now assumed by the 
 Decapods the highest of the known groups of the class. True 
 Crabs (Brachynrd) are by no means unknown ; but the prin- 
 cipal Oolitic Decapods belonged to the " Long-tailed " group 
 (Macrura), of which the existing Lobsters, Prawns, and 
 Shrimps are members. The fine-grained lithographic slates of 
 Solenhofen are especially famous as a depot for the remains 
 of these Crustaceans, and a characteristic species from this 
 locality (Eryon arctiformis, fig. 164) is here represented. 
 Amongst the air-breathing Articulates, we meet in the Oolitic 
 rocks with the remains of Spiders (Arachnida), Centipedes 
 (Myriapoda), and numerous true Insects (Insecta). In con- 
 nection with the last-mentioned of these groups, it is of interest 
 to note the occurrence of the oldest known fossil Butterfly 
 the Palceontina Oclitica of the Stonesfield slate the rela-
 
 234 
 
 HISTORICAL PALAEONTOLOGY. 
 
 tionships of which appear to be with some of the living 
 Butterflies of Tropical America. 
 
 Coming to the Mollusca, the Polyzoans, numerous and 
 
 Fig. 164. Eryon 
 
 ctiformis, a " Long-tailed Decapod," from the Middle 
 Oolites (Solennofen Slate). 
 
 beautiful as they are, must be at once dismissed; but the 
 Brachiopods deserve a moment's attention. The Jurassic 
 Lamp-shells (fig. 165) do not fill by any means such a pre- 
 dominant place in the marine fauna of the period, as in many 
 Palaeozoic deposits, but they are still individually numerous. 
 The two ancient genera Leptcena (fig. 165, a) and Spirifera (fig. 
 165, b}, dating the one from the Lower and the other from the 
 Upper Silurian, appear here for the last time upon the scene, 
 but they have not hitherto been recognised in deposits later 
 than the Lias. The great majority of the Jurassic Brachiopods, 
 however, belong to the genera Terebratula (fig. 165, c, e, f) 
 and RhyncJwnella (fig. 165, d\ both of which are represented 
 by living forms at the present day. The Tercbratulce, in par- 
 ticular, are very abundant, and the species are often confined 
 to special horizons in the series. 
 
 Remains of Bivalves (Lamellibranchiata} are very numerous
 
 THE JURASSIC PERIOD. 
 
 235 
 
 in the Jurassic deposits, and in many cases highly character- 
 istic. In the marine beds of the Oolites, which constitute by 
 
 U 
 
 Fig. 165. Jurassic Brachiopods. a. l.efitre-ia L'ttsnica, 
 
 the figure indicating the true size of the shel Lias ; b, Spir'fe. 
 
 Terebratnla gnadrifida, ] 
 
 way Rock ; e. TerebratnL. _, .... 
 
 ford Clay, Forest-marble, and G 
 
 11 cross below 
 
 true size 01 tne snei i,ias ; o, opirjera rosirata, Lias ; c, 
 Lias ; d, d, Rhyiiclioiielia variant, Fuller's Earth and Kello- 
 la sfihirroida 'is. Inferior Oolite ; f, Teretiratula digoua, 
 ~ it Oolite. (After Davidson). 
 
 far the greater portion of the whole formation, the Bivalves 
 are of course marine, and belong to such genera as Trt'gom'a, 
 Lima, Pholadomya, Cardinia, Avicula, Hippopodium, &c. ; but 
 in the Purbeck beds, at the summit of the series, we find 
 bands of Oysters alternating with strata containing fresh-water 
 or brackish-water Bivalves, such as Cyrenee and Corbula. The 
 .predominant Bivalves of the Jurassic, however, are the Oysters, 
 which occur under many forms, and often in vast numbers, 
 particular species being commonly restricted to particular 
 horizons. Thus of the true Oysters, Ostrca distorta is char- 
 acteristic of the Purbeck series, where it forms a bed twelve 
 feet in thickness, known locally as the " Cinder-bed ; " Osfrea 
 cxpansa abounds in the Portland beds ; Ostrca ddtoidca is 
 characteristic of the Kimmeridge clay ; Ostrca grfgaria pre- 
 dominates in the Coral-rag ; Ostnca acuminata characterises the 
 small group of the Fuller's Earth ; whilst the plaited Ostrea 
 MarsJiii (fig. 166) is a common shell in the Lower and Middle 
 Oolites. Besides the more typical Oysters, the Oolitic rocks 
 abound in examples of the singularly unsymmetrical forms
 
 HISTORICAL PALEONTOLOGY. 
 
 belonging to the genera Exogyra and Gryphcea (fig. 167). In 
 the former of these are included Oysters with the beaks 
 
 Fig. 166.-- Ostrea Marshii. Middle 
 and Lower Oolites. 
 
 Fig. 167. Gryphcea incuiva. Lias. 
 
 " reversed " that is to say, turned towards the hinder part of 
 the shell ; whilst in the latter are Oysters in which the lower 
 valve of the shell is much the largest, and has a large incurved 
 beak, whilst the upper valve is small and concave. One of 
 the most characteristic Exogyrce. is the E. -virgula of the Oxford 
 Clay, and of the same horizon on the Continent ; and the 
 Gryphcea incurva (fig. 167) is equally abundant in, and char- 
 acteristic of, the formation of the Lias. Lastly, we may 
 notice the extraordinary shells belonging to the genus Diceras 
 (fig. 1 68;, which are exclusively confined to the Middle 
 Oolites. In this formation in 
 the Alps they occur in such 
 abundance as to give rise to 
 the name of "Calcaire a Di- 
 cerates," applied to beds of 
 the same age as the Coral- 
 rag of Britain. The genus Di- 
 ceras belongs to the same fam- 
 ily as the "Thorny Clams" 
 (Chama) of the present day 
 the shell being composed of 
 nearly equally-sized valves, the 
 beaks of which are extremely 
 prominent and twisted into a 
 spiral. The shell was attached to some foreign body by the 
 beak of one of its valves. 
 
 Amongst the Jurassic Univalves (Gasteropoda) there are 
 many examples of the ancient and long-lived Pleurotomaria ; 
 but on the whole the Univalves begin to have a modern 
 aspect. The round-mouthed (" holostomatous "), vegetable- 
 
 Fig. 168. Diceras arietina. Middle 
 Oolite.
 
 THE JURASSIC PERIOD. 
 
 237 
 
 eating Sea-snails, such as the Limpets (Pateltitfoe), the Nerites 
 (Nerita), the Turritellte, C/iemnitzi<z\ &c., still hold a predomi- 
 nant place. The two most noticeable genera of this group 
 are Cerithium and Nerincea the former of these attaining 
 great importance in the Tertiary and Recent seas, whilst the 
 latter (fig. 169) is highly characteristic of the Jurassic series, 
 though not exclusively confined to 
 it. One of the limestones of the 
 Jura, believed to be of the age of 
 the Coral-rag (Middle Oolite) of Bri- 
 tain, abounds to such an extent in 
 the turreted shells of Ncrincza as to 
 have gained the name of " Calcaire 
 a Nerine'es." In addition to forms 
 such as the preceding, we now for 
 the first time meet, in any force, 
 with the Carnivorous Univalves, in 
 which the mouth of the shell is 
 notched or produced into a canal, 
 giving rise to the technical name 
 of " siphonostomatous," applied to 
 the shell. Some of the carnivorous 
 forms belong to extinct types, such 
 as the Purpuroidea of the Great Oo- 
 lite; but others are referable to well-known existing genera. 
 Thus we meet here 'with species of the familiar groups of the 
 Whelks (Bnccimim\ the Spindle -shells (Fustts), the Spider- 
 shells (Pteroceras), Murex, Rostellaria, and others which are 
 not at present known to occur in any earlier formation. 
 
 Amongst the Wing-shells (Pfffopoda), it is sufficient to mark 
 the final appearance in the Lias of the ancient genus Conularia. 
 
 Lastly, the order of the Cephalopoda, in both its Tetrabran- 
 chiate and Dibranchiate sections, undergoes a vast devel- 
 opment in the Jurassic period The old and comparatively 
 simple genus Nautilus is still well represented, one species 
 being very similar to the living Pearly Nautilus (JV. pompihus}; 
 but the Orthocerata and Goniatites of the Trias have finally 
 disappeared ; and the great majority of the Tetrabranchiate 
 forms are referable to the comprehensive genus Ammonites, 
 with its many sub-genera and its hundreds of recorded species. 
 The shell in Ammonites is in the form of a flat spiral, all the 
 coils of which are in contact (figs. 170 and 171). The inner- 
 most whorls of the shell are more or less concealed ; and the 
 body-chamber is elongated and narrow, rather than expanded 
 towards the mouth. The tube or siphuncle which runs through 
 ' 
 
 Fig. Lfxj.Nerina-a GoodhaUU, 
 one-fourth of the natural size. The 
 left-hand figure shows the appear- 
 ance presented by the shell when 
 vertically divided. Coral -rag, 
 England.
 
 238 HISTORICAL PALEONTOLOGY. 
 
 the air-chambers is placed on the dorsal or convex side of the 
 shell ; but the principal character which distinguishes Amman- 
 
 Fig. 170. Ammonites Humphresiaims. Inferior Oolite. 
 
 ites from Goniatitcs and Ceratites is the wonderfully complex 
 manner in which the septa, or partitions between the air-cham- 
 bers, are folded and undulated. To such an extent does this 
 take place, that the edges of the septa, when exposed by the 
 
 removal of the shell-substance, present in an exaggerated man- 
 ner the appearance exhibited by an elaborately-dressed shirt- 
 frill when viewed edgewise. The species of Ammonites range 
 from the Carboniferous to the Chalk ; but they have not been
 
 THE JURASSIC PERIOD. 239 
 
 found in deposits older than the Secondary, in any region 
 except India ; and they are therefore to be regarded as essen- 
 tially Mesozoic fossils. Within these limits, each formation 
 is characterised by particular species, the number of individ- 
 uals being often very great, and the size which is sometimes 
 attained being nothing short of gigantic. In the Lias, par- 
 ticular species of Ammonites may succeed one another regu- 
 larly, each having a more or less definite horizon, which it does 
 not transgress. It is thus possible to distinguish a certain 
 number of zones, each characterised by a particular Ammonite, 
 together with other associated fossils. Some of these zones 
 are very persistent and extend over very wide areas, thus afford- 
 ing valuable aid to the geologist in his determination of 
 rocks. It is to be remembered, however, that there are other 
 species which are not thus restricted in their vertical range, 
 even in the same formations in which definite zones occur. 
 
 The Cuttle-fishes or Dibranchiate Cep/ialopods constitute a 
 feature in the life of the Jurassic period little less conspicuous 
 and striking than that afforded by the multitudinous and varied 
 chambered shells of the Ammonitidce. The remains by which 
 these animals are recognised are necessarily less perfect, as a 
 rule, than those of the latter, as no external shell is present 
 (except in rare and more modern groups), and the internal 
 skeleton is not necessarily calcareous. Nevertheless, we have 
 an ample record of the Cuttle-fishes of the Jurassic period, in 
 the shape of the fossilised jaws or beak, the ink-bag, and, most 
 commonly of all, the horny or calcareous structure which is 
 embedded in the soft tissues, and is variously known as the 
 " pen " or " bone." The beaks of Cuttle-fishes, though not 
 abundant, are sufficiently plentiful to have earned for them- 
 selves the general title of " Rhyncholites ; " and in their form 
 and function they resemble the horny, parrot-like beak of the 
 existing Cephalopods. The ink-bag or leathery sac in which 
 the Cuttle-fishes store up the black pigment with which they 
 obscure the water when attacked, owes its preservation to the 
 fact that the colouring-matter which it contains is finely-divid- 
 ed carbon, and therefore nearly indestructible except by heat. 
 Many of these ink-bags have been found in the Lias; and the 
 colouring-matter is sometimes so well preserved that it has 
 been, as an experiment, employed in painting as a fossil 
 " sepia." The " pens " of the Cuttle-fishes are not commonly 
 preserved, owing to their horny consistence, but they are not 
 unknown. The form here figured (Belotenthis stibcostata, fig. 
 172) belonged to an old type essentially similar to our modern 
 Calamaries, the skeleton of which consists of a horny shaft
 
 240 
 
 HISTORICAL PALAEONTOLOGY. 
 
 i/u's subcostata. } ur- 
 assic (Lias). 
 
 and two lateral wings, somewhat like a feather in general 
 shape. When, on the other hand, the internal skeleton is 
 calcareous, then it is very easily preserved 
 in a fossil condition ; and the abundance 
 of remains of this nature in the Secondary 
 rocks, combined with their apparent total 
 absence in Palaeozoic strata, is a strong pre- 
 sumption in favour of the view that the order 
 of the Cuttle-fishes did not come into exis- 
 tence till the commencement of the Meso- 
 zoic period. The great majority of the skele- 
 tons of this kind which are found in the Jur- 
 assic rocks belong to the great extinct family 
 of the " Belemnites " (Belemnitidtz), which, so 
 far as known, is entirely confined to rocks 
 of Secondary age. From its pointed, gener- 
 ally cylindro - conical form, the skeleton of 
 the Belemnite is popularly known as a "thun- 
 derbolt " (fig. 1 73, C). In its perfect condition 
 in which it is, however, rarely obtainable 
 the skeleton consists of a chambered conical 
 shell (the "phragmacone "), the partitions between the chambers 
 of which are pierced by a marginal tube or " siphuncle." This 
 conical shell curiously similar in its structure to the external 
 shell of the Nautilus is extended forwards into a horny 
 "pen," and is sunk in a corresponding conical pit (fig. 173, B), 
 excavated in the substance of a nearly cylindrical fibrous 
 body or "guard," which projects backwards for a longer or 
 shorter distance, and is the part most usually found in a fossil 
 condition. Many different kinds of Belemnites are known, and 
 their guards literally swarm in many parts of the Jurassic series, 
 whilst some specimens attain very considerable dimensions. 
 Not only is the internal skeleton known, but specimens of 
 Belemnites and the nearly allied Belemnoteuthis have been found 
 in some of the fine-grained sediments of the Jurassic formation, 
 from which much has been learnt even as to the anatomy of 
 the soft parts of the animal. Thus we know that the Belem- 
 nites were in many respects comparable with the existing 
 Calamaries or Squids, the body being furnished with lateral 
 fins, and the head carrying a circle of ten " arms," two of 
 which were longer than the others (fig. 173, A). The suckers 
 on the arms were provided, further, with horny hooks ; there 
 was a large ink-sac ; and the mouth was armed with horny 
 mandibles resembling in shape the beak of a parrot. 
 
 Coming next to the Vertebrates, we find that the Jurassic
 
 THE JURASSIC PERIOD. 
 
 2 4 I 
 
 Fishes are still represented by Ganoids and Placoids. The 
 Ganoids, however, unlike the old forms, now for the most 
 
 Fig. 173. A, Restoration of the animal of the Belemnite ; B, Diagram showing the 
 complete skeleton of a Belemnite, consisting of the chambered phragmacone (ft), the 
 guard (b), and the horny pen (c) ; C, Specimen of Belemnites canalicitlatus, from the 
 Inferior Oolite. (After Phillips.) 
 
 part possess nearly or quite symmetrical (" homocercal ") tails. 
 A characteristic genus is Tetragonolepis (fig. 174), with its 
 
 Fig. 174. Tetragonolepis (restored), and scales of the same. Lias. 
 
 deep, compressed body, its rhomboidal, closely-fitting scales, 
 and its single long dorsal fin. Amongst the Placoids the teeth
 
 242 HISTORICAL PALEONTOLOGY. 
 
 of true Sharks (Notidanus) occur for the first time ; but by far 
 the greater number of remains referable to this group are still 
 the fin-spines and teeth of " Cestracionts," resembling the 
 living Port-Jackson Shark. Some of these teeth are pointed 
 (Hybodus) ; but others are rounded, and are adapted for crush- 
 ing shell-fish. Of these latter, the commonest are the teeth of 
 Acrodus (fig. 175), of which the hinder ones are of an elon- 
 gated form, with a rounded 
 surface, covered with fine 
 transverse striae proceed- 
 ing from a central longi- 
 tudinal line. From their 
 
 general form and striation, 
 
 Fig. i 75 .-Tooth rf Acrodus nobiiis. Lias. and their dark colour, these 
 
 teeth are commonly called 
 " fossil leeches " by the quarrymen. 
 
 The Amphibian group of the Labyrinthodonts, which was so 
 extensively developed in the Trias, appears to have become 
 extinct, no representative of the order having hitherto been 
 detected in rocks of Jurassic age. 
 
 Much more important than the Fishes of the Jurassic series 
 are the Reptiles, which are both very numerous, and belong to 
 a great variety of types, some of these being very extraordinary 
 in their anatomical structure. The predominant group is that 
 of the " Enaliosaurs " or " Sea-lizards," divided into two great 
 orders, represented respectively by the Iclithyosaurus and the 
 Pies iosaur its. 
 
 The Ichthyosauri or " Fish-Lizards " are exclusively Meso- 
 zoic in their distribution, ranging from the Lias to the Chalk, 
 but abounding especially in the former. They were huge 
 Reptiles, of a fish-like form, with a hardly conspicuous neck 
 (fig. 176), and probably possessing a simply smooth or 
 
 Fij. \-j6.-Ichthyosa 
 
 wrinkled skin, since no traces of scales or bony integumentary 
 plates have ever been discovered. The tail was long, and 
 was probably furnished at its extremity with a powerful ex- 
 pansion of the skin, constituting a tail-fin similar to that pos- 
 sessed bv the Whales. The limbs are also like those of Whales
 
 THE JURASSIC PERIOD. 243 
 
 ill the essentials of their structure, and in their being adapted 
 to act as swimming-paddles. Unlike the Whales, however, 
 the Ichthyosaurs possessed the hind-limbs as well as the fore- 
 limbs, both pairs having the bones flattened out and the fin- 
 gers completely enclosed in the skin, the arm and leg being at 
 the same time greatly shortened. The limbs are thus con- 
 verted into efficient " flippers," adapting the animal for an 
 active existence in the sea. The different joints of the back- 
 bone (vertebrae) also show the same adaptation to an aquatic 
 mode of life, being hollowed out at both ends, like the bicon- 
 cave vertebras of Fishes. The spinal column in this way was 
 endowed with the flexibility necessary for an animal intended 
 to pass the greater part of its time in water. Though the Ich- 
 thyosaurs are undoubtedly marine animals, there is, however, 
 reason to believe that they occasionally came on shore, as they 
 possess a strong bony arch, supporting the fore-limbs, such as 
 would permit of partial, if laborious, terrestrial progression. 
 The head is of enormous size, with greatly prolonged jaws, 
 holding numerous powerful conical teeth lodged in a common 
 groove. The nature of the dental apparatus is such as to 
 leave no doubt as to the rapacious and predatory habits of the 
 Ichthyosaurs an inference which is further borne out by the 
 examination of their petrified droppings, which are known to 
 geologists as " coprolites," and which contain numerous frag- 
 ments of the bones and scales of the Ganoid fishes which 
 inhabited the same seas. The orbits are of huge size ; and as 
 the eyeball was protected, like that of birds, by a ring of bony 
 plates in its outer coat, we even know that the pupils of the 
 eyes were of correspondingly large dimensions. As these bony 
 plates have the function of protecting the eye from injury 
 under sudden changes of pressure in the surrounding medium, 
 it has been inferred, with great probability, that the Ichthy- 
 osaurs were in the habit of diving to considerable depths in 
 the sea. Some of the larger specimens of Ichthyosaurus which 
 have been discovered in the Lias indicate an animal of from 
 20 to nearly 40 feet in length ; and many species are known to 
 have existed, whilst fragmentary remains of their skeletons are 
 very abundant in some localities. We may therefore safely 
 conclude that these colossal Reptiles were amongst the most 
 formidable of the many tyrants of the Jurassic seas. 
 
 The Plcsiosaurus (fig. 177) is another famous Oolitic 
 Reptile, and, like the preceding, must have lived mainly or 
 exclusively in the sea. It agrees with the Ichthyosaur in some 
 important features of its organisation, especially in the fact 
 that both pairs of limbs are converted into "flippers" or
 
 244 HISTORICAL PALAEONTOLOGY. 
 
 swimming-paddles, whilst the skin seems to have been equally 
 destitute of any scaly or bony investiture. Unlike the Jchthy- 
 
 Fig. 177. Plesioscmnis dolichocteirtts, restored. Li 
 
 osaur, however, the Plesiosanr had the paddles placed far back, 
 the tail being extremely short, and the neck greatly lengthened 
 out, and composed of from twenty to forty vertebras. The 
 bodies of the vertebrae, also, are not deeply biconcave, but are 
 flat, or only slightly cupped. The head is of relatively small 
 size, with smaller orbits than those of the Ichthyosaur, and with 
 a snout less elongated. The jaws, however, were armed with 
 numerous conical teeth, inserted in distinct sockets. As re- 
 gards the habits of the Plesiosaur, Dr Conybeare arrives at the 
 following conclusions : " That it was aquatic is evident from 
 the form of its paddles"; that it was marine is almost equally 
 so from the remains with which it is universally associated; 
 that it may have occasionally visited the shore, the resem- 
 blance of its extremities to those of the Turtles may lead us to 
 conjecture : its movements, however, must have been very 
 awkward on land; and its long neck must have impeded its 
 progress through the water, presenting a strong contrast to the 
 organisation which so admirably fits the Ichthyosaurus to cut 
 through the waves." As its respiratory organs were such that 
 it must of necessity have required to obtain air frequently, we 
 may conclude " that it swam upon or near the surface, arching 
 back its long neck like a swan, and occasionally darting it 
 down at the fish which happened to float within its reach. It 
 may perhaps have lurked in shoal water along the coast, con- 
 cealed amongst the sea -weed; and raising its nostrils to a
 
 THE JURASSIC PERIOD. 245 
 
 level with the surface from a considerable depth, may have 
 found a secure retreat from the assaults of powerful enemies ; 
 while the length and flexibility of its neck may have compen- 
 sated for the want of strength in its jaws, and its incapacity 
 for swift motion through the water." 
 
 About twenty species of Plesiosaitnis are known, ranging 
 from the Lias to the Chalk, and specimens have been found 
 indicating a length of from eighteen to twenty feet. The 
 nearly related " Pliosaurs" however, with their huge heads 
 and short necks, must have occasionally reached a length of at 
 least forty feet the skull in some species being eight, and the 
 paddles six or seven feet long, whilst the teeth are a foot in 
 length. 
 
 Another extraordinary group of Jurassic Reptiles is that of 
 the " Winged Lizards " or Pterosaiiria. These are often spoken 
 of collectively as " Pterodactyles," from Pterodactylns, the 
 type-genus of the group. As now restricted, however, the 
 genus Ptcrodactylns is more Cretaceous than Jurassic, and it is 
 associated in the Oolitic rocks with the closely allied genera 
 Dimorphodon and Rhamphorhynehus. In all three of these 
 genera we have the same general structural organisation, in- 
 volving a marvellous combination of characters, which we are in 
 the habit of regarding as peculiar to Birds on the one hand, to 
 Reptiles on another hand, and to the Flying Mammals or 
 Bats in a third direction. The " Pterosaurs " are " Flying " 
 Reptiles, in the true sense of the term, since they were indu- 
 bitably possessed of the power of active locomotion in the air, 
 after the manner of Birds. The so-called " Flying " Reptiles 
 of the present day, such as the little Draco volans of the East 
 Indies and Indian Archipelago, possess, on the other hand, no 
 power of genuine flight, being merely able to sustain themselves 
 in the air through the extensive leaps which they take from tree 
 to tree, the wing-like expansions of the skin simply exercising 
 the mechanical function of a parachute. The apparatus of flight 
 in the "Pterosaurs" is of the most remarkable character, and 
 most resembles the "wing" of a Bat, though very different in 
 some important particulars. The "wing" of the Pterosaurs is 
 like that of Bats, namely, in consisting of a thin leathery expan- 
 sion of the skin which is attached to the sides of the body, and 
 stretches between the fore and hind limbs, being mainly sup- 
 ported by an enormous elongation of certain of the digits of 
 the hand. In the Bats, it is the four outer fingers which are 
 thus lengthened out ; but in the Pterosaurs, the wing-membrane 
 is borne by a single immensely -extended finger (fig. 178). 
 No trace of the actual wing-membrane itself has, of course,
 
 246 HISTORICAL PALAEONTOLOGY. 
 
 been found fossilised ; but we could determine that the " Ptero- 
 dactyles" possessed the power of flight, quite apart from the ex- 
 
 Fig. \^.Pterodactylus crassirostris. From the Lithographic Slates of Solenhofen 
 (Middle Oolite). The figure is " restored," and it seems certain that the restoration is 
 incorrect in the comparatively unimportant particular, that the hand should consist of no 
 more than four fingers, three short and one long, instead of five, as represented. 
 
 traordinary conformation of the hand. The proofs of this are to 
 be found partly in the fact that the breast-bone was furnished 
 with an elevated ridge or keel, serving for the attachment of 
 the great muscles of flight, and still more in the fact that the 
 bones were hollow and were filled with air a peculiarity 
 wholly confined amongst living animals to Birds only. The 
 skull of the Pterosaurs is long, light, and singularly bird-like in 
 appearance a resemblance which is further increased by the 
 comparative length of the neck and the size of the vertebrae of 
 this region (fig. 178). The jaws, however, unlike those of any 
 existing Bird, were, with one exception to be noticed hereafter, 
 furnished with conical teeth sunk in distinct sockets ; and 
 there was always a longer or shorter tail composed of distinct 
 vertebrae ; whereas in all existing Birds the tail is abbreviated, 
 and the terminal vertebrae are amalgamated to form a single 
 bone, which generally supports the great feathers of the tail. 
 
 Modern naturalists have been pretty generally agreed that 
 the Pterosaurs should be regarded as a peculiar group of the 
 Reptiles ; though they have been and are still regarded by 
 high authorities, like Professor Seeley, as being really referable
 
 THE JURASSIC PERIOD. 247 
 
 to the Birds, or as forming a class by themselves. The chief 
 points which separate them from Birds, as a class, are the 
 character of the apparatus of flight, the entirely different struc- 
 ture of the fore-limb, the absence of feathers, the composition 
 of the tail out of distinct vertebrae, and the general presence 
 of conical teeth sunk in distinct sockets in the jaws. The gap 
 between the Pterosaurs and the Birds has, however, been 
 greatly lessened of late by the discovery of fossil animals 
 (Ichthyomis and Hesperornis] with the skeleton proper to Birds 
 combined with the presence of teeth in the jaws, and by the 
 still more recent discovery of other fossil animals (Ptcranodoii) 
 with a Pterosaurian skeleton, but without teeth ; whilst the un- 
 doubtedly feathered Archceoptcryx possessed a long tail com- 
 posed of separate vertebras. Upon the whole, therefore, the 
 relationships of the Pterosaurs cannot be regarded as absolutely 
 settled. It seems certain, however, that they did not possess 
 feathers this implying that they were cold-blooded animals ; 
 and their affinities with Reptiles in this, as in other characters, 
 are too strong to be overlooked. 
 
 The Pterosaurs are wholly Mesozoic, ranging from the Lias 
 to the Chalk inclusive ; and the fine-grained Lithographic Slate 
 of Solenhofen has proved to be singularly rich in their remains. 
 The genus Pterodactylus itself has the jaws toothed to the ex- 
 tremities with equal-sized conical teeth, and its species range 
 from the Middle Oolites to the Cretaceous series, in connec- 
 tion with which they will be again noticed, together with the 
 toothless genus Pteranodon. The genus Dimorphodon is Li- 
 assic, and is characterised by having the front teeth long and 
 pointed, whilst the hinder teeth are small and lancet-shaped. 
 Lastly, the singular genus RhamphorhyncJms, also from the 
 Lower Oolites, is distinguished by the fact that there are teeth 
 present in the hinder portions of both jaws ; but the front por- 
 tions are toothless, and may have constituted a horny beak. 
 Like most of the other Jurassic Pterosaurs, Rhamphorhynclms 
 (fig. 179) does not seem to have been much bigger than a 
 pigeon, in this respect falling far below the giant "Dragons" 
 of the Cretaceous period. It differed from its relatives, not 
 only in the armature of the mouth, but also in the fact that 
 the tail was of considerable length. With regard to its habits 
 and mode of life, Professor Phillips remarks that, "gifted with 
 ample means of flight, able at least to perch on rocks and 
 scuffle along the shore, perhaps competent to dive, though not 
 so well as a Palmiped bird, many fishes must have yielded to 
 the cruel beak and sharp teeth of Rhamphorhynchus. If we 
 ask to which of the many families of Birds the analogy of
 
 248 HISTORICAL PALEONTOLOGY. 
 
 structure and probable way of life would lead us to assimilate 
 Rhamphorhynchus, the answer must point to the swimming 
 
 Fig. iv).Rhamphorhynchus Bncklandi, restored. Bath Oolite, England. 
 (After the late Professor Phillips.) 
 
 races with long wings, clawed feet, hooked beak, and habits of 
 violence and voracity ; and for preference, the shortness of the 
 legs, and other circumstances, may be held to claim for the 
 Stonesfield fossil a more than fanciful similitude to the groups 
 of Cormorants, and other marine divers, which constitute an 
 effective part of the picturesque army of robbers of the sea." 
 
 Another extraordinary and interesting group of the Mesozoic 
 Reptiles is constituted by the Deiiwsauna, comprising a series 
 of mostly gigantic forms, which range from the Trias to the 
 Chalk. All the " Deinosaurs " are possessed of the two pairs 
 of limbs proper to Vertebrate animals, and these organs are in 
 the main adapted for walking on the dry land. Thus, whilst 
 the Mesozoic seas swarmed with the huge Ichthyosaurs and 
 Plesiosaurs, and whilst the air was tenanted by the Dragon-like 
 Pterosaurs, the land -surfaces of the Secondary period were 
 peopled by numerous forms of Deinosaurs, some of them of 
 even more gigantic dimensions than their marine brethren. 
 The limbs of the Deinosaurs are, as just said, adapted for pro- 
 gression on the land ; but in some cases, at any rate, the 
 hind-limbs were much longer and stronger than the fore-limbs ; 
 and there seems to be no reason to doubt that many of these 
 forms possessed the power of walking, temporarily or perman- 
 ently, on their hind-legs, thus presenting a singular resemblance 
 to Birds. Some very curious and striking points connected 
 with the structure of the skeleton have also been shown to 
 connect these strange Reptiles with the true Birds ; and such 
 high authorities as Professors Huxley and Cope are of opinion 
 that the Deinosaurs are distinctly related to this class, being in 
 some respects intermediate between the proper Reptiles and 
 the great wingless Birds, like the Ostrich and Cassowary. On 
 the other hand, Professor Owen has shown that the Deinosaurs
 
 THE JURASSIC PERIOD. 
 
 249 
 
 possess some weighty points of relationship with the so-called 
 " Pachydermatous " Quadrupeds, such as the Rhinoceros and 
 Hippopotamus. The most important Jurassic genera of 
 Deinosauria are Megalosaurus and Cetiosaurus, both of which 
 extend their range into the Cretaceous period, in which 
 flourished, as we shall see, some other well-known members 
 of this order. 
 
 Megalosaurus attained gigantic dimensions, its thigh and 
 shank bones measuring each about three feet in length, and its 
 total length, including the tail, being estimated at from forty 
 to fifty feet. As the head of the thigh-bone is set on nearly 
 at right angles with the shaft, whilst all the long bones of the 
 skeleton are hollowed out internally for the reception of the 
 marrow, there can be no doubt as to the terrestrial habits of 
 the animal. The skull (fig. 180) was of large size, four or five 
 
 Fig. 180. Skull of Mega'ctsauriis, on a scale one-tenth of nature. Restored. 
 (After Professor Phillips.) 
 
 feet in length, and the jaws were armed with a series of power- 
 ful pointed teeth. The teeth are conical in shape, but are 
 strongly compressed towards their summits, their lateral edges 
 being finely serrated. In their form and their saw-like edges, 
 they resemble the teeth of the " Sabre-toothed Tiger" (Machai- 
 rodns], and they render it certain that the Megalosaur was in 
 the highest degree destructive and carnivorous in its habits. 
 So far as is known, the skin was not furnished with any armour 
 of scales or bony plates ; and the fore-limbs are so dispro- 
 portionately small as compared with the hind-limbs, that this 
 huge Reptile like the equally huge Iguanodon may be
 
 250 HISTORICAL PAL/EONTOLOGY. 
 
 conjectured to have commonly supported itself on its hind- 
 legs only. 
 
 The Cetiosaur attained dimensions even greater than those 
 of the Megalosaur, one of the largest thigh-bones measuring 
 over five feet in length and a foot in diameter in the middle, 
 and the total length of the animal being probably not less than 
 fifty feet. It was originally regarded as a gigantic Crocodile, 
 but it has been shown to be a true Deinosaur. Having ob- 
 tained a magnificent series of remains of this reptile, Professor 
 Phillips has been able to determine many very interesting 
 points as to the anatomy and habits of this colossal animal, 
 the total length of which he estimates as being probably not 
 less than sixty or seventy feet. As to its mode of life, this 
 accomplished writer remarks : 
 
 " Probably when ' standing at ease ' not less than ten feet 
 in height, and of a bulk in proportion, this creature was un- 
 matched in magnitude and physical strength by any of the 
 largest inhabitants of the Mesozoic land or sea. Did it live 
 in the sea, in fresh waters, or on the land ? This question 
 cannot be answered, as in the case of Ichthyosaurus, by appeal 
 to the accompanying organic remains ; for some of the bones 
 lie in marine deposits, others in situations marked by estuarine 
 conditions, and, out of the Oxfordshire district, in Sussex, in 
 fluviatile accumulations. Was it fitted to live exclusively in 
 water? Such an idea was at one time entertained, in conse- 
 quence of the biconcave character of the caudal vertebrae, and 
 it is often suggested by the mere magnitude of the creature, 
 which would seem to have an easier life while floating in water, 
 than when painfully lifting its huge bulk, and moving with 
 slow steps along the ground. But neither of these arguments 
 is valid. The ancient earth was trodden by larger quadrupeds 
 than our elephant ; and the biconcave character of vertebra;, 
 which is not uniform along the column in Cetiosaurus, is per- 
 haps as much a character of a geological period as of a me- 
 chanical function of life. Good evidence of continual life in 
 water is yielded in the case of Ichthyosaurus and other Ena- 
 liosaurs, by the articulating surfaces of their limb-bones, for 
 these, all of them, to the last phalanx, have that slight and 
 indefinite adjustment of the bones, with much intervening 
 cartilage, which fits the leg to be both a flexible and forcible 
 instrument of natation, much superior to the ordinary oar- 
 blade of the boatman. On the contrary, in Cetiosaur, as well 
 as in Megalosaur and Iguanodon, all the articulations are 
 definite, and made so as to correspond to determinate move- 
 ments in particular directions, and these are such as to be
 
 THE JURASSIC PERIOD. 251 
 
 suited for walking. In particular, the femur, by its head pro- 
 jecting freely from the acetabulum, seems to claim a movement 
 of free stepping more parallel to the line of the body, and 
 more approaching to the vertical than the sprawling gait of 
 the crocodile. The large claws concur in this indication of 
 terrestrial habits. But, on the other hand, these characters 
 are not contrary to the belief that the animal may have been 
 amphibious ; and the great vertical height of the anterior part 
 of the tail seems to support this explanation, but it does not 
 go further. . . . We have therefore a marsh-loving or 
 river-side animal, dwelling amidst h'licine, cycadaceous, and 
 coniferous shrubs and trees full of insects and small mamma- 
 lia. What was its usual diet ? If- ex ungue leonem, surely ex 
 dente cibum. We have indeed but one tooth, and that small 
 and incomplete. It resembles more the tooth of Iguanodon 
 than that of any other reptile ; for this reason it seems pro- 
 bable that the animal was nourished by similar vegetable food 
 which abounded in the vicinity, and was not obliged to con- 
 tend with Megalosaurus for a scanty supply of more stimu- 
 lating diet." 
 
 All the groups of Jurassic Reptiles which we have hitherto 
 been considering are wholly unrepresented at the present day, 
 and do not even pass upwards into the Tertiary period. It 
 may be mentioned, however, that the Oolitic deposits have 
 also yielded the remains of Reptiles belonging to three of the 
 existing orders of the class namely, the Lizards (Lacertilta), 
 the Turtles (Chelonia), and the Crocodiles (Crocodilia). The 
 Lizards occur both in the marine strata of the Middle Oolites 
 and also in the fresh-water beds of the Purbeck series ; and 
 they are of such a nature that their affinities with the typical 
 Lacertilians of the present day cannot be disputed. The 
 Chelonians, up to this point only known by the doubtful evi- 
 dence of footprints in the Permian and Triassic sandstones, are 
 here represented by unquestionable remains, indicating the ex- 
 istence of marine Turtles (the Chehne planiceps of the Portland 
 Stone). No remains of Serpents (Ophidians} have as yet been 
 detected in the Jurassic ; but strata of this age have yielded 
 the remains of numerous Crocodilians, which probably inhab- 
 ited the sea. The most important member of this group is 
 Teleosaurus, which attained a length of over thirty feet, and 
 is in some respects allied to the living Gavials of India. 
 
 The great class of the Birds, as we have seen, is represented 
 in rocks earlier than the Oolites simply by the not absolutely 
 certain evidence of the three-toed footprints of the Connecti- 
 cut Trias. In the Lithographic Slate of Solenhofen (Middle
 
 252 HISTORICAL PALAEONTOLOGY. 
 
 Oolite), there has been discovered, however, the at present 
 unique skeleton of a Bird well known under the name of the 
 Archceopteryx macrura (figs. 181, 182). The only known 
 
 Fig. 181. Arclutopteryx macnira, showing tail and tail-feathers, with detached bones. 
 Reduced. From the Lithographic Slate of Solenhofen. 
 
 specimen now in the British Museum unfortunately does 
 not exhibit the skull; but the fine-grained matrix has pre- 
 
 Fig. 182. Restoration of A rck&opteryx macruia. (After Owen.) 
 
 served a number of the other bones of the skeleton, along with 
 the impressions of the tail and wing feathers. From these 
 remains we know that Archtzopteryx differed in some remark-
 
 THE JURASSIC PERIOD. 253 
 
 able peculiarities of its structure from all existing members of 
 the class of Birds. This extraordinary Bird (fig. 182) appears 
 to have been about as big as a Rook the tail being long and 
 extremely slender, and composed of separate vertebrae, each 
 of which supports a single pair of quill-feathers. In the flying 
 Birds of the present day, as before mentioned, the terminal 
 vertebrae of the tail are amalgamated to form a single bone 
 (" ploughshare-bone "), which supports a cluster of tail-feathers ; 
 and the tail itself is short. In the embryos of existing Birds 
 the tail is long, and is made up of separate vertebrae, and the 
 same character is observed in many existing Reptiles. The 
 tail of Archceopteryx, therefore, is to be regarded as the per- 
 manent retention of an embryonic type of structure, or as an 
 approximation to the characters of the Reptiles. Another 
 remarkable point in connection with Archceopteryx, in which 
 it differs from all known Birds, is, that the wing was furnished 
 with two free claws. From the presence of feathers, Archce- 
 opteryx may be inferred to have been hot-blooded ; and this 
 character, taken along with the structure of the skeleton of the 
 wing, may be held as sufficient to justify its being considered 
 as belonging to the class of Birds. In the structure of the 
 tail, however, it is singularly Reptilian ; and there is reason to 
 believe that its jaws were furnished with teeth sunk in distinct 
 sockets, as is the case in no existing Bird. This conclusion, 
 at any rate, is rendered highly probable by the recent discovery 
 of "Toothed Birds" (Odontornithes) in the Cretaceous rocks 
 of North America. 
 
 The Mammals of the Jurassic period are known to us by 
 a number of small forms which occur in the " Stonesfield 
 Slate" (Great Oolite) and in the Purbeck beds (Upper 
 Oolite). The remains of these are almost exclusively sepa- 
 rated halves of the lower jaw, and they indicate the existence 
 during the Oolitic period in Europe of a number of small 
 " Pouched animals " (Marsupials). In the horizon of the 
 Stonesfield Slate four genera of these little Quadrupeds have 
 been described viz., Amphile$tes y Amphitherium, Phascolo- 
 iherium, and Stereognathus. In Amphitherium (fig. 183), the 
 molar teeth are furnished with small pointed eminences or 
 " cusps ; " and the animal was doubtless insectivorous. By 
 Professor Owen, the highest living authority on the subject, 
 Amphitherium is believed to be a small Marsupial, most 
 nearly allied to the living Banded Ant-eater (Myrmecobius) of 
 Australia (fig. 158). Amphilestes and Phascolotherium (fig. 
 184) are also believed by the same distinguished anatomist 
 and paleontologist to have been insect-eating Marsupials, and 
 18
 
 254 
 
 HISTORICAL PALAEONTOLOGY. 
 
 the latter is supposed to find its nearest living ally in the 
 Opossums (Didelphys} of America. Lastly, the Stereognathus 
 
 Fig. 1 83. -Lower jaw of A mfihitherium (Thylacothe 
 Stonesfield Slate (Great Oolite.) 
 
 i) P revest it. 
 
 of the Stonesfield Slate is in a dubious position. It may have 
 been a Marsupial ; but, upon the whole, Professor Owen is 
 inclined to believe that it must have been a hoofed and her- 
 bivorous Quadruped belonging to the series of the higher Mam- 
 mals (Placentalid). In the Middle Purbeck beds, near to the 
 close of the Oolitic period, we have also evidence of the exist- 
 ence of a number of small Mammals, all of which are probably 
 Marsupials. Fourteen species are known, all of small size, 
 the largest being no bigger than a Polecat or Hedgehog. The 
 genera to which these little quadrupeds have been referred are 
 Plagiaulax, Spalacotherium, Triconodon, and Galestes. The 
 first of these (fig. 184, 4) is believed by Professor Owen to 
 
 Fig. 184. Oolitic Mammals. i, Lower jaw and teeth of Phascofatfierium, Stonesfield 
 Slate ; 2, Lower jaw and teeth of Amphitheriwn, Stonesfield Slate ; 3, Lower jaw and 
 teeth of Tricoiiodon, Purbeck beds ; 4, Lower jaw and teeth of Plagiaulax, Purbeck 
 beds. All the figures are of the natural size. 
 
 have been carnivorous in its habits ; but other authorities 
 maintain that it was most nearly allied to the living Kangaroo- 
 rats {Hypsiprymnus) of Australia, and that it was essentially 
 herbivorous. The remaining three genera appear to have 
 been certainly insectivorous, and find their nearest living rep- 
 resentatives in the Australian Phalangers and the American 
 Opossums. 
 
 Finally, it is interesting to notice in how many respects the
 
 THE JURASSIC PERIOD. 255 
 
 Jurassic fauna of Western Europe approached to that nov/ 
 inhabiting Australia. At the present day, Australia is almost 
 wholly tenanted by Marsupials ; upon its land-surface flourish 
 Araucarice and Cycadaceous plants, and in its seas swims the 
 Port-Jackson Shark ( Cestracion Philippi) ; whilst the Mollus- 
 can genus Trigonia is nowadays exclusively confined to the 
 Australian coasts. In England, at the time of the deposition 
 of the Jurassic rocks, we must have had a fauna and flora very 
 closely- resembling what we now see in Australia. The small 
 Marsupials, Ampliitherium, Phascolotherium, and others, prove 
 that the Mammals were the same in order ; cones of Arau- 
 carian pines, with tree-ferns and fronds of Cycads, occur 
 throughout the Oolitic series ; spine-bearing fishes, like the 
 Port-Jackson Shark, are abundantly represented by genera 
 such as Acrodus and Strophodus ; and lastly, the genus Tri- 
 gonia, now exclusively Australian, is represented in the Oolites 
 by species which differ little from those now existing. More- 
 over, the discovery during recent years of the singular Mud-fish, 
 the Ceraiodus Fosteri, in the rivers of Queensland, has added 
 another and a very striking point of resemblance to those 
 already mentioned ; since this genus of Fishes, though pre- 
 eminently Triassic, nevertheless extended its range into the 
 Jurassic. Upon the whole, therefore, there is reason to con- 
 clude that Australia has undergone since the close of the 
 Jurassic period fewer changes and vicissitudes than any other 
 known region of the globe ; and that this wonderful continent 
 has therefore succeeded in preserving a greater number of 
 the characteristic life-features of the Oolites than any other 
 country with which we are acquainted. 
 
 LITERATURE. 
 
 The following list comprises some of the more important sources of 
 information as to the rocks and fossils of the Jurassic series : 
 
 (1) ' Geology of Oxford and the Thames Valley.' Phillips. 
 
 (2) 'Geology of Yorkshire,' vol. ii. Phillips. 
 
 (3) ' Memoirs of the Geological Survey of Great Britain.' 
 
 (4) ' Geology of Cheltenham.' Murchison, 2d ed. Bucl<man. 
 
 (5) ' Introduction to the Monograph of the Oolitic Asteriadas' (Pakeon- 
 
 tographical Society). XVright. 
 ; Zone of Avicula contorta and the Lower Lias of the South of 
 
 England " -' Quart. Journ. Geol. Soc.,' vol. xvi., 1860. Wright. 
 'Oolites of Northamptonshire " 'Quart. Journ. Geol. Soc.,' Vols. 
 
 xxvi. and xxix. Sharp. 
 
 (8) 'Manual of Geology.' Dana. 
 
 (9) 'Derjura.' Ouenstedt. 
 
 (10) ' Das Flotzgebirge Wiirttembergs.' Quenstedt. 
 
 (11) 'Jura Formation.' Oppel.
 
 256 HISTORICAL PALEONTOLOGY. 
 
 (12) ' Paleontologie du Departement de la Moselle.' Terquem. 
 
 (13) ' Cours elementaire de Paleontologie.' D Orbigny. 
 
 (14) ' Paleontologie Francaise.' D'Orbigny. 
 
 (15) 'Fossil Echinodermata of the Oolitic Formation' (Paloeontographi- 
 
 cal Society). Wright. 
 
 (16) ' Brachiopoda of the Oolitic Formation' (Palaeontographical So- 
 
 ciety). Davidson. 
 
 (17) ' Mollusca of the Great Oolite' (Palaeontographical Society). Mor- 
 
 ris and Lycett. 
 
 (18) ' Monograph of the Fossil Trigoniae' (Palseontographical Society). 
 
 Lycett. 
 
 (19) 'Corals of the Oolitic Formation' (Palseontographical Society). 
 
 Edwards and Ilaime. 
 
 (20) ' Supplement to the Corals of the Oolitic Formation ' (Pakeonto- 
 
 graphical Society). Martin Duncan. 
 
 (21) 'Monograph of the Belemnitidae' (Palaeontographical Society). 
 
 Phillips. 
 
 (22) 'Structure of the Belemnitidae' (Mem. Geol. Survey). Huxley. 
 
 (23) ' Sur les Belemnites.' Blainville. 
 
 (24) ' Cephalopoden.' Quenstedt. 
 
 (25) ' Mineral Conchology.' Sowerby. 
 
 (26) 'Jurassic Cephalopoda' (Palseontologica Indica). Waagen. 
 
 (27) 'Manual of the Mollusca.' Woodward. 
 
 (28) 'Petrefaktenkunde.' Schlotheim. 
 
 (29) ' Bridge water Treatise.' Buckland. 
 
 (30) ' Versteinerungen des Oolithengebirges.' Roemer. 
 
 (31) ' Catalogue of British Fossils.' Morris. 
 
 (32) ' Catalogue of Fossils in the Museum of Practical Geology.' Ether- 
 
 id ge. 
 
 (33) 'Beitrage zur Petrefaktenkunde.' Minister. 
 
 (34) ' Petrefacta Germanise. ' Goldfuss. 
 
 (35) ' Lethaea Rossica. ' Eichwald. 
 
 (36) ' Fossil Fishes ' (Decades of the Geol. Survey). Sir Philip Egerton. 
 
 (37) ' Manual of Palaeontology.' Owen. 
 
 (38) 'British Fossil Mammals and Birds.' Owen. 
 
 (39) ' Monographs of the Fossil Reptiles of the Oolitic Formation ' (Palae- 
 
 ontographical Society). Owen. 
 
 (40) ' Fossil Mammals of the Mesozoic Formations ' (Palaeontographical 
 
 Society). Owen. 
 
 (41) 'Catalogue of Ornithosauria.' Seeley. 
 
 (42) "Classification of the Deinosauria" 'Quart. Journ. Geol. Soc.,' 
 
 vol. xxvi., 1870. Huxley. 
 
 CHAPTER XVII. 
 THE CRETACEOUS PERIOD. 
 
 The next series of rocks in ascending order is the great and 
 important series of the Cretaceous Rocks, so called from the 
 general occurrence in the system.of chalk (Lat. creta, chalk).
 
 THE CRETACEOUS PERIOD. 2$/ 
 
 As developed in Britain and Europe generally, the following 
 leading subdivisions may be recognised in the Cretaceous 
 
 2! L^weforeensand or Neocomian, j Lower Cretaceous. 
 
 3- Gault, ) 
 
 t. Ch P aT; GreenSand ' Upper Cretaceous. 
 
 6. Maastricht beds, ) 
 
 I. Wealden. The Wealden formation, though of consider- 
 able importance, is a local group, and is confined to the south- 
 east of England, France, and some other parts of Europe. Its 
 name is derived from the Weald, a district comprising parts of 
 Surrey, Sussex, and Kent, where it is largely developed. Its 
 lower portion, for a thickness of from 500 to 1000 feet, is 
 arenaceous, and is known as the Hastings Sands. Its Upper 
 portion, for a thickness of 150 to nearly 300 feet, is chiefly 
 argillaceous, consisting of clays with sandy layers, and occa- 
 sionally courses of limestone. The geological importance of 
 the Wealden formation is very great, as it is undoubtedly the 
 delta of an ancient river, being composed almost wholly of 
 fresh-water beds, with a few brackish-water and even marine 
 strata, intercalated in the lower portion. Its geographical 
 extent, though uncertain, owing to the enormous denudation 
 to which it has been subjected, is nevertheless great, since it 
 extends from Dorsetshire to France, and occurs also in North 
 Germany. Still, even if it were continuous between all these 
 points, it would not be larger than the delta of such a modern 
 river as the Ganges. The river which produced the Wealden 
 series must have flowed from an ancient continent occupying 
 what is now the Atlantic Ocean ; and the time occupied in 
 the formation of the Wealden must have been very great, 
 though we have, of course, no data by which we can accurately 
 calculate its duration. 
 
 The fossils of the Wealden series are, naturally, mostly the 
 remains of such animals as we know at the present day as in- 
 habiting rivers. We have, namely, fresh-water Mussels ( Unto), 
 River-snails (Paluditia), and other fresh - water shells, with 
 numerous little bivalved Crustaceans, and some fishes. 
 
 II. Lower Greensand (Neocomien of D'Orbigny). The 
 Wealden beds pass upward, often by insensible gradations, 
 into the Lower Greensand. The name Lower Greensand is 
 not an appropriate one, for green sands only occur sparingly 
 and occasionally, and are found in other formations. For this
 
 258 HISTORICAL PALAEONTOLOGY. 
 
 reason it has been proposed to substitute for Lower Greensand 
 the name Neocomian, derived from the town of Neufchatel 
 anciently called Neocomum in Switzerland. If this name 
 were adopted, as it ought to be, the Wealden beds would be 
 called the Lower Neocomian. 
 
 The Lower Greensand or Neocomian of Britain has a thick- 
 ness of about 850 feet, and consists of alternations of sands, 
 sandstones, and clays, with occasional calcareous bands. The 
 general colour of the series is dark brown, sometimes red ; and 
 the sands are occasionally green, from the presence of silicate 
 of iron. 
 
 The fossils of the Lower Greensand are purely marine, and 
 among the most characteristic are the shells of Cephalopods. 
 
 The most remarkable point, however, about the fossils of 
 the Lower Cretaceous series, is their marked divergence from 
 the fossils of the Upper Cretaceous rocks. Of 280 species of 
 fossils in the Lower Cretaceous series, only 51, or about 18 
 per cent, pass on into the Upper Cretaceous. This break in 
 the life of the two periods is accompanied by a decided phy- 
 sical break as well ; for the Gault is often, if not always, un- 
 conformably superimposed on the Lower Greensand. At the 
 same time, the Lower and Upper Cretaceous groups form a 
 closely-connected and inseparable series, as shown by a com- 
 parison of their fossils with those of the underlying Jurassic 
 rocks and the overlying Tertiary beds. Thus, in Britain no 
 marine fossil is known to be common to the marine beds of 
 the Upper Oolites and the Lower Greensand and of more 
 than 500 species of fossils in the Upper Cretaceous rocks, 
 almost every one died out before the formation of the lowest 
 Tertiary strata, the only survivors being one Brachiopod and a 
 few Foraminifera. 
 
 III. Gault (Aptien of D'Orbigny). The lowest member of 
 the Upper Cretaceous series is a stiff, dark - grey, blue, or 
 brown clay, often worked for brick-making, and known as the 
 Gault, from a provincial English term. It occurs chiefly in 
 the south-east of England, but can be traced through France 
 to the flanks of the Alps and Bavaria. It never exceeds 100 
 feet in thickness ; but it contains many fossils, usually in a 
 state of beautiful preservation. 
 
 IV. Upper Greensand (Albien of D'Orbigny ; Unterquader 
 and Lower Pldnerkalk of Germany). The Gault is succeeded 
 upward by the Upper Greensand, which varies in thickness 
 from 3 up to 100 feet, and which derives its name from the 
 occasional occurrence in it of green sands. These, however, 
 are local and sometimes wanting, and the name " Upper
 
 THE CRETACEOUS PERIOD. 259 
 
 Greensand " is to be regarded as a name and not a description. 
 The group consists, in Britain, of sands and clays, sometimes 
 with bands of calcareous grit or siliceous limestone, and occa- 
 sionally containing concretions of phosphate of lime, which are 
 largely worked for agricultural purposes. 
 
 V. White Chalk. The top of the Upper Greensand be- 
 comes argillaceous, and passes up gradually into the base of 
 the great formation known as the true Chalk, divided into 
 the three subdivisions of the chalk-marl, white chalk without 
 flints, and white chalk with flints. The first of these is sim- 
 ply argillaceous chalk, and passes up into a great mass of 
 obscurely- stratified white chalk in which there are no flints 
 (Turonien of D'Orbigny; Mittdquader of Germany). This, in 
 turn, passes up into a great mass of white chalk, in which the 
 stratification is marked by nodules of black flint arranged in 
 layers (Senom'en of D'Orbigny ; Oberquader of Germany). The 
 thickness of these three subdivisions taken together is some- 
 times over 1000 feet, and their geographical extent is very 
 great. White Chalk, with its characteristic appearance, may 
 be traced from the north of Ireland to the Crimea, a distance 
 of about 1 140 geographical miles; and, in an opposite direction, 
 from the south of Sweden to Bordeaux, a distance of about 
 840 geographical miles. 
 
 VI. In Britain there occur no beds containing Chalk fossils, 
 or in any way referable to the Cretaceous period, above the 
 true White Chalk with flints. On the banks of the Maes, 
 however, near Maestricht in Holland, there occurs a series of 
 yellowish limestones, of about 100 feet in thickness, and un- 
 doubtedly superior to the White Chalk. These Maestricht 
 beds (Danien of D'Orbigny) contain a remarkable series of 
 fossils, the characters of which are partly Cretaceous and 
 partly Tertiary. Thus, with the characteristic Chalk fossils, 
 Belcmnites,B acuities, Sea-Urchins, &c., are numerous Univalve 
 Molluscs, such as Cowries and Volutes, which are otherwise 
 exclusively Tertiary or Recent. 
 
 1 Holding a similar position to the Maestricht beds, and 
 showing a similar intermixture of Cretaceous forms with later 
 types, are certain beds which occur in the island of Seeland, 
 in Denmark, and which are known as the Faxoe Limestone. 
 
 Of a somewhat later date than the Maestricht beds is the 
 Pisolitic Limestone of France, which rests unconformably on 
 the White Chalk, and contains a large number of Tertiary 
 fossils along with some characteristic Cretaceous types. 
 
 The subjoined sketch-section exhibits the general succession 
 of the Cretaceous deposits in Britain :
 
 260 
 
 HISTORICAL PALEONTOLOGY. 
 
 GENERALISED SECTION OF THE CRETACEOUS SERIES 
 OF BRITAIN. 
 
 Eocene. 
 
 White Chalk with Flints. 
 
 \~- White Chalk without Flints. 
 
 - -Chalk Marl. 
 
 Upper Greensand. 
 
 Gault. 
 
 Lower Greensand or Neo- 
 comian. 
 
 . _ ....Weald Clay. 
 
 Wealden Series. 
 
 - Hastings Sands. 
 
 In North America, strata of Lower Cretaceous age are well 
 represented in Missouri, Wyoming, Utah, and in some other 
 areas ; but the greater portion of the American deposits of 
 this period are referable to the Upper Cretaceous. The rocks 
 of this series are mostly sands, clays, and limestones Chalk 
 itself being unknown except in Western Arkansas. Amongst 
 the sandy accumulations, one of the most important is the so-
 
 THE CRETACEOUS PERIOD. 26l 
 
 called " marl " of New Jersey, which is truly a " Greensand," 
 and contains a large proportion of glauconite (silicate of iron 
 and potash). It also contains a little phosphate of lime, and is 
 largely worked for agricultural purposes. The greatest thick- 
 ness attained by the Cretaceous rocks of North America is 
 about 9000 feet, as in Wyoming, Utah, and Colorado. Ac- 
 cording to Dana, the Cretaceous rocks of the Rocky Mountain 
 territories pass upwards "without interruption into a coal- 
 bearing formation, several thousand feet thick, on which the 
 following Tertiary strata lie unconformably." The lower por- 
 tion of this "Lignitic formation" appears to be Cretaceous, 
 and contains one or more beds of Coal; but the upper part of it 
 perhaps belongs to the Lower Tertiary. In America, therefore, 
 the lowest Tertiary strata appear to rest conformably upon the 
 highest Cretaceous ; whereas in Europe, the succession at this 
 point is invariably an unconformable one. Owing, however, to 
 the fact that the American " Lignitic formation " is a shallow- 
 water formation, it can hardly be expected to yield much 
 material whereby to bridge over the great palasontological gap 
 between the White Chalk and Eocene in the Old World. 
 
 Owing to the fact that so large a portion of the Cretaceous 
 formation has been deposited in the sea, much of it in deep 
 water, the plants of the period have for the most part been 
 found special members of the series, such as the Wealden beds, 
 the Aix-la-Chapelle sands, and the Lignitic beds of North 
 America. Even the purely marine strata, however, have 
 yielded plant-remains, and some of these are peculiar and 
 proper to the deep-sea deposits of the series. Thus the little 
 calcareous discs termed " coccoliths," which are known to be 
 of the nature of calcareous sea-weeds (A/gce) have been de- 
 tected in the White Chalk ; and the flints of the same forma- 
 tion commonly contain the spore-cases of the microscopic 
 Desmids (the so-called Xanthidia), along with the siliceous cases 
 of the equally diminutive Diatoms. 
 
 The plant-remains of the Lower Cretaceous greatly resemble 
 those of the Jurassic period, consisting mainly of Ferns, Cy- 
 cads, and Conifers. The Upper Cretaceous rocks, however, 
 both in Europe and in North America, have yielded an abun- 
 dant flora which resembles the existing vegetation of the globe 
 in consisting mainly of Angiospermous Exogens and of Mono- 
 cotyledons.* In Europe the plant-remains in question have 
 
 * The " Flowering plants" are divided into the two great groups of the 
 Endogens and Exogens. The Endogens (such as Grasses, Palms, Lilies, 
 &c.) have no true bark, nor rings of growth, and the stem is said to be 
 "endogenous; " the young plant also possesses but a single seed-leaf or
 
 262 HISTORICAL PALEONTOLOGY. 
 
 been found chiefly in certain sands in the neighbourhood of Aix- 
 la-Chapelle, and they consist of numerous Ferns, Conifers (such 
 as Cycadopteris\ Screw Pines (Pandanus\ Oaks (Quercus), \Va\- 
 nut (Juglans), Fig (fiats), and many Proteacetz, some of which are 
 referred to existing genera (Dryandra, Banksia, Grevillea, &c.) 
 
 In North America, the Cretaceous strata of New Jersey, 
 Alabama, Nebraska, Kansas, &c., have yielded the remains of 
 numerous plants, many of which belong to existing genera. 
 Amongst these may be mentioned Tulip-trees (Liriodendron), 
 vSassafras (fig. 186), Oaks (Quemts), Beeches (Fagus\ Plane- 
 trees (Platanus), Alders (Alnus\ Dog-wood (Cornus), Willows 
 (Salix), Poplars (Populus), Cypresses (Cupressus), Bald Cy- 
 presses {Taxodiuni), Magnolias, &c. Besides these, however, 
 there occur other forms which have now entirely disappeared 
 from North America as, for example, species of Cinnamornum 
 and Araucaria. 
 
 It follows from the above, that the Lower and Upper Creta- 
 ceous rocks are, from a botanical point of view, sharply sepa- 
 rated from one another. The Palaeozoic period, as we have 
 seen, is characterised by the prevalance of " Flowerless" plants 
 (Cryptogams), its higher vegetation consisting almost exclu- . 
 sively of Conifers. The Mesozoic period, as a whole, is charac- 
 terised by the prevalence of the Cryptogamic group of the 
 Ferns, and the Gymnospermic groups of the Conifers and the 
 Cycads. Up to the close of the Lower Cretaceous, no Angio- 
 spermous Exogens are certainly known to have existed, and 
 Monocotyledonous plants or Endogens are very poorly repre- 
 sented. With the Upper Cretaceous, however, a new era of 
 plant-life, of which our present is but. the culmination, com- 
 menced, with a great and apparently sudden development of new 
 forms. In place of the Ferns, Cycads, and Conifers of the earlier 
 Mesozoic deposits, we have now an astonishingly large number 
 of true Angiospermous Exogens, many of them belonging to 
 existing types ; and along with these are various Monocotyle- 
 donous plants, including the first examples of the great and im- 
 
 "cotyledon. " Hence these plants are often simply called "Monocotyledons. " 
 The Exogens, on the other hand, have a true bark ; and the stem increases 
 
 by annual additions to the outside, so that rings of growth are produced. 
 
 The yoi 
 
 are therefore called "Dicotyledons." Amongst the Exogens, the Pines 
 
 ^oung plant has two seed-leaves or "cotyledons," and these plants 
 
 (Conifers) and the Cycads have seeds which are unprotected by a seed- 
 vessel, and they are therefore called " Gymnospenn s. " All the other 
 Exogens, including the ordinary trees, shrubs, and flowering plants, have 
 the seeds enclosed in a seed-vessel, and are therefore called " Angio- 
 sperms." The derivation of these terms will be found in the Glossary at 
 the end of the volume.
 
 THE CRETACEOUS PERIOD. 263 
 
 portant group of the Palms. It is thus a matter of interest to 
 reflect that plants closely related to those now inhabiting the 
 
 Fig. 186 Cretaceous Angiosperms. a. Sassafras Cretacenm ; b, I.iriidendron 
 Meekii", c, Legumitwsites Marcouanus; d, Salix Meekii. (After Dana.) 
 
 earth, were in existence at a time when the ocean was tenanted 
 by Ammonites and Belemnites, and when land and sea and 
 air were peopled by the extraordinary extinct Reptiles of the 
 Mesozoic period. 
 
 As regards animal life, the Protozoans of the Cretaceous 
 period are exceedingly numerous, and are represented by Fora- 
 minifera and Sponges. As we have already seen, the White 
 Chalk itself is a deep-sea deposit, almost entirely composed 
 of the microscopic shells of Foraminifcrs, along with Sponge- 
 spicules, and organic debris of different kinds (seep. 22, fig. 7). 
 The green grains which are so abundant in several minor sub- 
 divisions of the Cretaceous, are also in many instances really 
 casts in glauconite of the chambered shells of these minute 
 organisms. A great many species of Foraminifera have been 
 recognised in the Chalk ; but the three principal genera are
 
 264 HISTORICAL PALEONTOLOGY. 
 
 Globigerina, Rotalia (fig. 187), and Textularia groups which 
 are likewise characteristic of the " ooze " of the Atlantic and 
 
 Fig. 187. Rotalia oue, 
 
 Pacific Oceans at great depths. The flints of the Chalk also 
 commonly contain the shells of Foraminifera. The Upper 
 Greensand has yielded in considerable numbers the huge 
 Foraminifera described by Dr Carpenter under the name of 
 Parkeria, the spherical shells of which are composed of sand- 
 grains agglutinated together, and sometimes attain a diameter 
 of two and a quarter inches. The Cretaceous Sponges are 
 extremely numerous, and occur under a great number of varie- 
 ties of shape and structure ; but the two most characteristic 
 genera are Siphonia and Vetitriculites ; both of which are ex- 
 clusively confined to strata of this age. The Siphonice (fig. 
 1 88) consist of a pear-shaped, sometimes lobed head, supported 
 by a longer or shorter stem, which breaks up at its base into a 
 number of root-like processes of attachment. The water gained 
 access to the interior of the Sponge by a number of minute 
 openings covering the surface, and ultimately escaped by a 
 single, large, chimney-shaped aperture at the summit. In some 
 respects these sponges present a singular resemblance to the 
 beautiful " Vitreous Sponges " (Holtenia or Pheronema} of the 
 deep Atlantic ; and, like these, they were probably denizens 
 of a deep sea. The Ventricnlites of the Chalk (fig. 189) is, 
 however, a genus still more closely allied to the wonderful 
 flinty Sponges, which have been shown, by the researches of 
 the Porcupine, Lightning, and Challenger expeditions, to live 
 half buried in the calcareous ooze of the abysses of our great 
 oceans. Many forms of this genus are known, having " usu- 
 ally the form of graceful vases, tubes, or funnels, variously 
 ridged or grooved, or otherwise ornamented on the surface, 
 frequently expanded above into a cup-like lip, and continued 
 below into a bundle of fibrous roots. The minute structure of 
 these bodies shows an extremely delicate tracery of fine tubes, 
 sometimes empty, sometimes filled with loose calcareous mat-
 
 THE CRETACEOUS PERIOD. 
 
 26 5 
 
 ter dyed with peroxide of iron." (Sir Wyville Thomson.) 
 Many of the Chalk sponges, originally calcareous, have been 
 converted into flint subsequently ; but the Ventriculites are 
 
 Fig. -Lt&. 
 
 Upper Greensand, Europe. 
 
 Fig. i%g.VentriciiUtes simplex. 
 White Chalk, Britain. 
 
 really composed of this substance, and are therefore genuine 
 " Siliceous Sponges," like the existing Venus's Flower-Basket 
 (Euplectdla). Like the latter, the skeleton was doubtless ori- 
 ginally composed, in the young state, of disconnected six- 
 rayed spicules, which ultimately become fixed together to 
 constitute a continuous frame-work. The sea-water, as in the 
 recent forms, must have been admitted to the interior of the 
 Sponge by numerous apertures on its exterior, subsequently 
 escaping by a single large opening at its summit. 
 
 Amongst the Co* tenter ates, the " Hydroid Zoophytes " are 
 represented by a species of the encrusting genus Hydractinia, 
 the horny polypary of which is so commonly found at the 
 present day adhering to the exterior of shells. The occurrence 
 of this genus is of interest, because it is the first known instance 
 in the entire geological series of the occurrence of an unques- 
 tionable Hydroid of a modern type, though many of the exist- 
 ing forms of these animals possess structures which are per-
 
 266 HISTORICAL PALEONTOLOGY. 
 
 fectly fitted for preservation in the fossil condition. The corals 
 of the Cretaceous series are not very numerous, and for the 
 most part are referable to types such as Trochocyathus, Stephano- 
 phyllia, Parasmilia, Synhelia (fig. 190), &c., which belong to 
 the same great group of corals as the majority of existing 
 
 Fig. T.<y>.SynhfliaSharpeana. Chalk, England. 
 
 forms. We have also a few " Tabulate Corals " (Polytre- 
 macis), hardly, if at all, generically separable from very ancient 
 forms (Heliolites); and the Lower Greensand has yielded the 
 remains of the little Holocystis elegans, long believed to be the 
 last of the great Palaeozoic group of the Rugosa. 
 
 As regards the Echinoderms, the group of the Crinoids nov/ 
 exhibits a marked decrease in the number and variety of its 
 types. The " stalked " forms are represented by Pentacrinus 
 and Bourgucticrinus, and the free forms by Feather-stars like 
 our existing Comatulce ; whilst a link between the stalked and 
 free groups is constituted by the curious "Tortoise Encrinite 
 (Marsupites). " By far the most abundant Cretaceous Echino- 
 derms, however, are Sea-urchins (EcAinouis) though several 
 Star-fishes are known as well. The remains of Sea-urchins are 
 so abundant in various parts of the Cretaceous series, especi- 
 ally in the White Chalk, and are often so beautifully preserved, 
 that they constitute one of the most marked features of the 
 fauna of the period. From the many genera of Sea-urchins 
 which occur in strata of this age, it is difficult to select char- 
 acteristic types; but the genera Galeritcs (fig. 191), Discoidea 
 (fig. 192), Micmster, Ananchytes, Diadema, Salenia, and Ci-
 
 THE CRETACEOUS PERIOD. 
 
 26 7 
 
 daris, may be mentioned as being all important Cretaceous 
 groups. 
 
 Coming to the Annulose Animals of the Cretaceous period, 
 
 Fig. 191. Galeriies albogalems, viewed from below, from the side, and from above. 
 White Chalk. 
 
 there is little special to remark. The Crustaceans belong for 
 the most part to the highly-organised groups of the Lobsters 
 
 Fig. 192. Discoidea cylindrica. ; tinder, side, and upper aspect. 
 Upper Greensand. 
 
 and the Crabs (the Macrurous and Brachyurous Decapods) ; 
 but there are also numerous little Ostracodes, especially in the 
 fresh-water strata of the Wealden. It should further be noted 
 that there occurs here a great development of the singular 
 Crustaceans family of the Barnacles (Lepadidce), whilst the allied 
 family of the equally singular Acorn-shells (Balanida) is feebly 
 represented as well. 
 
 Passing on to the Mollusca, the class of the Sea-mats and 
 Sea-mosses (Polyzoa) is immensely developed in the Cretaceous 
 period, nearly two hundred species being known to occur in 
 the Chalk. Most of the Cretaceous forms belong to the family 
 of the Escharidce, the genera Eschara and Escharina (fig. 193) 
 being particularly well represented. Most of the Cretaceous 
 Polyzoans are of small size, but some attain considerable di- 
 mensions, and many simulate Corals in their general form and 
 appearance.
 
 268 
 
 HISTORICAL PALEONTOLOGY. 
 
 The Lamp-shells (BracMopods] have now reached a further 
 stage of the progressive decline, which they have been under- 
 going ever since the close of 
 the Palaeozoic period. Though 
 individually not rare, especially 
 in certain minor subdivisions 
 of the series, the number of 
 generic types has now be- 
 come distinctly diminished, the 
 principal forms belonging to 
 the genera Terebratula, Tere- 
 bratella (fig. 194), Terebratulina, 
 RJiynchonella, and Crania, (fig. 
 195). In the last mentioned 
 of these, the shell is attached 
 to foreign bodies by the sub- 
 stance of one of the valves (the ventral), whilst the other or 
 free valve is more or less limpet-shaped. All the above-men- 
 
 193. A small fragment of Esch 
 
 Fig. 194. Terebratella Astieriana. Gault. 
 
 tioned genera are in existence at the present day ; and one 
 species namely, Terebratulina striata appears to be undis- 
 tinguishable from one now living the Terebratulina caput- 
 serpentis. 
 
 Whilst the Lamp-shells are slowly declining, the Bivalves 
 (Lamellibranchs} are greatly developed, and are amongst the 
 most abundant and characteristic fossils of the Cretaceous 
 period. In the great river-deposit of the Wealden, the Bivalves 
 are forms proper to fresh water, belonging to the existing 
 River-mussels ( Unio\ Cyrena and Cyclas ; but most of the 
 Cretaceous Lamellibranchs are marine. Some, of the most 
 abundant and characteristic of these belong to the great family 
 of the Oysters (Ostreidce). Amongst these are the genera 
 Gryphcza and Exogyra, both of which we have seen to occur
 
 THE CRETACEOUS PERIOD. 269 
 
 abundantly in the Jurassic ; and there are also numerous true 
 Oysters (Ostrea, fig. 196) and Thorny Oysters (Spondylus, fig. 
 
 Fig. 195. Crania Ignabergensis. The left-hand figure shows the perfect shell, at- 
 tached by its ventral valve to a foreign body; the middle figure shows the exterior of the 
 limpet-shaped dorsal valve ; and the right-hand figure represents the interior of the at- 
 tached valve. White Chalk. 
 
 197). The genus Trigonia, so characteristic of the Mesozoic 
 deposits in general, is likewise well represented in the Greta- 
 
 Fig. 196. Ostrea Coitloni. Lower Greensand. 
 
 ceous strata. No single genus of Bivalves is, however, so highly 
 characteristic of the Cretaceous period as Inoceramus, a group 
 belonging to the family of the Pearl-mussels (Aviculitfct). The 
 shells of this genus (fig. 198) have the valves unequal in size, 
 the larger valve often being much twisted, and both valves 
 being marked with radiating ribs or concentric furrows. The 
 hinge-line is long and straight, with numerous pits for the 
 attachment of the ligament which serves to open the shell. 
 Some of the Inocerami attain a length of two or three feet, and 
 fragments of the shell are often found perforated by boring 
 19
 
 2/O HISTORICAL PALAEONTOLOGY. 
 
 Sponges. Another extraordinary family of Bivalves, which is 
 exclusively confined to the Cretaceous rocks, is that of the 
 
 ns. White Chalk. 
 
 Hippuritidcz. All the members of this group (fig. 199) were 
 attached to foreign objects, and lived associated in beds, like 
 
 Fig. i<$.Inoceraitnis sukatus. Gault 
 
 Oysters. The two valves of the shell are always altogether 
 unlike in sculpturing, appearance, shape, and size ; and the 
 cast of the interior of the shell is often extremely unlike the 
 form of the outer surface. The type-genus of the family is 
 Hippurites itself (fig. 199), in which the shell is in the shape of 
 a straight or slightly-twisted horn, sometimes a foot or more in 
 length, constituted by the attached lower valve, and closed 
 above by a small lid-like free upper valve. About a hundred 
 species of the family of the Hippuritida are known, all of these 
 being Cretaceous, and occurring in Britain (one species only), 
 in Southern Europe, the West Indies, North America, Algeria, 
 and Egypt. Species of this family occur in such numbers in 
 certain compact marbles in the south of Europe, of the age of 
 the Upper Cretaceous (Lower Chalk), as to have given origin 
 to the name of " Hippurite Limestones," applied to these 
 strata.
 
 THE CRETACEOUS PERIOD. 
 
 The Univalves (Gasttropods) of the Cretaceous period are 
 not very numerous, nor particularly remarkable. Along with 
 species of the persistent genus Plcurotomaria and the Meso- 
 
 Fig. ^.Hippurites Toucastann. 
 A large individual, with two smaller 
 ones attached to it. Upper Cretace- 
 ous, South of Kurope. 
 
 Fig. 200. Valuta elongaia. 
 White Chalk. 
 
 zoic Nerin&a, we meet with examples of such modern types 
 as Turritella and Natica, the Staircase-shells {Solarium}, the 
 Wentle-traps (Scalaria], the Carrier-shells (Phorus), &c. To- 
 wards the close of the Cretaceous period, and especially in 
 such transitional strata as the Maestricht beds, the Faxoe 
 Limestone, and the Pisolitic Limestone of France, we meet 
 with a number of carnivorous (" siphonostomatous ") Uni- 
 valves, in which the mouth of the shell is notched or pro- 
 duced into a canal. Amongst these it is interesting to 
 recognise examples of such existing genera as the Volutes 
 (Valuta, fig. 200), the Cowries (Cyprcea), the Mitre-shells 
 (Mitra), the Wing - shells (Strombus), the Scorpion - shells 
 (Pleroceras], &c.
 
 2/2 HISTORICAL PALEONTOLOGY. 
 
 Upon the whole, the most characteristic of all the Creta- 
 ceous Molluscs are the Cephalopods, represented by the remains 
 of both Tetr -abranchiate and Dibranchiate forms. Amongst the 
 former, the long-lived genus Nautilus (fig. 201) again reap- 
 
 Fig. 201. Different views of Nautilus Danicus. Faxoe Limestone 
 (Upper Cretaceous), Denmark. 
 
 pears, with its involute shell, its capacious body-chamber, its 
 simple septa between the air-chambers, and its nearly or quite 
 central siphuncle. The majority of the chambered Cephalo- 
 pods of the Cretaceous belong, however, to the complex and 
 beautiful family of the Ammonitidce, with their elaborately- 
 folded and lobed septa and dorsally-placed siphuncle. This 
 family disappears wholly at the close of the Cretaceous period ; 
 but its approaching extinction, so far from being signalised by 
 any slow decrease and diminution in the number of specific 
 or generic types, seems to have been attended by the develop- 
 ment of whole series of new forms. The genus Ammonites 
 itself, dating from the Carboniferous, has certainly passed its 
 prime, but it is still represented by many species, and some of 
 these attained enormous dimensions (two or three feet in 
 diameter). The genus Ancyloceras (fig. 202), though likewise 
 of more ancient origin (Jurassic), is nevertheless very charac- 
 teristic of the Cretaceous. In this genus the first portion of 
 the shell is in the form of a flat spiral, the coils of which are 
 not in contact ; and its last portion is produced at a tangent, 
 becoming ultimately bent back in the form of a crosier. Be- 
 sides these pre - existent types, the Cretaceous rocks have 
 yielded a great number of entirely new forms of the Ammoni- 
 tidce, which are. not known in any deposits of earlier or later 
 date. Amongst the more important of these may be men- 
 tioned Crioceras, Turrilites, Scaphites, Hamites, Ptychoceras,
 
 THE CRETACEOUS PERIOD. 2/3 
 
 and Bacitlites. In the genus Crioceras (fig. 204, d), the shell 
 consists of an open spiral, the volutions of which are not in 
 
 -Ancyloceras Matheronic.nus. Ga 
 
 contact, thus resembling a partially-unrolled Ammonite or the 
 inner portion of an Ancyloceras. In Turrilties (fig. 203), the 
 shell is precisely like that of the Ammonite in its structure ; 
 but instead of forming a flat spiral, it is coiled into an ele- 
 vated turreted shell, the whorls of which are in contact with 
 one another. In the genus Scaphites (fig. 204, e), the shell 
 resembles that of Ancyloceras in consisting of a series of volu- 
 tions coiled into a flat spiral, the last being detached from the 
 others, produced, and ultimately bent back in the form of a 
 crosier; but the whorls of the enrolled part of the shell are in 
 contact, instead of being separate as in the latter, In the 
 genus Hamitcs (fig. 204,7), tne sne ^ IS an extremely elongated 
 cone, which is bent upon itself more than once, in a hook-like 
 manner, all the volutions being separate. The genus Ptycho- 
 ceras (fig. 204, a) is very like Hamites, except that the shell is 
 only bent once ; and the two portions thus bent are in contact 
 with one another. Lastly, in the genus Baculites (fig. 204, b 
 and f) the shell is simply a straight elongated cone, not bent 
 in any way, but possessing the folded septa which characterise 
 the whole Ammonite family. The Baculite is the simplest of 
 all the forms of the Ammonitidce ; and all the other forms, how- 
 ever complex, may be regarded as being simply produced by 
 the bending or folding of such a conical septate shell in differ- 
 ent ways. The Baculite, therefore, corresponds, in the series 
 of the Ammonitidce, to the Orthoceras in the series of the Nau- 
 tilida. All the above-mentioned genera are characteristically, 
 or exclusively, Cretaceous, and they are accompanied by a 
 number of other allied forms, which cannot be noticed here. 
 Not a single one of these genera, further, has hitherto been 
 detected in any strata higher than the Cretaceous. We may 
 therefore consider that these wonderful, varied, and elaborate
 
 274 
 
 HISTORICAL PALEONTOLOGY. 
 
 forms of Ammotiitida constitute one of the most conspicuous 
 features in the life of the Chalk period. 
 
 The Dibranchiate Cephalopods are represented partly by the 
 
 Fig. 203. Turr:lites caie- Fig 204. a, Ptychoceras Einericianum, reduced 
 
 natus. The lower figure rep- Lower Greensand ; b, Bacnlites anceps, reduced 
 
 resents the entire shell ; the Chalk : c, Portion of the same, showing the folded 
 
 upper figure represents the edges of the septa ; d, Crioceras cristatum, reduced 
 
 base of the shell seen from Gault; e, Scaphitcs izqualis, natural size Chalk; 
 
 below. Gault. f, Hamites rotundus, restored Gault. 
 
 beak like jaws of unknown species of Cuttle-fishes and partly 
 by the internal skeletons of Belemnites. Amongst the latter, 
 the genus Belcmnites itself holds its place in the lower part of
 
 THE CRETACEOUS PERIOD. 275 
 
 the Cretaceous series ; but it disappears in the upper portion 
 of the series, and its place is taken by the nearly-allied genus 
 Belemnitella (fig. 205), distinguished by the possession of a 
 straight fissure in the upper end of the guard. This 
 also disappears at the close of the Cretaceous 
 period; and no member of the great Mesozoic 
 family of the Beleinnitidtz has hitherto been dis- 
 covered in any Tertiary deposit, or is known to 
 exist at the present day. 
 
 Passing on next to the Vertebrate Animals of the 
 Cretaceous period, we find the Fishes represented 
 as before by the Ganoids and the Placoids, to which, 
 however, we can now add the first known examples 
 of the great group of the Bony Fishes or Telcosteans, 
 comprising the great majority of existing forms. 
 The Ganoid fishes of the Cretaceous (Lepidotus, 
 Pycnodus, &c.) present no features of special in- 
 terest. Little, also, need be said about the Placoid 
 fishes of this period. As in the Jurassic deposits, Fig. 205. 
 the remains of these consist partly of the teeth of Bttenmittila. 
 gen nine Sha rks (Lamna, Odontaspis, &c. ), and partly white chalk 
 of the teeth and defensive spines of Cestracionts, 
 such as the living Port-Jackson Shark. The pointed and sharp- 
 edged teeth of true Sharks are very abundant in some beds, such 
 as the Upper Greensand, and are beautifully preserved. The 
 teeth of some forms (CarchaHas, &c.) attain occasionally a 
 length of three or four inches, and indicate the existence in the 
 Cretaceous seas of huge predaceous fishes, probably larger than 
 any existing Sharks. The remains of Cestracionts consist 
 partly of the flattened teeth of genera such as Acrodus and 
 Ptychodus (the latter confined to rocks of this age), and partly 
 of the pointed teeth of Jfybodus, a genus which dates from the 
 Trias. In this genus the teeth (fig. 206) consist of a principal 
 central cone, flanked by minor lateral cones; and the fia- 
 
 Fig. 206. T^oth Fig. 207. Fin-spine of Hybodus. Lower Greensand. 
 
 otllybodus. 
 
 spines (fig. 207) are longitudinally grooved, and carry a series 
 of small spines on their hinder or concave margin. Lastly,
 
 2 7 6 
 
 HISTORICAL PALEONTOLOGY. 
 
 the great modern order of the Bony Fishes or Tcleosteans 
 makes its first appearance in the Upper Cretaceous rocks, 
 where it is represented by forms belonging to no less than 
 three existing groups namely, the Salmon family (Sal- 
 monidce), the Herring family (Cliipeidtz}, and the Perch family 
 (Percida}. All these fishes have thin, horny, overlapping 
 
 Fig. 208. i, Beryx Lcivcsiensis, a Percoid fish from the Chalk ; 2, Osnieroides 
 ManteUi, a Salraonoid fish from the Chalk. 
 
 scales, symmetrical (" homocercal") tails, and bony skeletons. 
 The genus Beryx (fig. 208, i) is one represented by existing 
 species at the present day, and belongs to the Perch family. 
 The genus Osmeroidcs, again (fig. 208, 2), is supposed to be 
 related to the living Smelts (Osmerus), and, therefore, to 
 belong to the Salmon tribe. 
 
 No remains of Amphibians have hitherto been detected in 
 any part of the Cretaceous series ; but Reptiles are extremely 
 numerous, and belong to very varied types. As regards the 
 great extinct groups of Reptiles which characterise the Meso- 
 zoic period as a whole, the huge " Enaliosaurs " or " Sea- 
 Lizards" are still represented by the Ichthyosaur and the 
 Plcsiosaur. Nearly allied to the latter of these is the Elas- 
 tnosaurus of the American Cretaceous, which combined the
 
 THE CRETACEOUS PERIOD. 2// 
 
 long tail of the Ichthyosaur with the long neck of the Plesio- 
 saur. The length of this monstrous Reptile could not have 
 been less than fifty feet, the neck consisting of over sixty 
 vertebrae and measuring over twenty feet in length. The 
 extraordinary Flying Reptiles of the Jurassic are likewise well 
 represented in the Cretaceous rocks by species of the genus 
 Pterodactylus itself, and these later forms are much more 
 gigantic in their dimensions than their predecessors. Thus 
 some of the Cretaceous Pterosaurs seem to have had a spread 
 of wing of from twenty to twenty-five feet, more than realising 
 the " Dragons" of fable in point of size. The most remark- 
 able, however, of the Cretaceous Pterosaurs are the forms 
 which have recently been described by Professor Marsh under 
 the generic title of Pteranodon. In these singular forms so 
 far only known as American the animal possessed a skeleton 
 in all respects similar to that of the typical Pterodactyles, 
 except that the jaws are completely destitute of teeth. There 
 is, therefore, the strongest probability that the jaws were 
 encased in a horny sheath, thus coming to resemble the beak 
 of a Bird. Some of the recognised species of Pteranodon are 
 very small ; but the skull of one species (P. longiceps) is not 
 less than a yard in length, and there are portions of the skull 
 of another species which would indicate a length of four feet 
 for the cranium. These measurements would point to dimen- 
 sions larger than those of any other known Pterosaurs. 
 
 The great Mesozoic order of the Deinosaurs is largely rep- 
 resented in the Cretaceous rocks, partly by genera which 
 previously existed in the Jurassic period, and partly by entirely 
 new types. The great delta-deposit of the Wealden, in the 
 Old World, has yielded the remains of various, of these huge 
 terrestrial Reptiles, and very many others have been found in 
 the Cretaceous deposits of North America. One of the most 
 celebrated of the -Cretaceous Deinosaurs is the Iguanodon, so 
 called from the curious resemblance of its teeth to those of the 
 existing but comparatively diminutive Iguana. The teeth (fig. 
 209) are soldered to the inner face of the jaw, instead of being 
 sunk in distinct sockets; and they have the form of somewhat 
 flattened prisms, longitudinally ridged on the outer surface, 
 with an obtusely triangular crown, and having the enamel 
 crenated on one or both sides. They present the extraordinary 
 feature that the crowns became worn down flat by mastication, 
 showing that the Iguanodan employed its teeth in actually 
 chewing and triturating the vegetable matter on which it fed. 
 There can therefore be no doubt but that the Iguanodon, in 
 spite of its immense bulk, was an herbivorous Reptile, and
 
 2 7 3 
 
 HISTORICAL PALEONTOLOGY. 
 
 lived principally on the foliage of the Cretaceou-s forests 
 amongst which it dwelt. Its size has been variously estimated 
 
 Fig. 209. Teeth < Iguanoden Matttellii. Wealden, Britain. 
 
 at from thirty to fifty feet, the thigh-bone in large examples 
 measuring nearly five feet in length, with a circumference of 
 twenty-two inches in its smallest part. With the strong and 
 massive hind-limbs are associated comparatively weak and 
 small fore-limbs ; and there seems little reason to doubt that 
 the Iguanodon must have walked temporarily or permanently 
 upon its hind-limbs, after the manner of a Bird. This conjec- 
 ture is further supported by the occurrence in the strata which 
 contain the bones of the Iguanodon of gigantic three-toed foot- 
 prints, disposed singly in a double track. These prints have 
 undoubtedly been produced by some animal walking on two 
 legs; and they can hardly, with any probability, be ascribed to 
 any other than this enormous Reptile. Closely allied to the 
 Iguanodon is the Hadrosaunts of the American Cretaceous, the 
 length of which is estimated at twenty-eight feet. Iguanodon 
 does not appear to have possessed any integumentary skeleton; 
 but the great Hylceosaurus of the Wealden seems to have been 
 furnished with a longitudinal crest of large spines running 
 down the back, similar to that which is found in the compara- 
 tively small Iguanas of the present day. The Megalosaurus of 
 the Oolites continued to exist in the Cretaceous period; and, as 
 we have previously seen, it was carnivorous in its habits. The 
 American Lczlaps was also carnivorous, and, like the Megalosaur,
 
 THE CRETACEOUS PERIOD. 279 
 
 which ft very closely resembles, appears to have walked upon 
 its hind-legs, the fore-limbs being disproportionately small. 
 
 Another remarkable group of Reptiles, exclusively confined 
 to the Cretaceous series, is that of the Mosasauroids, so called 
 from the type-genus Mosasaurus. The first species of Mosa- 
 saurus known to science was the M. Camperi (fig. 210), the 
 
 Fig. 210. Skull of Mosasminis Camfcri, greatly reduced Maestricht Chalk. 
 
 skull of which six feet in length was discovered in 1780 in 
 the Maestricht Chalk at Maestricht. As this town stands on 
 the river Meuse, the name of Mosasaurus (" Lizard of the 
 Mease") was applied to this immense Reptile. Of late years 
 the remains of a large number of Reptiles more or less closely 
 related to Mosasaurus, or absolutely belonging to it, have been 
 discovered in the Cretaceous deposits of North America, and 
 have been described by Professors Cope and Marsh. All 
 the known forms of this group appear to have been of large 
 size one of them, Mosasaurus princeps, attaining the length of 
 seventy-five or eighty feet, and thus rivalling the largest of ex- 
 isting Whales in its dimensions. The teeth in the " Mosa- 
 sauroids" are long, pointed, and slightly curved; and instead 
 of being sunk in distinct sockets, they are firmly amalgamated 
 with the jaws, as in modern Lizards. The palate also carried 
 teeth, and the lower jaw was so constructed as to allow of the 
 mouth being opened to an immense width, somewhat as in the 
 living Serpents. The body was long and snake-like, with a 
 very long tail, which is laterally compressed, and must have 
 served as a powerful swimming-apparatus. In addition to this, 
 both Dairs of limbs have the bones connecting them with the
 
 280 
 
 HISTORICAL PALEONTOLOGY. 
 
 trunk greatly shortened ; whilst the digits were enclosed in the 
 integuments, and constituted paddles, closely resembling in 
 structure the " nippers " of Whales and Dolphins. The neck 
 is sometimes moderately long, but oftener very short, as the 
 great size and weight of the head would have led one to anti- 
 cipate. Bony plates seem in some species to have formed an 
 at any rate partial covering to the skin ; but it is not certain 
 that these integumentary appendages were present in all. Up- 
 on the whole, there can be no doubt but that the Mosasauroid 
 Reptiles the true " Sea-serpents " of the Cretaceous period 
 were essentially aquatic in their habits, frequenting the sea, 
 and only occasionally coming to the land. 
 
 The " Mosasauroid s " have generally been regarded as a 
 greatly modified group of the Lizards (Lacertilia). Whether 
 this reference be correct or not and recent investigations 
 render it dubious the Cretaceous rocks have yielded the 
 remains of small Lizards not widely removed from existing 
 forms. The recent order of the Chclonians is also represented 
 
 in the Cretaceous rock's, 
 by forms closely re- 
 sembling living types. 
 Thus the fresh - water 
 deposits of the W T ealden 
 have yielded examples 
 of the "Terrapins" or 
 " Mud-Turtles" (Emys); 
 and the marine Creta- 
 ceous strata have been 
 found to contain the 
 remains of various spe- 
 cies of Turtles, one of 
 which is here figured 
 (fig. 211). No true 
 Serpents ( Ophidia)\\axe. 
 as yet been detected in 
 the Cretaceous rocks; 
 and this order does not 
 appear to have come 
 into existence till the 
 Tertiary period. Last- 
 ly, true Crocodiles are 
 known to have existed 
 in considerable num- 
 bers in the Cretaceous period. The oldest of these occur 
 in the fresh-water deposit of the Wealden ; and they differ from 
 
 Fig. 211. Carapace of Chelone Bcnstedi. 
 Lower Chalk. (After Owen.)
 
 THE CRETACEOUS PERIOD. 28 1 
 
 the existing forms of the group in the fact that the bodies 
 of the vertebrae, like those of the Jurassic Crocodiles, are 
 bi-concave, or hollowed out at both ends. In the Greensand 
 of North America, however, occur the remains of Crocodiles 
 which agree with all the living species in having the bodies of 
 the vertebrae in the region of the back hollowed out in front 
 and convex behind. 
 
 Birds have not hitherto been shown, with certainty, to have 
 existed in Europe during the Cretaceous period, except in a 
 few instances in which fragmentary remains belonging to this 
 class have been discovered. The Cretaceous deposits of 
 North America have, however, been shown by Professor 
 Marsh to contain a considerable number of the remains of 
 Birds, often in a state ^of excellent preservation. Some of 
 these belong to Swimming or Wading Birds, differing in no 
 point of special interest from modern birds of similar habits. 
 Others, however, exhibit such extraordinary peculiarities that 
 they merit more than a passing notice. One of the forms in 
 question constitutes the genus Ichthyornis of Marsh, the type- 
 species of which (/. dispar) was about as large as a Pigeon. 
 In two remarkable respects, this singular Bird differs from all 
 known living members of the class. One of these respects 
 concerns the jaws, both of which exhibit the Reptilian char- 
 acter of being armed with numerous small pointed teeth (fig. 
 2 [ 2, a), sunk in distinct sockets. No existing bird possesses 
 teeth; and this character forcibly recalls the Bird-like Ptero- 
 saurs, with their toothed jaws. Ichthyornis^ however, possessed 
 fore-limbs constructed strictly on the type of the "wing" of the 
 living Birds; and it cannot, therefore, be separated from this 
 class. Another extraordinary peculiarity of Ichthyornis is, that 
 the bodies of the vertebra (fig. 212, c) were bi-concave^ as is the 
 case with many extinct Reptiles and almost all Fishes, but as 
 does not occur in any living Bird. There can be little doubt 
 that IcJithyorniswas aquatic in its habits, and that it lived prin- 
 cipally upon fishes ; but its powerful wings at the same time 
 indicate that it was capable of prolonged flight. The tail of 
 Ichthyornis has, unfortunately, not been discovered ; and it is 
 at present impossible to say whether this resembled the tail of 
 existing Birds, or whether it was elongated and composed of 
 separate vertebrae, as in the Jurassic Archaopteryx. 
 
 Still more wonderful than Ichthyornis is the marvellous bird 
 described by Marsh under the name of Hesperornis regalis. 
 This presents us with a gigantic diving bird, somewhat re- 
 sembling the existing "Loons" {Colymbus\ but agreeing 
 with Ichthvornis in having the jaws furnished with conical,
 
 282 
 
 HISTORICAL PAL/EONTOLOGY. 
 
 recurved, pointed teeth (fig. 212, b}. Hence these forms are 
 grouped together in a new sub-class, under the name of Odon- 
 tornithes or " Toothed Birds." The teeth of Hesperornis (fig. 
 212, d] resemble those of Ichthyornis in their general form; 
 
 Fig. 212. Toothed Birds (Otlontortiittus) 
 Left lower jaw of Ichthyornis dispar, slightly enlarged ; b, Left lower jaw of Hesperornis 
 
 of the Cretaceous Rocks of America, a, 
 
 ower aw of Ichthyornis dispar, slightly enlarged ; b, Left lower jaw of Hesperor 
 ecall's, reduced to nearly one-fourth of the natural size ; c, Cervical vertebra oS Ickthyo 
 dispar, front view, twice the natural size ; </, Side view of the same ; d, Tooth of Hesper- 
 ornis regalis, enlarged to twice the natural size. (After Marsh.) 
 
 but instead of being sunk in distinct sockets, they are simply 
 implanted in a deep continuous groove in the bony substance 
 of the jaw. The front of the upper jaw does not carry teeth, 
 and was probably encased in a horny beak. The breast-bone 
 is entirely destitute of a central ridge or keel, and the wings 
 are minute and quite rudimentary ; so that Hcsperornis, unlike 
 Ichthyornis, must have been wholly deprived of the power of 
 flight, in this respect approaching the existing Penguins. The 
 tail consists of about twelve vertebras, of which the last three or 
 four are amalgamated to form a flat terminal mass, there being 
 at the same time clear indications that the tail was capable 
 of up and down movement in a vertical plane, this proba- 
 bly fitting it to serve as a swimming-paddle or rudder. The 
 legs were powerfully constructed, and the feet were adapted to 
 assist the bird in rapid motion through the water. The known 
 remains of Hesperornis regalis prove it to have been a swim- 
 ming and diving bird, of larger dimensions than any of the
 
 THE CRETACEOUS PERIOD. 283 
 
 aquatic members of the class of Birds with which we are ac- 
 quainted at the present day. It appears to have stood between 
 five and six feet high, and its inability to fly is fully compen- 
 sated for by the numerous adaptations of its structure to a 
 watery life. Its teeth prove it to have been carnivorous in its 
 habits, and it probably lived upon fishes. It is a curious fact 
 that two Birds agreeing with one another in the wholly abnor- 
 mal character of possessing teeth, and in other respects so 
 entirely different, should, like Ichthyornis and Hesperornis, 
 have lived not only in the same geological period, but also in 
 the same geographical area ; and it is equally curious that 
 the area inhabited by these toothed Birds should at the same 
 time have been tenanted by winged and bird-like Reptiles 
 belonging to the toothed genus Pterodactylus and the toothless 
 genus Pteranodon. 
 
 No remains of Mammals, finally, have as yet been detected 
 in any sedimentary accumulations of Cretaceous age. 
 
 LITERATURE. 
 
 The following list comprises some of the more important works and 
 memoirs which may be consulted with reference to the Cretaceous strata 
 and their fossil contents : 
 
 (1) ' Memoirs of the Geological Survey of Great Britain.' 
 
 (2) 'Geology of England and Wales.' Conybeare and Phillips. 
 
 (3) ' Geology of Yorkshire,' vol. ii. Phillips. 
 
 (4) 'Geology of Oxford and the Thames Valley.' Phillips. 
 
 (5) ' Geological Excursions through the Isle of Wight.' Mantell. 
 
 (6) 'Geology of Sussex.' Mantell. 
 
 (7) ' Report on Londonderry,' &c. Portlock. 
 
 (&) ' Recherches sur le Terrain Cretace Superieur de 1'Angleterre et de 
 
 1'Irlande.' Barrois. 
 
 (9) "Geological Survey of Canada" 'Report of Progress, 1872-73.' 
 (10) 'Geological Survey of California.' Whitney. 
 
 (n) 'Geological Survey of Montana, Idaho, Wyoming, and Utah.' 
 Hayden and Meek. 
 
 (12) 'Report on Geology,' &c. (British North American Boundary 
 
 Commission). G. M. Dawson. 
 
 (13) ' Manual of Geology.' Dana. 
 
 (14) ' Lethaea Rossica. ' Eichwald. 
 
 (15) ' Petrefacta Germanicc.' Goldfuss. 
 
 (16) 'Fossils of the South Downs.' Mantell. 
 
 (17) ' Medals of Creation. ' Mantell. 
 
 (18) 'Mineral Conchology.' Sowerby. 
 
 (19) 'Lethcea Geognostica.' Bronn. 
 
 (20) ' Malacostracous Crustacea of the British Cretaceous Formation' 
 
 (Palseontographical Society). Bell. 
 
 (21) 'Brachiopoda of the Cretaceous Formation' (Palseontographical 
 
 Society). Davidson. 
 
 (22) 'Corals of the Cretaceous Formation ' (Palreontographical Society). 
 
 Mi'ne-Edvvards and Haime.
 
 284 HISTORICAL PAL/EONTOLOGY. 
 
 (23) ' Supplement to the Fossil Corals ' (Palaeontographical Society). 
 
 Martin Duncan. 
 
 (24) ' Echinodermata of the Cretaceous Formation' (P^ikeontographical 
 
 Society). Wright. 
 
 (25) 'Monograph of the I'elemnitidze ' (Palseontographical Society). 
 
 Phillips. 
 
 (26) 'Monograph of the Trigonise' (Palaeontographical Society). 
 
 Lycett. 
 
 (27) ' Fossil Cirripedes ' (Palneontdgraphical Society). Darwin. 
 
 (28) ' Fossil Mollusca of the Chalk of Britain ' (Palaeomographical 
 
 Society). Sharpe. 
 
 (29) ' Entomostraca of the Cretaceous Formation ' (Palseontographical 
 
 Society). Rupert Jones. 
 
 (30) 'Monograph of the Fossil Reptiles of the Cretaceous Formation' 
 
 (Palaeontographical Society). Owen. 
 
 (31) ' Manual of Palaeontology. ' Owen. 
 
 (32) ' Synopsis of Extinct Batrachia and Reptilia.' Cope. 
 
 (33) "Structure of the Skull and Limbs in Mosasauroid Reptiles" 
 
 ' American Journ. Sci. and Arts, 1872.' Marsh. 
 
 (34) "On Odontornithes " 'American Journ. Sci. and Arts, 1875.' 
 
 Marsh. 
 
 (35) 'Ossemens Fossiles.' Cuvier. 
 
 (36) 'Catalogue of Ornithosauria.' Seeley. 
 
 (37) ' Paleontologie Francaise. * D'Orbigny. 
 
 (38) ' Synopsis des Echinides fossiles.' Desor. 
 
 (39) 'Cat. Raisonne des Echinides.' Agassiz and Desor. 
 
 (40) "Echinoids" ' Decades of the Geol. Survey of Britain.' E. Forbes. 
 
 (41) 'Paleontologie Fransaise.' Cotteau. 
 
 (42) ' Versteinerungen der Bohmischen Kreide-formation.' Reuss. 
 
 (43) "Cephalopoda, Gasteropoda, Pelecypoda, Brachiopoda, &c., of the 
 
 Cretaceous Rocks of India" ' Paloeontologica Indica,' ser. i., 
 iii., v., vi., viii. Stoliczka. 
 
 (44) "Cretaceous Reptiles of the United States" 'Smithsonian Contri- 
 
 butions to Knowledge,' vol. xiv. L^idy. 
 
 (45) ' Invertebrate Cretaceous, and Tertiary Fossils of the Upper Mis- 
 
 souri Country.' 1876. Meek. 
 
 CHAPTER XVIII. 
 'THE EOCENE PERIOD. 
 
 Before commencing the study of the subdivisions of the 
 Kainozoic series, there are some general considerations to be 
 noted. In the first place, there is in the Old World a com- 
 plete and entire physical break between the rocks of the 
 Mesozoic and Kainozoic periods. In no instance in Europe 
 are Tertiary strata to be found resting conformably upon any 
 Secondary rock. The Chalk has invariably suffered much 
 erosion and denudation before the lowest Tertiary strata were 
 deposited upon it. This is shown by the fact that the actually
 
 THE EOCENE PERIOD. 285 
 
 eroded surface of the Chalk can often be seen ; or, failing this, 
 that we can point to the presence of the chalk-flints in the 
 Tertiary strata. This last, of course, affords unquestionable 
 proof that the Chalk must have been subjected to enormous 
 denudation prior to the formation of the Tertiary beds, all the 
 chalk itself having been removed, and nothing left but the 
 flints, while these are all rolled and rounded. In the continent 
 of North America, on the other hand, the lowest Tertiary strata 
 have been shown to graduate downwards conformably with the 
 highest Cretaceous beds, it being a matter of difficulty to draw 
 a precise line of demarcation between the two formatio-ns. 
 
 In the second place, there is a marked break in the life of 
 the Mesozoic and Kainozoic periods. With the exception of 
 a few Foraminifera, and one Brachiopod (the latter doubtful), 
 no Cretaceous species is known to have survived the Creta- 
 ceous period ; while several characteristic families, such as the 
 AmmonitidcE, Belemnitida, and Hipputitida^ died out entirely 
 with the close of the Cretaceous rocks. In the Tertiary rocks, 
 on the other hand, not only are all the animals and plants 
 more or less like existing types, but we meet with a constantly- 
 increasing number of living species as we pass from the bottom 
 of the Kainozoic series to the top. Upon this last fact is 
 founded the modern classification of the Kainozoic rocks, 
 propounded by Sir Charles Lyell. 
 
 The absence in strata of Tertiary age of the chambered 
 Cephalopods, the Belemnites, the Hippurites, the Inocerami, 
 and the diversified types of Reptiles which form such con- 
 spicuous features in the Cretaceous fauna, render the palaeon- 
 tological break between the Chalk and the Eocene one far too 
 serious to be overlooked. At the same time, it is to be re- 
 membered that the evidence afforded by the explorations car- 
 ried out of late years as to the animal life of the deep sea, ren- 
 ders it certain that the extinction of marine forms of life at the 
 close of the Cretaceous period was far less extensive than had 
 been previously assumed. It is tolerably certain, in fact, that 
 we may look upon some of the inhabitants of the depths of our 
 existing oceans as the direct, if modified, descendants of ani- 
 mals which were in existence when the Chalk was deposited. 
 
 It follows from the general want of conformity between the 
 Cretaceous and Tertiary rocks, and still more from the great 
 difference in life, that the Cretaceous and Tertiary periods are 
 separated, in the Old World at any rate, by an enormous lapse 
 of unrepresented time. How long this interval may have been, 
 we have no means of judging exactly, but it very possibly was 
 as long as the whole Kainozoic epoch itself. Some day we 
 20
 
 286 ' HISTORICAL PALEONTOLOGY. 
 
 shall doubtless find, at some part of the earth's surface, marine 
 strata which were deposited during this period, and which will 
 contain fossils intermediate in character between the organic 
 remains which respectively characterise the Secondary and 
 Tertiary periods. At present, we have only slight traces of 
 such deposits as, for instance, the Maestricht beds, the Faxoa 
 Limestone, and the Pisolitic Limestone of France. 
 
 CLASSIFICATION OB- THE TERTIARY ROCKS. The classifica- 
 tion of the Tertiary rocks is a matter of unusual difficulty, in 
 consequence of their occurring in disconnected basins, form- 
 ing a series of detached areas, which hold no relations of 
 superposition to one another. The order, therefore, of the 
 Tertiaries in point of time, can only be determined by an ap- 
 peal to fossils ; and in such determination Sir Charles Lyell 
 proposed to take as the basis of classification the proportion of 
 living or existing species of Mollusca which occurs in each stratum 
 or group of strata. Acting upon this principle, Sir Charles 
 Lyell divides the Tertiary series into four groups : 
 
 I. The Eocene formation (Or. eos, dawn ; kainos, new), con- 
 taining the smallest proportion of existing species, and being, 
 therefore, the oldest division. In this classification, only the 
 Mollusca are taken into account ; and it was found that of 
 these about three and a half per cent were identical with ex- 
 isting species. 
 
 II. The Miocene formation (Gr. meion, less; kainos, new), 
 with more recent species than the Eocene, but less than the suc- 
 ceeding formation, and less than one-half the total number in the 
 formation. As before, only the Mollusca are taken into account, 
 and about 17 per cent of these agree with existing species. 
 
 III. The Pliocene formation (Gr. pleion, more; kainos, new), 
 with generally mvr than half the species of shells identical with 
 existing species the proportion of these varying from 35 to 
 50 per cent in the lower beds of this division, up to 90 or 95 
 per cent in its higher portion. 
 
 IV. The Post-Tertiary formations, in which all the shells 
 belong to existing species. This, in turn, is divided into two 
 minor groups the Post-Pliocene and Recent Formations. In 
 the Post-Pliocene formations, while all the Mollusca belong to 
 existing species, most of the Mammals belong to extinct 
 species. In the Recent period, the quadrupeds, as well as the 
 shells, belong to living species. 
 
 The above, with some modifications, was the original classi- 
 fication proposed by Sir Charles Lyell for the Tertiary rocks, 
 and now universally accepted. More recent researches, it is 
 true, have somewhat altered the proportions of existing species
 
 THE EOCENE PERIOD. 2oJ 
 
 to extinct, as stated above. The general principle, however, 
 of an increase in the number of living species, still holds good ; 
 and this is as yet the only satisfactory basis upon which it has 
 been proposed to arrange the Tertiary deposits. 
 
 EOCENE FORMATION. 
 
 The Eocene rocks are the lowest of the Tertiary series, and 
 comprise all those Tertiary deposits in which there is only a 
 small proportion of existing Mollusca from three and a half 
 to five per cent. The Eocene rocks occur in several basins in 
 Britain, France, the Netherlands, and other parts of Europe, 
 and in the United States. The subdivisions which have been 
 established are extremely numerous, and -it is often impossible 
 to parallel those of one basin with those of another. It will 
 be sufficient, therefore, to accept the division of the Eocene 
 formation into three great groups Lower, Middle, and Upper 
 Eocene and to consider some of the more important beds 
 comprised under these heads in Europe and in North America. 
 
 I. EOCENE OF BRITAIN, (i.) LOWER EOCENE. The base 
 of the Eocene series in Britain is constituted by about 90 feet 
 of light-coloured, sometimes argillaceous sands (Thanct Sands), 
 which are of marine origin. Above these, or forming the base 
 of the formation where these are wanting, come mottled clays 
 and sands with lignite ( Woolwich and Reading series], which 
 are estuarine or fluvio-marine in origin. The highest member 
 of the Lower Eocene of Britain is the " London Clay," consist- 
 ing of a great mass of dark-brown or blue clay, sometimes with 
 sandy beds, or with layers of " septaria," the whole attaining a 
 thickness of from 200 to as much as 500 feet. The London 
 Clay is a purely marine deposit, containing many marine fossils, 
 with the remains of terrestrial animals and plants ; all of which 
 indicate a high temperature of the sea and tropical or sub- 
 tropical conditions of the land. 
 
 (2.) MIDDLE EOCENE. The inferior portion of the Middle 
 Eocene of Britain consists of marine beds, chiefly consisting 
 of sand, clays, and gravels, and attaining a very considerable 
 thickness (Bagshol and Bracklcsliam beds}. The superior por- 
 tion of the Middle Eocene of Britain, on the other hand, con- 
 sists of deposits which are almost exclusively fresh : water or 
 brackish-water in origin (Hcadon and Osborne scries}. 
 
 The chief Continental formations of Middle Eocene age are 
 the " Calcaire grossier" of the Paris basin, and the "Num- 
 mulitic Limestone " of the Alps. 
 
 (3.) UPPER EOCENE. If the Headon and Osborne beds of
 
 288 HISTORICAL PALEONTOLOGY. 
 
 the Isle of Wight be placed in the Middle Eocene, the only 
 British representatives of the Upper Eocene are the Bembridge 
 beds. These strata consist of limestones, clays, and marls, 
 which have for the most part been deposited in fresh or brack- 
 ish water. 
 
 II. EOCENE BEDS OF THE PARIS BASIN. The Eocene 
 strata are very well developed in the neighbourhood of Paris, 
 where they occupy a large area or basin scooped out of the 
 Chalk. The beds of this area are partly marine, partly fresh- 
 water in origin ; and the following table (after Sir Charles 
 Lyell) shows their subdivisions and their parallelism with the 
 English series : 
 
 GENERAL TABLE OF FRENCH EOCENE STRATA. 
 
 UPPER EOCENE. 
 
 French Subdivisions. English Equivalents. 
 
 A. I. Gypseous series of Mont- I. Bembridge series. 
 
 mart re. 
 
 A. 2. Calcaire silicieux, or Tra- 2. Osborne and Headon series, 
 vertin Inferieur. 
 
 A. 3. Gres de Beauchamp, or 3. White sand and clay of Barton 
 
 Sables Moyens. Cliff, Hants. 
 
 MIDDLE EOCENE. 
 
 B. I. Calcaire Grossier. I. Bagshot and Bracklesham beds. 
 
 B. 2. Soissonnais Sands, or Lits 2. Wanting. 
 
 Coquiliiers. 
 
 LOWER EOCENE. 
 
 C. I. Argile de Londres at base of i. London clay. 
 
 HillofCassel, near Dun- 
 kirk. 
 
 C. 2. Argile p-lastique and lignite. 2. Plastic clay and sand with lig- 
 nite (Woolwich and Reading 
 series). 
 C. 3. Sables de Bracheux. 3 Thanet sands. 
 
 III. EOCENE STRATA OF THE UNITED STATES. The low- 
 est member of the Eocene deposits of North America is the 
 so-called " Lignitic Formation" which is largely developed in 
 Mississippi, Tennessee, Arkansas, Wyoming, Utah, Colorado, 
 and California, and sometimes attains a thickness of several 
 thousand feet. Stratigraphically, this formation exhibits the 
 interesting point that it graduates downwards insensibly and 
 conformably into the Cretaceous, whilst it is succeeded uncon- 
 formably by strata of Middle Eocene age. Lithologically, the 
 series consists principally of sands and clays, with beds of lig- 
 nite and coal, and its organic remains show that it is principally" 
 of fresh-water origin with a partial intermixture of marine beds.
 
 THE EOCENE PERIOD. 289 
 
 These marine strata of the " Lignitic formation " are of special 
 interest, as showing such a commingling of Cretaceous and 
 Tertiary types of life, that it is impossible to draw any rigid 
 line in this region between the Mesozoic and Kainozoic sys- 
 tems. Thus the marine beds of the Lignitic series contain 
 such characteristic Cretaceous forms as Inoceramus and Atn- 
 monifes, along with a great number of Univalves of a distinctly 
 Tertiary type (Cones, Cowries, &c.) Upon the whole, there- 
 fore, we must regard this series of deposits as affording a kind 
 of transition between the Cretaceous and the Eocene, holding 
 in some respects a position which may be compared with that 
 held by the Purbeck beds in Britain as regards the Jurassic 
 and Cretaceous. 
 
 The Middle Eocene of the United States is represented 
 by the Claiborne and Jackson beds. The Claiborne series is 
 extensively developed at Claiborne, Alabama, and consists of 
 sands, clays, lignites, marls, and impure limestones, containing 
 marine fossils along with numerous plant-remains. The^Jwfe- 
 son series is represented by lignitic clays and marls which occur 
 at Jackson, Mississippi. Amongst the more remarkable fossils 
 of this series are the teeth and bones of Cetaceans of the 
 genus Zeuglodon, 
 
 Strata of Upper Eocene age occur in North America at 
 Vicksburg, Mississippi, and are known as the Vicksburg series. 
 They consist of lignites, clays, marls, and limestones. Fresh- 
 water deposits of Eocene age are also largely developed in 
 parts of the Rocky Mountain region. The most remarkable 
 fossils of these beds are Mammals, of which a large number of 
 species have been already determined. 
 
 LIFE OF THE EOCENE PERIOD. 
 
 The fossils of the Eocene deposits are so numerous that 
 nothing more can be attempted here than to give a brief and 
 general sketch of the life of the period, special attention being 
 directed to some of the more prominent and interesting types, 
 amongst which as throughout the Tertiary series the Mam- 
 mals hold the first place. It is not uncommon, indeed, to 
 speak of the Tertiary period as a whole under the name of the 
 " Age of Mammals," a title at least as well deserved as that of 
 " Age of Reptiles " applied to the Mesozoic, or " Age of Mol- 
 luscs " applied to the Palaeozoic epoch. 
 
 As regards the plants of the Eocene, the chief point to be 
 noticed is, that the conditions which had already set in with 
 the commencement of the Upper Cretaceous, are here con-
 
 290 HISTORICAL PAL/EONTOLOGY. 
 
 tinued, and still further enforced. The Cycads of the Secondary 
 period, if they have not totally disappeared, are exceedingly 
 rare; and the Conifers, losing the predominance which they 
 enjoyed in the Mesozoic, are now relegated to a subordinate 
 though well-defined place in the terrestrial vegetation. The 
 great majority of the Eocene plants are referable to the groups 
 of the Angiospermous Exogens and the Monocotyledons ; and 
 the vegetation of the period, upon the whole, approximates 
 closely to that now existing upon the earth. The plants of the 
 European Eocene are, however, in the main most closely allied 
 to forms which are now characteristic of tropical or sub-tropical 
 regions. Thus, in the London Clay are found numerous fruits 
 of Palms (NipaditeS) fig. 213), along with various other plants, 
 most of which indicate a warm climate 
 as prevailing in the south of England 
 at the commencement of the Eocene 
 period. In the Eocene strata of North 
 America occur numerous plants belong- 
 ing to existing types such as Palms, 
 Conifers, the Magnolia, Cinnamon, Fig, 
 Dog-wood, Maple, Hickory, Poplar, 
 Plane, &c. Taken as a whole, the 
 Eocene flora of North America is nearly 
 related to that of the Miocene strata of 
 Europe, as well as to that now existing 
 in ' he American area. We may con- 
 London clay, isle of sheppey. cluue, therefore, that the torests ot 
 the American Eocene resembled those 
 
 of the European Miocene, and even of modern America" 
 (Dana). 
 
 As regards the animals of the Eocene period, the Protozoans 
 are represented by numerous Foraminifera, which reach here 
 their maximum of development, both as regards the size of 
 individuals and the number of generic types. Many of the 
 Eocene Foraminifers are of small size ; but even these not 
 uncommonly form whole rock-masses. Thus, the so-called 
 " Miliolite Limestone" of the Paris basin, largely used as a 
 building-stone, is almost wholly composed of the shells of a 
 small species of Miliola. The most remarkable, however, of 
 the many members of this group of animals which flourished in 
 Eocene times, are the " Nummulites " (Nummulina), so called 
 from their resemblance in shape to coins (Lat. nummus, a coin). 
 The Nummulites are amongst the largest of all known Fora- 
 minifera. sometimes attaining a size of three inches in circum- 
 ference ; and their internal structure is very complex (fig. 214).
 
 THE EOCENE PERIOD. 29 1 
 
 Many species are known, and they are particularly character- 
 istic of the Middle and Upper of these periods their place 
 
 Fig. 214. Ninnmulina limigtita. Middle Eocene. 
 
 being sometimes taken by Orbitoidc$ y a form very similar to the 
 Nummulite in external appearance, but differing in its internal 
 details. In the Middle Eocene, the remains of Nummulites 
 are found in vast numbers in a very widely-spread and easily- 
 recognised formation known as the " Nummulitic Limestone " 
 (fig. 10). According to Sir Charles Lyell, "the Nummulitic 
 Limestone of the Swiss Alps rises to more than 10,000 feet 
 above the level of the sea, and attains here and in other moun- 
 tain-chains a thickness of several thousand feet. It may be 
 said to play a far more conspicuous part than any other Tertiary 
 group in the solid framework of the earth's crust, whether in 
 Europe, Asia, or Africa. It occurs in Algeria and Morocco, 
 and has been traced from Egypt, where it was largely quarried 
 of old for the building of the Pyramids, into Asia Minor, and 
 across Persia by Bagdad to the mouths of the Indus. It has 
 been observed not only in Cutch, but in the mountain-ranges 
 which separate Scinde from Persia, and which form the passes 
 leading to Cabul ; and it has been followed still further east- 
 ward into India, as far as Eastern Bengal and the frontiers of 
 China." The shells of Nummulites have been found at an 
 elevation of 16,500 feet above the level of the sea in Western 
 Thibet ; and the distinguished and philosophical geologist just 
 quoted, further remarks, that "when we have once arrived at 
 the conviction that the Nummulitic formation occupies a mid- 
 dle and upper place in the Eocene series, we are struck with 
 the comparatively modern date to which some of the greatest 
 revolutions in the physical geography of Europe, Asia, and 
 Northern Africa must be referred. All the mountain-chains 
 such as the Alps, Pyrenees, Carpathians, and Himalayas into 
 the composition of whose central and loftiest parts the Num- 
 mulitic strata enter bodily, could have had no existence till
 
 292 
 
 HISTORICAL PALEONTOLOGY. 
 
 after the Middle Eocene period. During that period, the sea 
 prevailed where these chains now rise ; for Nummulites and 
 their accompanying Testacea were unquestionably inhabitants 
 of salt water." 
 
 The Ccelenterates of the Eocene are represented principally 
 by Corals, mostly of types identical with or nearly allied to 
 those now in existence. Perhaps the most characteristic group 
 of these is that of the Turbinolida, comprising a number of 
 simple " cup-corals," which probably lived in moderately deep 
 water. One of the forms belonging to this family is here 
 figured (fig. 215). Besides true Corals, the Eocene deposits 
 have yielded the remains of the " Sea- 
 pens " {PennatulidcE) and the branched 
 skeletons of the "Sea-shrubs" (Gorgonida). 
 The Echinoderms are represented prin- 
 cipally by Sea-urchins, and demand nothing 
 more than mention. It is to be observed, 
 however, that the great group of the Sea- 
 lilies (Crinoids) is now verging on extinc- 
 tion, and is but very feebly represented. 
 
 Amongst the Mollusca,t\\t Polyzoans and 
 Brachiopods also require no special men- 
 tion, beyond the fact that the latter are 
 greatly reduced in numbers, and belong 
 principally to the existing genera Tere- 
 bratula and RhyncJionella. The Bivalves 
 (Lamellibranchs) and the Univalves (Gas- 
 teropods) are exceedingly numerous, and 
 almost all the principal existing genera are 
 now represented ; though less than five 
 per cent of the Eocene species are identical 
 with those now living. It is difficult to 
 make any selection from the many Bivalves 
 which are known in deposits of this age ; 
 but species of Cardita, Crassatella, Leda, 
 Cyrena, Macira, Cardium, Psanimol>ta,$ac., 
 may be mentioned as very characteristic. 
 The Cardita planicosta here figured (fig. 
 216) is not only very abundant in the 
 Middle Eocene, but is very widely distri- 
 buted, ranging from Europe to the Pacific coast of North 
 America. The Univalves of the Eocene are extremely nu- 
 merous, and generally beautifully preserved. The majority 
 of them belong to that great section of the Gasteropods in 
 which the mouth of the shell is notched or produced into 
 
 Fig. 215. Turl'inolia 
 stilcata, viewed from one 
 side, and from above. 
 Eocene.
 
 THE EOCENE PERIOD. 
 
 293 
 
 a canal (when the shell is said to be " siphonostomatous ") 
 this section including the carnivorous and most highly-or- 
 
 Fig. 216. Cardita platiicosta.. Middle Eocene. 
 
 ganised groups of the class. Not only is this the case, but 
 a large number of the Eocene Univalves belong to types 
 which now attain their maximum of development in the 
 warmer regions of the globe. Thus we find numerous species 
 of Cones (Conus), Volutes (Valuta}, Cowries (Cypreea, fig. 218), 
 
 Fig. 
 
 17. Typhis tubifer, a "siphonostc 
 matous " Univalve. Eocene. 
 
 Fig. 218. 
 eiegans. Eocene. 
 
 Olives and Rice-shells (O/iva), Mitre-shells (Mitra), Trumpet- 
 shells (Triton), Auger-shells (Terebra), and Fig-shells (Pyrula). 
 Along with these are many forms of Pleurotoma, Rostdlaria, 
 Spindle-shells (Fusus\ Dog-whelks (Nassa), Mtirices, and many 
 round-mouthed (" holostomatous ") species, belonging to such 
 genera as Turritdla, Ncrita, Natica, Scalar ia, &c. The genus 
 Cerithium (fig. 219), most of the living forms of which are 
 found in warm regions, inhabiting fresh or brackish waters, 
 undergoes- a vast development in the Eocene period, where it
 
 294 
 
 HISTORICAL PALAEONTOLOGY. 
 
 is represented by an immense number of specific forms, some 
 of which attain very large dimensions. In the Eocene strata 
 of the Paris basin alone, nearly one hundred 
 and fifty species of this genus have been 
 detected. The more strictly fresh - water 
 deposits of the Eocene period have also 
 yielded numerous remains of Univalves such 
 as are now proper to rivers and lakes, to- 
 gether with the shells of true Land-snails. 
 Amongst these may be mentioned numerous 
 species of Limnaa (fig. 22o\Physa (fig. 221), 
 Mdania, Paludina, Planorbis, Helix, Buli- 
 mus, and Cydostoma (fig. 222). 
 
 With regard to the Cephalopods, the chief 
 point to be noticed is, that all the beautiful 
 and complex forms which peculiarly char- 
 acterised the Cretaceous period have here 
 disappeared. We no longer meet with a 
 single example of the Turrilite, the Baculite, 
 the Hamite, the Scaphite, or the Ammonite. The only ex- 
 ception to this statement is the occurrence of one species 
 
 Fig. 222. Cyclostoma 
 Arnoudii. Locene. 
 
 of Ammonite in the so-called " Lignitic Formation " of North 
 America ; but the beds containing this may possibly be rather 
 referable to the Cretaceous and this exception does not 
 affect the fact that the Amnwnttida;, as a family, had be- 
 come extinct before the Eocene strata were deposited. The 
 ancient genus Nautilus still survives, the sole representative of 
 the once mighty order of the Tetrabranchiate Cephalopods. 
 In the order of the Dibranchiates, we have a like phenomenon 
 to observe in .the total extinction of the great family of the 
 " Belemnites." No form referable to this group has hitherto
 
 THE EOCENE PERIOD. 
 
 295 
 
 been found in any Tertiary stratum; but the internal skeletons 
 .of Cuttle-fishes (such as Belosepia) are not unknown. 
 
 Remains of Fishes are very abundant in strata of Eocene 
 age, especially in certain localities. The most famous depot 
 for the fossil fishes of this period is the limestone of Monte 
 Bolca, near Verona, which is interstratified with beds of vol- 
 canic ashes, the whole being referable to the Middle Eocene. 
 The fishes here seem to have been suddenly destroyed by a 
 volcanic eruption, and are found in vast numbers. Agassiz 
 has described over one hundred and thirty species of Fishes 
 from this locality, belonging to seventy-seven genera. All 
 the species are extinct ; but about one-half of the genera are 
 represented by living forms. The great majority of the 
 
 Fig. 223. Rhotahis minimus, a small fossil Turbot from the Eocene Tertiary, 
 Monte Bolca. 
 
 Eocene Fishes belong to the order of the "Bony Fishes" 
 (Teteosteans), so that in the main the forms of Fishes charac- 
 terising the Eocene are similar to those which predominate 
 in existing seas. In addition to the above, a few Ganoids and 
 a large number of Placoids are known to occur in the Eocene 
 rocks. Amongst the latter are found numerous teeth of true 
 Sharks, such as Otodus (fig. 224) and Carcharodon. The 
 pointed and serrated teeth of the latter sometimes attain a 
 length of over half a foot, indicating that these predaceous 
 fishes attained gigantic dimensions; and it is interesting to 
 note that teeth, in external appearance very similar to those 
 of the early Tertiary genus Carcharodon, have been dredged 
 from great depths during the recent expedition of the Chal- 
 lenger. There also occur not uncommonly the flattened
 
 296 HISTORICAL PALAEONTOLOGY. 
 
 teeth of Rays (fig. 225), consisting of flat bony pieces placed 
 close together, and forming " a kind of mosaic pavement on 
 both the upper and lower jaws" (Owen). 
 
 In the class of the Reptiles, the disappearance of the char- 
 
 Fig. 224. Tooth of Fig. 225. Flattened dental plates of a Ray 
 
 Otodns obliquus. (Myliobatis Ediuardiii). Eocene. 
 
 Eocene. 
 
 acteristic Mesozoic types is as marked a phenomenon as the 
 introduction of new forms. The Ichthyosaurs, the Plesio- 
 saurs, the Pterosaurs, and the Mosasaurs of the Mesozoic, 
 find no representatives in the Eocene Tertiary ; and the same 
 is true of the Deinosaurs, if we except a few remains from the 
 doubtfully-situated " Lignitic formation" of the United States. 
 On the other hand, all the modern orders of Reptiles are 
 known to have existed during the Eocene period. The 
 Chelonians are represented by true marine Turtles, by " Ter- 
 rapins" (Emydidcz), and by "Soft Tortoises" (Trionydde^. 
 The order of the Snakes and Serpents (Ophidia] makes its 
 appearance here for the first time under several forms all of 
 which, however, are referable to the non-venomous group of 
 the " Constricting Serpents " (Boida). The oldest of these 
 is the Palczophis toliapicus of the London Clay of Sheppey, 
 first made known to science by the researches of Professor 
 Owen. The nearly -allied Palceophis typhceus of the Eocene 
 beds of Bracklesham appears to have been a Boa-constrictor- 
 like Snake of about twenty feet in length. Similar Python- 
 like Snakes (Paltzophis, Dinophis, &c.) have been described 
 from the Eocene deposits of the United States. True Lizards 
 (Lacertilians) are found in some abundance in the Eocene 
 deposits, some being small terrestrial forms, like the common 
 European lizards of the present day ; whilst others equal or 
 exceed the living Monitors in size. Lastly, the modern order 
 of the Crocodilia is largely represented in Eocene times, by 
 species belonging to all the existing genera, together with 
 others referable to extinct types. As pointed out by Owen, 
 it is an interesting fact that in the Eocene rocks of the south-
 
 THE EOCENE PERIOD. 
 
 297 
 
 west of England, there occur fossil remains of all the three 
 living types of Crocodilians namely, the Gavials, the true 
 Crocodiles, and the Alligators (fig. 226) though at the 
 
 Fig. 226. Upper jaw of Alligator. Eocene Tertiary, Isle of Wight. 
 
 present day these forms are all geographically restricted in 
 their range, and are never associated together. 
 
 Almost all the existing orders of Birds, if not all, are 
 represented in the Eocene deposits by remains often very 
 closely allied to existing types. Thus, amongst the Swimming 
 Birds (Natatores) we find examples of forms allied to the 
 living Pelicans and Mergansers; amongst the Waders (Gral- 
 latores) we have birds resembling the Ibis (the Numenitts 
 gypsorum of the Paris basin) ; amongst the Running Birds 
 (Cursores) we meet with the great Gastornis Parisiensis, which 
 equalled the African Ostrich in height, and the still more 
 gigantic Dasornis Londinensis ; remains of a Partridge rep- 
 resent the Scratching Birds (Rasores] ; the American Eocene 
 has yielded the bones of one of the Climbing Birds (Scan- 
 sores], apparently referable to the Woodpeckers ; the Protornis 
 Glarisiensis of the Eocene Schists of Claris is the oldest 
 known example of the Perching Birds (Inscssores) ; and the 
 Birds of Prey (Raptores) are represented by Vultures, Owls, 
 and Hawks. The toothed Birds of the Upper Cretaceous 
 are no longer known to exist ; but Professor Owen has 
 recently described from the London Clay the skull of a very 
 remarkable Bird, in which there is, at any rate, an approxi- 
 mation to the structure of Ic/it/iyornis and Hcspcrornis. The 
 bird in question has been named the Odontopteryx toliapicus, 
 its generic title being derived from the very remarkable char- 
 acters of its jaws. In this singular form (fig. 227) the margins
 
 298 
 
 HISTORICAL PALEONTOLOGY. 
 
 of both jaws are furnished with tooth-like denticulations, which 
 differ from true teeth in being actually portions of the bony 
 
 Fig. 227. Skull of Odontopteryx toliaficiis, restored. (After Owen.) 
 
 substance of the jaw itself, with which they are continuous, 
 and which were probably encased by extensions of the horny 
 sheath of the bill. These tooth - like processes are of two 
 cizes, the larger ones being comparable to canines ; and they 
 are all directed forwards, and have a triangular or compressed 
 conical form. From a careful consideration of all the dis- 
 covered remains of this bird, Professor Owen concludes that 
 "Odontopteryx was a warm-blooded feathered biped, with 
 Avings ; and further, that it was web-footed and a fish-eater, 
 and that in the catching of its slippery prey it was assisted by 
 this Pterosauroid armature of its jaws." Upon the whole, 
 Odontopteryx would appear to be most nearly related to the 
 family of the" Geese (Anserince) or Ducks (Anatidce) ; but the 
 extension of the bony substance of the jaws into tooth-like 
 processes is an entirely unique character, in which it stands 
 quite alone. 
 
 The known Mammals of the Mesozoic period, as we have 
 seen, are all of small size ; and with one not unequivocal 
 exception, they appear to be referable to the or*der of the 
 Pouched Quadrupeds (Marsupials), almost the lowest group 
 of the whole class of the Mammalia. In the Eocene rocks, 
 on the other hand, numerous remains of Quadrupeds have 
 been brought to light, representing most of the great Mam- 
 malian orders now in existence upon the earth, and in many 
 cases indicating animals of very considerable dimensions. We 
 are, in fact, in a position to assert that the majority of the 
 great groups of Quadrupeds with which we are familiar at the 
 present day were already in existence in the Eocene period, 
 and that their ancient root-stocks were even in this early time 
 separated by most of the fundamental differences of structure
 
 THE EOCENE PERIOD. 299 
 
 which distinguish their living representatives. At the same 
 time, there are some amongst the Eocene quadrupeds which 
 have a " generalised " character, and which may be regarded 
 as structural types standing midway between groups now 
 sharply separated from one another. 
 
 The order of the Marsupials including the existing Kan- 
 garoos, Wombats, Opossums, Phalangers, &c. is poorly 
 represented in deposits of Kocene age. The most celebrated 
 example of this group is the Didelphys gypsorum of the 
 Gypseous beds of Montmartre, near Paris, an Opossum very 
 nearly allied to the living Opossums of North and South 
 America. 
 
 No member of the Edentates (Sloths, Ant-eaters, and Arma- 
 dillos) has hitherto been detected in any Eocene deposit. 
 The aquatic order of the Sirenians (Dugongs and Manatees), 
 with their fish-like bodies and tails, paddle - shaped fore- 
 limbs, and wholly deficient hind-limbs, are represented in 
 strata of this age by remains of the ancient " Sea-Cows," to 
 which the name of Halitheriwn has been applied. Nearly 
 allied to the preceding is the likewise aquatic order of the 
 Whales and Dolphins (Cetaceans), in which the body is also 
 fish-like, the hind limbs are wanting, the fore-limbs are con- 
 verted into powerful " flippers " or swimming-paddles, and 
 the terminal extremity of the body is furnished with- a 
 horizontal tail-fin. Many existing Cetaceans (such as the 
 Whalebone Whales) have no true teeth ; but others (Dol- 
 phins, Porpoises, Sperm Whales) possess simple conical teeth. 
 
 Fig. 228. Zeuglodon cetoides. A, Molar tooth of the natural size ; B, Vertebra, 
 reduced in size. From the Middle Eocene of the United States. (After Lyell.) 
 
 In strata of Eocene age, however, we find a singular group 
 of Whales, constituting the genus Zaiglodon (fig. 228), in
 
 30O HISTORICAL PAL/EONTOLOGY. 
 
 which the teeth differed from those of all existing forms in 
 being of two kinds, the front ones being conical incisors, 
 whilst the back teeth or molars have serrated triangular 
 crowns, and are inserted in the jaw by two roots. Each 
 molar (fig. 228, A) looks as if it were composed of two 
 separate teeth united on one side by their crowns ; and it is 
 this peculiarity which is expressed by the generic name (Gr. 
 zetigle, a yoke; odons, tooth). The best -known species of 
 the genus is the Zeuglodon cetoides of Owen, which attained 
 a length of seventy feet. Remains of these gigantic Whales 
 are very common in the "Jackson Beds" of the Southern 
 United States. So common are they that, according to Dana, 
 " the large vertebrae, some of them a foot and a half long and 
 a foot in diameter, were formerly so abundant over the 
 country, in Alabama, that they were used for making walls, or 
 were burned to rid the fields of them." 
 
 The great and important order of the Hoofed Quadrupeds 
 ( Ungulata) is represented in the Eocene by examples of both 
 ot its two principal sections namely, those with an uneven 
 number of toes (one or three) on the foot (Perissodadyle Ungu- 
 lates], and those with an even number of toes (two or four) to 
 each foot (Artiodactyle Ungulates}. Amongst the Odd-toed 
 Ungulates, the living family of the Tapirs (Tapirid<e) is repre- 
 sented by the genus Coryphodon of Owen. Nearly related to 
 the preceding are the species of Palxotherium, which have 
 a historical interest as being amongst the first of the Tertiary 
 Mammals investigated by the illustrious Cuvier. Several 
 species of Palceothere are known, varying greatly in size, the 
 smallest being little bigger than a hare, whilst the largest must 
 have equalled a good-sized horse in its dimensions. The 
 species of Palaotherium appear to have agreed with the 
 existing Tapirs in possessing a lengthened and flexible nose, 
 which formed a short proboscis or trunk (fig. 229), suitable as 
 an instrument for snipping off the foliage of trees the char- 
 acters of the molar teeth showing them to have been strictly 
 herbivorous in their habits. They differ, however, from the 
 Tapirs, amongst other characters, in the fact- that both the 
 fore and the hind feet possessed three toes each ; whereas in 
 the latter there are four toes on each fore-foot, and the hind- 
 feet alone are three-toed. The remains of Palceotheria have 
 been found in such abundance in certain localities as to show 
 that these animals roamed in great herds over the fertile plains 
 of France and the south of England during the later portion 
 of the Eocene period. The accompanying illustration (fig. 
 229) represents the notion which the great Cuvier was induced
 
 THE EOCENE PERIOD. 30! 
 
 by his researches to form as to the outward appearance of 
 Palaotherium magnum. Recent discoveries, however, have 
 
 Fig. 229. Outline of PalaotJierittm magnum, restored. Upper Eocene, Europe. 
 (After Cuvier.) 
 
 rendered it probable that this restoration is in some important 
 respects inaccurate. Instead of being bulky, massive, and 
 more or less resembling the living Tapirs in form, it would rather 
 appear that Palaotherium magnum was in reality a slender, 
 graceful, and long-necked animal, more closely resembling in 
 general figure a Llama, or certain of the Antelopes. 
 
 The singular genus Anchitherium forms a kind of transition 
 between the Pal&otheria and the true Horses (Equidoe). The 
 Horse (fig. 230, D) possesses but one fully-developed toe to 
 each foot, this being terminated by a single broad hoof, and 
 representing the middle toe the third of the typical five- 
 fingered or five-toed limb of Quadrupeds in general. In 
 addition, however, to this fully-developed toe, each foot in 
 the horse carries two rudimentary toes which are concealed 
 beneath the skin, and are known as the " splint-bones." 
 These are respectively the second and fourth toes, in an 
 aborted condition ; and the first and fifth toes are wholly 
 wanting. In Hipparion (fig. 230, C), the foot is essentially 
 like that of the modern Horses, except that the second and 
 fourth toes no longer are mere " splint-bones," hidden be- 
 neath the skin ; but have now little hoofs, and hang freely, 
 but uselessly, by the side of the great middle toe, not being 
 sufficiently developed to reach the ground. In Anchitherium, 
 again (fig. 230, B), the foot is three-toed, like that of Hipparion; 
 but the two lateral toes (the second and fourth) are so far 
 21
 
 302 
 
 HISTORICAL PAL/EON TO LOGY. 
 
 developed that they now reach the ground. The first digit 
 (thumb or great toe) is still wanting ; as also is the fifth digit 
 
 Fig. 230. Skeleton of the foot in various forms belonging to the family of the Equidtr. 
 A, Foot of Orokippus, Eocene ; B, Foot of Anchitheriitm, Upper Eocene and Lower 
 Miocene ; C, Fact of Hipparlon, Upper Miocene and Pliocene ; D, Foot of Horse 
 (Equns), Pliocene and Recent. 1'he figures indicate the numbers of the digits in the 
 typical five-fingered hand of Mammals. (After Marsh.) 
 
 (little finger or little toe). Lastly, the Eocene rocks have 
 yielded in North America the remains of a small Equine 
 quadruped, to which Marsh has given the name of Orohippus. 
 In this singular form which was not larger than a fox the 
 foot (fig. 230, A) carries four toes, all of which are hoofed and 
 touch the ground, but of which the third toe is still the largest. 
 The first toe (thumb or great toe) is still wanting ; but in this 
 ancient representative of the Horses, the fiftJi or " little " toe 
 appears for the first time. As all the above-mentioned forms 
 succeed one another in point of time, it may be regarded as 
 probable that we shall yet be able to point, with some cer- 
 tainty, to some still older example of the Eqtiidoe, in which 
 the first digit is developed, and the foot assumes its typical 
 five-fingered condition. 
 
 Passing on to the Even-toed or Artiodactyle Ungulates, no 
 representative of the Hippotamus seems yet to have existed, 
 but there are several forms (Chceropotcumis, Hyopotamus, &c.) 
 more or less closely allied to the Pigs (Siiida) ; and the 
 singular group of the Anoplotheridoc may be regarded as form- 
 ing a kind of transition between the Swine and the Ruminants. 
 The Anoplotheria (fig. 231) were slender in form, the largest 
 not exceeding a donkey in size, with long tails, and having the 
 feet terminated by two hoofed toes each, sometimes with a 
 pair of small accessory hoofs as well. The teeth exhibit the
 
 THE EOCENE PERIOD. 303 
 
 peculiarity that they are arranged in a continuous series, with- 
 out any gap or interval between the molars and the canines; and 
 
 Fig. 231. Anoplotherium commune. Eocene Tertiary, France. (After Cuvier.) 
 
 the back teeth, like those of all the Ungulates, are adapted for 
 grinding vegetable food, their crowns resembling in form those 
 of the true Ruminants. The genera Dichobune and Xiphodoii, 
 of the Middle and Upper Eocene, are closely related to 
 Anoplotherium, but are more slender and deer-like in form. 
 No example of the great Ruminant group of the Ungulate 
 Quadrupeds has as yet been detected in deposits of Eocene 
 age. 
 
 Whilst true Ruminants appear to be unknown, the Eocene 
 strata of North America have yielded to the researches of 
 Professor Marsh examples of an extraordinary group (Dino- 
 ceratci), which may be considered as in some respects inter- 
 mediate between the Ungulates and the Proboscideans. In 
 Dinoceras itself (fig. 232) we have a large animal, equal in 
 dimensions to the living Elephants, which it further resembles 
 in the structure of the massive limbs, except that there are 
 only four toes to each foot. The upper jaw was devoid of 
 front teeth, but there were two very large canine teeth, in the 
 form of tusks directed perpendicularly downwards ; and there 
 was also a series of six small molars on each. Each upper 
 jaw-bone carried a bony projection, which was probably of the 
 nature of a "horn-core," and was originally sheathed in horn. 
 Two similar, but smaller, horn-cores are carried on the nasal 
 bones ; and two much larger projections, also probably of the 
 nature of horn-cores, were carried upon the forehead. We 
 may thus infer that Dinoceras possessed three pairs of horns, 
 all of which resembled the horns of the Sheep and Oxen in 
 consisting of a central bony "core," surrounded by a horny
 
 304 
 
 HISTORICAL PALEONTOLOGY. 
 
 sheath. The nose was not prolonged into a proboscis or 
 {< trunk," as in the existing Elephants ; and the tail was short 
 
 Vw ; / 
 
 Fig. 232. Skull of Dinoceras mirabilis, greatly reduced. Eocene, North America. 
 (After Marsh.) 
 
 and slender. Many forms of the Dinocerata are known ; but all 
 these singular and gigantic quadrupeds appear to have been 
 confined to the North American continent, and to be restricted 
 to the Eocene period. 
 
 The important order of the Elephants (Proboscidea} is also 
 not known to have come into existence during the Eocene 
 period. On the other hand, the great order of the Beasts of 
 Prey (^Carnivora) is represented in Eocene strata by several 
 forms belonging to different types. Thus the Arctocyon pre- 
 sents us with an Eocene Carnivore more or less closely allied 
 to the existing Racoons ; the Palceonyctis appears to be related 
 to the recent Civet-cats ; the genus Hycenodon is in some 
 respects comparable to the living Hyaenas ; and the Cants 
 Parisiensis of the gypsum-bearing beds of Montmartre may 
 perhaps be allied to the Foxes. 
 
 The order of the Bats ( Cheiroptera) is represented in Eocene 
 strata of the Paris basin (Gypseous series of Montmartre) by 
 the Vespertilio Parisiensis (fig. 233), an insect-eating Bat very 
 similar to some of the existing European forms. Lastly, the 
 Eocene deposits have yielded more or less satisfactory evi-
 
 THE MIOCENE PERIOD. 
 
 305 
 
 dence of the existence in Europe at this period of examples of 
 the orders of the Gnawing Mammals (Rodent ia), the Insect- 
 
 Fig. 233. Portion of the skeleton of Vespertilio Parisiensis. Eocene Tertiary, France. 
 
 eating Mammals (Insect ivora), and the Monkeys (Quadru- 
 mana).* 
 
 CHAPTER XIX. 
 
 THE MIOCENE PERIOD. 
 
 The Miocene rocks comprise those Tertiary deposits which 
 contain less than about 35 per cent of existing species of shells 
 (MffUusca), and more than 5 per cent or those deposits in 
 which the proportion of living shells is less than of extinct 
 species. They are divisible into a Lower Miocene (Oligocene) 
 and an Upper Miocene series. 
 
 In Britain, the Miocene rocks are very poorly developed, 
 one of their leading developments being at Bovey Tracy in 
 Devonshire, where there occur sands, clays, and beds of lignite 
 
 * A short list of the more important works relating to the Eocene 
 rocks and fossils will be given after all the Tertiary deposits have been 
 treated of.
 
 306 HISTORICAL PALEONTOLOGY. 
 
 or imperfect coal. These strata contain numerous plants, 
 amongst which are Vines, Figs, the Cinnamon-tree, Palms, 
 and many Conifers, especially those belonging to the genus 
 Sequoia (the "Red-woods"). These Bovey Tracy lignites are 
 of Lower Miocene age, and they are lacustrine in origin. Also 
 of Lower Miocene age are the so-called " Hempstead Beds " 
 of Yarmouth in the Isle of Wight. These attain a thickness of 
 less than 200 feet, and are shown by their numerous fossils to 
 be principally a true marine formation. Lastly, the Duke of 
 Argyll, in 1851, showed that there existed at Ardtun, in the 
 island of Mull, certain Tertiary strata containing numerous 
 remains of plants ; and these also are now regarded as belong- 
 ing to the Lower Miocene. 
 
 In France, the Lower Miocene is represented in Auvergne, 
 Cantal, and Velay, by a great thickness of nearly horizontal 
 strata of sands, sandstone, clays, marls, and limestones, the 
 whole of fresh-water origin. The principal fossils of these 
 lacustrine deposits are Mammalia, of which the remains occur 
 in great abundance. In the valley of the Loire occur the 
 typical European deposits of Upper Miocene age. These are 
 known as the " Faluns," from a provincial term applied to 
 shelly sands, employed to spread upon soils which are deficient 
 in lime ; and the Upper Miocene is hence sometimes spoken 
 of as the " Falunian " formation. The Faluns occur in scat- 
 tered patches, which are rarely more than 50 feet in thickness, 
 and consist of sands and marls. The fossils are chiefly marine; 
 but there occur also land and fresh-water shells, together with 
 the remains of numerous Mammals. About 25 per cent of the 
 shells of the Faluns are identical with existing species. The 
 sands, limestones, and marls of the Department of Gers, near 
 the base of the Pyrenees, rendered famous by the number of 
 Mammalian remains exhumed from them by M. Lartet, also 
 belong to the age of the Faluns. 
 
 In Switzerland, between the Alps and the Jura, there occurs 
 a great series of Miocene deposits, known collectively as the 
 " Molasse," from the soft nature of a greenish sandstone, 
 which constitutes one of its chief members. It attains a thick- 
 ness of many thousands of feet, and rises into lofty mountains, 
 some of which as the Rigi are more than 6000 feet in 
 height. The middle portion of the Molasse is of marine 
 origin, and is shown by its fossils to be of the age of the 
 Faluns; but the lower and upper portions of the formation 
 are mainly or entirely of fresh -water origin. The Lower 
 Molasse (of Lower Miocene age) has yielded about 500 species 
 of plants, mostly of tropical or sub-tropical forms. The Upper
 
 THE MIOCENE PERIOD. 307 
 
 Molasse has yielded about the same number of plants, with 
 about 900 species of Insects, such as wood-eating Beetles 
 Water-beetles, White Ants, Dragon-flies, &c. 
 
 In Belgium, strata of both Lower and Upper Miocene age 
 are known, the former (Rupelian Clays] containing numerous 
 marine fossils ; whilst the latter (Bolderberg Sands] have 
 yielded numerous shells corresponding with those of the 
 Faluns. 
 
 In Austria, Miocene strata are largely developed, marine 
 beds belonging to both the Lower and Upper division of the 
 formation occurring extensively in the Vienna basin. The 
 well-known Brown Coals of Radaboj, in Croatia, with numer- 
 ous plants and insects, are also of Lower Miocene age. 
 
 In Germany, deposits belonging to both the Lower and 
 Upper division of the Miocene formation are extensively de- 
 veloped. To the former belong the marine strata of the May- 
 ence basin, and the marine Rupelian Clay near Berlin ; whilst 
 a celebrated group of strata belonging to the Upper Miocene 
 occurs near Epplesheim, in Hesse-Darmstadt, and is well 
 known for the number of its Mammalian remains. 
 
 In Greece, at Pikerme, near Athens, there occurs a celebrated 
 deposit of Upper Miocene age, well known to paleontologists 
 through the researches of M.M. Wagner, Roth, and Gaudry 
 upon the numerous Mammalia which it contains. In Italy, 
 also, strata of both Lower and Upper Miocene age are well 
 developed in the neighbourhood of Turin. 
 
 In the Siwalik Hills, in India, at the southern foot of the 
 Himalayas, occurs a series of Upper Miocene strata, which 
 have become widely celebrated through the researches of Dr 
 Falconer and Sir Proby Cautley upon the numerous remains 
 of Mammals and Reptiles which they contain. Beds of corre- 
 sponding age, with similar fossils, are known to occur in the 
 island of Perim in the Gulf of Cambay. 
 
 Lastly, Miocene deposits are found in North America, in 
 New Jersey, Maryland, Virginia, Missouri, California, Oregon, 
 &c., attaining a thickness of 1500 feet or more. They consist 
 principally of clays, sands, and sandstones, sometimes of 
 marine and sometimes of fresh-water origin. Near Richmond, 
 in Virginia, there occurs a remarkable stratum, wrongly called 
 " Infusorial Earth," which is occasionally 30 feet in thickness, 
 and consists almost wholly of the siliceous envelopes of cer- 
 tain low forms of plants (Diatoms), along with the spicules of 
 Sponges and other siliceous organisms (see fig. 16). The 
 White River Group of Hayden occurs in the Upper Missouri 
 region, and is largely exposed over the barren and desolate
 
 308 HISTORICAL PALAEONTOLOGY. 
 
 district known as the " Mauvaises Terres." They have a 
 thickness of 1000 feet or more, and contain numerous remains 
 of Mammals. They are of lacustrine origin, and are believed 
 to be of the age of the Lower Miocene. Upon the whole, 
 about from 15 to 30 per cent of the Mollusca of the American 
 Miocene are identical with existing species. 
 
 In addition to the regions previously enumerated, Miocene 
 strata are known to be developed in Greenland, Iceland, Spitz- 
 bergen, and in other areas of less importance. 
 
 The life of the Miocene period is extremely abundant, and, 
 from the nature of the deposits of this age, also extremely 
 varied in its character. The marine beds of the formation 
 have yielded numerous remains of both Vertebrate and Inver- 
 tebrate sea-animals ; whilst the fresh-water deposits contain 
 the skeletons of such shells, fishes, &c., as now inhabit rivers 
 or lakes. Both the marine and the lacustrine beds have been 
 shown to contain an enormous number of plants, the latter 
 more particularly ; whilst the Brown Coals of the formation 
 are made up of vegetable matter little altered from its original 
 condition. The remains of air-breathing animals, such as 
 Insects, Reptiles, Birds, and Mammals, are also abundantly 
 found, more especially in the fresh-water beds. 
 
 The plants of the Miocene period are extraordinarily num- 
 erous, and only some of the general features of the vegetation of 
 this epoch can be indicated here. Our chief sources of informa- 
 tion as to the Miocene plants are the Brown Coals of Germany 
 and Austria, the Lower and Upper Molasse of Switzerland, 
 and the Miocene strata of the Arctic regions. The lignites of 
 Austria have yielded very numerous plants, chiefly of a tropical 
 character one of the most noticeable forms being a Palm of 
 the genus Sabal (fig. 234, B), now found in America. The 
 plants of the Lower Miocene of Switzerland are also mostly 
 of a tropical character, but include several forms now found 
 in North America, such as a Tulip-tree (Liriodendron} and a 
 Cypress (Taxodiuni). Amongst the more remarkable forms 
 from these beds may be mentioned Fan-Palms (Chamierops, 
 fig 234, A), numerous tropical ferns, and two species of Cin- 
 namon. The plant-remains of the Upper Molasse of Switzer- 
 land indicate an extraordinarily rank and luxuriant vegetation, 
 composed mainly of plants which now live in warm countries. 
 Among the commoner plants of this formation may be enume- 
 rated many species of Maple (Acer), Plane-trees (Platanus 
 fig. 235), Cinnamon-trees (fig. 236), and other members of the 
 Lauracea, many species of Proteaccce (Banksia, Grevillea, &c. ), 
 several species of Sarsaparilla (Smilax], Palms, Cypresses, &c.
 
 THE MIOCENE PERIOD. 
 
 309 
 
 In Britain, the Lower Miocene strata of Bovey Tracy have 
 yielded remains of Ferns, Vines, Fig, Cinnamon, Proteacece, 
 
 Fig. 234. Miocene Palms. A, Chama-rops Hehietica ; B, Snbal major. 
 Lower Miocene of Switzerland and France. 
 
 &c., along with numerous Conifers. The most abundant of 
 these last is a gigantic pine the Sequoia Couttsice which is 
 
 Fig. 235. /Ynrtoa 
 Fpper Miocene Plane-tree, a. Leaf; 
 
 A single fruit. 
 
 of a bundle of fruits ; c, 
 
 very nearly allied, to the huge Sequoia ( Wellingtonia] gigantea 
 of California. A nearly-allied form (Sequoia Laiigsdorjfi) has 
 been detected in the leaf-bed of Ardtun, in the Hebrides. 
 
 In Greenland, as well as in other parts of the Arctic regions, 
 Miocene strata have been discovered which have yielded a 
 great number of plants, many of which are identical with 
 species found in the European Miocene. Amongst these
 
 3IO HISTORICAL PALEONTOLOGY. 
 
 plants are found many trees, such as Conifers, Beeches, Oaks, 
 Maples, Plane-trees, Walnuts, Magnolias, &c., with numerous 
 shrubs, ferns, and other smaller plants. With regard to the 
 Miocene flora of the Arctic regions, Sir Charles Lyell remarks 
 that "more than thirty species of Coniferse have been found, 
 including several Sequoias (allied to the gigantic Wellingtonia 
 of California), with species of Thujopsis and Salisburia, now 
 peculiar to Japan. There are also beeches, oaks, planes, 
 poplars, maples, walnuts, limes, and even a magnolia, two 
 cones of which have recently been obtained, proving that 
 this splendid evergreen not only lived but ripened its fruit 
 within the Arctic circle. Many of the limes, planes, and 
 oaks were large-leaved species ; and both flowers and fruits, 
 besides immense quantities of leaves, are in many cases pre- 
 served. Among the shrubs are many evergreens, as Andro- 
 meda, and two extinct genera, Daphnogene and M'Clintockia, 
 with fine leathery leaves, together with hazel, blackthorn, 
 holly, logwood, and hawthorn. A species of Zamia (Zciinites] 
 grew in the swamps, with Potamogeton, Sparganiuin, and 
 Menyanthes ; while ivy and vines twined around the forest- 
 trees, and broad-leaved ferns grew beneath their shade. Even 
 in Spitzbergen, as far north as lat. 78 56', no less than ninety- 
 five species of fossil plants have been obtained, including 
 Taxodium of two species, hazel, poplar, alder, beech, plane- 
 tree, and lime. Such a vigorous growth of trees within 12 of 
 the pole, where now a dwarf willow and a few herbaceous 
 plants form the only vegetation, and where the ground is 
 covered with almost perpetual snow and ice, is truly remark- 
 able." 
 
 Taking the Miocene flora as a whole, Dr Heer concludes 
 from his study of about 3000 plants contained in the Euro- 
 pean Miocene alone, that the Miocene plants indicate tropical 
 or sub-tropical conditions, but that there is a striking inter- 
 mixture of forms which are at present found in countries 
 widely removed from one another. It is impossible to state 
 with certainty how many of the Miocene plants belong to 
 existing species, but it appears that the larger number are 
 extinct. According to Heer, the American types of plants 
 are most largely represented in the Miocene flora, next those 
 of Europe and Asia, next those of Africa, and lastly those of 
 Australia. Upon the whole, however, the Miocene flora of 
 Europe is mostly nearly allied to the plants which we now 
 find inhabiting the warmer parts of the United States ; and 
 this has led to the suggestion that in Miocene times the 
 Atlantic Ocean was dry land, and that a migration of Ameri-
 
 THE MIOCENE PERIOD. 311 
 
 can plants to Europe was thus permitted. This view is borne 
 out by the fact that the Miocene plants of Europe are most 
 nearly allied to the living plants of the eastern or Atlantic 
 seaboard of the United States, and also by the occurrence of 
 a rich Miocene flora in Greenland. As regards Greenland, 
 Dr Heer has determined that the Miocene plants indicate a 
 temperate climate in that country, with a mean annual tem- 
 perature at least 30 warmer than it is at present. 
 
 The present limit of trees is the isothermal which gives the 
 mean temperature of 50 Fahr. in July, or about the parallel 
 of 67 N. latitude. In Miocene times, however, the Eimes, 
 Cypresses, and Plane-trees reach the 79th degree of latitude, 
 and the Pines and Poplars must have ranged even further 
 north than this. 
 
 The Invertebrate Animals of the Miocene period are very 
 numerous, but they belong for the most part to existing types, 
 and they can only receive scanty consideration here. The 
 little shells of Foraminifera are extremely abundant in some 
 beds, the genera being in many cases such as now flourish 
 abundantly in our seas. The principal forms belong to the 
 genera Textularia (fig. 237), Robulina, Glandulina, Poly- 
 stomella, Amphistegina, &c. 
 Corals are very abundant, 
 in many instances forming 
 regular " reefs ;" but all the 
 more important groups are 
 in existence at the present 
 day. The Red Coral (Cor- 
 allium\ so largely sought 
 after as an ornamental ma- 
 terial, appears for the first 
 time in deposits of this age. 
 Amongst the Echinoderms, 
 we meet with Heart -Urchins (Spatatigus), Cake - Urchins 
 (Scutel/a, fig. 238), and various other forms, the majority of 
 which are closely allied to forms now in existence. 
 
 Numerous Crabs and Lobsters represent the Crustacea; but 
 the most important of the Miocene Articulate Animals are the 
 Insects. Of these, more than thirteen hundred species have 
 been determined by Dr Heer from the Miocene strata of 
 Switzerland alone. They include almost all the existing 
 orders of insects, such as numerous and varied forms of 
 Beetles (Coleoptera\ Forest-bugs (Hemiptera}, Ants (flytnen- 
 optera), Flies (Diptera}, Termites and Dragon -flies (Netirop- 
 tera], Grasshoppers (Orthoptera\ and Butterflies (Lepidoptera).
 
 3 I2 
 
 HISTORICAL PAL/EON TOLOGY. 
 
 One of the latter, the well-known Vanessa Pluto of the Brown 
 Coals of Croatia, even exhibits the pattern of the wing, and to 
 
 Fig. 238. Different views of ScnteHa snbrotunda, a Miocene " Cake-Urchin " 
 from the south of France. 
 
 some extent its original coloration ; whilst the more durably- 
 constructed insects are often in a state of exquisite preser- 
 vation. 
 
 The Mollusca of the Miocene period are very numerous, 
 but call for little special comment. Upon the whole, they are 
 genetically very similar to the Shell-fish of the present day; 
 whilst, as before stated, from fifteen to thirty per cent of the 
 species are identical with those new in existence. So far as the 
 European area is concerned, the Molluscs indicate a decidedly 
 hotter climate than the present one, though they have not such 
 a distinctly tropical character as is the case with the Eocene 
 shells. Thus we meet with many Cones, Volutes, Cowries, 
 Olive-shells, Fig-shells, and the like, which are decidedly 
 indicative of a high temperature of the sea. Polyzoans are 
 abundant, and often attain considerable dimensions ; whilst 
 Brachiopods, on the other hand, are few in number. Bivalves 
 and Univalves are extremely plentiful ; and we meet here with 
 the shells of Winged -Snails (Pferopods}, belonging to such 
 existing genera as Hyalea (fig. 239) and Cleodora. Lastly, 
 the Cephalopods are represent- 
 ed both by the chambered 
 shells of Naittili and by the 
 internal skeletons of Cuttle- 
 fishes (Spirulirostra.} 
 
 The fishes of the Miocene 
 period are very abundant, but 
 of little special importance. 
 Besides the remains of Bony Fishes, we meet in the marine 
 deposits of this age with numerous pointed teeth belonging 
 to different kinds of Sharks. Some of the genera of these 
 such as Carcharodon (fig. 241), Oxyrhina (fig. 240), Lamna, 
 and Galeoccrdo are very widely distributed, ranging through 
 
 Fig. 239. Different views of the shell 
 of Hyalea Orbignyaiiciy a Miocene 
 Pteropod.
 
 THE MIOCENE PERIOD. 313 
 
 both the Old and New Worlds ; and some of the species attain 
 gigantic dimensions. 
 
 Amongst the Amphibians we meet with distinctly modern 
 types, such as Frogs (Ratio) . 
 and Newts or Salamanders. 
 The most celebrated of the 
 latter is the famous Andrias 
 Scheuchzeri (fig. 242), dis- 
 covered in the year 1725 
 in the fresh-water Miocene 
 deposits of OEningen, in 
 Switzerland. The skeleton 
 indicates an animal nearly 
 
 five feet in length ; and it Fig. 240. Tooth Fig. 24 i.-Tooth 
 was originally described by 
 Scheuchzer, a Swiss physi- 
 cian, in a dissertation published in 1731, as the remains of one 
 of the human beings who were in existence at the time of the 
 Noachian Deluge. Hence he applied to it the name of Homo 
 diluvii testis. In reality, however, as shown by Cuvier, we 
 have here the skeleton of a huge Newt, very closely allied to 
 the Giant Salamander (Menopoma maxima) of Java. 
 
 The remains of Reptiles are far from uncommon in the 
 Miocene rocks, consisting principally of Chelonians and Cro- 
 codilians. The Land-tortoises (Testudinidce) make their first 
 appearance during this period. The most remarkable form 
 of this group is the huge Colossochelys Atlas of the Upper 
 Miocene deposits of the Siwalik Hills in India, described by 
 Dr Falconer and Sir Proby Cautley. Far exceeding any 
 living Tortoise in its dimensions, this enormous animal is 
 estimated as having had a length of about twenty feet, measured 
 from the tip of the snout to the extremity of the tail, and to. 
 have stood upwards of seven feet high. All the details of its 
 organisation, however, prove that it must have been " strictly 
 a land animal, with herbivorous habits, and probably of the 
 most inoffensive nature." The accomplished palaeontologist 
 just quoted, shows further that some of the traditions of the 
 Hindoos would render it not improbable that this colossal 
 Tortoise had survived into the earlier portion of the human 
 period. 
 
 Of the Birds of the Miocene period it is sufficient to re- 
 mark that though specifically distinct, they belong, so far as 
 known, wholly to existing groups, and therefore present no 
 points of special palasontolgical interest. 
 
 The Mammals of the Miocene are very numerous, and only
 
 HISTORICAL PALEONTOLOGY. 
 
 :>^te^ K 
 
 Fig. 242. Front portion of the skeleton of Andrias Schewhseri,a.G\mt Salamander 
 from the Miocene Tertiary of CEningen, in Switzerland. Reduced m size.
 
 THE MIOCENE PERIOD. 315 
 
 the more important forms can be here alluded to. Amongst 
 the Marsupials, the Old World still continued to possess 
 species of Opossum (Didepkys\ allied to the existing American 
 forms. The Edentates (Sloths, Armadillos, and Ant-eaters), at 
 the present day mainly South American, are represented by 
 two large European forms. One of these is the large Macro- 
 therium giganteum of the Upper Miocene of Gers in Southern 
 France, which appears to have been in many respects allied to 
 the existing Scaly Ant-eaters or Pangolins, at the same time 
 that the disproportionately long fore-limbs would indicate that 
 it possessed the climbing habits of the Sloths. The other is 
 the still more gigantic Ancyl'otherium Pentclici of the Upper 
 Miocene of Pikerme', which seems to have been as large as, or 
 larger than, the Rhinoceros, and which must have been terres- 
 trial in its habits. This conclusion is further borne out by the 
 comparative equality of length which subsists between the fore 
 and hind limbs, and is not affected by the curvature and 
 crookedness of the claws, this latter feature being well marked 
 in such existing terrestrial Edentates as the Great Ant-eater. 
 
 The aquatic Sirenians and Cetaceans are represented in 
 Miocene times by various forms of no special importance. 
 Amongst the former, the previously existing genus Halitherium 
 continued to survive, and amongst the latter we meet with 
 remains of Dolphins and of Whales of the "Zeuglodont" 
 family. We may also note here the first appearance of true 
 " Whalebone Whales," two species of which, resembling the 
 living " Right Whale" of Arctic seas, and belonging to the 
 same genus (Balcena), have been detected in the Miocene 
 beds of North America. 
 
 The great order of the Ungulates or Hoofed Quadrupeds is 
 very largely developed in strata of Miocene age, various new 
 types of this group making their appearance here for the first 
 time, whilst some of the characteristic genera of the preceding 
 period are still represented under new shapes. Amongst the 
 Odd-toed or " Perissodactyle " Ungulates, we meet for the first 
 time with representatives of the family Rhinocerida compris- 
 ing only the existing Rhinoceroses. In India in the Upper 
 Miocene beds of the Siwalik Hills, and in North America, 
 several species of Rhinoceros have been detected, agreeing with 
 the existing forms in possessing three toes to each foot, and in 
 having one or two solid fibrous "horns" carried upon the front 
 of the head. On the other hand, the forms of this group which 
 distinguish the Miocene deposits of Europe appear to have 
 been for the most part hornless, and to have resembled the 
 Tapirs in having three-toed hind-feet, but four-toed fore-feet.
 
 316 HISTORICAL PALEONTOLOGY. 
 
 The family of the Tapirs is represented, both in the Old 
 and New Worlds, by species of the genus Lophiodon, some of 
 which were quite diminutive in point of size, whilst others 
 attained the dimensions of a horse. Nearly allied to this 
 family, also, is the singular group of quadrupeds which Marsh 
 has described from the Miocene strata of the United States 
 under the name of Brontotheridcz. These extraordinary ani- 
 mals, typified by Brontotherium (fig. 243) itself, agree with the 
 
 Fig. 243. Skull of Brontotherium ing-ens. Miocene Tertiary, United States. 
 (After Marsh.) 
 
 existing Tapirs of South America and the Indian Archipelago 
 in having the fore-feet four-toed, whilst the hind-feet are three- 
 toed ; and a further point of resemblance is found in the fact 
 (as shown by the form of the nasal bones) that the nose was 
 long and flexible, forming a short movable proboscis or trunk, 
 by means of which the animal was enabled to browse on 
 shrubs or trees. They differ, however, from the Tapirs, not 
 only in the apparent presence of a long tail, but also in the 
 possession of a pair of very large " horn-cores," carried upon 
 the nasal bones, indicating that the animal possessed horns of 
 a similar structure to those of the "Hollow-horned" Rumin- 
 ants (e.g., Sheep and Oxen). Brontotherium gigas is said to be 
 nearly as large as an Elephant, whilst B. ingens appears to 
 have attained dimensions still more gigantic. The well-known 
 genus Titanotherium of the American Miocene would also 
 appear to belong to this group. 
 
 The family of the Horses (Equidce) appears under various 
 forms in the Miocene, but the most important and best known 
 of these is Hipparion. In this genus the general conformation 
 of the skeleton is extremely similar to that of the existing 
 Horses, and the external appearance of the animal must have 
 been very much the same. The foot of Hipparion, however,
 
 THE MIOCENE PERIOD. 317 
 
 as has been previously mentioned, differed from that of the 
 Horse in the fact that whilst both possess the middle toe greatly 
 developed and enclosed in a broad hoof, the former, in addition, 
 possessed two lateral toes, which were sufficiently developed 
 to carry hoofs, but were so far rudimentary that they hung idly 
 by the side of the central toe without touching the groirfid 
 (see fig. 230). In the Horse, on the other hand, these lateral 
 toes, though present, are not only functionally useless, but are 
 concealed beneath the skin. Remains of the Hipparion have 
 been found in various regions in Europe and in India ; and 
 from the immense quantities of their bones found in certain 
 localities, it may be safely inferred that these Middle Tertiary 
 ancestors of the Horses lived, like their modern representa- 
 tives, in great herds, and in open grassy plains or prairies. 
 
 Amongst the Even-toed or Artiodactvle Ungulates, we for 
 the first time meet with examples of the 'Hippopotamus, with its 
 four-toed feet, its massive body, and huge tusk-like lower 
 canine teeth. The Miocene deposits of Europe have not 
 hitherto yielded any remains of Hippopotamus ; but several 
 species have been detected in the Upper Miocene of the Siwalik 
 Hills by Dr Falconer and Sir Proby Cautley. These ancient 
 Indian forms, however, differ from the existing Hippopotamus 
 amphibius of Africa in the fact that they possessed six incisor 
 teeth in each jaw (fig. 244), whereas the latter has only four. 
 
 Amongst the other Even-toed Ungulates, the family of the 
 Pigs (Suida) is represented by true Swine (Sus Erymanthitis}, 
 Peccaries (Dicotyles anliquus), and by forms which, like the 
 great Elotherium of the American Miocene, have no represen- 
 tative at the present day. The Upper Miocene of India has 
 yielded examples of the Camels. Small Musk-deer (Amphi- 
 tragulus and Dretnotherium} are known to have existed in 
 France and Greece; and the true Deer ( Cervidce), with their 
 solid bony antlers, appear for the first time here in the person of 
 species allied to the living Stags (Ccrvus), accompanied by the 
 extinct genus Dorcatherinm. The Giraffes (Camelopardalidce), 
 now confined to Africa, are known to have lived in India and 
 Greece ; and the allied HelladotJicrium, in some repects inter- 
 mediate between the Giraffes and the Antelopes, ranged over 
 Southern Europe from Attica to France. The great group of 
 the "Hollow-horned" Ruminants (Cavicornia), lastly, came 
 into existence in the Miocene period ; and though the typical 
 families of the Sheep and Oxen are apparently wanting, there 
 are true Antelopes, together with forms which, if systemati- 
 cally referable to the Antilopidcz, nevertheless are more or less 
 clearly transitional between this and the family of the Sheep
 
 318 HISTORICAL PALAEONTOLOGY. 
 
 and Goats. Thus the Palceoreas of the Upper Miocene of 
 Greece may be regarded as a genuine Antelope ; but the 
 
 Fig. 244. a, Skull of Hippopotamus Sivalensis, viewed from below, one-eighth of the 
 natural size ; b, Molar tooth of the same, showing the surface of the crown, one-half of 
 the natural size ; c, Front of the lower jaw of the same, showing the six incisors and the 
 tusk-like canines, one-eighth of the natural size. Upper Miocene, Siwalik Hills. (After 
 Falconer and Cautley.) 
 
 Tragoceras of the same deposit is intermediate in its characters 
 between the typical Antelopes and the Goats. Perhaps the 
 most remarkable, however, of these Miocene Ruminants is the 
 Sivathcrium giganteum (fig. 245) of the Siwalik Hills, in India. 
 In this extraordinary animal there were two pairs of horns, 
 supported by bony " horn-cores," so that there can be no 
 hesitation in referring Sivatherium to the Cavicorn Rumin- 
 ants. If all these horns had been simple, there would have 
 been no difficulty in considering Sivathcriutn as simply a 
 gigantic four-horned Antelope, essentially similar to the living 
 Antilope (Tetraccros) quadricornis of India. The hinder pair 
 of horns, however, is not only much larger than the front pair, 
 but each possesses two branches or snags a peculiarity not to 
 be paralleled amongst any existing Antelope, save the abnormal 
 Prongbuck (Antilocaprd) of North America. Dr Murie, how- 
 ever, in an admirable memoir on the structure and relationships
 
 THE MIOCENE PERIOD. 
 
 319 
 
 of Sivafherium, has drawn attention to the fact that.the Prong- 
 buck sheds the sheath of its horns annually, and has suggested 
 
 Fig. 245. Skull of Sivatlieriuin gtgantenm, reduced in size. Miocene, India. 
 (After Murie.) 
 
 that this may also have been the case with the extinct form. 
 This conjecture is rendered probable, amongst other reasons, 
 by the fact that no traces of a horny sheath surrounding the 
 horn-cores of the Indian fossil have been as yet detected. 
 Upon the whole, therefore, we may regard the elephantine 
 Sivathenum as being most nearly allied to the Prongbuck of 
 Western America, and thus as belonging to the family of the 
 Antelopes. 
 
 It is to the Miocene period, again, to which we must refer 
 the first appearance of the important order of the tlephants 
 and their allies (Proboscideans), all of which are characterised by 
 their elongated trunk-like noses, the possession of five toes to 
 the foot, the absence of canine teeth, the development of two 
 or more of the incisor teeth into long tusks, and the adaptation 
 of the molar teeth to a vegetable diet. Only three generic 
 groups of this order are known namely, the extinct Deino- 
 therium, the equally extinct Mastodons, and the Elephants ; and 
 all these three types are known to have been in existence as
 
 32O HISTORICAL PALEONTOLOGY. 
 
 early as thq Miocene period, the first of them being exclusively 
 confined to deposits of this age. Of the three, the genus 
 Deinotherium is much the most abnormal in its characters ; 
 so much so, that good authorities regard it as really being one 
 of the Sea-cows (Sirenia) though this view has been rendered 
 untenable by the discovery of limb-bones which can hardly 
 belong to any other animal, and which are distinctly Probosci- 
 dean in type. The most celebrated skull of the Deinothere 
 (fig. 246) is one which was exhumed from the Upper Miocene 
 deposits of Epplesheim, in Hesse- 
 Darmstadt, in the year 1836. 
 This skull was four and a half 
 feet in length, and indicated an 
 animal larger than any existing 
 species of Elephant. The upper 
 jaw is destitute of incisor or 
 canine teeth, but is furnished on. 
 each side with five molars, which 
 are opposed to a corresponding 
 series of grinding teeth in the 
 lower jaw. No canines are pre- 
 sent in the lower jaw ; but the 
 front portion of the jaw is ab- 
 Fig. 246. skull of Deinotherium riiptly bent downwards, and car- 
 
 fhfupper'kfoc^of Germany. ^ ' rieS tWO huge tusk-like incisor 
 
 teeth, which are curved down- 
 wards and backwards, and the use of which is rather proble- 
 matical. Not only does the Deinothere occur in Europe, but 
 remains belonging to this genus have also been detected in the 
 Siwalik Hills, in India. 
 
 The true Elephants (Elephas) do not appear to have ex- 
 isted during the Miocene period in Europe, but several species 
 have been detected in the Upper Miocene deposits of the 
 Siwalik Hills, in India. The fossil forms, though in all cases 
 specifically, and in some cases even sub-generically, distinct, 
 agree with those now in existence in the general conformation 
 of their skeleton, and in the principal characters of their den- 
 tition. In all, the canine teeth are wanting in both jaws ; and 
 there are no incisor teeth in the lower jaw, whilst there are 
 two incisors in the front of the upper jaw, which are de- 
 veloped into two huge "tusks." There are six molar teeth 
 on each side of both the upper and lower jaw, but only 
 one, or at most a part of two, is in actual use at any given 
 time ; and as this becomes worn away, it is pushed forward 
 and replaced by its successor behind it. The molars are of
 
 THE MIOCENE PERIOD. 
 
 321 
 
 very large size, and are each composed of a number of trans- 
 verse plates of enamel united together by ivory ; and by the 
 
 Fig. 247. A, Molar tooth of Elephas planifrons, one-third of the natural size, show- 
 ing the grinding surface from the Upper Miocene of India ; B, Profile view of the 
 last upper molar of Mastodon Sivalensis, one-third of the natural size from the Upper 
 Miocene of India. (After Falconer.) 
 
 process of mastication, the teeth become worn down to a flat 
 surface, crossed by the enamel-ridges in varying patterns. 
 These patterns are different in the different species of Ele- 
 phants, though constant for each ; and they constitute one of 
 the most readily available means of separating the fossil 
 forms from one another! Of the seven Miocene Elephants 
 of India, as judged by the characters of the molar teeth, 
 two are allied to the existing Indian Elephant, one is related 
 to the living African Elephant, and the remaining four are in 
 some respects intermediate between the true Elephants and 
 the Mastodons. 
 
 The Mastodons, lastly, though quite elephantine in their
 
 322 HISTORICAL PALAEONTOLOGY. 
 
 general characters, possess molar teeth which have their crowns 
 furnished with conical eminences or tubercles placed in pairs 
 (fig. 247, B), instead of having the approximately flat surface 
 characteristic of the grinders of the Elephants. As in the 
 latter, there are two upper incisor teeth, which grow perma- 
 nently during the life of the animal, and which constitute great 
 tusks ; but the Mastodons, in addition, often possess two lower 
 incisors, which in some cases likewise grow into small tusks. 
 Three species of Mastodon are known to occur in the Upper 
 Miocene of the Siwalik Hills of India ; and the Miocene de- 
 posits of the European area have yielded the remains of four 
 species, of which the best known are the M. longirostris and the 
 M. angustidens. 
 
 Whilst herbivorous Quadrupeds, as we have seen, were 
 extremely abundant during Miocene times, and often attained 
 gigantic dimensions, Beasts of Prey (Carnivora) were by no 
 means wanting, most of the principal existing families of the 
 order being represented in deposits of this age. Thus, we find 
 aquatic Carnivores belonging to both the living groups of the 
 Seals and Walruses ; true Bears are wanting, but their place 
 is filled by the closely-allied genus Amphicyon, of which various 
 species are known ; Weasels and Otters were not unknown, 
 and the Hytznictis and Ictitherium of the Upper Miocene of 
 Greece are apparently intermediate between the Civet-cats and 
 the Hyasnas ; whilst the great Cats of subsequent periods are 
 more than adequately represented by the huge " Sabre-toothed 
 Tiger " (Mac hair odus), with its immense trenchant and serrated 
 canine teeth. 
 
 Amongst the Rodent Mammals, the Miocene rocks have 
 yielded remains of Rabbits, Porcupines (such as the Hystrix 
 primigenius of Greece), Beavers, Mice, Jerboas, Squirrels, and 
 Marmots. All the principal living groups of this order were 
 therefore differentiated in Middle Tertiary times. 
 
 The Cheiroptera are represented by small insect-eating Bats; 
 and the order of the Insectivorous Mammals is represented by 
 Moles, Shrew-mice, and Hedgehogs. 
 
 Lastly, the Monkeys (Quadrumana) appear to have existed 
 during the Miocene period under a variety of forms, remains 
 of these animals having been found both in Europe and in 
 India ; but no member of this order has as yet been detected 
 in the Miocene Tertiary of the North American continent. 
 Amongst the Old World Monkeys of the Miocene, the two 
 most interesting are the Pliopithccus and Dryopithecus of France. 
 The former of these (fig. 248) is supposed to' have been most 
 nearly related to the living Semnopitheci of Southern Asia, in
 
 THE PLIOCENE PERIOD. 323 
 
 which case it must have possessed a long tail. The Mcsopi- 
 thecus of the Upper Miocene of Greece is also one of the lower 
 
 Fig. 248. Lower jaw of Pliopithecus antiquns. Upper Miocene, France. 
 
 Monkeys, as it is most closely allied to the existing Macaques. 
 On the other hand, the Dryopithccus of the French Upper 
 Miocene is referable to the group of the "Anthropoid Apes," 
 and is most nearly related to the Gibbons of the present day, 
 in which the tail is rudimentary and there are no cheek- 
 pouches. Dryopithecus was, also, of large size, equalling Man 
 in stature, and apparently living amongst the trees and feed- 
 ing upon fruits. 
 
 CHAPTER XX. 
 
 THE PLIOCENE PERIOD. 
 
 The highest division of the Tertiary deposits is termed the 
 Pliocene formation, in accordance with the classification pro- 
 posed by Sir Charles Lyell. The Pliocene formations contain 
 from 40 to 95 per cent of existing species of Molhisca, the re- 
 maindes belonging to extinct species. They are divided by Sir 
 Charles Lyell into two divisions, the Older Pliocene and Newer 
 Pliocene. 
 
 The Pliocene deposits of Britain occur in Suffolk, and are 
 known by the name of " Crags," this being a local term used 
 for certain shelly sands, which are employed in agriculture. 
 Two of these Crags are referable to the Older Pliocene, viz.,
 
 324 HISTORICAL PALAEONTOLOGY. 
 
 the White and Red Crags, and one belongs to the Newer 
 Pliocene, viz., the Norwich Crag. 
 
 The White or Coralline Crag of Suffolk is the oldest of the 
 Pliocene deposits of Britain, and is an exceedingly local for- 
 mation, occurring in but a single small area, and having a 
 maximum thickness of not more than 50 feet. It consists of 
 soft sands, with occasional intercalations of flaggy limestone. 
 Though of small extent and thickness, the Coralline Crag is of 
 importance from the number of fossils which it contains. The 
 name " Coralline " is a misnomer ; since there are few true 
 Corals, and the so-called "Corals" of the formation are really 
 Polyzoa, often of very singular forms. The shells of the Coral- 
 line Crag are mostly such as inhabit the seas of temperate 
 regions ; but there occur some forms usually looked upon as 
 indicating a warm climate. 
 
 The Upper or Red Crag of Suffolk like the Coralline Crag 
 has a limited geographical extent and a small thickness, 
 rarely exceeding 40 feet. It consists of quartzose sands, usu- 
 ally deep red or brown in colour, and charged with numerous 
 fossils. 
 
 Altogether more than 200 species of shells are known from 
 the Red Crag, of which 60 per cent are referable to existing 
 species. The shells indicate, upon the whole, a temperate or 
 even cold climate, decidedly less warm than that indicated by 
 the organic remains of the Coralline Crag. It appears, there- 
 fore, that a gradual refrigeration was going on during the 
 Pliocene period, commencing in the Coralline Crag, becoming 
 intensified in the Red Crag, being still more severe in the 
 Norwich Crag, and finally culminating in the Arctic cold of the 
 Glacial period. 
 
 Besides the Mollusca, the Red Crag contains the ear-bones 
 of Whales, the teeth of Sharks and Rays, and remains of the 
 Mastodon, Rhinoceros, and Tapir. 
 
 The Newer Pliocene deposits are represented in Britain by 
 the Norwich Crag, a local formation occurring near Norwich. 
 It consists of incoherent sands, loams, and gravels, resting in 
 detached patches, from 2 to 20 feet in thickness, upon an 
 eroded surface of Chalk. The Norwich Crag contains a mix- 
 ture of marine, land, and fresh-water shells, with remains of 
 fishes and bones of mammals ; so that it must have been de- 
 posited as a local sea-deposit near the mouth of an ancient 
 river. It contains altogether more than 100 marine shells, 
 of which 89 per cent belong to existing species. Of the 
 Mammals, the two most important are an Elephant (Elep/ias 
 meridionalis), and the characteristic Pliocene Mastodon (M.
 
 THE PLIOCENE PERIOD. 325 
 
 Arvcrnensis), which is hitherto the only Mastodon found in 
 Britain. 
 
 According to the most recent views of high authorities, 
 certain deposits such as the so-called " Bridlington Crag " of 
 Yorkshire, and the " Chillesford beds " of Suffolk are to be 
 also included in the Newer Pliocene, upon the ground that 
 they contain a small proportion of extinct shells. Our know- 
 ledge, however, of the existing Mclluscan fauna, is still so far 
 incomplete, that it may reasonably be doubted if these sup- 
 posed extinct forms have actually made their final disappear- 
 ance, whilst the strata in question have a strong natural con- 
 nection with the " Glacial deposits," as shown by the number 
 of Arctic Mollusca which they contain. Here, therefore, these 
 beds will be included in the Post-Pliocene series, in spite of 
 the fact that some of their species of shells are not known to 
 exist at the present day. 
 
 The following are the more important Pliocene deposits 
 which have been hitherto recognised out of Britain: 
 
 1. In the neighbourhood of Antwerp occur certain "crags," 
 which are the equivalent of the White and Red Crag in part. 
 The lowest of these contains less than 50 per cent, and the 
 highest 60 per cent, of existing species of shells, the remainder 
 being extinct. 
 
 2. Bordering the chain of the Apennines, in Italy, on both 
 sides is a series of low hills made up of Tertiary strata, which 
 are known as the Sub-Apennine beds. Part of these is of 
 Miocene age, part is Older Pliocene, and a portion is Newer 
 Pliocene. The Older Pliocene portion of the Sub-Apennines 
 consists of blue or brown marls, which sometimes attain a 
 thickness of 2000 feet. 
 
 3. In the valley of the Arno, above Florence, are both 
 Older and Newer Pliocene strata. The former consist of blue 
 clays and lignites, with an abundance of plants. The latter 
 consist of sands and conglomerates, with remains of large Car- 
 nivorous Mammals, Mastodon, Elephant, Rhinoceros, Hippo- 
 potamus, &c. 
 
 4. In Sicily, Newer Pliocene strata are probably more largely 
 developed than anywhere else in the world, rising sometimes 
 to a height of 3000 feet above the sea. The series consists 
 of clays, marls, sands, and conglomerates, capped by a com- 
 pact limestone, which attains a thickness of from 700 to 800 
 feet The fossils of these beds belong almost entirely to living 
 species, one of the commonest being the Great Scallop of the 
 Mediterranean (Pecten Jacobans). 
 
 5. Occupying an extensive area round the Caspian, Aral,
 
 326 HISTORICAL PALAEONTOLOGY. 
 
 and Azof Seas, are Pliocene deposits known as the " Aralo- 
 Caspian " beds. The fossils in these beds are partly fresh- 
 water, partly marine, and partly intermediate in character, and 
 they are in great part identical with species now inhabiting 
 the Caspian. The entire formation appears to indicate the 
 former existence of a great sheet of brackish water, forming an 
 inland sea, like the Caspian, but as large as, or larger than, the 
 Mediterranean. 
 
 6. In the United States, strata of Pliocene age are found in 
 North and South Carolina. They consist of sands and clays, 
 with numerous fossils, chiefly Molluscs and Echinoderms. 
 From 40 to 60 per cent of the fossils belong to existing 
 species. On the Loup Fork of the river Platte, in the Upper 
 Missouri region, are strata which are also believed to be refer- 
 able to the Pliocene period, and probably to its upper division. 
 They are from 300 to 400 feet thick, and contain land-shells, 
 with the bones of numerous Mammals, such as Camels, Rhino- 
 ceroses, Mastodons, Elephants, the Horse, Stag, &c. 
 
 As regards the life of the Pliocene period, there are only 
 two classes of organisms to which our attention need be 
 directed namely, the Shell-fish and the Mammals. So far as 
 the former are concerned, we have to note in the first place 
 that the introduction of new species of animals upon the globe 
 went on rapidly during this period. In the Older Pliocene 
 deposits, the number of shells of existing species is only from 
 40 to 60 per cent; but in the Newer Pliocene the pro- 
 portion of living forms rises to as much as from 80 to 
 95 per cent. Whilst the Molluscs thus become rapidly mo- 
 dernised, the Mammals still all belong to extinct species, 
 though modern generic types gradually supersede the more 
 antiquated forms of the Miocene. In the second place, there 
 is good evidence to show that the Pliocene period was one in 
 which the climate of the northern hemisphere underwent a 
 gradual refrigeration. In the Miocene period, there is evi- 
 dence to show that Europe possessed a climate very similar 
 to that now enjoyed by the Southern United States, and cer- 
 tainly very much warmer than it is at present. The presence 
 of Palm-trees upon the land, and of numerous large Cowries, 
 Cones, and other shells of warm regions in the sea, sufficiently 
 proves this. In the Older Pliocene deposits, on the o'ther 
 hand, northern forms predominate amongst the Shells, though 
 some of the types of hotter regions still survive. In the Newer 
 Pliocene, again, the Molluscs are such as almost exclusively 
 inhabit the seas of temperate or even cold regions ; whilst if 
 we regard deposits like the " Bridlington Crag" and "Chilles-
 
 THE PLIOCENE PERIOD. 327 
 
 ford beds " as truly referable to this period, we meet at the 
 close of this period with shells such as nowadays are distinct- 
 ively characteristic of high latitudes. It might be thought 
 that the occurrence of Quadrupeds such as the Elephant, 
 Rhinoceros, and Hippopotamus, would militate against this 
 generalisation, and would rather support the view that the 
 climate of Europe and the United States must have been a 
 hot one during the later portion of the Pliocene period. We 
 have, however, reason to believe that many of these extinct 
 Mammals were more abundantly furnished with hair, and more 
 adapted to withstand a cool temperature, than any of their 
 living congeners. We have also to recollect that many of 
 these large herbivorous quadrupeds may have been, and 
 indeed probably were, more or less migratory in their habits ; 
 and that whilst the winters of the later portion of the Pliocene 
 period were cold, the summers might have been very hot. 
 This would allow of a northward migration of such terrestrial 
 animals during the summer-time, when there would be an 
 ample supply of food and a suitably high temperature, and a 
 southward recession towards the approach of winter. 
 The chief palaeontological interests of the Pliocene deposits, 
 as of the succeeding Post-Pliocene, centre round the Mammals 
 of the period ; and amongst the many forms of these we may 
 restrict our attention to the orders of the Hoofed Quadrupeds 
 ( Ungulates], the Proboscideans, the Carnivora, and the Quad- 
 rumana. Almost all the other Mammalian orders are more 
 or less fully represented in Pliocene times, but none of them 
 attains any special interest till we enter upon the Post-Pliocene. 
 Amongst the Odd-toed Ungulates, in addition to the remains 
 of true Tapirs ( Tapirus Arveriicnsis\ we meet with the bones 
 of several species of Rhinoceros, of which the Rhinoceros Etrus- 
 cus and R. megarhinus (fig. 249) are the most important. The 
 former of these (fig. 249, A) derives its specific name from its 
 abundance in the Pliocene deposits of the Val d'Arno, near 
 Florence, and though principally Pliocene in its distribution, 
 it survived into the earlier portion of the Post-Pliocene period. 
 Rhinoceros Etruscus agreed with the existing African forms in 
 having two horns placed one behind the other, the front one 
 being the longest ; but it was comparatively slight and slender 
 in its build, whilst the nostrils were separated by an incom- 
 plete bony partition. In the Rhinoceros megarhinus (fig. 249, 
 B), on the other hand, no such partition exists between the 
 nostrils, and the nasal bones are greatly developed in size. It 
 was a two-horned form, and is found associated with Elephas 
 meridionalis and E. antiqiiits in the Pliocene deposits of the
 
 32; 
 
 HISTORICAL PALAEONTOLOGY. 
 
 Val d'Arno, near Florence. Like the preceding, it survived, 
 in diminished numbers, into the earlier portion of the Post- 
 Pliocene period. 
 
 The Horses (Equidce) are represented, both in Europe and 
 
 Fig. 249. A, Under surface of the skull of Rhinoceros Etniscus, one-seventh of the 
 natural size Pliocene, Italy ; B, Crowns of the three true molars of the upper jaw, left 
 side, of Rhinoceros megarhinus (R. leptorhinus, Falconer), one-half of the natural size 
 Pliocene, France. (After Falconer.) 
 
 America, by the three-toed Hipparions, which survive from the 
 Miocene, but are now verging upon extinction. For the first 
 time, also, we meet with genuine Horses (Equus), in which 
 each foot is provided with a single complete toe only, encased 
 in a single broad hoof. One of the American species of this 
 period (the Equus excelsus) quite equalled the modern Horse 
 in stature ; and it is interesting to note the occurrence of indi- 
 genous horses in America at such a comparatively late geo- 
 logical epoch, seeing that this continent certainly possessed 
 none of these animals when first discovered by the Spaniards. 
 Amongst the Even-toed Ungulates, we may note the occur-
 
 THE PLIOCENE PERIOD. 329 
 
 rence of Swine (Snida), of forms allied to the Camels (Caniel- 
 ida), and of various kinds of Deer (Cervidce) ; but the most 
 interesting Pliocene Mammal belonging to this section is the 
 great Hippopotamus major of Britain and Europe. This well- 
 known species is very closely allied to the living Hippopotamus 
 amphibius of Africa, from which it is separated only by its 
 larger dimensions, and by certain points connected with the 
 conformation of the skeleton. It is found very abundantly in 
 the Pliocene deposits of Italy and France, associated with the 
 remains of the Elephant, Mastodon, and Rhinoceros, and it 
 survived into the earlier portion of the Post-Pliocene period. 
 During this last-mentioned period, it extended its range north- 
 wards, and is found associated with the Reindeer, the Bison, 
 and other northern animals. From this fact it has been infer- 
 red, with great probability, that the Hippopotamus major was 
 furnished with a long coat of hair and fur, thus differing from 
 its nearly hairless modern representative, and resembling its 
 associates, the Mammoth and the Woolly Rhinoceros. 
 
 Passing on to the Pliocene Proboscideans, we find that the 
 great Deinotheria of the Miocene have now wholly disappeared, 
 and the sole representatives of the order are Mastodons and 
 Elephants. The most important member of the former group 
 is the Mastodon Arvcrnensis (fig. 250), which ranged widely 
 
 250. Third milk-molar of the left side of the upper jaw of Mastodon 
 Arvemensis, showing the grinding surface. Pliocene. 
 
 over Southern Europe and England, being generally associated 
 with remains of the Elcphas meridionalis, E. antiquus, Rhino- 
 ceros megarhimis, and Hippopotamus major. The lower jaw 
 seems to have been destitute of incisor teeth ; but the upper 
 incisors are developed into great tusks, which sometimes reach
 
 330 HISTORICAL PALAEONTOLOGY, 
 
 a length of nine feet, and which have the simple curvature of 
 the tusks of the existing Elephants. Amongst the Pliocene 
 Elephants the two most important are the Elephas meridionalis 
 and the Elephas antiquus. Of these, the Elephas meridionalis 
 (fig. 251) is found abundantly in the Pliocene deposits of 
 
 Fig. 251. Molar tooth of Elephas meridionalis, one-third of the natural size. 
 Pliocene and Post-Pliocene. 
 
 Southern Europe and England, and also survived into the 
 earlier portion of the Post- Pliocene period. Its molar teeth 
 are of the type of those of the existing African Elephant, the 
 spaces enclosed by the transverse enamel-plates being more 
 or less lozenge-shaped, whilst the curvature of the tusks is 
 simple. The Elephas antiquus (fig. 252) is very generally 
 
 Fig. 252. Molar tooth of Elephas 'antiquns, one-third of the natural size. 
 Pliocene and Post-Pliocene. 
 
 associated with the preceding, and it survived to an even 
 later stage of the Post-Pliocene period. The molar teeth are 
 of the type of the existing Indian Elephant, with compara- 
 tively thin enamel-ridges, placed closer together than in the 
 African type ; whilst the tusks were nearly straight. 
 
 Amongst the Pliocene Carnivores, we meet with true Bears 
 ( Ursus Arvernensis\ Hyaenas (such as Hytzna Hipparionum\ 
 and genuine Lions (such as the Pel is angustus of North 
 America) ; but the most remarkable of the beasts of prey of
 
 THE PLIOCENE PERIOD. 
 
 331 
 
 this period is the great " Sabre-toothed Tiger" (Afachairodus), 
 species of which existed in the earlier Miocene, and survived 
 to the later Post-Pliocene. In this remarkable form we are 
 presented with perhaps the most highly carnivorous type of 
 all known beasts of prey. Not only aie the jaws shorter in 
 proportion even than those of the great Cats of the present 
 day, but the canine teeth (fig. 253) are of enormous size, 
 
 Fig. 253. A, Skull of Machatrodns ciilMdetis, without the lower jaw, reduced in 
 size ; B, Canine tooth of the same, one-half the natural size. Pliocene, France. 
 
 greatly flattened so as to assume the form of a poignard, and 
 having their margins finely serrated. Apart from the charac- 
 ters of the skull, the remainder of the skeleton, so far as known, 
 exhibits proofs that the Sabre-toothed Tiger was extraordi- 
 narily muscular and powerful, and in the highest degree adapt- 
 ed for a life of rapine. Species of Machairodus must have 
 been as large as the existing Lion ; and the genus is not only 
 European, but is represented both in South America and in 
 India, so that the geographical range of these predaceous 
 beasts must have been very extensive. 
 
 Lastly, we may note that the Pliocene deposits of Europe 
 have yielded the remains of Monkeys (Qiuadrumana\ allied to 
 the existing Scmnopitkeci and Macaques.
 
 332 HISTORICAL PALEONTOLOGY. 
 
 LITERATURE. 
 
 The following list comprises a small selection of some of the more im- 
 j ortant and readily accessible works and memoirs relaf 
 rocks and their fossils. With few exceptions, foreign 
 
 portant and readily accessible works and memoirs relating to the Tertiary 
 rocks and their fossils. With few exceptions, foreign works relating to 
 the Tertiary strata of the continent of Europe or their organic remains 
 
 have been omitted : 
 
 (1) 'Elements of Geology.' Lyell. 
 
 (2) 'Students' Elements of Geology.' Lyell. 
 
 (3) 'Manual of Paleontology.' Owen. 
 
 (4) 'British Fossil Mammals and Birds.' Owen. 
 
 (5) 'Traite de Paleontologie.' Pictet. 
 
 (6) ' Cours Elemenlaire de Paleontologie. ' D'Orbigny. 
 
 (7) "Probable Age of the London Clay," &c. 'Quart. Journ. Geol. 
 
 Soc.,' vol. iii. Prestwich. 
 
 (8) ' Structure and Probable Age of the Bagshot Sands' Ibid., vol. iii. 
 
 Prestwich. 
 
 (9) 'Tertiary Formations of the Isle of Wight' Ibid., vol. ii. Prest- 
 
 wich. 
 
 (10) 'Structure of the Strata between the London Clay and the Chalk,' 
 
 &c. Ibid., vols. vi., viii., and x. Prestwich. 
 
 (11) 'Correlation of the Eocene Tertiaries of England, France, and 
 
 Belgium' Ibid., vol. xxvii. Prestwich. 
 
 (12) 'On the Fluvio-marine Formations of the Isle of Wight ' Ibid., 
 
 vol. ix. Edward Forbes. 
 
 (13) 'Newer Tertiary Deposits of the Sussex Coast' Ibid., vol. xiii. 
 
 Godwin-Austen. 
 
 (14) 'Kainozoic Formations of Belgium' Ibid., vol. xxii. Godwin- 
 
 Austen. 
 
 (15) 'Tertiary Strata of Belgium and French Flanders ' Ibid., vol. viii. 
 
 Lyell. 
 
 (16) 'On Tertiary Leaf-beds in the Isle of Mull' Ibid., vol. vii. The 
 
 Duke of Argyll. 
 
 (17) 'Newer Tertiaries of Suffolk and their Fauna' Ibid., vol. xxvi. 
 
 Ray Lankester. 
 
 (18) ' Lower London Tertiaries of Kent ' Ibid., vol. xxii. Whitaker. 
 
 (19) "Guide to the Geology of London " 'Mem. Geol. Survey.' 
 
 Whitaker. 
 
 (20) ' Memoirs of the Geological Survey of Great Britain.' 
 
 (21) 'Introductory Outline of the Geology of the Crag District' (Sup- 
 
 plement to Crag Mollusca, Palreontographical Society). S. V. 
 Wood, jun., and F. W. Harmer. 
 
 (22) "Tertiary Fluvio-marine Deposits of the Isle of Wight." Edward 
 
 Forbes. Edited by Godwin-Austen ; with Descriptions of the 
 Fossils by Morris, Salter, and Rupert Jones ' Memoirs of the 
 Geological Survey.' 
 
 (23) 'Geological Excursions round the Isle of Wight.' Mantell. 
 
 (24) 'Catalogue of British Fossils.' Morris. 
 
 (25) 'Catalogue of Fossils in the Museum of Practical Geology.' Ethe- 
 
 ridge. 
 
 (26) 'Monograph of the Crag Polyz.oa' (Palreontographical Society). Busk. 
 (27) 'Monograph of the Tertiary Brachiopoda ' (Ibid.) Davidson. 
 
 (28) 'Monograph of the Tertiary Malacostracous Crustacea' (Ibid.) 
 Bell.
 
 THE PLIOCENE PERIOD. 333 
 
 (29) 'Monograph of the Tertiary Corals' (Ibid.) Milne-Edwards a;id 
 
 Haime. 
 
 (30) ' Supplement to the Tertiary Corals ' (Ibid.) Martin Duncan. 
 
 (31) 'Monograph of the Eocene Mollusca' (Ibid.) Fred. E. Edwards. 
 
 (32) ' Monograph of the Eocene Mollusca ' (Ibid.) Searles V. Wood. 
 
 (33) ' Monograph of the Crag Mollusca' (Ibid.) Searles V. Wood. 
 
 (34) 'Monograph of the Tertiary Entomostraca' (Ibid.) Rupert Jones. 
 
 (35) ' Monograph of the Foraminifera of the Crag' (Ibid.) Rupert Jones, 
 
 Parker, and H. B. Brady. 
 
 (36) ' Monograph of the Radiaria of the London Clay ' (Ibid.) Edward 
 
 Forbes. 
 
 (37) ' Monograph of the Cetacea of the Red Crag ' (Ibid. ) Owen. 
 
 (38) 'Monograph of the Fossil Reptiles of the London Clay' (Ibid.) 
 
 Owen and Bell. 
 
 (39) " On the Skull of a Dentigerous Bird from the London Clay of 
 
 Sheppey"' Quart. Journ. Geol. Soc.,' vol. xxix. Owen. 
 
 (40) 'Ossemens Fossiles.' Cuvier. 
 
 (41) ' Fauna Antiqua Sivalensis.' Falconer and Sir Proby Cautley. 
 
 (42) ' Palasontological Memoirs.' Falconer. 
 
 (43) ' Animaux Fossiles et Geologic de 1'Attique.' Gaudry. 
 
 (44) "Principal Characters of the Dinocerata'' 'American Journ. of 
 
 Science and Arts,' vol. xi. Marsh. 
 
 (45) 'Principal Characters of the Brontotheridse ' (Ibid.) Marsh. 
 
 (46) ' Principal Characters of the Tillodontia ' (Ibid. ) Marsh. 
 
 (47) "Extinct Vertebrata of the Eocene of Wyoming" 'Geological 
 
 Survey of Montana,' &c., 1872. Cope. 
 
 (48) "Ancient Fauna of Nebraska'' ' Smithsonian Contributions to 
 
 Knowledge,' vol. vi. Leidy. 
 
 (49) 'Manual of Geology.' Dana. 
 
 (50) "Palaeontology and Evolution" (Presidential Address to the 
 
 Geological Society of London, 1870) 'Quart. Journ. Geol. 
 Soc.,' vol. xxvi. Huxley. 
 
 (51) 'Mineral Conchology.' Sowerby. 
 
 (52) 'Description des Coquilles Fossiles,' &c. Deshayes. 
 
 (53) 'Description des Coquilles Tertiaires de Belgique.' Nyst. 
 
 (54) ' Fossilen Polypen des Wiener Tertiar-beckens. ' Reuss. 
 
 (55) ' Palseontologlsche Studien Uber die alteren Tertiar-schichten der 
 
 Alpen.' Reuss. 
 
 (56) 'Land und Siiss-wasser Concliylien der Vorwelt.' Sandberger. 
 
 (57) ' Flora Tertiaria Helvetica.' Heer. 
 
 (58) 'Flora Fossilis Arctica.' Heer. 
 
 (59) ' Recherches sur le Climat et la Vegetation du Pays Tertiaire.' Heer. 
 
 (60) 'Fossil Flora of Great Britain.' Lindley and Hutton. 
 
 (61) * Fossil Fruits and Seeds of the London Clay. ' Bowerbank. 
 
 (62) "Tertiary Leaf-beds of the Isle of Mull" 'Quart. Journ. Geol. 
 
 Soc.,' vol. vii. Edward Forbes. 
 
 (63) ' The Geology of England and Wales.' Horace B. Woodward.* 
 
 * This work published whilst these sheets were going through the press gives to the 
 Student a detailed view of all the strata of England and Wales, with their various sub- 
 divisions, from the base of the Palxozoic to the top of the Tertiary.
 
 334 HISTORICAL PALAEONTOLOGY. 
 
 CHAPTER XXI. 
 
 THE QUATERNARY PERIOD. 
 
 THE POST-PLIOCENE PERIOD. 
 
 Later than any of the Tertiary formations are various de- 
 tached and more or less superficial accumulations, which are 
 generally spoken of as the Post- Tertiary formations, in accord- 
 ance with the nomenclature of Sir Charles Lyell or as the 
 Quaternary formations, in accordance with the general usage 
 of Continental geologists. In all these formations we meet 
 with no Mollusca except such as are now alive with the 
 partial and very limited exception of some of the oldest de- 
 posits of this period, in which a few of the shells occasionally 
 belong to species not known to be in existence at the pre- 
 sent day. Whilst the Shell-fish of the Quaternary deposits are, 
 generally speaking, identical with existing forms, the Mammals 
 are sometimes referable to living, sometimes to extinct species. 
 In accordance with this, the Quaternary formations are divided 
 into two groups : (i) The Post-Pliocene, in which the shells are 
 almost invariably referable to existing species, but some of the 
 Mammals are extinct ; and (2) the Recent, in which the shells 
 and the Mammals alike belong to existing species. The Post- 
 Pliocene deposits are often spoken of as the Pleistocene forma- 
 tions (Gr. pleistos, most; kainos, new or recent), in allusion to 
 the fact that the great majority of the living beings of this 
 period belong to the species characteristic of the " new " or 
 Recent period. 
 
 The Recent deposits, though of the highest possible interest, 
 do not properly concern the palaeontologist strictly so-called, 
 but the zoologist, since they contain the remains of none but 
 existing animals. They are " Pre-historic," but they belong 
 entirely to the existing terrestrial order. The Post '- Pliocene 
 deposits, on the other hand, contain the remains of various 
 extinct Mammals ; and though Man undoubtedly existed in, 
 at any rate, the later portion of this period, if not through- 
 out the whole of it, they properly form part of the domain of 
 the palaeontologist. 
 
 The Post-Pliocene deposits are extremely varied, and very 
 widely distributed ; and owing to the mode of their occurrence, 
 the ordinary geological tests of age are in their case but very 
 partially available. The subject of the classification of these
 
 THE QUATERNARY PERIOD. 335 
 
 deposits is therefore an extremely complicated one ; and as 
 regards the age of even some of the most important of them, 
 there still exists considerable difference of opinion. For our 
 present purpose, it will be convenient to adopt a classifica- 
 tion of the Post-Pliocene deposits founded on the relations 
 which they bear in time to the great " Ice-age " or " Glacial 
 period;" though it is not pretended that our present know- 
 ledge is sufficient to render such a classification more than a 
 provisional one. 
 
 In the early Tertiary period, as we have seen, the climate of 
 the northern hemisphere, as shown by the Eocene animals and 
 plants, was very much hotter than it is at present partaking, 
 indeed, of a sub-tropical character. In the Middle Tertiary or 
 Miocene period, the temperature, though not so high, was still 
 much warmer than that now enjoyed by the northern hemi- 
 sphere ; and we know that the plants of temperate regions at 
 this time flourished within the Arctic circle. In the later 
 Tertiary or Pliocene period, again, there is evidence that the 
 northern hemisphere underwent a further progressive diminu- 
 tion of temperature ; though the climate of Europe generally 
 seems at the close of the Tertiary period to have been if any- 
 thing warmer, or at any rate not colder, than it is at the present 
 day. With the commencement of the Quaternary period, 
 however, this diminution of temperature became more de- 
 cided ; and beginning with a temperate climate, we find the 
 greater portion of the northern hemisphere to become gradu- 
 ally subjected to all the rigours of intense Arctic cold. All 
 the mountainous regions of Northern and Central Europe, of 
 Britain, and of North America, became the nurseries of huge 
 ice-streams, and large areas of the land appear to have been 
 covered with a continuous ice-sheet. The Arctic conditions of 
 this, the well-known " Glacial period," relaxed more than once, 
 and were more than once re-established with lesser intensity. 
 Finally, a gradual but steadily progressive amelioration of tem- 
 perature took place ; the ice slowly gave way, and ultimately 
 disappeared altogether; and the climate once more became 
 temperate, except in high northern latitudes. 
 
 The changes of temperature sketched out above took place 
 slowly and gradually, and occupied the whole of the Post- 
 Pliocene period. In each of the three periods marked out by 
 these changes in the early temperate, the central cold, and 
 the later temperate period certain deposits were laid down 
 over the surface of the northern hemisphere ; and these de- 
 posits collectively constitute the Post- Pliocene formations. 
 Hence we may conveniently classify all the accumulations of
 
 336 HISTORICAL PALEONTOLOGY. 
 
 this age under the heads of (i) Pre-Glacial deposits, (2) Glacial 
 deposits, and (3) Post-Glacial deposits, according as they were 
 formed before, during, or after the " Glacial period." It can- 
 not by any means be asserted that we can definitely fix the 
 precise relations in time of all the Post-Pliocene deposits to the 
 Glacial period. On the contrary, there are some which hold a 
 very disputed position as regards this point; and there are 
 others which do not admit of definite allocation in this manner 
 at all, in consequence of their occurrence in regions where no 
 " Glacial Period " is known to have been established. For 
 our present purpose, however, dealing as we shall have to do 
 principally with the northern hemisphere, the above classifi- 
 cation, with all its defects, has greater advantages than any 
 other that has been yet proposed. 
 
 I. PRE-GLACIAL DEPOSITS. The chief pre glacial deposit of 
 Britain is found on the Norfolk coast, reposing upon the Newer 
 Pliocene (Norwich Crag), and consists of an ancient land-sur- 
 face which is known as the " Cromer Forest-bed." 
 
 This consists of an ancient soil, having embedded in it the 
 stumps of many trees, still in an erect position, with remains 
 of living plants, and the bones of recent and extinct quadru- 
 peds. It is overlaid by fresh-water and marine beds, all the 
 shells of which belong to existing species, and it is finally sur- 
 mounted by true "glacial drift." While all the shells and 
 plants of the Cromer Forest-bed and its associated strata belong 
 to existing species, the Mammals are partly living, partly ex- 
 tinct. Thus we find the existing Wolf (Cants lupus), Red 
 Deer (Cennts claphus), Roebuck (Cennis capreolus), Mole 
 (Talpa Europcea}, and Beaver (Castor fiber), living in western 
 England side by side with the Hippopotamus major, ElcpJias 
 antiquus, Elephas meridionalis, Rhinoceros Etruscus, and R. 
 megarhinus of the Pliocene period, which are not only extinct, 
 but imply an at any rate moderately warm climate. Besides 
 the above, the Forest-bed has yielded the remains of several 
 extinct species of Deer, of the great extinct Beaver (Trogon- 
 therium Cuvierz), of the Caledonian Bull or " Urus " (Bos 
 primigenius\ and of a Horse (Equus fossilis), little if at all 
 distinguishable from the existing form. 
 
 The so called " Bridlington Crag" of Yorkshire, and the 
 " Chillesford Beds " of Suffolk, are probably to be regarded as 
 also belonging to this period; though many of the shells which 
 they contain are of an Arctic character, and would indicate 
 that they were deposited in the commencement of the Glacial 
 period itself. Owing, however, to the fact that a few of the 
 shells of these deposits are not known to occur in a living con-
 
 THE QUATERNARY PERIOD. 337 
 
 dition, these, and some other similar accumulations, are some- 
 times considered as referable to the Pliocene period. 
 
 II. GLACIAL DEPOSITS. Under this head is included a 
 great series of deposits which are widely spread over both 
 Europe and America, and which were formed at a time when 
 the climate of these countries was very much colder than it is 
 at present, and approached more or less closely to what we see 
 at the present day in the Arctic regions. These deposits are 
 known by the general name of the Glacial deposits, or by the 
 more specialised names of the Drift, the Northern Drift, the 
 Boulder-clay, the Till, c. 
 
 These glacial deposits are found in Britain as far south as 
 the Thames, over the whole of Northern Europe, in all the 
 more elevated portions of Southern and Central Europe, and 
 over the whole of North America, as far south as the 39th 
 parallel. They generally occur as sands, clays, and gravels, 
 spread in widely-extended sheets over all the geological forma- 
 tions alike, except the most recent, and are 'commonly spoken 
 of under the general term of " Glacial drift." They vary much 
 in their exact nature in different districts, but they universally 
 consist of one, or all, of the following members : 
 
 1. Unstratified clays, or loams, containing numerous angular 
 or sub-angular blocks of stone, which have often been trans- 
 ported for a greater or less distance from their parent rock, 
 and which often exhibit polished, grooved, or striated surfaces. 
 These beds are what is called Boulder-clay, or Till. 
 
 2. Sands, gravels, and clays, often more or less regularly 
 stratified, but containing erratic blocks, often of large size, and 
 with their edges unworn, derived from considerable distances 
 from the place where they are now found. In these beds it is 
 not at all uncommon to find fossil shells; and these, though of 
 existing species, are generally of an Arctic character, compris- 
 ing a greater or less number of forms which are now exclusively 
 found in the icy waters of the Arctic seas. These beds are 
 often spoken of as " Stratified Drift." 
 
 3. Stratified sands and gravels, in which the pebbles are 
 worn and rounded, and which have been produced by a re- 
 arrangement of ordinary glacial beds by the sea. These beds 
 are commonly known as " Drift-gravels," or " Regenerated 
 Drift." 
 
 Some of the last-mentioned of these are doubtless post- 
 glacial ; but, in the absence of fossils, it is often impossible to 
 arrive at a positive opinion as to the precise age of superficial 
 accumulations of this nature. It is also the opinion of high 
 authorities that a considerable number of the so-called " cave-
 
 338 HISTORICAL PALEONTOLOGY. 
 
 deposits," with the bones of extinct Mammals, truly belong to 
 the Glacial period, being formed during warm intervals when 
 the severity of the Arctic cold had become relaxed. It is 
 further believed that some, at any rate, of the so-called "high- 
 level " river-gravels and " brick-earths " have likewise been 
 deposited during mild or warm intervals in the great age of 
 ice ; and in two or three instances this has apparently been 
 demonstrated deposits of this nature, with the bones of ex- 
 tinct animals and the implements of man, having been shown 
 to be overlaid by true Boulder-clay. 
 
 The fossils of the undoubted Glacial deposits are principally 
 shells, which are found in great numbers in certain localities, 
 sometimes with Foraminifera, the bivalved cases of Ostracode 
 Crustaceans, &c. Whilst some of the shells of the "Drift" 
 are such as now live in the seas of temperate regions, others, 
 as previously remarked, are such as are now only known to 
 live in the seas of high latitudes ; and these therefore afford 
 unquestionable evidence of cold conditions. Amongst these 
 Arctic forms of shells which characterise the Glacial beds 
 may be mentioned Pecten Islandicus (fig. 254), Pecten Grcen- 
 
 Fig. 254. Left valve of Fccten Islandicns. Glacial and Recent. 
 
 landicus, Scalaria GroenJandica, Leda truncata, Astarte borealis, 
 Tellina proxima, Natlca clausa, &c. 
 
 III. POST-GLACIAL DEPOSITS. As the intense cold of the 
 Glacial period became gradually mitigated, and temperate
 
 THE QUATERNARY PERIOD. 339 
 
 conditions of climate were once more re-established, various 
 deposits were formed in the northern hemisphere, which are 
 found to contain the remains of extinct Mammals, and which, 
 therefore, are clearly of Post-Pliocene age. To these deposits 
 the general name of Post-Glacial formations is given ; but it is 
 obvious that, from the nature of the case, and with our present 
 limited knowledge, we cannot draw a rigid line of demarcation 
 between the deposits formed towards the close of the Glacial 
 period, or during warm " interglacial" periods, and those laid 
 down after the ice had fairly disappeared. Indeed it is ex- 
 tremely improbable that any such rigid line of demarcation 
 should ever have existed ; and it is far more likely that the 
 Glacial and Post-Glacial periods, and their corresponding de- 
 posits, shade into one another by an imperceptible gradation. 
 Accepting this reservation, we may group together, under the 
 general head of " Post-Glacial Deposits," most of the so-called 
 " Valley- gravels," " Brick - earths," and " Cave - deposits," to- 
 gether with some "rai ed beaches" and various deposits of 
 peat. Though not strictly within the compass of this work, 
 a few words may be said here as to the origin and mode 
 of formation of the Brick-earths, Valley-gravels, and Cave- 
 deposits, as the subject will thus be rendered more clearly 
 intelligible. 
 
 Every river produces at the present day beds of fine mud 
 and loam, and accumulations of gravel, which it deposits at 
 various parts of its course the gravel generally occupying the 
 lowest position, and the finer sands and mud coming above. 
 Numerous deposits of a similar nature are found in most 
 countries in various localities, and at various heights above 
 the present channels of our rivers. Many of these fluviatile 
 ( Lat. fluvius, a river) deposits consist of fine loam, worked for 
 brick-making, and known as " Brick-earths ;" and they have 
 yielded the remains of numerous extinct Mammals, of which 
 the Mammoth {Elephas primigenius) is the most abundant. 
 In the valley of the Rhine these fluviatile loams (known as 
 " Loess ") attain a thickness of several hundred feet, and con- 
 tain land and fresh-water shells of existing species. With 
 these occur the remains of Mammals, such as the Mammoth 
 and Woolly Rhinoceros. Many of these Brick -earths are 
 undoubtedly Post-Glacial, but others seem to be clearly "inter- 
 glacial ; " and instances have recently been brought forward in 
 which deposits of Brick-earth containing bones and shells of 
 fresh-water Molluscs have been found to be overlaid by regu- 
 lar unstratified boulder-clay. 
 
 The so-called "Valley-gravels," like the Brick-earths, are
 
 340 
 
 HISTORICAL PAL/EONTOLOGY. 
 
 fluviatile deposits, but are of a coarser nature, consisting of 
 sands and gravels. Every river gives origin to deposits of 
 this kind at different points along the course of its valley; 
 and it is not uncommon to find that there exist in the valley 
 of a single river two or more sets of these gravel-beds, formed 
 by the river itself, but formed at times when the river ran 
 at different levels, and therefore formed at different periods. 
 These different accumulations are known as the " high-level " 
 and "low-level" gravels; and a reference to the accompany- 
 ing diagram will explain the origin and nature of these de- 
 posits (fig. 255). When a river begins to occupy a particular 
 
 Fig. 255. Recent and Post- Pliocene Alluvial Deposits. T, Peat of the recent period ; 
 2, Gravel of the modern river: 2', Loam of the modern river; 3. Lower-level valley- 
 gravel with bones of extinct Mammals (Post-Pliocene) ; 3', Loam of the same age as 3 ; 
 4, Higher-level valley-gravel (Post-Pliocene) ; 4', Loam of the same age as 4 ; 5, Upland 
 gravels of various kinds (often glacial drift) ; 6, Older rocks. (After Sir Charles Lyell.) 
 
 line of drainage, and to form its own channel, it will deposit 
 fluviatile sands and gravels along its sides. As it goes on 
 deepening the bed or valley through which it flows, it will 
 deposit other fluviatile strata at a lower level beside its new 
 bed. In this way have arisen the terms " high-level " and 
 "low-level" gravels. We find, for instance, a modern river 
 flowing through a valley which it has to a great extent or 
 entirely formed itself; by the side of its immediate channel 
 we may find gravels, sand, and loam (fig. 255, 2 2') deposited 
 by the river flowing in its present bed. These are recent 
 fluviatile or alluvial deposits. At some distance from the 
 present bed of the river, and at a higher level, we may find 
 other sands and gravels, quite like the recent ones in charac- 
 ter and origin, but formed at a time when the stream flowed 
 at a higher level, and before it had excavated its valley to its 
 present depth. These (fig. 255, 3 3') are the so-called " low- 
 Jevel gravels " of a river. At a still higher level, and still 
 farther removed from the present bed of the river, we may 
 find another terrace, composed of just the same materials as 
 .the lower one, but formed at a still earlier period, when the
 
 THE QUATERNARY PERIOD. 341 
 
 excavation of the valley had proceeded to a much less extent. 
 These (fig. 255, 44') are the so-called "high-level gravels :1 
 of a river, and there may be one or more- terraces of these. 
 
 The important fact to remember about these fluviatile de- 
 posits is this that here the ordinary geological rule is reversed. 
 The high-level gravels are, of course, the highest, so far as 
 their actual elevation above the sea is concerned ; but geo- 
 logically the lowest, since they are obviously much older than 
 the low-level gravels, as these are than the recent gravels. 
 How much older the high-level gravels may be than the low- 
 level ones, it is impossible to say. They occur at heights 
 varying from 10 to 100 feet above the present river- chan 
 nels, and they are therefore older than the recent gravels 
 by the time required by the river to dig out its own bed to 
 this depth. How long this period may be, our data do not 
 enable us to determine accurately ; but if we are to calculate 
 from the observed rate of erosion of the actually existing 
 rivers, the period between the different valley-gravels must 
 be a very long one. 
 
 The lowest or recent fluviatile deposits which occur beside 
 the bed of the present river, are referable to the Recent period, 
 as they contain the remains of none but living Mammals. The 
 two other sets of gravels are Post-Pliocene, as they contain 
 the bones of extinct Mammals, mixed with land and fresh- 
 water shells of existing species. Among the more important 
 extinct Mammals of the low-level and high-level valley-gravels 
 may be mentioned the Elcpkas antiquus, the Mammoth (Ele- 
 phas priinigenius), the Woolly Rhinoceros (.R. tichorhinus), the 
 Hippopotamus, the Cave-lion, and the Cave-bear. Along 
 with these are found unquestionable traces of the existence 
 of Man, in the form of rude flint 'implements of undoubted 
 human workmanship. 
 
 The so-called " Cave - deposits," again, though exhibiting 
 peculiarities due to the fact of their occurrence in caverns or 
 fissures in the rocks, are in many respects essentially similar 
 to the older valley-gravels. Caves, in the great majority of 
 instances, occur in limestone. When this is not the case, it 
 will generally be found that they occur along lines of sea-coast, 
 or along lines which can be shown to have anciently formed 
 the coast-line. There are many caves, however, in the making 
 of which it can be shown that the sea has had no hand; and 
 these are most of the caves of limestone districts. These owe 
 their origin to the solvent action upon lime of water holding 
 carbonic aciJ in solution. The rain which falls upon a lime- 
 stone district absorbs a certain amount of carbonic acid from
 
 342 HISTORICAL PALAEONTOLOGY. 
 
 the air, or from the soil. It then percolates through the rock, 
 generally along the lines of jointing so characteristic of lime- 
 stones, and in its progress it dissolves and carries off a certain 
 quantity of carbonate of lime. In this way, the natural joints 
 and fissures in the rock are widened, as can be seen at the 
 present day in any or all limestone districts. By a continu- 
 ance of this action for a sufficient length of time, caves may 
 ultimately be produced. Nothing, also, is commoner in a 
 limestone district than for the natural drainage to take the 
 line of some fissure, dissolving the rock in its course. In this 
 way we constantly meet in limestone districts with springs 
 issuing from the limestone rock sometimes as large rivers 
 the waters of which are charged with carbonate of lime, ob- 
 tained by the solution of the sides of the fissure through which 
 the waters have flowed. By these and similar actions, every 
 district in which limestones are extensively developed will be 
 found to exhibit a number of natural caves, rents, or fissures. 
 The first element, therefore, in the production of cave-deposits, 
 is the existence of a period in which limestone rocks were 
 largely dissolved, and caves were formed in consequence of 
 the then existing drainage taking the line of some fissure. 
 
 Secondly, there must have been a period in which various 
 deposits were accumulated in the caves thus formed. These 
 cavern-deposits are of very various nature, consisting of mud, 
 loam, gravel, or breccias of different kinds. In all cases, these 
 materials have been introduced into the cave at some period 
 subsequent to, or contemporaneous with, the formation of the 
 cave. . Sometimes the cave communicates with the surface by 
 a fissure through which sand, gravel, &c., may be washed by 
 rains or by floods from some neighbouring river. Sometimes 
 the cave has been the bed of an ancient stream, and the de- 
 posits have been formed as are fluviatile deposits at the surface. 
 Or, again, the river has formerly flowed at a greater elevation 
 than it does at present, and the cave has been filled with 
 fluviatile deposits by the river at a time prior to the excava- 
 tion of its bed to the present depth (fig. 256). In this last 
 case, the cave-deposits obviously bear exactly the same rela- 
 tion in point of antiquity to recent deposits, as do the low- 
 level and high-level valley-gravels to recent river-gravels. In 
 any case, it is necessary for the physical geography of the dis- 
 trict to change to some extent, in order that the cave-deposits 
 should be preserved. If the materials have been introduced 
 by a fissure, the cave will probably become ultimately filled 
 to the roof, and the aperture of admission thus blocked up. 
 If a river has flowed through the cave, the surface configura-
 
 THE QUATERNARY PERIOD. 
 
 343 
 
 tion of the district must be altered so far as to divert the river 
 into a new channel. And if the cave is placed in the side of 
 a river- valley, as in fig. 256, the river must have excavated 
 
 Fig. 256. Diagrammatic section across a river-valley and cave, a a. Recent valley- 
 gravels near the channel (6) of the existing river ; c, Cavern, partly filled with cave- 
 earth ; d d. High-level gravels, filling fissures in the limestone, which perhaps communi- 
 cate in some instances with the cave, and form a channel by which materials of various 
 kinds were introduced into it; e e, Inclined beds of limestone. 
 
 its channel to such a depth that it can no longer wash out the 
 contents of the cave even in high floods. 
 
 If the cave be entirely filled, the included deposits generally 
 get more or less completely cemented together by the percola- 
 tion through them of water holding carbonate of lime in solu- 
 tion. If the cave is only partially filled, the dropping of water 
 from the roof holding lime in solution, and its subsequent 
 evaporation, would lead to the formation over the deposits 
 below of a layer of stalagmite, perhaps several inches, or even 
 feet, in thickness. In this way cave- deposits, with their con- 
 tained remains, may be hermetically sealed up and preserved 
 without injury for an altogether indefinite period of time. 
 
 In all caves in limestone in which deposits containing bones 
 are found, we have then evidence of three principal sets of 
 changes, (r.) A period during which the cave was slowly 
 hollowed out by the percolation of acidulated water ; (2.) A 
 period in which the cave became the channel of an engulfed 
 river, or otherwise came to form part* of the general drainage- 
 system of the district; (3.) A period in which the cave was 
 inhabited by various animals. 
 
 As a typical example of a cave with fossiliferous Post- 
 Pliocene deposits, we may take Kent's Cavern, near Torquay, 
 in which a systematic and careful examination has revealed the 
 following sequence of accumulations in descending order : 
 
 (a} Large blocks of limestone, which lie on the floor of the 
 cave, having fallen from the roof, and which are sometimes 
 cemented together by stalagmite. 
 
 (fr) A layer of black mould, from three to twelve inches 
 thick, with human bones, fragments of pottery, stone and
 
 344 HISTORICAL PALAEONTOLOGY. 
 
 bronze implements, and the bones of animals now living in 
 Britain. This, therefore, is a recent deposit. 
 
 (c) A layer of stalagmite, from sixteen to twenty inches 
 thick, but sometimes as much as five feet, containing the bones 
 of Man, together with those of extinct Post-Pliocene Mammals. 
 
 (d) A bed of red cave-earth, sometimes four feet in thick- 
 ness, with numerous bones of extinct Mammals (Mammoth, 
 Cave-bear, &c.), together with human implements of flint and 
 horn. 
 
 (e) A second bed of stalagmite, in places twelve feet in 
 thickness, with bones of the Cave bear. 
 
 (/) A red-loam and cave-breccia, with remains of the Cave- 
 bear and human implements. 
 
 The most important Mammals which are found in cave- 
 deposits in Europe generally, are the Cave-bear, the Cave-lion, 
 the Cave-hyaena, the Reindeer, the Musk-ox, the Glutton, and 
 the Lemming of which the first three are probably identical 
 with existing forms, and the remainder are certainly so to- 
 gether with the Mammoth and the Woolly Rhinoceros, which 
 are undoubtedly extinct. Along with these are found the 
 implements, and in some cases the bones, of Man himself, in 
 such a manner as to render it absolutely certain that an early 
 race of men was truly contemporaneous in Western Europe 
 with the animals above mentioned. 
 
 IV. UNCLASSIFIED POST-PLIOCENE DEPOSITS. Apart from 
 any of the afore-mentioned deposits, there occur other accumu- 
 lations sometimes superficial, sometimes in caves which are 
 found in regions where a " Glacial period " has not been fully 
 demonstrated, or where such did not take place ; and which, 
 therefore, are not amenable to the above classification. The 
 most important of these are known to occur in South America 
 and Australia ; and though their numerous extinct Mammalia 
 place their reference to the Post-Pliocene period beyond 
 doubt, their relations to the glacial period and its deposits in 
 the northern hemisphere have not been precisely determined. 
 
 CHAPTER XXII. 
 
 THE POST-PLIOCENE PERIOD Continued. 
 
 As regards the life of the Post-Pliocene period, we have, in. 
 the first place, to notice the effect produced throughout the
 
 FAUNA OF THE POST-PLIOCENE. 345 
 
 northern hemisphere by the gradual supervention of the Glacial 
 period. Previous to this the climate must have been temper- 
 ate or warm-temperate ; but as the cold gradually came on, 
 two results were produced as regards the living beings of the 
 area thus affected. In the first place, all those Mammals 
 which, like the Mammoth, the Woolly Rhinoceros, the Lion, 
 the Hy.a2iia, and the Hippopotamus, require, at any rate, mode- 
 rately warm conditions, would be forced to migrate southwards 
 to regions not affected by the new state of things. In the 
 second place, Mammals previously inhabiting higher latitudes, 
 such as the Reindeer, the Musk-ox, and the Lemming, would 
 be enabled by the increasing cold to migrate southwards, and 
 to invade provinces previously occupied by the Elephant and 
 the Rhinoceros. A precisely similar, but more slowly-executed 
 process, must have taken place in the sea, the northern Mollus- 
 ca moving southwards as the arctic conditions of the Glacial 
 period became established, whilst the forms proper to temperate 
 seas receded. As regards the readily locomotive Mammals, 
 also, it is probable that this process was carried on repeatedly 
 in a partial manner, the southern and northern forms alternately 
 fluctuating backwards and forwards over the same area, in ac- 
 cordance with the fluctuations of temperature which have been 
 shown by Mr James Geikie to have characterised the Glacial 
 period as a whole. We can thus readily account for the inter- 
 mixture which is sometimes found of northern and southern types 
 of Mammalia in the same deposits, or in deposits apparently 
 synchronous, and within a single district. Lastly, at the final 
 close of the arctic cold of the Glacial period, and the re estab- 
 lishment of temperate conditions over the northern hemisphere, 
 a reversal of the original process took place the northern 
 Mammals retiring within their ancient limits, and the southern 
 forms pressing northwards and reoccupying their original 
 domains. 
 
 The Invertebrate animals of the Post-Pliocene deposits re- 
 quire no further mention all the known forms, except a few 
 of the shells in the lowest beds of the formation, being iden- 
 tical with species now in existence upon the globe. The only 
 point of importance in this connection 'has been previously 
 noticed namely, that in the true Glacial deposits themselves 
 a considerable number of the shells belong to northern or 
 Arctic types. 
 
 As regards the Vertebrate animals of the period, no extinct 
 forms of Fishes, Amphibians, or Reptiles are known to occur, 
 but we meet with both extinct Birds and extinct Mammals. 
 The remains of the former are of great interest, as indicating
 
 346 HISTORICAL PALAEONTOLOGY. 
 
 the existence during Post - Pliocene times, at widely remote 
 points of the southern hemisphere, of various wingless, and for 
 the most part gigantic, Birds. All the great wingless Birds of 
 the order Cursores which are known as existing at the pres- 
 ent day upon the globe, are restricted to regions which are 
 either wholly or in great part south of the equator. Thus the 
 true Ostriches are African ; the Rheas are South American ; 
 the Emeus are Australian ; the Cassowaries are confined to 
 Northern Australia, Papua, and the Indian Archipelago ; the 
 species of Apteryx are natives of New Zealand ; and the 
 Dodo and Solitaire (wingless, though probably not true Cur- 
 sores], both of which have been exterminated within histori- 
 cal times, were inhabitants of the islands of Mauritius and 
 Rodriguez, in the Indian Ocean. In view of these facts, it 
 is noteworthy that, so far as known, all the Cursorial Birds 
 of the Post-Pliocene period should have been confined to the 
 same hemisphere as that inhabited by the living representatives 
 of the order. It is still further interesting to notice that the 
 extinct forms in question are only found in geographical prov- 
 inces which are now, or have been within historical times, inhab- 
 ited by similar types. The greater number of the remains of 
 these have been discovered in New Zealand, where there now 
 live several species of the curious wingless genus Apteryx ; and 
 they have been referred by Professor Owen to several generic 
 groups, of which Dinornis is the most important (fig. 257). 
 Fourteen species of Dinornis have been described by the dis- 
 tinguished palaeontologist just mentioned, all of them being 
 large wingless birds of the type of the existing Ostrich, having 
 enormously powerful hind-limbs adapted for running, but with 
 the wings wholly rudimentary, and the breast-bone devoid of 
 the keel or ridge which characterises this bone in all birds 
 which fly. The largest species is the Dinornis giganleus, one 
 of the most gigantic of living or fossil birds, the shank (tibia) 
 measuring a yard in length, and the total height being at least 
 ten feet Another species, the Dinornis elephantopus (fig. 257), 
 though not standing more than about six feet in height, was 
 of an even more ponderous construction "the framework 
 of the skeleton being the most massive of any in the whole 
 class of Birds," whilst " the toe-bones almost rival those of the 
 Elephant" (Owen). The feet in Dinornis were furnished with 
 three toes, and are of interest as presenting us with an un- 
 doubted Bird big enough to produce the largest of the foot- 
 prints of the Triassic Sandstones of Connecticut. New Zea- 
 land has now been so far explored, that it seems questionable 
 if it can retain in its recesses any living example of Dinornis ;
 
 FAUNA OF THE POST-PLIOCENE. 
 
 347 
 
 but it is certain that species of this genus were alive during the 
 human period, and survived up to quite a recent date. Not 
 only are the bones very numerous in certain localities, but 
 
 Fig. 257. Skeleton of Dinornis elephnntopus, greatly reduced. Post-Pliocene, 
 New Zealand. (After Owen.) 
 
 they are found in the most recent and superficial deposits, and 
 they still contain a considerable proportion of animal matter ; 
 whilst in some instances bones have been found with the 
 feathers attached, or with the horny skin of the legs still ad- 
 hering to them. Charred bones have been found in connec- 
 tion with native " ovens ; " and the traditions of the Maories 
 contain circumstantial accounts of gigantic wingless Birds, the 
 " Moas," which were hunted both for their flesh and their 
 plumage. Upon the whole, therefore, there can be no doubt
 
 34^ HISTORICAL PALAEONTOLOGY. 
 
 but that the Moas of New Zealand have been exterminated at 
 quite a recent period perhaps within the last centmy by the 
 unrelenting pursuit of Man, a pursuit which their wingless 
 condition rendered them unable to evade. 
 
 In Madagascar, bones have been discovered of another huge 
 wingless Bird, which must have been as large as, or larger 
 than, the Dinornis gigantcHS, and which has been described 
 -under the name of sEpiornii, maximus. With the bones have 
 been found eggs measuring from thirteen to fourteen inches in 
 diameter, and computed to have the capacity of three Ostrich 
 eggs. At least two other smaller species of ^Epiornis have been 
 described by Grandidier and Milne-Edwards as occurring in 
 Madagascar; and they consider the genus to be so closely allied 
 to the Dinoriiis of New Zealand, as to prove that these regions, 
 now so remote, were at one time united by land. Unlike New 
 Zealand, where there is the Aptcryx, Madagascar is not known 
 to possess any living wingless Birds ; but in the neighbouring 
 island of Mauritius the wingless Dodo (Didus incptus) has been 
 exterminated less than three hundred years ago ; and the little 
 island of Rodriguez, in the same geographical province, has in 
 a similar period lost the equally wingless Solitaire (Pezophaps), 
 both of these, however, being generally referred to the Rasores. 
 The Mammals of the Post- Pliocene period are so numerous, 
 that in spite of the many points of interest which they present, 
 only a few of the more important forms can be noticed here, 
 and that but briefly. The first order that claims our attention 
 is that of the Marsupials, the headquarters of which at the 
 present day is the Australian province. In Oolitic times 
 Europe possessed its small Marsupials, and similar forms 
 existed in the same area in the Eocene and Miocene periods ; 
 but if size be any criterion, the culminating point in the history 
 of the order was attained during the Post-Pliocene period in 
 Australia. From deposits of 
 this age there has been disen- 
 tombed a whole series of re- 
 mains of extinct, and for the 
 most part gigantic, examples 
 of this group of Quadrupeds. 
 Not to speak of Wombats and 
 Phalangers, two forms stand 
 out prominently as represen- 
 
 Fi?. 258. SkuRofDffrvfalttmAMsiraZi's, t n t,,,*c nf t1i<a Pncf Plinrf>np 
 greatly reduced. Pos^Pliocene, Australia. tatlVCS Ot UlC fOSt-V 
 
 animals of Australia. One of 
 
 these is Diprotodon (fig. 258), representing, with many differ- 
 ences, the well-known modern group of the Kangaroos. In
 
 FAUNA OF THE POST-PLIOCENE. 349 
 
 its teeth, Diprotodon shows itself to be closely allied to the 
 living, grass-eating Kangaroos ; but the hind-limbs were not 
 so disproportionately long. In size, also, Diprotodon must 
 have many times exceeded the dimensions of the largest of 
 its living successors, since the skull measures no less than 
 three feet in length. The other form in question is Thylacoleo 
 (fig. 259), which is believed by Professor Owen to belong to 
 the same group as the existing "Native Devil " (Dasyurus] of 
 Van Diemen's Land, and therefore to have been flesh-eating 
 and rapacious in its habits, though this view is not accepted 
 by others. The principal feature in the skull of Thylacoleo is 
 
 Fig. 259. Skull of Thylacoleo. Post- Pliocene, Australia. Greatly reduced. 
 (After Flower.) , 
 
 the presence, on each side of each jaw, of a single huge tooth, 
 which is greatly compressed, and has a cutting edge. This 
 tooth is regarded by Owen as corresponding to the great cut- 
 ting tooth of the jaw of the typical Carnivores, but Professor 
 Flower considers that Thylacoleo is rather related to the Kan- 
 garoo-rats. The size of the crown of the tooth in question is 
 not less than two inches and a quarter ; and whether carnivo- 
 rous or not, it indicates an animal of a size exceeding that of 
 the largest of existing Lions. 
 
 The order of the Edentates, comprising the existing Sloths, 
 Ant-eaters, and Armadillos, and entirely restricted at the present 
 day to South America, Southern Asia, and Africa, is one alike 
 24
 
 350 HISTORICAL PALEONTOLOGY. 
 
 singular for the limited geographical range of its members, 
 their curious habits of life, and the well-marked peculiarities 
 of their anatomical structure. South America is the metropo- 
 lis of the existing forms ; and it is an interesting fact that there 
 flourished within Post-Pliocene times in this continent, and to 
 some extent in North America also, a marvellous group of ex- 
 tinct Edentates, representing the living Sloths and Armadillos, 
 but of gigantic size. The most celebrated of these is the huge 
 Megatherium Cuvieri (fig. 260) of the South American Pampas. 
 
 Fig. 260. Megatherium Cnvieri. Post-Pliocene, South America. 
 
 The Megathere was a colossal Sloth-like animal which attained 
 a length of from twelve to eighteen feet, with bones more mas- 
 sive than those of the Elephant. Thus the thigh-bone is 
 nearly thrice the thickness of the same bone in the largest 
 of existing Elephants, its circumference at its narrowest point 
 nearly equalling its total length ; the massive bones of the 
 shank (tibia and fibula) are amalgamated at their extremities ; 
 the heel-bone (calcaneum) is nearly half a yard in length ; the 
 haunch-bones (ilia) are from four to five feet across at their 
 crests ; and the borlies of the vertebrae at the root of the tail 
 are from five to seven inches in diameter, from which it has 
 been computed that the circumference of the tail at this part 
 might have been from five to six feet. The length of the fore- 
 foot is about a yard, and the toes are armed with powerful 
 curved claws. It is known now that the Megathere, in spite 
 of its enormous weight and ponderous construction, walked, 
 like the existing Ant-eaters and Sloths, upon the outside edge 
 of the fore-feet, with the claws more or less bent inwards
 
 FAUNA OF THE POST-PLIOCENE. 351 
 
 towards the palm of the hand. As in the great majority of 
 the Edentate order, incisor and canine teeth are entirely 
 wanting, the front of the jaws being toothless. The jaws, 
 however, are furnished with five upper and four lower molar 
 teeth on each side. These grinding teeth are from seven to 
 eight inches in length, in the form of four-sided prisms, the 
 crowns of which are provided with, well -marked transverse 
 ridges ; and they continue to grow during the whole life of 
 the animal. There are indications that the snout was pro- 
 longed, and more or less flexible; and the tongue was proba- 
 bly prehensile. From the characters of the molar teeth it 
 is certain that the Megathere was purely herbivorous in its 
 habits ; and from the enormous size and weight of the body, 
 it is equally certain that it could not have imitated its modern 
 allies, the Sloths, in the feat of climbing, back downwards, 
 amongst the trees. It is clear, therefore, that the Megathere 
 sought its sustenance upon the ground ; and it was originally 
 supposed to have lived upon roots. By a masterly piece of 
 deductive reasoning, however, Professor Owen showed that 
 this great "Ground-Sloth" must have truly lived upon the 
 foliage of trees, like the existing Sloths but with this differ- 
 ence, that instead of climbing amongst the branches, it actually 
 uprooted the tree bodily. In this tour de force, the animal 
 sat upon its huge haunches and mighty tail, as on a tripod, 
 and then grasping the trunk with its powerful arms, either 
 wrenched it up by the roots or broke it short off above the 
 ground. Marvellous as this may seem, it can be shown that 
 every detail in the skeleton of the Megathere accords with the 
 supposition that it obtained its food in this" way. Similar 
 habits were followed by the allied Mylodon (fig. 261), another 
 of the great " Ground-Sloths," which inhabited South America 
 during the Post-Pliocene period. In most respects, the Mylo- 
 don is very like the Megathere ; but the crowns of the molar 
 teeth are flat instead of being ridged. The nearly- related 
 genus Megalonyx, unlike the Megathere, but like the Mylodon, 
 extended its range northwards as far as the United States. 
 
 Just as the Sloths of the present day were formerly repre- 
 sented in the same geographical area by the gigantic Megathe- 
 roids, so the little banded and cuirassed Armadillos of South 
 America were formerly represented by gigantic species, con- 
 stituting the genus Glyptodon. The Glyptodons (fig. 262) 
 differed from the living Armadillos in having no bands in 
 their armour, so that they must have been unable to roll 
 themselves up. It is rare at the present day to meet with any 
 Armadillo over two or three feet in length ; but the length of
 
 352 
 
 HISTORICAL PALEONTOLOGY. 
 
 the Glyptodon davipes, from the tip of the snout to the end of 
 the tail, was more than nine feet. 
 
 There are no canine or incisor teeth in the Glyptodon, but 
 
 Fig. 261. Skeleton of Mylodon robustus. Post-Pliocene, South America. 
 
 there are eight molars on each side of each jaw, and the crowns 
 of these are fluted and almost trilobed. The head is covered 
 
 Fig. 262. Skeleton of Glyptodon clavifies. Post- Pliocene, South America. 
 
 by a helmet of bony plates, and the trunk was defended by an 
 armour of almost hexagonal bony pieces united by sutures, and
 
 FAUNA OF THE POST-PLIOCENE. 
 
 353 
 
 exhibiting special patterns of sculpturing in each species. The 
 tail was also defended by a similar armour, and the vertebrae 
 were mostly fused together so as to form a cylindrical bony 
 rod. In addition to the above-mentioned forms, a number 
 of other Edentate animals have been discovered by the re- 
 searches of M. Lund in the Post-Pliocene deposits of the 
 Brazilian bone-caves. Amongst these are true Ant-eaters, 
 Armadillos, and Sloths, many of them of gigantic size, and all 
 specifically or generically distinct from existing forms. 
 
 Passing over the aquatic orders of the Sirenians and Ce- 
 taceans, we come next to the great group of the Hoofed Quad- 
 rupeds, the remains of which are very abundant in Post- 
 Pliocene deposits both in Europe and North America. 
 Amongst the Odd - toed Ungulates the most important are 
 the Rhinoceroses, of which three species are known to have 
 existed in Europe during the Post-Pliocene period. Two 
 of these are the well-known Pliocene forms, the Rhinoceros 
 Etruscus and the R. megarhinus, still surviving in diminished 
 numbers ; but the most famous is the Rhinoceros tichorhimis 
 (fig. 263), or so-called " Woolly Rhinoceros." This species 
 
 Fig. 263. Skull of the Tichorhine Rhinoceros, the horns heing wanting. On-tenth 
 of the natural size. Post- Pliocene deposits of Europe and Asia. 
 
 is known not only by innumerable bones, but also by a car- 
 cass, at the time of its discovery complete, which was found 
 embedded in the frozen soil of Siberia towards the close of 
 last century, and which was partly saved from destruction by 
 the exertions of the naturalist Pallas. From this, we know 
 that the Tichorhine Rhinoceros, like its associate the Mam- 
 moth, was provided with a coating of hair, and therefore was 
 enabled to endure a more severe climate than any existing
 
 354 HISTORICAL PALEONTOLOGY. 
 
 species. The skin was not thrown into the folds which char- 
 acterise most of the existing forms ; and the technical name 
 of the species refers to the fact that the nostrils were com- 
 pletely separated by a bony partition. The head carried two 
 horns, placed one behind the other, the front one being un- 
 usually large. As regards its geographical range, the Woolly 
 Rhinoceros is found in Europe in vast numbers north of the 
 Alps and Pyrenees, and it also abounded in Siberia ; so that 
 it would appear to be a distinctly northern form, and to have 
 been adapted for a temperate climate. It is not known to 
 occur in Pliocene deposits, but it makes its first appearance 
 in the Pre-Glacial deposits, surviving the Glacial period, and 
 being found in abundance in Post-Glacial accumulations. It 
 was undoubtedly a contemporary of the earlier races of men 
 in Western Europe ; and it may perhaps be regarded as being 
 the actual substantial kernel of some of the " Dragons " of 
 fable. 
 
 The only other Odd-toed Ungulate which needs notice is 
 the so-called Equus fossilis of the Post-Pliocene of Europe. 
 This made its appearance before the Glacial period, and ap- 
 pears to be in reality identical with the existing Horse (Equus 
 caballus) True Horses also occur in the Post-Pliocene of 
 North America ; but, from some cause or another, they must 
 have been exterminated before historic times. 
 
 Amongst the Even-toed Ungulates, the great Hippopotamus 
 major of the Pliocene still continued to exist in Post-Pliocene 
 times in Western Europe ; and the existing Wild Boar (Sus 
 scrofa), the parent of our domestic breeds of Pigs, appeared 
 for the first time. The Old World possessed extinct repre- 
 sentatives of its existing Camels, and lost types of the living 
 Llamas inhabited South America. Amongst the Deer, the 
 Post- Pliocene accumulations have yielded the remains of 
 various living species, such as the Red Deer (Cervus elaphus}, 
 the Reindeer (Cervus tarandus), the Moose or Elk (Alces 
 malchis), and the Roebuck (Cervus capreolus), together with 
 a number of extinct forms. Among the latter, the great 
 "Irish Elk" ( Cervus megaceros) is justly celebrated both for 
 its size and for the number and excellent preservation of its 
 discovered remains. This extinct species (fig. 264) has been 
 found principally in peat- mosses and Post-Pliocene lake- 
 deposits, and is remarkable for the enormous size of the 
 spreading antlers, which are widened out towards their ex- 
 tremities, and attain an expanse of over ten feet from tip to 
 tip. It is not a genuine Elk, but is intermediate between 
 the Reindeer and the Fallow-deer. Among the existing Deer
 
 FAUNA OF THE POST-PLIOCENE. 
 
 355 
 
 of the Post-Pliocene, the most noticeable is the Reindeer, 
 an essentially northern type, existing at the present day in 
 
 Fig. 264. Skeleton of the " Irish Elk" (Cervus tnegaceros). 
 Posl-Pliocene, Britain. 
 
 Northern Europe, and also (under the name of the " Caribou") 
 in North America. When the cold of the Glacial period be- 
 came established, this boreal species was enabled to invade 
 Central and Western Europe in great herds, and its remains 
 are found abundantly in cave-earths and other Post-Pliocene 
 deposits as far south as the Pyrenees. 
 
 In addition to the above, the Post -Pliocene deposits of 
 Europe and North America have yielded the remains of vari- 
 ous Sheep and Oxen. One of the most interesting of the
 
 356 HISTORICAL PALEONTOLOGY. 
 
 latter is the " Urus" or Wild Bull (Eos primigenius, fig. 265), 
 which, though much larger than any of the existing forms, is 
 
 Fig. 265. Skull of the Urus (Bos primigenius). Post- Pliocene and Recent. 
 (After Owen.) 
 
 believed to be specifically undistinguishable from the domes- 
 tic Ox (Bos taurus), and to be possibly the ancestor of some 
 of the larger European varieties of oxen. In the earlier part 
 of its existence the Urus ranged over Europe and Britain in 
 company with the Woolly Rhinoceros and the Mammoth; but 
 it long survived these, and does not appear to have been 
 finally exterminated till about the twelfth century. Another 
 remarkable member of the Post-Pliocene Cattle, also to be- 
 gin with an associate of the Mammoth and Rhinoceros, is 
 the European Bison or " Aurochs " (Bison priscus). This 
 "maned" ox formerly abounded in Europe in Post-Glacial 
 times, and was not rare even in the later periods of the 
 Roman empire, though vnuch diminished in numbers, and 
 driven back into the wilder and more inaccessible parts of the 
 country. At present this fine species has been so nearly 
 exterminated that it no longer exists in Europe save in 
 Lithuania, where its preservation has been secured by rigid 
 protective laws. Lastly, the Post -Pliocene deposits have 
 yielded the remains of the singular living animal which is 
 known as the Musk-ox or Musk-sheep (Ovibos moschatus}. 
 At the present day, the Musk-ox is an inhabitant of the 
 " barren grounds " of Arctic America, and it is remarkable for 
 the great length of its hair. It is, like the Reindeer, a dis-
 
 FAUNA OF THE POST-PLIOCENE. 357 
 
 tinctively northern animal ; but it enjoyed during the Glacial 
 period a much wider range than it has at the present day, the 
 conditions suitable for its existence being then extended over 
 a considerable portion of the northern hemisphere. Thus 
 remains of the Musk-Ox are found in greater or less abun- 
 dance in Post-Pliocene deposits over a great part of Europe, 
 extending even to the south of France; and closely - related 
 forms are found in similar deposits in the United States. 
 
 Coming to the Proboscideans, we find that the Mastodons 
 seem to have disappeared in Europe at the close of the 
 Pliocene period, or at the very commencement of the Post- 
 Pliocene. In the New World, on the other hand, a species of 
 Mastodon (M, Americamis or M. Ohioticus] is found abun- 
 dantly in deposits of Post - Pliocene age, from Canada to 
 Texas. Very perfect skeletons of this species have been 
 exhumed from morasses and swamps, and large individuals 
 attained a length (exclusive of the tusks) of seventeen feet and 
 a height of eleven feet, the tusks being twelve feet in length. 
 Remains of Elephants are also abundant in the Post-Pliocene 
 deposits of both the Old and the New World. Amongst these, 
 we find in Europe the two familiar Pliocene species E. meri- 
 dionalis and E, antiquus still surviving, but in diminished 
 numbers. With these are found in vast abundance the re- 
 mains of the characteristic Elephant of the Post-Pliocene, the 
 well-known " Mammoth " (Elephas primigenius), which is ac- 
 companied in North America by the nearly-allied, but more 
 southern species, the Elephas Americamis. The Mammoth (fig. 
 266) is considerably larger than the largest of the living Ele- 
 phants, the skeleton being over sixteen feet in length, exclusive 
 of the tusks, and over nine feet in height. The tusks are bent 
 almost into a circle, and are sometimes twelve feet in length, 
 measured along their curvature. In the frozen soil of Siberia 
 several carcasses of the Mammoth have been discovered with 
 the flesh and skin still attached to the bones, the most cele- 
 brated of these being a Mammoth which was discovered at the 
 beginning of this century at the mouth of the Lena, on the borders 
 of the Frozen Sea, and the skeleton of which is now preserved 
 at St Petersburg (fig. 266). From the occurrence of the remains 
 of the Mammoth in vast numbers in Siberia, it might have been 
 safely inferred that this ancient Elephant was able to endure a far 
 more rigorous climate than its existing congeners. This infer- 
 ence has, however, been rendered a certainty by the specimens 
 just referred to, which show that the Mammoth was protected 
 against the cold by a thick coat of reddish-brown wool, some 
 nine or ten inches long, interspersed with strong, coarse black
 
 353 
 
 HISTORICAL PALEONTOLOGY. 
 
 hair more than a foot in length. The teeth of the Mammoth 
 (fig. 267) are of the type of those of the existing Indian Ele- 
 phant, and are found in immense numbers in certain localities. 
 
 The Mammoth was essentially northern in its distribution, 
 never passing south of a line drawn through the Pyrenees, the 
 Alps, the northern shores of the Caspian, Lake Baikal, Kam-
 
 FAUNA OF THE POST-PLIOCENE. 
 
 359 
 
 schatka, and the Stanovi Mountains (Dawkins). It occurs in 
 the Pre-Glacial forest-bed of Cromer in Norfolk, survived the 
 
 Fig. 207. Molar tooth of the Mammoth (Elephas primigenius), upper jaw, right side, 
 one-third of the natural size, a, Grinding surface ; b, Side view. Post- Pliocene. 
 
 Glacial period, and is found abundantly in Post-Glacial de- 
 posits in France, Germany, Britain, Russia in Europe, Asia, 
 and North America, being often associated with the Reindeer, 
 Lemming, and Musk-ox. That it survived into the earlier 
 portion of the human period is unquestionable, its remains 
 having been found in a great number of instances associated 
 with implements of human manufacture ; whilst in one instance 
 a recognisable portrait of it has been discovered, carved on 
 bone. 
 
 Amongst other Elephants which occur in Post-Pliocene de- 
 posits may be mentioned, as of special interest, the pigmy 
 Elephants of Malta. One of these the Elephas Mditensis, or 
 so-called "Donkey-Elephant" was not more than four and 
 a half feet in height. The other the Elephas Falconeri, of 
 Busk was still smaller, its average height at the withers not 
 exceeding two and a half to three feet. 
 
 Whilst .herbivorous animals abounded during the Post- 
 Pliocene, we have ample evidence of the coexistence with 
 them of a number of Carnivorous forms, both in the New and 
 the Old World. The Bears are represented in Europe by at 
 least three species, two of which namely, the great Grizzly 
 Bear ( Urs us ferox) and the smaller Brown Bear (Ursus arctos) 
 are in existence at the present day. The third speciesis the>
 
 360 HISTORICAL PALEONTOLOGY. 
 
 celebrated Cave-bear (Ursus spelceus, fig. 268), which is now 
 extinct. The Cave-bear exceeded in its dimensions the largest 
 
 Fig. 268. Skull of Ursus spelaus. Post-Pliocene, Europe. One-sixth 
 of the natural size. 
 
 of modern Bears ; and its remains, as its name implies, have 
 been found mainly in cavern-deposits. Enormous numbers of 
 this large and ferocious species must have lived in Europe in 
 Post-Glacial times ; and that they survived into the human 
 period, is clearly shown by the common association of their 
 bones with the implements of man. They are occasionally 
 accompanied by the remains of a Glutton (the Gulo spelceus), 
 which does not appear to be really separable from the existing 
 Wolverine or Glutton of northern regions (the Gulo luscus). 
 In addition, we meet with the bones of the Wolf, Fox, Weasel, 
 Otter, Badger, Wild Cat, Panther, Hyasna, and Lion, &c., 
 together with the extinct Machairodus or "Sabre-toothed 
 Tiger." The only two of these that deserve further mention 
 are . the Hyaena and the Lion. The Cave-hyasna (Hyzna 
 spelcea, fig. 269) is regarded by high authorities as nothing 
 more than a variety of the living Spotted Hyaena (H. crocuta) 
 of South Africa. This well-known species inhabited Britain 
 and a considerable portion of Europe during a large part of 
 the Post-Pliocene period ; and its remains often occur in great 
 abundance. Indeed, some caves, such as the Kirkdale Cavern 
 in Yorkshire, were dens inhabited during long periods by these 
 animals, and thus contain the remains of numerous individuals 
 and of successive generations of Hyaenas, together with in- 
 numerable gnawed and bitten bones of their prey. That the 
 Cave-hyasna was a contemporary with Man in Western Europe 
 during Post-Glacial times is shown beyond a doubt by the 
 common association of its bones with human implements.
 
 FAUNA OF THE POST-PLIOCENE. 
 
 3 6l 
 
 Lastly, the so-called Cave-lion (Felis spelcea}, long supposed 
 to be a distinct species, has been shown to be nothing more 
 
 Fig. 269. Skull of Hyana spelaa, one-fourth of the natural size. 
 Post-Pliocene, Europe. 
 
 than a large variety of the existing Lion (Felis leo). This 
 animal inhabited Britain and Western Europe in times pos- 
 terior to the Glacial period, and was a contemporary of the 
 Cave-hygena, Cave-bear, Woolly Rhinoceros, and Mammoth. 
 The Cave-lion also unquestionably survived into the earlier 
 portion of the human period in Europe. 
 
 The Post-Pliocene deposits of Europe have further yielded 
 the remains of numerous Rodents such as the Reaver, the 
 Northern Lemming, Marmots, Mice, Voles, Rabbits, &c. to- 
 gether with the gigantic extinct Beaver known as the Trogon- 
 therium Cuvieri (fig. 270). The great Castoroides Ohivensis of 
 the Post-Pliocene of North 
 America is also a great ex- 
 tinct Beaver, which reached 
 a length of about five feet. 
 Lastly, the Brazilian bone- 
 caves have yielded the re- 
 mains of numerous Rodents 
 of types now characteristic 
 of South America, such as 
 
 ("ninpq nio-s finvhir-m trpp F ' 1 S- 270. Lower jaw of Trogontherium 
 
 (juinea-pigSj^apyDaras, trt - Cw7 , r; -/ one .f ourt ] 10 f t he natural size. Post- 
 inhabiting Porcupines, and Pliocene, Britain. 
 
 Coypus. 
 
 The deposits just alluded to have further yielded the 
 remains of various Monkeys, such as Howling Monkeys, 
 Squirrel Monkeys, and Marmosets, all of which belong to the 
 group of Quadrumana which is now exclusively confined to
 
 362 HISTORICAL PALAEONTOLOGY. 
 
 the South American continent namely, the " Platyrhine " 
 Monkeys. 
 
 We still have very briefly to consider the occurrence of 
 Man in Post-Pliocene deposits ; but before doing so, it will be 
 well to draw attention to the evidence afforded by the Post- 
 Pliocene Mammals as to the climate of Western Europe at 
 this period. The chief point which we have to notice is, that 
 a considerable revolution of opinion has taken place on this 
 point. It was originally believed that the presence of such 
 animals as Elephants, Lions, the Rhinoceros, and the Hippo- 
 potamus afforded an irrefragable proof that the climate of 
 Europe must have been a warm one, at any rate during Post- 
 Glacial times. The existence, also, of numbers of Mammoths 
 in Siberia, was further supposed to indicate that this high tem- 
 perature extended itself very far north. Upon the whole, how- 
 ever, the evidence is against this view. Not only is there great 
 difficulty in supposing that the Arctic conditions of the Glacial 
 period were immediately followed by anything warmer than a 
 cold-temperate climate ; but there is nothing in the nature of 
 the Mammals themselves which would absolutely forbid their 
 living in a temperate climate. The Hippopotamus major, though 
 probably clad in hair, offers some difficulty since, as pointed 
 out by Professor Busk, it must have required a climate suffi- 
 ciently warm to insure that the rivers were not frozen over in the 
 winter ; but it was probably a migratory animal, and its occur- 
 rence may be accounted for by this. The Woolly Rhinoceros 
 and the Mammoth are known with certainty to have been pro- 
 tected with a thick covering of wool and hair ; and their ex- 
 tension northwards need not necessarily have been limited by 
 anything except the absence of a sufficiently luxuriant vege- 
 tation to afford them food. The great American Mastodon, 
 though not certainly known to have possessed a hairy covering, 
 has been shown to have lived upon the shoots of Spruce and 
 Firs, trees characteristic of temperate regions as shown by the 
 undigested food which has been found with its skeleton, oc- 
 cupying the place of the stomach. The Lions and Hyaenas, 
 again, as shown by Professor Boyd Dawkins, do not indicate 
 necessarily a warm climate. Wherever a sufficiency of her- 
 bivorous animals to supply them with food can live, there they 
 can live also ; and they have therefore no special bearing upon 
 the question of climate. After a review of the whole evidence, 
 Professor Dawkins concludes that the nearest approach at the 
 present day to the Post-Pliocene climate of Western Europe 
 is to be found in the climate of the great Siberian plains which 
 stretch from the Altai Mountains to the Frozen Sea. "Covered
 
 FAUNA OF THE POST-PLIOCENE. 363 
 
 by impenetrable forests, for the most part of Birch, Poplar, 
 Larch, and Pines, and low creeping dwarf Cedars, they present 
 every gradation in climate from the temperate to that in which 
 the cold is too severe to admit of the growth of trees, which 
 decrease in size as the traveller advances northwards, and are 
 replaced by the grey mosses and lichens that cover the low 
 marshy ' tundras.' The maximum winter cold, registered by 
 Admiral Von Wrangel at Nishne Kolymsk, on the banks of 
 the Kolyma, is 65 in January. 'Then breathing becomes 
 difficult ; the Reindeer, that citizen of the Polar region, with- 
 draws to the deepest thicket of the forest, and stands there 
 motionless as if deprived of life ;' and trees burst asunder with 
 the cold. Throughout this area roam Elks, Black Bears, 
 Foxes, Sables, and Wolves, that afford subsistence to the 
 Jakutian and Tungusian fur-hunters. In the northern part 
 countless herds of Reindeer, Elks, Foxes, and Wolverines 
 make up for the poverty of vegetation by the rich abundance 
 of animal life. ' Enormous flights of Swans, Geese, and Ducks 
 arrive in the spring, and seek deserts where they may moult 
 and build their nests in safety. Ptarmigans run in troops 
 amongst the bushes ; little Snipes are busy along the brooks 
 and in the morasses ; the social Crows seek the neighbourhood 
 of new habitations ; and when the sun shines in spring, one 
 may even sometimes hear the cheerful note of the Finch, and 
 in autumn that of the Thrash.' Throughout this region of 
 woods, a hardy, middle-sized breed of horses lives under the 
 mastership and care of man, and is eminently adapted to bear 
 the severity of the climate. . . . The only limit to their 
 northern range is the difficulty of obtaining food. The severity 
 of the winter through the southern portion of this vast wooded 
 area is almost compensated for by the summer heat and its 
 marvellous effect on vegetation." (Dawkins, ' Monograph of 
 Pleistocene Mammalia.') 
 
 Finally, a few words must be said as to the occurrence of the 
 remains of Man in Post-Pliocene deposits. That Man existed 
 in Western Europe and in Britain during the Post-Pliocene 
 period, is placed beyond a doubt by the occurrence of his bones 
 in deposits of this age, along with the much more frequent 
 occurrence of implements of human manufacture. At what 
 precise point of time during the Post-Pliocene period he first 
 made his appearance is still a matter of conjecture. Recent 
 researches would render it probable that the early inhabitants 
 of Britain and Western Europe were witnesses of the stupend- 
 ous phenomena of the Glacial period ; but this cannot be said 
 to have been demonstrated. That Man existed in these
 
 364 HISTORICAL PALEONTOLOGY. 
 
 regions during the Post-Glacial division of Post-Pliocene time 
 cannot be doubted for a moment. As to the physical peculi- 
 arities of the ancient races that lived with the Mammoth and 
 the Woolly Rhinoceros, little is known compared with what 
 we may some day hope to know. Such information as we 
 have, however, based principally on the skulls of the Engis, 
 Neanderthal, Cro-Magnon, and Bruniquel caverns, would lead 
 to the conclusion that Post-Pliocene Man was in no respect 
 inferior in his organisation to, or less highly developed than, 
 many existing races. All the known skulls of this period, with 
 the single exception of the Neanderthal cranium, are in all 
 respects average and normal in their characters ; and even the 
 Neanderthal skull possessed a cubic capacity at least equal to 
 that of some existing races. The implements of Post-Pliocene 
 Man are exclusively of stone or bone ; and the former are 
 invariably of rude shape and undressed. These "palaeolithic" 
 tools (Gr. palaios, ancient ; lithos, stone) point to a very early 
 condition of the arts ; since the men of the earlier portion 
 of the Recent period, though likewise unacquainted with the 
 metals, were in the habit of polishing or dressing the stone 
 implements which they fabricated. 
 
 It is impossible here to enter further into this subject ; and 
 it would be useless to do so without entering as well into a 
 consideration of the human remains of the Recent period a 
 period which lies outside the province of the present work. So 
 far as Post-Pliocene Man is concerned, the chief points which 
 the palseontological student has to remember have been else- 
 where summarised by the author as follows : 
 
 1. Man unquestionably existed during the later portion of 
 what Sir Charles Lyell has termed the "Post-Pliocene" period. 
 In other words, Man's existence dates back to a time when 
 several remarkable Mammals, previously mentioned, had not 
 yet become extinct ; but he does not date back to a time 
 anterior to the present Molluscan fauna. 
 
 2. The antiquity of the so-called Post-Pliocene period is 
 a matter which must be mainly settled by the evidence of 
 Geology proper, and need not be discussed here. 
 
 3. The extinct Mammals with which man coexisted in 
 Western Europe are mostly of large size, the most important 
 being the Mammoth (Elephas primigenius}, the Woolly Rhino- 
 ceros (Rhinoceros tichorhinus), the Cave-lion (Felis spelcea}, the 
 Cave-hyaena (Hycena spelcea), and the Cave-bear ( Ursus spelceus}. 
 We do not know the causes which led to the extinction of 
 these Mammals ; but we know that hardly any Mammalian 
 species has become extinct during the historical period.
 
 FAUNA OF THE POST-PLIOCENE. 365 
 
 4. The extinct Mammals with which man coexisted are re- 
 ferable in many cases to species which presumably required a 
 very different climate to that now prevailing in Western Europe. 
 How long a period, however, has been consumed in the bring- 
 ing about of the climatic changes thus indicated, we have no 
 means of calculating with any approach to accuracy. 
 
 5. Some of the deposits in which the remains of man have 
 been found associated with the bones of extinct Mammals, are 
 such as to show incontestably that great changes in the phy- 
 sical geography and surface-configuration of Western Europe 
 have taken place since the period of their accumulation. We 
 have, however, no means at present of judging of the lapse of 
 time thus indicated except by analogies and comparisons which 
 may be disputed. 
 
 6. The human implements which are associated with the 
 remains of extinct Mammals, themselves bear evidence of an 
 exceedingly barbarous condition of the human species. Post- 
 Pliocene or " Palaeolithic " Man was clearly unacquainted with 
 the use of any of the metals. Not only so, but the workman- 
 ship of these ancient races was much inferior to that of the 
 later tribes, who were also ignorant of the metals, and who 
 also used nothing but weapons and tools of stone, bone, &c. 
 
 7. Lastly, it is only with the human remains of the Post- 
 Pliocene period that the palaeontologist proper has to deal. 
 When we enter the " Recent" period, in which the remains of 
 Man are associated with those of existing species of Mammals, 
 we pass out of the region of pure paleontology into the do- 
 main of the Archaeologist and the Ethnologist. 
 
 LITERATURE. 
 
 The following are some of the principal works and memoirs to which 
 the student may refer for information as to the Post-Pliocene deposits and 
 the remains which they contain, as well as to the primitive races of man- 
 kind : 
 
 (1) 'Elements of Geology.' Lyell. 
 
 (2) 'Antiquity of Man.' Lyell. 
 
 (3) ' Palaeontological Memoirs.' Falconer. 
 
 (4) 'The Great Ice-age.' James Geikie. 
 'Manual of Palaeontology.' Owen. 
 
 1 British Fossil Mammals and Birds.' Owen. 
 'Cave-Hunting.' Boyd Dawkins. 
 ' Prehistoric Times.' Lubbock. 
 (9) ' Ancient Stone Implements.' Evans, 
 (to) ' Prehistoric Man.' Daniel Wilson, 
 (n) 'Prehistoric Races of the United States.' Foster. 
 (12) ' Manual of Geology.' Dana. 
 25
 
 366 HISTORICAL PALAEONTOLOGY. 
 
 (13) 'Monograph of Pleistocene Mammalia' (Palaeontographical So- 
 
 ciety). Boyd Dawkins and Sanford. 
 
 (14) 'Monograph of the Post-Tertiary Entomostraca of Scotland, &c., 
 
 with an Introduction on the Post-Tertiary Deposits of Scotland ' 
 (Ibid.) G. S. Brady, H. W. Crosskey, and D. Robertson. 
 
 (15) "Reports on Kent's Cavern" 'British Association Reports.' 
 
 Pengelly. 
 
 (16) "Reports on the Victoria Cavern, Settle" 'British Association 
 
 Reports.' Tiddeman. 
 
 (17) ' Ossemens Fossiles. ' Cuvier. 
 
 (18) 'Reliquiae Diluvianre.' Buckland. 
 
 (19) "Fossil Mammalia" 'Zoology of the Voyage of the Beagle.' 
 
 Owen. 
 
 (20) ' Description of the Tooth and Part of the Skeleton of the Glyp- 
 
 todonS Owen. 
 
 (21) " Memoir on the Extinct Sloth Tribe of North America " ' Smith- 
 
 sonian Contributions to Knowledge. ' Leidy. 
 
 (22) " Report on Extinct Mammals of Australia " ' British Association,' 
 
 1844. Owen. 
 
 (23) ' Description of the Skeleton of an Extinct Gigantic Sloth (Mylodon 
 
 robustus).' Owen. 
 
 (24) "Affinities and Probable Habits of Thylacoleo" 'Quart. Journ. 
 
 Geol. Soc.,' vol. xxiv. Flower. 
 
 (25) ' Prodromus of the Palaeontology of Victoria.' M'Coy. 
 
 (26) ' Les Ossemens Fossiles des Cavernes de Liege.' Schmerling. 
 
 (27) ' Die Fauna der Pfahlbauten in der Schweiz.' Riitimeyer. 
 
 (28) " Extinct and Existing Bovine Animals of Scandinavia " ' Annals 
 
 of Natural History,' ser. 2, vol. iv., 1849. Nilsson. 
 
 (29) ' Man's Place in Nature.' Huxley. 
 
 (30) 'Les Temps Antehistoriques en Belgique.' Dupont. 
 
 (31) "Classification of the Pleistocene Strata of Britain and the Conti- 
 
 nent" 'Quart. Journ. Geol. Soc., 'vol. xxviii. Boyd Dawkins. 
 
 (32) ' Distribution of the Post -Glacial Mammalia' (Ibid.), vol. xxv. 
 
 Boyd Dawkins. 
 
 (33) 'On British Fossil Oxen' (Ibid.), vols. xxii. and xxiii. Boyd 
 
 Dawkins. 
 
 (34) 'British Prehistoric Mammals' (Congress of Prehistoric Archae- 
 
 ology, 1868). Boyd Dawkins. 
 
 (35) ' Reliquiae Aquitanicse.' Lartet and Christy. 
 
 (36) 'Zoologie et Paleontologie Fra^aises.' Gervais. 
 
 (37) ' Notes on the Post-Pliocene Geology of Canada.' Dawson. 
 
 (38) " On the Connection between the existing Fauna and Flora ol Great 
 
 Britain and certain Geological Changes" 'Mem. Geol. Survey.' 
 Edward Forbes. 
 
 (39) 'Cavern-Researches.' M'Enery. Edited by Vivian. 
 
 (40) "Quaternary Gravels" 'Quart. Journ. Geol. Soc.,' vol. xxv. 
 
 Tylor.
 
 SUCCESSION OF LIFE UPON THE GLOBE. 367 
 
 CHAPTER XXIII. 
 THE SUCCESSION OF LIFE UPON THE GLOBE. 
 
 In conclusion, it may not be out of place if we attempt to 
 summarise, in the briefest possible manner, some of the prin- 
 cipal results which may be deduced as to the succession of 
 life upon the earth from the facts which have in the preceding 
 portion of this work been passed in review. That there was 
 a time when the earth was void of life is universally admitted, 
 though it may be that the geological record gives us no direct 
 evidence of this. That the globe of to-day is peopled with 
 innumerable forms of life whose term of existence has been, 
 for the most part, but as it were of yesterday, is likewise an 
 assertion beyond dispute. Can we in any way connect the 
 present with the remote past, and can we indicate even im- 
 perfectly the conditions and laws under which the existing 
 order was brought about? The long series of fossiliferous 
 deposits, with their almost countless organic remains, is the 
 link between what has been and what is ; and if any answer 
 to the above question can be arrived at, it will be by the 
 careful and conscientious study of the facts of Palaeontology. 
 In the present state of our knowledge, it may be safely said 
 that anything like a dogmatic or positive opinion as to the 
 precise sequence of living forms upon the globe, and still 
 more as to the manner in which this sequence may have been 
 brought about, is incapable of scientific proof. There are, 
 however, certain general deductions from the known facts 
 which may be regarded as certainly established. 
 
 In the first place, it is certain that there has been a succession 
 of life upon the earth, different specific and generic types suc- 
 ceeding one another in successive periods. It follows from 
 this, that the animals and plants with which we are familiar as 
 living, were not always upon the earth, but that they have been 
 preceded by numerous races more or less differing from them. 
 What is true of the species of animals and plants, is true also 
 of the higher zoological divisions ; and it is, in the second 
 place, quite certain that there has been a similar succession in 
 the order of appearance of the primary groups (" sub-king- 
 doms," "classes," &c.) of animals and vegetables. These 
 great groups did not all come into existence at once, but they 
 made their appearance successively. It is true that we can- 
 not be said to be certainly acquainted with the first absolute
 
 368 HISTORICAL PALAEONTOLOGY. 
 
 appearance of any great group of animals. No one dare 
 assert positively that the apparent first appearance of Fishes 
 in the Upper Silurian is really their first introduction upon the 
 earth : indeed, there is a strong probability against any such 
 supposition. To whatever extent, however, future discoveries 
 may push back the first advent of any or of all of the great 
 groups of life, there is no likelihood that anything will be found 
 out which will materially alter the relative succession of these 
 groups as at present known to us. It is not likely, for 
 example, that the future has in store for us any discovery by 
 which it would be shown that Fishes were in existence before 
 Molluscs, or that Mammals made their appearance before 
 Fishes. The sub-kingdoms of Invertebrate animals were all 
 represented in Cambrian times and it might therefore be in- 
 ferred that these had all come simultaneously into existence ; 
 but it is clear that this inference, though incapable of actual 
 disproof, is in the last degree improbable. Anterior to the 
 Cambrian is the great series, of the Laurentian, which, owing 
 to the metamorphism to which it has been subjected, has so 
 far yielded but the singular Eozoon. We may be certain, 
 however, that others of the Invertebrate sub-kingdoms besides 
 the Protozoa were in existence in the Laurentian period ; and 
 we may infer from known analogies that they appeared suc- 
 cessively, and not simultaneously. 
 
 When we come to smaller divisions than the sub -king- 
 doms such as classes, orders, and families a similar suc- 
 cession of groups is observable. The different classes of 
 any given sub-kingdom, or the different orders of any given 
 class, do not make their appearance together and all at once, 
 but they are introduced upon the earth in succession. More 
 than this, the different classes of a sub-kingdom, or the differ- 
 ent orders of a class, in the main succeed one another in the 
 relative order of their zoological rank the lower groups appear- 
 ing first and the higher groups last. It is true that in the 
 Cambrian formation the earliest series of sediments in which 
 fossils are abundant we find numerous groups, some very 
 low, others very high, in the zoological scale, which appear 
 to have simultaneously flashed into existence. For reasons 
 stated above, however, we cannot accept this appearance as 
 real ; and we must believe that many of the Cambrian groups 
 of animals really came into being long before the commence- 
 ment of the Cambrian period. At any rate, in the long series 
 of fossiliferous deposits of later date than the Cambrian the 
 above-stated rule holds good as a broad generalisation that 
 the lower groups, namely, precede the higher in point of time ;
 
 SUCCESSION OF LIFE UPON THE GLOBE. 369 
 
 and though there are apparent exceptions to the rule, there 
 are none of such a nature as not to admit of explanation. 
 Some of the leading facts upon which this generalisation is 
 founded will be enumerated immediately ; but it will be well, 
 in the first place, to consider briefly what we precisely mean 
 when we speak of " higher" and " lower" groups. 
 
 It is well known that naturalists are in the habit of " clas- 
 sifying" the innumerable animals which now exist upon the 
 globe ; or, in other words, of systematically arranging them into 
 groups. The precise arrangement adopted by one naturalist 
 may differ in minor details from that adopted by another ; but 
 all are agreed as to the fundamental points of classification, 
 and all, therefore, agree in placing certain groups in a certain 
 sequence. What, then, is the principle upon which this 
 sequence is based ? Why, for example, are the Sponges placed 
 below the Corals; these below the Sea-urchins; and these, again, 
 below the Shell-fish? Without entering into a discussion of 
 the principles of zoological classification, which would here be 
 out of place, it must be sufficient to say that the sequence in 
 question is based upon the relative type of organisation of the 
 groups of animals classified. The Corals are placed above the 
 Sponges upon the ground that, regarded as a whole, the pic,;:, 
 or type of structure of a Corai is more complex than that of a 
 Sponge. It is not in the slightest degree that the Sponge is in 
 any respect less highly organised or less perfect, as a Sponge, 
 than is the Coral as a Coral. Each is equally perfect in its 
 o\vn way ; but the structural pattern of the Coral is the highest, 
 and therefore it occupies a higher place in the zoological scale. 
 It is upon this principle, then, that the primary subdivisions 
 of the animal kingdom (the so-called "sub-kingdoms") are 
 arranged in a certain order. Coming, again, to the minor 
 subdivisions (classes, orders, &c.) of each sub-kingdom, we 
 find a different but entirely analogous principle employed as a 
 means of classification. The numerous animals belonging to 
 any given sub-kingdom are formed upon the same fundamental 
 plan of structure; but they nevertheless admit of being ar- 
 ranged in a regular series of groups. All the Shell-fish, for 
 example, are built upon a common plan, this plan representing 
 the ideal Mollusc; but there are at the same time various 
 groups of the Mollusca, and these groups admit of an arrange- 
 ment in a given sequence. The principle adopted in this case 
 is simply of the relative elaboration of the common type. The 
 Oyster is built upon the same ground-plan as the Cuttle-fish; but 
 this plan is carried out with much greater elaboration, and with 
 many more complexities, in the latter than in the former : and
 
 3/0 HISTORICAL PALAEONTOLOGY. 
 
 in accordance with this, the Cephalopoda constitute a higher 
 group than the Bivalve Shell-fish. As in the case of superiority 
 of structural type, so in this case also, it is not in the least that 
 the Oyster is an imperfect animal. On the contrary, it is just 
 as perfectly adapted by its organisation to fill its own sphere 
 and to meet the exigencies of its own existence as is the 
 Cuttle-fish ; but the latter lives a life which is, physiologically, 
 higher than the former, and its organisation is correspondingly 
 increased in complexity. 
 
 This being understood, it may be repeated that, in the 
 main, the succession of life upon the globe in point of time 
 has corresponded with the relative order of succession of the 
 great groups of animals in zoological rank ; and some of the 
 more striking examples of this may be here alluded to. 
 Amongst the Echinoderms, for instance, the two orders gen- 
 erally admitted to be the " lowest " in the zoological scale 
 namely, the Crinoids and the Cystoids are likewise the oldest, 
 both appearing in the Cambrian, the former slowly dying out 
 as we approach the Recent period, and the latter disappearing 
 wholly before the close of the Palaeozoic period. Amongst the 
 Crustaceans, the ancient groups of the Trilobites, Ostracodes, 
 Phyllopods, Eurypterids, and Limuloids, some of which exist 
 at the present day, are all "low" types; whereas the highly- 
 organised Decapods do not make their appearance till near the 
 close of the Palaeozoic epoch, and they do not become abun- 
 dant till we reach Mesozoic times. Amongst the Mol/usca, 
 those Bivalves which possess breathing-tubes (the " siphonate 
 Bivalves) are generally admitted to be higher than those which 
 are destitute of these organs (the "asiphonate" Bivalves); and 
 the latter are especially characteristic of the Palaeozoic period, 
 whilst the former abound in Mesozoic and Kainozoic forma- 
 tions. Similarly, the Univalves with breathing-tubes and a 
 corresponding notch in the mouth of the shell ("siphonosto- 
 matous " Univalves) are regarded as higher in the scale than 
 the round-mouthed vegetable-eating Sea-snails, in which no 
 respiratory siphons exist ("holostomatous" Univalves); but 
 the latter abound in the Palseozoic rocks whereas the former 
 do not make their appearance till the Jurassic period, and 
 their higher groups do not seem to have existed till the close 
 of the Cretaceous. The Cephalopods, again the highest of all 
 the groups of Mollusca are represented in the Pakeozoic 
 rocks exclusively by Tetrabranchiate forms, which constitute 
 the lowest of the two orders of this class ; whereas the more 
 highly specialised Dibranchiates do not make their appearance 
 till the commencement of the Mesozoic. The Palaeozoic
 
 SUCCESSION OF LIFE UPON THE GLOBE. 371 
 
 Tetrabranchiates, also, are of a much simpler type than the 
 highly complex Ammonitidce of the Mesozoic. 
 
 Similar facts are observable amongst the Vertebrate animals. 
 The Fishes are the lowest class of Vertebrates, and they are 
 the first to appear, their first certain occurrence being in the 
 Upper Silurian ; whilst, even if the Lower Silurian and Upper 
 Cambrian " Conodonts " were shown to be the teeth of Fishes, 
 there would still remain the enormously long periods of the 
 Laurentian and Lower Cambrian, during which there were In- 
 vertebrates, but no Vertebrates. The Amphibians, the next 
 class in zoological order, appears later than the Fishes, and 
 is not represented till the Carboniferous; whilst its highest 
 group (that of the Frogs and Toads) does not make its entrance 
 upon the scene till Tertiary times are reached. The class of 
 the Reptiles, again, the next in order, does not appear till 
 the Permian, and therefore not till after Amphibians of very 
 varied forms had been in existence for a protracted period. 
 The Birds stem to be undoubtedly later than the Reptiles ; 
 but, owing to the uncertainty as tc the exact point of their first 
 appearance, it cannot be positively asserted that they pre- 
 ceded Mammals, as they should have done. Finally, the 
 Mesozoic types of Mammals are mainly, if not exclusively, 
 referable to the Marsupials, one of the lowest orders of the 
 class ; whilst the higher orders of the " Placental " Quadrupeds 
 are not with certainty known to have existed prior to the com- 
 mencement of the Tertiary period. 
 
 Facts of a very similar nature are offered by the succession 
 of Plants upon the globe. Thus the vegetation of the Palaeo- 
 zoic period consisted principally of the lowly-organised groups 
 of the Cryptogamous or Flowerless plants. The Mesozoic 
 formations, up to the Chalk, are especially characterised by the 
 naked seeded Flowering plants the Conifers and the Cycads; 
 whilst the higher groups of the Angiospermous Exogens and 
 Monocotyledons characterise the Upper Cretaceous and Ter- 
 tiary rocks. 
 
 Facts of the above nature and they could be greatly multi- 
 plied seem to point clearly to the existence of some law of 
 progression, though we certainly are not yet in a position to 
 formulate this law, or to indicate the precise manner in which 
 it has operated. Two considerations, also, must not be over- 
 looked. In the first place, there are various groups, some of 
 them highly organised, which make their appearance at an ex- 
 tremely ancient date, but which continue throughout geological 
 time almost unchanged, and certainly unprogressive. Many of 
 these " persistent types " are known such as various of the
 
 3/2 HISTORICAL PALAEONTOLOGY. 
 
 Foraminifera, the Lingula, the Nautili, &c. ; and they indicate 
 that under given conditions, at present unknown to us, it is 
 possible for a life-form to subsist for an almost indefinite period 
 without any important modification of its structure. In the 
 second place, whilst the facts above mentioned point to some 
 general law of progression of the great zoological groups, it 
 cannot be asserted that the primeval types of any given group 
 are necessarily " lower," zoologically speaking, than their 
 modern representatives. Nor does this seem to be at all 
 necessary for the establishment of the law in question. It 
 cannot be asserted, for example, that the Ganoid and Placoid 
 Fishes of the Upper Silurian are in themselves less highly 
 organised than their existing representatives ; nor can it even 
 be asserted that the Ganoid and Placoid orders are low groups 
 of the class Pisces. On the contrary, they are high groups ; 
 but then it must be remembered that these are probably not 
 really the first Fishes, and that if we meet with Fishes at some 
 future time in the Lower Silurian or Cambrian, these may 
 easily prove to be representatives of the lower orders of the 
 class. This question .cannot be further entered into here, as 
 its discussion could be carried out to an almost unlimited 
 length; but whilst there are facts pointing both ways, it 
 appears that at present we are not justified in asserting that the 
 earlier types of each group so far as these are known to us, 
 or really are without predecessors are necessarily or invariably 
 more " degraded " or " embryonic " in their structure than 
 their more modern representatives. 
 
 It remains to consider very briefly how far Palaeontology 
 supports the doctrine of " Evolution," as it is called ; and this, 
 too, is a question of almost infinite dimensions, which can but 
 be glanced at here. Does Palaeontology teach us that the 
 almost innumerable kinds of animals and plants which we 
 know to have successively flourished upon the earth in past 
 times were produced separately and wholly independently of 
 each other, at successive periods? or does it point to the 
 theory that a large number of these supposed distinct forms 
 have been in reality produced by the slow modification of a 
 comparatively small number of primitive types ? Upon the 
 whole, it must be unhesitatingly replied that the evidence of 
 Palaeontology is in favour of the view that the succession of 
 life-forms upon the globe has been to a large extent regulated 
 by some orderly and constantly-acting law of modification and 
 evolution. Upon no other theory can we comprehend how 
 the fauna of any given formation is more closely related to 
 that of the formation next below in the series, and to that of
 
 SUCCESSION OF LIFE UPON THE GLOBE. 373 
 
 the formation next above, than to that of any other series of 
 deposits. Upon no other view can we comprehend why the 
 Post-Tertiary Mammals of South America should consist prin- 
 cipally of Edentates, Llamas, Tapirs, Peccaries, Platyrhine 
 Monkeys, and other forms now characterising this continent ; 
 whilst those of Australia should be wholly referable to the 
 order of Marsupials. On no other view can we explain the 
 common occurrence of " intermediate " or " transitional " 
 forms of life, filling in the gaps between groups now widely 
 distinct. 
 
 On the other hand, there are facts which point clearly to the 
 existence of some law other than that of evolution, and pro- 
 bably of a deeper and more far-reaching character. Upon no 
 theory of evolution can we find a satisfactory explanation for 
 the constant introduction throughout geological time of new 
 forms of life, which do not appear to have been preceded by 
 pre-existent allied types. The Graptolites and Trilobites have 
 no known predecessors, and leave no known successors. The 
 Insects appear suddenly in the Devonian, and the Arachnides 
 and Myriapods in the Carboniferous, under well-differentiated 
 and highly-specialised types. The Dibranchiate Cephalopods 
 appear with equal apparent suddenness in the older Mesozoic 
 deposits, and no known type of the Palaeozoic period can be 
 pointed to as a possible ancestor, The Hippuritidtz of the 
 Cretaceous burst into a varied life to all appearance almost 
 immediately after their first introduction into existence. The 
 wonderful Dicotyledonous flora of the Upper Cretaceous 
 period similarly surprises us without any prophetic annuncia- 
 tion from the older Jurassic. 
 
 Many other instances could be given ; but enough has been 
 said to show that there is a good deal to be said on both sides, 
 and that the problem is one environed with profound difficul- 
 ties. One point only seems now to be universally conceded, 
 and that is, that the record of life in past time is not interrupted 
 by gaps other than those due to the necessary imperfections of 
 the fossiliferous series, to the fact that many animals are in- 
 capable of preservation in a fossil condition, or to other causes 
 of a like nature. All those who are entitled to speak on this 
 head are agreed that the introduction of new and the destruc- 
 tion of old species have been slow and gradual processes, in no 
 sense of the term " catastrophistic." Most are also willing to 
 admit that " Evolution " has taken place in the past, to a 
 greater or less extent, and that a greater or less number of so- 
 called species of fossil animals are really the modified descend- 
 ants of pre-existent forms. How this process of evolution has
 
 3/4 HISTORICAL PALEONTOLOGY. 
 
 been effected, to what extent it has taken place, under what 
 conditions and laws it has been carried out, and how far it 
 may be regarded as merely auxiliary and supplemental to some 
 deeper law of change and progress, are questions to which, in 
 spite of the brilliant generalisations of Darwin, no satisfactory 
 answer can as yet be given. In the successful solution of this 
 problem if soluble with the materials available to our hands 
 will lie the greatest triumph that Palaeontology can hope to 
 attain ; and there is reason to think that, thanks to the guiding- 
 clue afforded by the genius of the author of the ' Origin of 
 Species,' we are at least on the road to a sure, though it may 
 be a far-distant, victory.
 
 APPENDIX. 
 
 TABULAR VIEW OF THE CHIEF DIVISIONS 
 OF THE ANIMAL KINGDOM. 
 
 (Extinct groups are marked with an asterisk. Groups not represented 
 at all as fossils are marked with two asterisks. ) 
 
 INVERTEBRATE ANIMALS. 
 SUB-KINGDOM I. PROTOZOA. 
 
 Animal simple or compound ; body composed of "sarcode," not de- 
 gmented ; no nervous sy 
 lly a mouth and gullet. 
 
 finitely segmented ; no nervous system ; and no digestive apparatus, beyond 
 occasionall 
 
 CLASS I. GREGARINID^E.** 
 CLASS II. RHIZOPODA. 
 
 Order I. Monera.** 
 
 ii 2. Amcebea.** 
 
 it 3. Foraminifera. 
 
 ii 4. Radiolaria (Polycystines, &c.) 
 
 n 5. Spongida (Sponges). 
 CLASS III. INFUSORIA.** 
 
 SUB-KINGDOM II. CCELENTERATA. 
 
 Animal simple or compound ; body-wall composed of two principal 
 layers ; digestive canal freely communicating with the general cavity of the 
 body ; no circulating organs, and no nervous system or a rudimentary one ; 
 mouth surrounded by tentacles, arranged, like the internal organs, in a 
 " radiate " or star-like manner. 
 
 CLASS I. HYDROZOA. 
 
 Sub-class I. Hydroida (" Hydroid Zoophytes"). Ex. 'Fresh- 
 
 water Polypes,** Pipe - corallines (Tubularia), Sea - Firs 
 
 (Sertularia). 
 Sub-class 2. Siphonophora** ("Oceanic Hydrozoa"). Ex. 
 
 Portuguese Man-of-war {Physalia}.
 
 3/6 APPENDIX. 
 
 Sub-class 3. Discophora ("Jelly-fishes"). Only known as fossils 
 by impressions of their stranded carcasses. 
 
 Sub-class 4. Lucerncirida ("Sea-blubbers"). Also only known 
 as fossils by impressions left in fine-grained strata. 
 
 Sub-class 5. Graptolituice* (" Graptolites "). 
 CLASS II. ACTINOZOA. 
 
 Order I. Zoantharia. Ex. Sea-anemones** (Actinida), Star- 
 corals (Astrczida:), 
 
 Order 2. Alcyonaria. Ex. Sea-pens (Pennatuld), Organ-pipe 
 Coral (Tubipord), Red Coral (Corallium). 
 
 Order 3. Rugosa (" Rugose Corals"). 
 
 .. 4. Ctenophora** Ex. Venus's Girdle (Cesium}. 
 
 SUB-KINGDOM III. ANNULOIDA. 
 
 Animals in which the digestive canal is completely shut off from the 
 cavity of the body ; a distinct nervous system ; a system of branched 
 "water-vessels," which usually communicate with the exterior. Body of 
 the adult often ""radiate," and never composed of a succession of definite 
 rings. 
 CLASS I. ECHINODERMATA. 
 
 Order I. Crinoidea ("Sea-lilies"). Ex. Feather-star Coma- 
 tula), Stone-lily (Encrinus*). 
 Order 2. Blastoidm* (" Pentremites "). 
 .. 3. Cystoidea* ("Globe-lilies"). 
 
 ii 4. Ophiuroidea (" Brittle-stars "). Ex. Sand-stars (Ophi~ 
 ura), Brittle-stars (Ophiocoma). 
 Order 5. Asteroidea (" Star-fishes "). Ex. Cross-fish (Uraster), 
 
 Sun-star (Solaster). 
 Order 6. Echinoidea ("Sea-urchins"). Ex. Sea-eggs (Echinus), 
 
 Heart-urchins (Spatangus). 
 Order 7. Holothuroidea (" Sea -cucumbers "). Ex. Trepangs 
 
 (Holothuria). 
 CLASS II. SCOI.ECIDA ** (Intestinal Worms, Wheel Animalcules, &c.) 
 
 SUB-KINGDOM IV. ANNULOSA. 
 
 Animal composed of numerous definite segments placed one behind the 
 other ; nervous system forming a knotted cord placed along the lower 
 (ventral) surface of the body. 
 
 Division A. Anarthropoda. No jointed limbs. 
 CLASS I. GEPHYREA** ("Spoon-worms"). 
 CLASS II. ANNELIDA ("Ringed-worms"'). Ex. Leeches** (ffirudinea), 
 
 Earthworms** (Oligocha:ta\ Tube-worms (Tubicola), Sea -worms 
 
 and Sea-centipedes (Errantid). 
 CLASS III. CH^ETOGNATHA ** ("Arrow- worms"). 
 
 Division B. Arthropoda or Articulata. Limbs jointed to the body. 
 CLASS I. CRUSTACEA ("Crustaceans"). Ex. Barnacles and Acorn- 
 shells (Cirripedia) , Water -fleas (Ostracoda), Brine - shrimps and 
 Fairy-shrimps (PhyllopoJa), Trilobites * (Trilobita), King-crabs 
 and Eurypterids* (Merostomata), Wood-lice and Slaters (hopoda), 
 Sand-hoppers (Amphipoda), Lobsters, Shrimps, Hermit-crabs, and 
 Crabs (Decapodd).
 
 APPENDIX. 377 
 
 CLASS II. ARACHNIDA. Ex. Mites (Acarina), Scorpions (Pedipalpi), 
 Spiders (Aramida). 
 
 CLASS III. MYRIAPODA. Ex. Centipedes (Chtlopoda), Millipedes and 
 Galley- worms (Chilognatha). 
 
 CLASS IV. INSECTA ("Insects"). Ex. Field-bugs (Hemiptera) ; Crick- 
 ets, Grasshoppers, &c. (Orthoptera); Dragon-flies and May-flies 
 (Neuroptera) ; Gnats and House-flies (Diptera) ; Butterflies and 
 Moths (Lepidoptera) ; Bees, Wasps, and Ants (Hymenopterd) j 
 Beetles (Coleoptini). 
 
 SUB-KINGDOM V. MOLLUSCA. 
 
 Animal soft-bodied, generally with a hard covering or shell ; no dis- 
 tinct segmentation of the body ; nervous system of scattered masses. 
 CLASS I. POLVZOA ("Sea-Mosses"). Ex. Sea-mats (Flustra); Lace- 
 corals (Fenestellidee *). 
 
 CLASS II. TUNICATA** ("Tunicaries"). Ex. Sea-squirts (Ascidia}. 
 CLASS III. BRACHIOPODA ("Lamp-shells"). Ex. Goose-bill Lamp- 
 
 shell (Lingula). 
 CLASS IV. LAMKLLIBRANCHIATA ("Bivalves"). Ex. Oyster (Ostrea), 
 
 Mussel (Mytilus), Scallop (Pecten), Cockle (Cardium). 
 CLASS V. GASTEROPODA ("Univalves"). Ex. Whelks (Bucdmim), 
 
 Limpets (Patella), Sea-slugs** (Doris), Land-snails (ffelix). 
 CLASS VI. PTEROPODA (" Winged Snails"). Ex. Hyalea, Cleodora. 
 CLASS VII. CEPHALOPODA ("Cuttle-fishes"). Ex. Calamary (Loligo), 
 Poulpe (Octopus), Paper Nautilus (Argonattta), Pearly Nautilus 
 (Nautilus), Belemnites,* Orthoceratites,* Ammonites.* 
 
 VERTEBRATE ANIMALS. 
 
 SUB-KINGDOM VI. VERTEBRATA. 
 
 Body composed of definite segments arranged longitudinally one behind 
 the other ; main masses of the nervous system placed dorsally ; a back- 
 bone or " vertebral column " in the majority. 
 
 CLASS I. PISCES (" Fishes"). Ex. Lancelet** (Amphioxus) ; Lampreys 
 and Hag-fishes (Marsipobranchii'* *} ; Herring, Salmon, Perch, c. 
 (Telcostel or " Bony Fishes "); Gar-pike, Sturgeon, &c. (Ganoidei}; 
 Sharks, Dog-fishes, Rays, &c. (Elasmobranchii or "Placoids"). 
 CLASS II. AMPHIBIA ("Amphibians"). Ex. Labyrinthodontia,* Cse- 
 cilians,** Newts and Salamanders (Urodela), Frogs and Toads 
 (Anoura). 
 
 CLASS III. REPTILIA ("Reptiles"). Ex. Deinosaitria* Plerosauria* 
 Anomodontia* Plesiosaurs (Sauroptcrygia*), Ichthyosaurs (Ichthy- 
 opterygia *), Tortoises and Turtles (Chelonia), Snakes (Ophidia), 
 Lizards (Lacei'tilia), Crocodiles (Crocodilid). 
 
 CLASS IV. AVES ("Birds"). Ex. Toothed Birds (Odontornithes*} ; 
 Lizard-tailed Birds (Archccopteryx *) ; Ducks, Geese, Gulls, &c. 
 (Natatores) ; Storks, Herons, Snipes, Plovers, &c. (GraHotvrcs) ; 
 Ostrich, Emeu, Cassowary, Dinornis,* yEpiornis,* &c. (Cursorcs) ; 
 FcAvls, Game Birds, and Doves (Rasores) ; Cuckoos, Woodpeckers, 
 Parrots, &c. (Scansores) ; Crows, Starlings, Finches, Humming- 
 birds, Swallows, &c. (Insessores) ; Owls, Hawks, Eagles, Vultures 
 (Raptores).
 
 378 APPENDIX. 
 
 CLASS V. MAMMALIA ("Quadrupeds"). Ex. Duck-mole and Spiny 
 Ant-eater (Monotremata**) ; Kangaroos, Phalangers, Opossums, 
 Tasmanian Devil, &c. (Marsupialia) ; Sloths, Ant-eaters, Arma- 
 dillos (Edentata) ; Manatees and Dugongs (Sirenia) Whales, 
 Dolphins, Porpoises (Cetacea) ; Rhinoceros, Tapir, Horses, Hip- 
 popotamus, Pigs, Camels and Llamas, Giraffes, Deer, Antelopes, 
 Sheep, Goats, Oxen (Ungulata) ; Hyrax (Hyracoidea**}; Ele- 
 phants, Mastodon,* Deinotherium* (Proboscidea) ; Seals, Walrus, 
 Bears, Dogs, Wolves, Cats, Lions, Tigers, &c. (Carnivora) ; 
 Hares, Rabbits, Porcupines, Beavers, Rats, Mice, Lemmings, 
 Squirrels, Marmots, &c. (Rodentia) ; Bats (Cheiroptera) ; Moles, 
 Shrew-mice, Hedgehogs (Inscctivora) ; Lemurs, Spider-monkeys, 
 Macaques, Baboons, Apes (Quadrumana) ; Man (Bimana).
 
 GLOSSARY. 
 
 ABDOMEN (Lat. abdo, I conceal). The posterior cavity of the body, contain- 
 ing the intestines and others of the viscera. In many Invertebrates there 
 is no separation of the body-cavity into thorax and abdomen, and it is only 
 in the higher Annulosa that a distinct abdomen can be said to exist. 
 
 ABERRANT (Lat. aberro, I wander away). Departing from the regular type. 
 
 ABNORMAL (Lat. ab, from ; norma, a rule). Irregular ; deviating from the 
 ordinary standard. 
 
 ACRODUS (Gr. akros, high ; odous, tooth). A genus of the Cestraciont fishes, 
 so called from the elevated teeth. 
 
 ACROGENS (Gr. akros, high ; gennao, I produce). Plants which increase in 
 height by additions made to the summit of the stem by the union of the 
 bases of the leaves. 
 
 ACROTRETA (Gr. akros, high ; tretos, pierced). A genus of Brachiopods, so 
 called from the presence of a foramen at the summit of the shell. 
 
 ACTINOCRINUS (Gr. aktin, a ray ; krinon, a lily). A genus of Crinoids. 
 
 ACTINOZOA (Gr. aktin, a ray ; and zoon, an animal). That division of the 
 Ccelenterata of which the Sea-anemones may be taken as the type. 
 
 MOLINA (^Erjle, a sea-nymph). A genus of Trilobites. 
 
 ^EPIORNIS (Gr. aipus, 'huge ; ornis, bird). A genus of gigantic Cursorial 
 birds. 
 
 AGNOSTUS (Gr. a, not ; gignosko, I know). A genus of Trilobites. 
 
 ALCES ( Lat. alces, elk). The European Elk or Moose. 
 
 A-LECTO (the proper name of one of the Furies). A genus of Polyzoa. 
 
 ALETHOPTERIS (Gr. alethes, true ; pteris, fern). A genus of Ferns. 
 
 ALGJE (Lat. alga, a marine plant). The order of plants comprising the Sea- 
 weeds and many fresh-water plants. 
 
 ALVEOLUS (Lat. alvus, belly). Applied to the sockets of the teeth. 
 
 AMBLYPTERUS (Gr. amblus, blunt ; pteron, fin). An order of Ganoid Fishes. 
 
 AMBONYCHIA (Gr. ambon, a boss ; onux, claw). A genus of Palaeozoic Bi- 
 valves. 
 
 AMBULACRA (Lat. ambulacrum, a place for walking). The perforated spaces 
 or " avenues " through which are protruded the tube-feet, by means of which 
 locomotion is effected in the Echinodermata. 
 
 AMMONITID^E. A family of Tetrabranchiate Cephaloppds, so called from the 
 resemblance of the shell of the type-genus, Ammonites, to the horns of the 
 Egyptian God, Jupiter-Ammon. 
 
 AMORPHOZOA (Gr. a, without ; morphe, shape ; zob'n, animal). A name some- 
 times used to designate the Sponges. 
 
 AMPHIBIA (Gr. amphi, both ; bios, life). The Frogs, Newts, and the like, 
 which have gills when young, but can always breathe air directly when 
 adult. 
 
 AMPHICYON (Gr. amphi, both implying doubt ; kuon, dog). An extinct 
 genus of Carnivora.
 
 380 GLOSSARY. 
 
 AMPHILESTES (Gr. amphi, both ; lestes, a thief). A germs of Jurassic Mam- 
 
 mals. 
 AMPHISPONGIA (Gr. amphi, both ; spoygos, sponge). A genus of Silurian 
 
 sponges. 
 
 AMPHISTEGINA (Gr. amphi, both ; siege, roof). A genus of Foraminifera. 
 AMPHITHEBIUM (Gr. amphi, both ; therion, beast). A genus of Jurassic Mam- 
 mals. 
 AMPHITRAGULUS (Gr. amphi, both ; dim. of trar/os, goat). An extinct genus 
 
 related to the living Musk-deer. 
 
 AMPLEXUS (Lat. an embrace). A genus of Rugose Corals. 
 AMPYX (Gr. ampux, a wreath or wheel). A genus of Trilobites. 
 ANARTHROPODA (Gr. a. without ; arthros, a joint ; pous, foot). That division 
 
 of Annulose animals in which there are no articulated appendages. 
 ANCHITHERIOM (Gr. aychi, near ; therion, beast). An extinct genus of Mammals. 
 ANCYLOCERAS (Gr. agkulos, crooked; ceras, horn). A genus of A mnumitidce. 
 ANCYLOTHERIUM (Gr. agkulos, crooked ; therion, beast). An extinct genus of 
 
 Edentate Mammals. 
 
 ANDRIAS (Gr. andrias, image of man). An extinct genus of tailed Amphi- 
 bians. 
 ANGIOSPERMS (Gr. anyeion, a vessel ; sperma, seed). Plants which have their 
 
 seeds enclosed in a seed-vessel. 
 ANNELIDA (a Gallicised form of Annulatd). The Ringed Worms, which form 
 
 one of the divisions of the Anarthropoda. 
 ANNULARIA (Lat. annulus, a ring). A genus of Palaeozoic plants, with leaves 
 
 in whorls. 
 ANNULOSA (Lat. annulus). The sub-kingdom comprising the Anarthropoda 
 
 and the Arthropoda or Articulata, in all of which the body is more or less 
 
 evidently composed of a succession of rings. 
 ANOMODONTIA (Gr. anomos, irregular; odous, tooth). An extinct order of 
 
 Reptiles, often called Dicynodontia. 
 ANOMURA (Gr. anomos, irregular ; oura, tail). A tribe of Decapod Crustacea, 
 
 of which the Hermit-crab is the type. 
 ANOPLOTHERID.E (Gr. anoplos, unarmed ; thcr, beast). A family of Tertiary 
 
 Ungulates. 
 ANOURA (Gr. a, without ; oura, tail). The order of Amphibia comprising the 
 
 Frogs and Toads, in which the adult is destitute of a tail. Often called 
 
 Bairachia. 
 ANTENNA (Lat. antenna, a yard-arm). The jointed horns or feelers possessed 
 
 by the majority of the Articulata. 
 ANTEXNULES (dim. of Antennae). Applied to the smaller pair of antennae in 
 
 the Crustacea. 
 ANTHRACOSAURUS (Gr. anthrax, coal ; saura, lizard). A genus of Labyrintho- 
 
 dont Amphibians. 
 ANTHRAPAL.EMON (Gr. anthrax, coal ; palcemon, a prawn originally a proper 
 
 name). A genus of long-tailed Crustaceans from the Coal-measures. 
 ANTLERS. Properly the branches of the horns of the Deer tribe (Cervidce], but 
 
 generally applied to the entire horns. 
 APIOCRINID.E (Gr. ap'on, a pear; krinon, lily). A family of Crinoids the 
 
 " Pear-encrinites." 
 APTERYX (Gr. a, without ; pterux, a wing). A wingless bird of New Zealand, 
 
 belonging to the order L'ursores. 
 AQUEOUS (Lat. aqua, water). Formed in or by water. 
 ARACHNIDA (Gr. arachne, a spider). A class of the Articulata, comprising 
 
 Spiders, Scorpions, and allied animals. 
 ARBORESCENT. Branched like a tree. 
 
 ARCHJSOCIDARIS (Gr. archaios, ancient ; Lat. cidaris, a diadem). A Palaeo- 
 zoic genus of Sea-urchins, related to the existing Cidaris. 
 ARCHJEOCYATHUS (Gr. archaios, ancient ; kuathos, c\ip). A genus of Palaeozoic 
 
 fossils allied to the Sponges. 
 ARCH^EOPTERYX (Gr. archaios, ancient ; pterux, a wing). The singular fossil 
 
 bird which alone constitutes the order of the Kaururce.
 
 GLOSSARY. 381 
 
 ARCTOCYON (Gr. arctos, beai ; kuon, dog). An extinct genus of Carnivora. 
 
 ARENACEOUS. Sandy, or composed of grains of sand. 
 
 ARENICOLITES (Lat. arena, sand ; coin, I inhabit). A genus founded on bur- 
 
 rows supposed to be funned by worms resembling the living Lobworms 
 
 (Arenicola). 
 
 ARTICULATA (Lat. articulus, a joint). A division of the animal kingdom, com- 
 prising Insects, Centipedes, Spiders, and Crustaceans, characterised by the 
 possession of jointed bodies or jointed limbs. The term Arthropoda is now 
 
 more usually employed. 
 ARTIODAOTYLA (Gr. artios, even ; daktulos, a finger or toe). A division of the 
 
 hoofed quadrupeds (Uiujulata) in which each foot has an even number of 
 
 toea (two or four). 
 
 ASAPHUS (Gr. asaphes, obscure). A genus of Trilobites. 
 ASCOCERAS (Gr. askos, a leather bottle ; kcras, horn). A genua of Tetrabran- 
 
 chiate Cephalopods. 
 ASIPHONATE. Not possessing a respiratory tul>e or siphon. (Applied to a 
 
 division of the Lamellibrancl< io.te Molluscs.) 
 ASTEROID (Gr. aster, a star; and eidos, form). Star-shaped, or possessing 
 
 radiating lobes or rays like a star-fish. 
 ASTI;ROIDEA. An order of Kchiiwdermata, comprising the Star-fishes, charac- 
 
 terised by their rayed form. 
 ASTEROPHYLLITES (Gr. aster, a star ; phullon, leaf). A genus of Palaeozoic 
 
 plants, with leaves in whorls. 
 
 AsTRjEiD^E (Gr. Astrcea, a proper name). The family of the Star-corals. 
 ASTYLOSPOSGIA (Gr. a, without ; stulos, a column ; spoggos, a sponge). A 
 
 genus of Silurian Sponges. 
 
 ATHYRIS (Gr. a, without ; thura, door). A genus of Brachiopods. 
 ATRYPA (Gr. a, without ; trupa, a hole). A genus of Brachiopods. 
 AYES (Lat. avis, a bird). The class of the Birds. 
 AVICULA (Lat. a little bird). The genus of Bivalve Molluscs comprising the 
 
 Pearl-oysters. 
 AXOPHYLLUM (Gr. axon, a pivot; phullon, a leaf). A genus of Rugose 
 
 Corals. 
 Azoic (Gr. , without; zoe, life). Destitute of traces of living beings. 
 
 BACULITES (Lat. laculum, a staff). A genus of the Ammo nit idee. 
 
 BAL.ENA (Lat. a whale). The genus of the Whalebone Whales. 
 
 BALANIDJE (Gr. balanos, an acorn). A family of sessile Cirripedes, commonly 
 
 called " Acorn-shells." 
 BATRACHIA (Gr. latrachos, a frog). Often loosely applied to any of the Am- 
 
 phibia, but sometimes restricted to the Amphibians as a class, or to the 
 
 single order of the Anoura. 
 BELEMNITID^E (Gr. belemnon, a dart). An extinct group of Dibranchiate Ceph- 
 
 alopods, comprising the Belemnites and their allies. 
 BELEMNOTEUTHIS (Gr. belemnon, a dart ; teuthis, a cuttle-fish). A genus allied 
 
 to the Belemnites proper. 
 
 BELINURUS (Gr. belos, a dart ; oura, tail). A genus of fossil King-crabs. 
 BELLEROPHON (Gr. proper name). A genus of oceanic Univalves (Heteropoda). 
 BKLOTEUTHIS (Gr. belos, a dart ; teuthis, a cuttle-fish). An extinct genus of 
 
 Dibranchiate Cephalopods. 
 
 BEYRICHIA (named after Prof. Beyrich). A genus of Ostracode Crustaceans. 
 BILATERAL. Having two symmetrical sides. 
 BIMANA (Lat. bis, twice ; manus, a hand). The order of Mammalia compris- 
 
 ing man alone. 
 
 BIPEDAL (Lat. bis, twice ; pes, foot). Walking upon two legs. 
 BIVALVE (Lat. bis, twice ; valvte, folding-doors). Composed of two plates or 
 
 valves ; applied to the shell of the Lamellibranchiata and Erach',o L wda, and 
 
 to the carapace of certain Crustacea. 
 BLASTOIDEA (Gr. blastos, a bud ; and eidos, form). An extinct order of Kcld- 
 
 nodcrmata, often called Pentremites. 
 BRACHIOPODA (Gr, b-achion, an arm ; pous, the foot). A class of the Mollut-
 
 382 GLOSSARY. 
 
 coida, often called "Lamp-shells," characterised by possessing two fleshy 
 amis continued from the sides of the mouth. 
 
 BRACHYURA (Gr. brachus, short ; oura, tail). A tribe of the Decapod Crusta- 
 ceans with short tails (i.e., the Crabs). 
 
 BRADYPODID^B (Gr. bradus, slow; podes, feet). The family of Edentata com- 
 prising the Sloths. 
 
 BRANCHIA (Gr. bragchia, the gill of a fish). A respiratory organ adapted to 
 breathe air dissolved in water. 
 
 BRANCHIATE. Possessing gills or branchiae. 
 
 BRONTEUS (Gr. bi-onte, thunder an epithet of Jupiter the Thunderer). A 
 genus of Trilobites. 
 
 BRONTOTHERIUM (Gr. Ironte, thunder ; tliirion beast). An extinct genus of 
 Ungulate Quadrupeds. 
 
 BRONTOZOUM (Gr. bronte, thunder ; won, animal). A genus founded on the 
 largest footprints of the Triassic Sandstones of Connecticut. 
 
 BUCCINUM (Lat, bucdlnwn, a trumpet). The genus of Univalves comprising 
 the Whelks. 
 
 CAINOZOIC (See Kainozoic. ) 
 
 CALAMITES (Lat. calamus, a reed). Extinct plants with reed-like stems, be- 
 lieved to be gigantic representatives of the Equisetacece. 
 
 CALCAREOUS (Lat. calx, lime). Composed of carbonate of lime. 
 
 CALICE. The little cup in which the polype of a coralligenous Zoophyte (Ac- 
 tinozoon) is contained. 
 
 CALYME^E (Gr. kalumSne, concealed). A genus of Trilobites. 
 
 CALYX (Lat. a cup). Applied to the cup-shaped body of a Crinoid (Echino- 
 dermata). 
 
 CAMAROPHORIA (Gr. kamara, a chamber ; phero, I carry). A genus of Brachio- 
 pods. 
 
 CAMELOPARDALID.S; (Lat. camehis, a camel ; pardalis, a panther). The family 
 of the Giraffes. 
 
 CANINE (Lat. canis, a dog). The eye-tooth of Mammals, or the tooth which 
 is placed at or close to the prsemaxillary suture in the upper jaw, and the 
 corresponding tooth in the lower jaw. 
 
 CARAPACE. A protective shield. Applied to the upper shell of Crabs, Lobsters, 
 and many other Crustacea. Also the upper half of the immovable case in 
 which the body of a Chelouian is protected. 
 
 CARCHAUODON (Gr. karcharos. rough ; odous, tooth). A genus of Sharks. 
 
 CARDIOCAHPON (Gr. kardia, the heart ; karpos, fruit). A genus of fossil fruit 
 from the Coal-measures. 
 
 CARDIUM (Gr. kardia,, the heart). The genus of Bivalve Molluscs comprising 
 the Cockles. Cardinia, Cardiola, and C'ardita have the same derivation. 
 
 CARNIVORA (Lat. caro, flesh ; voro, I devour). An order of the Mammalia. 
 The " Beasts of Prey." 
 
 CARNIVOROUS (Lat. caro, flesh ; voro, I devour). Feeding upon flesh. 
 
 CARYOCARIS (Gr. karua, a nut ; karis, a shrimp). A genus of Phyllopod Crus- 
 taceans. 
 
 CARYOCRINUS (Gr. karua, a nut ; krinon, a lily). A genus of Cystideans. 
 
 CAUDAL (Lat. cauda, the tail). Belonging to the tail. 
 
 CAVICORNIA (Lat. cavus, hollow; cnrnu, a horn). The "hollow-horned" 
 Ruminants, in which the horn consists of a central bony "horn-core " sur- 
 rounded by a horny sheath. 
 
 CENTRUM (Gr. kentron, the point round which a circle is described by a pair 
 of compasses). The central portion or "body " of a vertebra. 
 
 CEPHALASPID.E (Gr. kephale, head ; aspis, shield). A family of fossil fishes. 
 
 CKPIIALIC (Gr. kephale, head). Belonging to the head. 
 
 CEPHALOPODA (Gr. kephale ; and podes, feet). A class of the Mollusca, com- 
 prising the Cuttle-fishes and their allies, in which there is a series of aims 
 ranged round the head. 
 
 CKRATIOCARIS (Gr. keras, a horn; karis, a shrimp). A genus of Phyllopod 
 Crustaceans.
 
 GLOSSARY. 383 
 
 CERATITES (Gr. keras, a horn). A genus of Ammonltidce. 
 
 CERATODUS (Gr. keras, a horn ; odous, tooth). A genus of Dipnoous fishes. 
 
 CERVICAL (Lat. cervix, the neck). Connected with or belonging to the region 
 
 of the neck. 
 
 CERVID.S: (Lat. cervus, a stag). The family of the Deer. 
 CESTRAPHORI (Gr. kestra t a weapon ; pfiero, I carry). The group of the " Ces- 
 
 traciont Fishes," represented at the present day by the Port-Jackson Shark ; 
 
 so called from their defensive spines. 
 CETACEA (Gr. ketos, a whale). The order of Mammals comprising the Whales 
 
 and the Dolphins. 
 CETIOSAURUS (Gr. ketos, whale ; saura, lizard). A genus of Deinosaurian 
 
 Reptiles. 
 CHEIROPTERA (Gr. cheir, hand ; pteron, wing). The Mammalian order of the 
 
 Bats. 
 CHEIROTHERIUM (Gr. cheir, hand ; tlierion, beast). The generic name applied 
 
 originally to the hand-shaped footprints of Labyrinthodonts. 
 iCHElRURUS (Gr. cheir, hand oura, tail). A genus of Trilobites. 
 CHELONIA (Gr. chelone, a tortoise). The Reptilian order of the Tortoises and 
 
 Turtles. 
 
 CHOXETES (Gr.. clione or choant, a chamber or box). A genus of Brachiopods. 
 CIDARIS (Lat. a diadem). A genus of Sea-urchins. 
 CLADODUS (Gr. klados, branch ; odoue, tooth). A genus of Fishes. 
 CLATHROPORA (Lat. clathri, a trellis ; porus, a pore). A genus of Lace-corals 
 
 (Polyzoa). 
 
 CLISIOPHYLLUM (Gr. klision, a hut ; phullon, leaf). A genus of Rugose Corals. 
 CLYMENIA (Clumene, a proper name). A genus of Tetrabranchiate Cephalopods. 
 COCCOSTEUS (Gr. kokkos, berry ; osteon, bone). A genus of Ganoid Fishes. 
 COCHLIODUS (Gr. kochlion, a snail-shell ; odous, tooth). A genus of Cestra- 
 
 ciont Fishes. 
 CCELENTERATA (Gr. koilos, hollow ; enteron, the bowel). The sub-kingdom 
 
 which comprises the Hydrozoa and Aclinozoa. Proposed by Frey and 
 
 Leuckhart in place of the old term Radiata, which included other animals 
 
 as well. 
 
 COLF.OPTERA (Gr. koleos, a sheath ; pteron, wing). The order of Insects 
 ( Beetles) in which the anterior pair of wings are hardened, and serve as ro- 
 tective cases for the posterior pair of membranous wings. 
 
 COLOSSOCHELYS (Gr. kolossos, a gigantic statue ; cJielus, a tortoise). A huge 
 
 extinct Land-tortoise. 
 COMATULA (Gr. koma, the hair). The Feather-star, so called in allusion to its 
 
 tress-like arms. 
 CONDYLE (Gr. kondulos, a knuckle). The surface by which one bone articulates 
 
 with another. Applied especially to the articular surface or surfaces by 
 
 which the skull articulates with the vertebral column. 
 CONIFEK^E (Lat. conus, a cone ; fero, I carry). The order of the Firs, Pines, 
 
 and their allies, in which the fruit is generally a " cone " or " fir-apple." 
 CONULARIA (Lat. conulut, a little cone). An extinct genus of Pteropods. 
 COPROLITES (Gr. kopros, dung ; lithos, stone). Properly applied to the fossil- 
 
 ised excrements of animals ; but often employed to designate phosphatic con- 
 
 cretions which are not of this nature. 
 CORALLITE. The corallum secreted by an Actinozoon which consists of a single 
 
 polype ; or the portion of a composite corallum which belongs to, and is 
 
 secreted by, an individual polype. 
 CORALLUM (from the Latin for Red Coral). The hard structures deposited in, 
 
 or by, the tissues of ari Actinozoon commonly called a " coral. 
 CORIACEOUS (Lat. corium. hide). Leathery. 
 CORYPHODON (Gr. korus, helmet ; odous, tooth). An extinct genus of Mam- 
 
 mals, allied to the Tapirs. 
 CRANIUM (Gr. kranion, the skull). The bony or cartilaginous case m which 
 
 the brain is contained, 
 CRETACEOUS (Lat. creta, chalk). The formation which in Europe contains 
 
 white chalk as one of its most conspicuous members.
 
 384 GLOSSARY. 
 
 CRINOIDEA (Gr. krinon, a lily ; eidos, form). An order of Echino<1ennata, 
 
 comprising forms which are usually stalked, and sometimes resemble lilies 
 
 in shape. 
 
 CRIOCERAS (Gr. krios, a ram ; keras, a horn). A genus of Ammonitidce. 
 CROCODILIA (Gr. krokodeilox, a crocodile). An order of Reptiles. 
 CROSSOPTERTGID^: (Gr. krossotos, a fringe ; plerux, a fin). A sub-order of 
 
 Ganoids in which the paired fins possess a central lobe. 
 CRUSTACEA (Lat. crusta, a crust). A class of Articulate animals, comprising 
 
 Crabs, Lobsters, &c., characterised by the possession of a hard shell or 
 
 crust, which they cast periodically. 
 CRYPTOGAMS (Gr. kru.ptos, concealed ; gamo?, marriage). A division of plants 
 
 in which the organs of reproduction are obscure and there are no true 
 
 flowers. 
 CTENACANTHUS (Gr. kteis, a comb ; akantha, a thorn). A genus of fossil fishes, 
 
 named from its fin-spines. 
 CTENOID (Gr. kteis, a comb ; eidos, form). Applied to those scales of fishes 
 
 the hinder margins of which are fringed with spines or comb-like projections. 
 CURSORES (Lat. curro, I run). An order of Avex, comprising birds destitute 
 
 of the power of flight, but formed for running vigorously (e.g., the Ostrich 
 
 and Emeu). 
 
 CUSPIDATE. Furnished with small pointed eminences or " cusps." 
 CYATHOCRINUS (Gr. kuathos, a cup ; krinon, a lily). A genus of Crinoids. 
 CYATHOPHYLLUM (Gr. kuathos, a cup ; phullon, a leaf). A genus of Rugose 
 
 Corals. 
 CYCLOID (Gr. kuklos, a circle ; eidos, form). Applied to those scales of fishes 
 
 which have a regularly circular or elliptical outline with an even margin. 
 CYCLOPHTHALMUS (Gr. kuklos, a circle ; ophthalmos, eye). A genus of fossil 
 ' Scorpions. 
 CYCLOSTOMI (Gr. kuklos, and stoma, mouth). Sometimes used to designate the 
 
 Hag-fishes and Lampreys, forming the order M>'rsipobranchii. 
 CYPRJEA (a name of Venus). The genus of Univalve Molluscs comprising the 
 
 Cowries. 
 CYRTOCERAS (Gr. kurtos, crooked ; keras, horn). A genus of Tetrabranchiate 
 
 Cephalopods. 
 CYSTIPHYLLUM (Gr. kustis, a bladder ; phullon, a leaf). A genus of Rugose 
 
 Corals. 
 CYSTOIDEA (Gr. kustis, a bladder ; eidos, form). The " Globe-crinoids," an 
 
 extinct order of Echinodermata. 
 
 DADOXYLON (Gr. dadion, a torch ; xulon, wood). An extinct genus of Con- 
 iferous trees. 
 
 DECAPODA (Gr. deka, ten ; podes, feet). The division of Crustacea which have 
 ten feet ; also the family of Cuttle-fishes, in which there are ten arms or 
 cephalic processes. 
 
 DECIDUOUS (Lat. decido, I fall off). Applied to parts which fall off or are shed 
 during the life of the animal. 
 
 DEINOSAURIA (Gr. deinos, terrible ; saura, lizard). An extinct order of Rep- 
 tiles. 
 
 DEINOTHERIUM (Gr. deinos, terrible ; thet-ion, beast). An extinct genus of 
 Proboscidean Mammals. 
 
 DENDROGRAPTUS (Gr. dendron, tree ; grapko, I write). A genus of Grapto- 
 lites. 
 
 DESMiDrffi. Minute fresh- water plants, of a green colour, without a siliceous 
 epidermis. 
 
 DIATOMACE.E (Gr. diatemno, I sever). An order of minute plants which are 
 
 provided with siliceous envelopes. 
 
 DIBRANCHIATA (Gr. dis, twice ; brac/chia, gill). The order of Cephalopoda. 
 (comprising the Cuttle-fishes, &c.) in which only two gills are present. 
 
 DICERAS (Gr. dis, twice ; keras, horn). An extinct genns of Bivalve Molluscs. 
 
 DICTYONEMA (Gr. diktuon, a net ; nema, thread). An extinct genus of Poly-
 
 GLOSSARY. 385 
 
 DICYNODONTIA (Gr. dis, twice ; kuon, dog ; odous, tooth). An extinct order of 
 
 Reptiles. 
 
 DIDYMOGRAFTUS (Gr. didumos, twin ; grapho, I write). A genus of Graptolites 
 DIMORPHODON (Gr. dis, twice ; morphe, shape ; odous, tooth). A genus of 
 
 Pterosaurian Reptiles. 
 
 DINICHTHYS (Gr. deinos, terrible ; ichthus, fish). An extinct genus of Fishes. 
 DINOCERAS (Gr. deinos, terrible ; keras, horn). An extinct genus of Mammals. 
 DINOPHIS (Gr. deinos, terrible ; ophis, snake). An extinct genus of Snakes 
 DINORNIS (Gr. deinos, terrible ; ornis, bird). An extinct genus of Birds. 
 DIPLOGRAPTOS (Gr. diplos, double ; grapho, I write). A genus of Graptolites. 
 DIPNOI (Gr. dis, twice \pnoe, breath). An order of Fishes, comprising the 
 
 Mud-fishes, so called in allusion to their double mode of respiration. 
 DIPROTODON (Gr. dis, twice ; protos, first ; odous, tooth). A genus of extinct 
 
 Marsupials. 
 DIPTKRA (Gr. dis, twice ; pteron, wing). An order of Insects characterised 
 
 by the possession of two wings. 
 DISCOID (Gr. diskos, a quoit; eidos, form). Shaped like a round plate or 
 
 quoit. 
 
 DOLOMITE (named after M. Dolomieu). Magnesian limestone. 
 DORSAL (Lat. dorsum, the back). Connected with or placed upon the back. 
 DROMATHKRIUM (Gr. dromaios, nimble ; therion, beast). A genus of Triassic 
 
 Mammals. 
 DRYOPITHECUS (Gr. drus, an oak ; pithekos, an ape). An extinct genus of 
 
 Monkeys. 
 
 ECHINODERMATA (Gr. echinos ; and derma, skin). A class of animals com- 
 prising the Sea-urchins, Star-fishes, and others, most of which have spiny 
 skins. 
 
 ECHINOIDEA (Gr. echinos; and eidos, form). An order of Echinodermata, com- 
 prising the Sea-urchins. 
 
 EDENTATA (Lat. e, without ; dens, tooth). An order of Mammalia, often called 
 Bruta. 
 
 EDENTULOUS. Toothless, without any dental apparatus. Applied to the 
 mouth of any animal, or to the hinge of the Bivalve Molluscs. 
 
 ELASMOBRANCHII (Gr. elasma, a plate ; bragchia, gill). An order of Fishes, 
 including the Sharks and Rays. 
 
 ENALIOSAURIA (Gr. enalios, marine ; saura, lizard). Sometimes employed as 
 a common term to designate the extinct Reptilian orders of the Ichthyosauria 
 and Plesiosauria. 
 
 EOCENE (Gr. eos, dawn ; kainos, new or recent). The lowest division of the 
 Tertiary rocks, in which species of existing shells are to a small extent 
 represented. 
 
 EOPHYTON (Gr. eos, dawn ; phuton, a plant). A genus of Cambrian fossils, 
 supposed to be of a vegetable nature. 
 
 EOZOON (Gr. eos, dawn ; zoon, animal). A genus of chambered calcareous or- 
 ganisms found in the Laurentian and Huronian formations. 
 
 EQUILATERAL (Lat. cequus, equal ; latus, side). Having its sides equal. Usu- 
 ally applied to the shells of the Brachwpoda. When applied to the spiral 
 shells of the Foraminifera, it means that all the convolutions of the shell lie 
 in the same plane. 
 
 EQUISETACE.E (Lat. equus, horse ; seta, bristle). A group of Cryptogamous 
 plants, commonly known as " Horse-tails." 
 
 EQUIVALVE (Lat. cequus, equal ; valwe, folding-doors). Applied to shells which 
 are composed of two equal pieces or valves. 
 
 ERRANTIA (Lat. erro, I wander). An order of Annelida, often called Nereidea, 
 distinguished by their great locomotive powers. 
 
 EUOMPHALUS (Gr. eu, well ; omphalos, navel). An extinct genus of Univalve 
 Molluscs. 
 
 EURYPTERIDA (Gr. eurus, broad ; pteron, wing). An extinct sub-order of Crus- 
 tacea. 
 
 EXOGYRA (Gr. exo, outside ; guros, circle). An extinct genus of Oysters.
 
 386 GLOSSARY. 
 
 FAUNA (Lat. Fauni, the rural deities of the Romans). The general assemblage 
 of the animals of any region or district. 
 
 FAVOSITES (Lat. favus, a honeycomb). A genus of Tabulate Corals. 
 
 FENESTELLIDJ-: (Lat. fenestella, a little window). The " Lace-corals," a group 
 of Palaeozoic Polyzoans. 
 
 FILICES (Lat. jUix, a fern). The order of Cryptogamic plants comprising the 
 Ferns. 
 
 FILIFORM (Lat. filum, a thread ; forma, shape). Thread-shaped. 
 
 FLORA (Lat. Flora, the goddess of flowers). The general assemblage of the 
 plants of any region or district. 
 
 FORAMINIFERA (Lat. foramen, an aperture ; fero, I carry). An order of Pro- 
 tozoa, usually characterised by the possession of a shell perforated by numer- 
 ous pseudopodial apertures. 
 
 FRUGIVOUOUS (Lat. frux, fruit ; voro, I devour). Living upon fruits. 
 
 FUCOIDS (Lat. fucus, sea-weed ; Gr. eidos, likeness). Fossils, often of an 
 obscure nature, believed to be the remains of sea-weeds. 
 
 FUSULINA (Lat. fusus, a spindle). An extinct genus of Foraminifera. 
 
 GANOID (Gr ganos, splendour, brightness). Applied to those scales or plates 
 which are composed of an inferior layer of true bone covered by a superior 
 layer of polished enamel. 
 
 GANOIDEI. An order of Fishes. 
 
 GASTEROPODA (Gr. gaster, stomach ; pous, foot). The class of the Mollusca 
 comprising the ordinary Univalves, in which locomotion is usually effected by 
 a muscular expansion of the under surface of the body (the "foot"). 
 
 GLOBIGERINA (Lat. globus, a globe ; gero, I carry). A genus of Foraminifera. 
 
 GLYPTODON (Gr. glupho, I engrave ; odous, tooth). An extinct genus of Arma- 
 dillos, so named in allusion to the fluted teeth. 
 
 GONIATITES (Gr. ffffnia, angle). A genus of Tetrabranchiate Cephalopods. 
 
 GRALLATORES (Lat. grallce, stilts). The order of the long-legged Wading Birds. 
 
 GRAPTOLITIIXS; (Gr. grapho, I write ; lithos, stone). An extinct sub-class of 
 the Hydrozoa. 
 
 GTMNOSPERMS (Gr. gumnos, naked ; sperma, seed). The Conifers and Cycads, 
 in which the seed is not protected within a seed-vessel. 
 
 HALITHEHIDM (Gr. lials, sea ; therion, beast). An extinct genus of Sea-cows 
 
 (Sirenia). 
 
 HAMITES (Lat. hamus, a hook). A genus of the Ammonitidee. 
 HELIOPHYLLUM (Gr. helios, the sun ; phullon, leaf). A genus of Rugose 
 
 Corals. 
 HELLADOTHERIUM (Gr. Hellas, Greece ; tJierion, beast). An extinct genus of 
 
 Ungulate Mammals. 
 HEMIPTERA (Gr. hemi ; and pteron, wing). An order of Insects in which the 
 
 anterior wings are sometimes " hemelytra." 
 HESPERORNIS (Gr. Hesperos, the evening star ; m-nis, bird). An extinct genus 
 
 of Birds. 
 HETEROCERCAL (Gr. heleros, diverse ; kerkos, tail). Applied to the tail of 
 
 Fishes when it is unsymmetrical, or composed of two unequal lobes. 
 HETEROPODA (Gr. Jieteros, diverse ; podes, feet). An aberrant group of the 
 
 Gasteropods, in which the foot is modified so as to fonn a swimming organ. 
 HIPPARION (Gr. hipparion, a little horse). An extinct genus of Kquidcu. 
 HIPPOPOTAMUS (Gr. hippos, horse ; potamos, river). A genus of Hoofed Quad- 
 rupeds the "River-horses." 
 HIPPURITID^; (Gr. hippos, horse ; oura, tail). An extinct family of Bivalve 
 
 Molluscs. 
 HOLOPTYCHIUS (Gr. holos, whole; pluclte, wrinkle). An extinct genus of 
 
 Ganoid Fishes. . 
 
 HOLOSTOMATA (Gr. holos, whole ; stoma, mouth). A division of Gasteroj>odous 
 
 Molluscs, in which the aperture of the shell is rounded, or " entire." 
 HOLOTHUROIDEA (Gr. fiolotfiourion ; and eidos, fonn). An order of Echinoder- 
 
 mata comprising the Trepangs.
 
 GLOSSARY. 387 
 
 HOMOCERCAL (Gr. homos, same ; kerkos, tail). Applied to the tail of Fishes 
 when it is symmetrical, or composed of two equal lobes. 
 
 HYBODONTS (Gr. kudos, curved ; odous, tooth). A group of Fishes of which 
 JJybodus is the type-genus. 
 
 HYDROIDA (Gr. hudra; and eidos, form). The sub-class of the Hydroz^a, 
 which comprises the animals most nearly allied to the Hydra. 
 
 HYDROZOA (Gr. hudra ; and zoiin, animal). The class of the Cielenterata which 
 comprises animals constructed after the type of the Hydra. 
 
 HYMENOPTERA (Gr. humen, a membrane ; pteron, a wing). An order of In- 
 sects (comprising Bees, Ants, &c.) characterised by the possession of four 
 membranous wings. 
 
 ICHTHYODORULITE (Gr. ichtkus, fish ; dorus, spear ; lithos, stone). The fossil 
 
 tin-spine of Fishes. 
 
 ICHTHYOPTERYGIA (Gr. ickthus ; pferux, wing). An extinct order of Reptiles. 
 ICHTHYORNIS (Gr. iclithus , fish ; ornis, bird). An extinct genus of Birds. 
 ICHTHYOSAURIA (Gr. ichthus ; saura, lizard). Synonymous with Ichthyop- 
 
 terygia. 
 IGUANODON (Iguana, a living lizard ; Gr. odous, tooth). A genus of Deinosau- 
 
 rian Reptiles. 
 INCISOR (Lat. incido, I cut). The cutting teeth fixed in the intermaxillary 
 
 bones of the Mammalia, and the corresponding teeth in the lower jaw. 
 INEQUILATERAL. Having the two sides unequal, as in the case of the shells of 
 
 the ordinary bivalves (Lamellibranchiata}. When applied to the shells of 
 
 the Foraminifera, it implies that the convolutions of the shell do not lie in 
 
 the same plane, but are obliquely wound round an axis. 
 INEQUIVALVE. Composed of two unequal pieces or valves. 
 INOCERAMUS (Gr. is, a fibre ; keramos, an earthen vessel). An extinct genus of 
 
 Bivalve Molluscs. 
 INSECTA (Lat. inseco, I cut into). The class of articulate animals commonly 
 
 known as Insects. 
 
 INSECTIVORA (Lat. insectum, an insect ; voro, I devour). An order of Mammals. 
 INSECTIVOROUS. Living upon Insects. 
 INSESSORES (Lat. insedeo, 1 sit upon). The order of the Perching Birds, often 
 
 called Passeres. 
 
 INTERAMBULACRA. The rows of plates in an Echinoid which are not per- 
 forated for the emission of the " tube-feet." 
 INTKRMAXILLJE or PR.EMAXILLJE. The two bones wiiich are situated between 
 
 the two superior maxillae in Vertelrata. In man, and some monkeys, the 
 
 praemaxillae anchylose with the maxillae, so as to be irrecognisable in the 
 
 adult. 
 INVERTEBRATA (Lat. in, without ; vertebra, a bone of the back). Animals 
 
 without a spinal column or backbone. 
 ISOPODA (Gr. isos, equal ; podes, feet). An order of Crustacea in which the 
 
 feet are like one another and equal. 
 
 KAINOZOIC (Gr. Jcainos, recent ; zoe, life). The Tertiary period in Geology 
 comprising those formations in which the organic remains approximate 
 more or less closely to the existing fauna and flora. 
 
 LABYRINTHODONTIA (Gr. lalurinthos, a labyrinth ; odous, tooth). An extinct 
 order of Amphibia, so called from the complex microscopic structure of the 
 teeth. 
 
 LACERTPLIA (Lat. lacerta, a lizard). An order of Keptilia comprising the Liz- 
 ards and Slow-worms. 
 
 LAMELLIBRANCHIATA (Lat. lamella, a plate ; Gr. bragchia, gill). The class of 
 Mollusca comprising the ordinary Jjivalves, characterised by the possession 
 of lamellar gills. 
 
 LEPIDODENDRON (Gr. If pis, a scale ; de.ndron, a tree). A genus of extinct plants, 
 so named from the scale-like scars upon the stem left by the falling off of the 
 leaves.
 
 388 GLOSSARY. 
 
 LEPIDOPTERA (Gr. lepis, a scale ; pteron, a wing). An order of Insects, com- 
 prising Butterflies and Moths, characterised by possessing four wings which 
 are usually covered with minute scales. 
 
 LEPIDOSIREN (Gr. lepis, a scale ; seiren, a siren the generic name of the Mud- 
 eel or Siren lacertina). A genus of Dipnoous fishes, comprising the " Jiud- 
 fishes." 
 
 LEPIDOSTROBUS (Gr. lepis, a scale ; strobiles, a fir-cone). A genus founded on 
 the cones of Lepidodendron. 
 
 LEPT^NA (Gr. leptos. slender). A genus of Brachiopods. 
 
 LlNQULA (Lat. linaula, a little tongue). A genus of Brachiopods. 
 
 LYCOPODIACK.-E (Gr. lupos, a wolf; pous, foot). The group of Cryptogarcic 
 plants generally known as "Club-mosses." 
 
 MACH.ERACANTHUS (Gr. machaira, a sabre ; acantha, thorn or spine). An ex- 
 tinct genus of Fishes. 
 
 MACHAIRODUS (Gr. machaira, a sabre ; odous, tooth). An extinct genus of 
 Carnivora. 
 
 MACROTHERIUM {Gr. makros, long: therion. beast). An extinct genus cf 
 Edentata. 
 
 MACRURA (Gr. makros, long ; oura, tail). A tribe of Decapod Crustaceans with 
 long tails (e.g. , the Lobster, Shrimp, &c. ) 
 
 ;MAMMALIA (Lat. tnamma, the breast). The class of Vertebrate animals which 
 suckle their young. 
 
 MANDIBLE (Lat. mandibulum, a jaw). The upper pair of jaws in Insects ; also 
 applied to one of the pairs of jaws in Crustacea and Spiders, to the beak of 
 Cephalopods, the lower jaw of Vertebrates, &c. 
 
 MANTLE. The external integument of most of the Mollusca, which is largely 
 developed, and forms a cloak in which the viscera are protected. Techni- 
 cally called the " pallium." 
 
 MANUS (Lat. the hand). The hand of the higher Vertebrates. 
 
 MARSIPOBRANCHII (Gr. marsipos, a pouch ; bragchia, gill). The order of 
 Fishes comprising the Hag-fishes and Lampreys, with pouch-like gills. 
 
 MARSUPIALIA (Lat. marsupium, a pouch). An order of Mammals in which the 
 females mostly have an abdominal pouch in which the young are carried. 
 
 MASTODON (Gr. mastos, nipple ; odous, tooth). An extinct genus of Elephant- 
 ine Mammals. 
 
 MEGALONYX (Gr. megas, great ; onux, nail). An extinct genus of Edentate 
 Mammals. 
 
 MEGALOSAURUS (Gr. 'inegas, great ; saura, lizard). A genus of Deinosaurian 
 Reptiles. 
 
 MEGATHERIUM (Gr. megas, great ; therion, beast). An extinct genus of 
 Edentata. 
 
 MESOZOIC (Gr. mesos, middle ; and zoe, life). The Secondary period in Geology. 
 
 MICROLESTES (Gr. mikros, little ; lestes, thief). An extinct genus of Triassic 
 Mammals. 
 
 MILLEPORA (Lat. mitte, one thousand ; porus, a pore). A genus of " Tabulate 
 Corals." 
 
 MIOCENE (Gr. melon, less ; kainos, new). The Middle Tertiary period. 
 
 MOLARS (Lat. mola, a mill). The " grinders" in man, or the teeth in diphyo 
 dont Mammals which are not preceded by milk-teeth. 
 
 MOLLUSCA (Lat. mollis, soft). The sub-kingdom which includes tlie Shell-fish 
 proper, the Polyzoa, the Tunicata, and the Lamp-shells ; so called from the 
 generally soft nature of their bodies. 
 
 MOLLUSCOIDA (Mollusca; Gr. eidos, form). The lower division of the Mol- 
 lusca, comprising the Polyzoa, Tunicata, and Brachiopoda. 
 
 MONOGRAPTUS (Gr. monos, single ; grapho, I write). A genus of Graptolites. 
 
 MYLODON (Gr. mulos, a mill ; odous, tooth). An extinct genus of Edentate 
 Mammals. 
 
 .MYRIAPODA or MYRIOPODA (Gr. murios, ten thousand ; podes, feet). A class 
 of Arthropoda comprising the Centipedes and their allies, characterised by 
 their numerous feet.
 
 GLOSSARY. 389 
 
 NATATORES (Lat. nare, to swim). The order of the Swimming Birds. 
 
 NATATORY (Lat. nare, to swim). Formed for swimming. 
 
 NAUTILOID. Resembling the shell of the Nautilus in shape. 
 
 NERVURES (Lat. uervus, a sinew). The ribs which support the membranous 
 wings of insects. 
 
 NEUROPTERA (Gr. neuron, a nerve ; pteron, a wing). An order of Insects char- 
 acterised by four membranous -wings with numerous reticulated nervures 
 (e.g., Dragon-flies). 
 
 NEUROPTERIS (Gr. neuron, a nerve ; pteris, a fern). An extinct genus of 
 Ferns. . 
 
 NOTHOSAURUS (Gr. nothos, spurious: saura, lizard). A genus of Plesiosaurian 
 Reptiles. 
 
 NOTOCHORD (Gr. notos, back ; chorde, string). A cellular rod which is devel- 
 oped in the embryo of Vertebrates immediately beneath the spinal cord, and 
 which is usually replaced in the adult by the vertebral column. Often it is 
 spoken of as the " chorda dorsalis." 
 
 NUDIBRANCHIATA (Lat. nudus, naked; and Gr. bragchia, gill). An order of 
 the Gasteropoda in which the gills are naked. 
 
 NUMMULINA (Lat. nummus, a coin). A genus of Foraminifera, comprising the 
 coin-shaped " Nummulites." 
 
 OBOLELLA (Lat. dim. of obolus, a small coin). An extinct genus of Brachio- 
 
 pods. 
 
 OCCIPITAL. Connected with the occiptit, or the back part of the head. 
 OCEANIC. Applied to animals which inhabit the open ocean { = pelagic). 
 ODONTOPTERYX (Gr. odous, tooth ; pterux, wing). An extinct genus of 
 
 Birds. 
 ODONTORNITHES (Gr. odous, tooth ; ornis, bird). The extinct order of Birds, 
 
 comprising forms with distinct teeth in sockets. 
 OLIGOCENE (Gr. oliyos, few ; kainos, new). A name used by many Continental 
 
 geologists as synonymous with the Lower Miocene. 
 
 OPHIDIA (Gr. ophis, a serpent). The order of Reptiles comprising the Snakes. 
 OPHIUHOIDEA (Gr. ophis, snake ; oura, tail ; eidos, form). An order of Echino- 
 
 dermata, comprising the Brittle-stars and Sand-stars. 
 ORNITHOSCELIDA (Gr. ornis, bird ; skelos, leg). Applied by Huxley to the 
 
 Deinosaurian Reptiles, together with the genus Compsoynathus, on account 
 
 of the bird-like character of their hind-limbs. 
 ORTHIS (Gr. ovthos, straight). A genus of Brachiopods, named in allusion to the 
 
 straight hinge-line. 
 OHTHOCERATID^E (Gr. orthos, straight ; keras, horn). A family of the Nau- 
 
 tilidce, in which the shell is straight, or nearly so. 
 ORTHOPTERA (Gr. orthos, straight ; pteron, wing). An order of Insects. 
 OSTEOLEPIS (Gr. osteon, bone; lepis, scale). An extinct genus of Ganoid 
 
 Fishes. 
 OSTRACODA (Gr. ostrakon, a shell). An order of small Crustaceans which are 
 
 enclosed in bivalve shells. 
 
 OTODUS (Gr. ota, ears ; odous, tooth). An extinct genus of Sharks. 
 OUDENODON (Gr. ouden, none ; odous, tooth). A genus of Dicynodont Rep- 
 tiles. 
 OviBOS (Lat. ovis, sheep ; bos, ox). The genus comprising the Musk-ox. 
 
 PACHYDERMATA (Gr. pachus, thick ; derma, skin). An old Mammalian order 
 constituted by Cuvier for the reception of the Rhinoceros, Hippopotamus, 
 Elephant, &c. 
 
 PAL^EASTER (Gr. palaios, ancient ; aster, star). An extinct genus of Star- 
 tishes. 
 
 PAL^OCARIS (Gr. palaios, ancient ; leans, shrimp). An extinct genus of Deca- 
 pod Crustaceans. 
 
 PALAEOLITHIC (Gr. palaios, ancient ; lithos, stone). Applied to the rude stone 
 implements of the earliest known races of men, to the men who made these 
 implements, or to the period at which they were made.
 
 39O GLOSSARY. 
 
 PALEONTOLOGY (Gr. palaios, ancient ; and logos, discourse). The science of 
 
 fossil remains or of extinct organised beings. 
 PAL/EOPHIS (Gr. palaios, ancient ; ophis, serpent). An extinct genus of 
 
 Snakes. 
 PAL.EOSAURUS (Gr. palaios, ancient ; saura, lizard). A genus of Thecodont 
 
 Reptiles. 
 PAL^OTHERID^! (Gr. palaios, ancient ; ther, beast). A group of Tertiary 
 
 Ungulates. 
 PAL/EOZOIC (Gr. palaios, ancient ; and zoe, life). Applied to the oldest of the 
 
 great geological epochs. 
 
 PARADOXIDES (Lat. paradoxus, marvellous). A genus of Trilobites. 
 PATAGIUM (Lat. the border of a dress). Applied to the expansion of the in- 
 tegument by which Bats, Flying Squirrels, and other animals support them- 
 selves in the air. 
 
 PECOPTERIS (Gr. peko, I comb ; pteris, a fern). An extinct genus of Ferns. 
 PECTEN (Lat. a comb). The genus of Bivalve Molluscs comprising the 
 
 Scallops. 
 
 PECTORAL (Lat. pectus, chest). Connected with, or placed upon, the chest. 
 PKNTACRINUS (Gr. penta, five ; krinon, lily). A genus of Crinoids in which 
 
 the column is five-sided. 
 
 PENTAMERUS (Gr. penta, five; meros, part). An extinct genus of Brachiopods. 
 PENTREMITES (Gr. penta, five ; trema, aperture). A genus of Blastoidea, so 
 
 named in allusion to the apertures at the summit of the calyx. 
 PERENNIBRANCHIATA (Lat. perennis, perpetual ; Gr. bragchia,, gill). Applied 
 
 to those Amphibia in which the gills are permanently retained throughout 
 
 life. 
 PERISSODACTYLA (Gr. perissos, uneven ; daktulos, finger). Applied to those 
 
 Hoofed Quadrupeds (Unyulata) in which the feet have an uneven number of 
 "toes. 
 
 PETALOID. Shaped like the petal of a flower. 
 PHACOPS (Gr. plmM, a lentil ; ops, the eye). A genus of Trilobites. 
 PHALANGES (Gr. phalanx, a row). The small bones composing the digits of 
 
 the higher Vertebrata. Normally each digit has three phalanges. 
 PHANEROGAMS (Gr. phaneros, visible ; gamos, marriage). Plants which have 
 
 the organs of reproduction conspicuous, and which bear true flowers. 
 PHARYNGOBRANCHII (Gr. pharugx, pharynx; bragchia, gill). The order of 
 
 Fishes comprising only the Laucelet. 
 PHASCOLOTHERIUM (Gr. phaskolos, a pouch ; therion, a beast). A genus of 
 
 Oolitic Mammals. 
 PHRAGMACONE (Gr. phragma, a partition ; and konos, a cone). The chambered 
 
 portion of the internal shell of a Belemnite. 
 
 PHYLLOPODA (Gr. phullon, leaf; smApous, foot). An order of Crustacea. 
 PINNATE (Lat. pinna, a feather). Feather-shaped ; or possessing lateral pro- 
 cesses. 
 PINNIGRADA (Lat. pinna, a feather ; gradior, I walk). The group of Carniv- 
 
 ora, comprising the Seals and Walruses, adapted for an aquatic life. Often 
 
 called Pinnipedia,. 
 
 PINNULE (Lat. dim. of pinna). The lateral processes of the arms of Crinoids. 
 PISCES (Lat. piscis, a fishV The class of Vertebrates comprising the Fishes. 
 PLACOID (Gr. plax, a plate ; eidos, form). Applied to the irregular bony 
 
 plates, grains, or spines which are found in the skin of various fishes 
 
 (Elasmobranchii). 
 PLAGIOSTOMI (Gr. playios, transverse ; stoma, mouth). The Sharks and Rays, 
 
 in which the mouth is transverse, and is placed on the under surface of the 
 
 head, 
 
 PLATYCERAS (Gr. platus, broad ; keras, horn). A genus of Univalve Molluscs. 
 PLATYCRINUS (Gr. platus, broad ; krinon, lily). A genus of Crinoidea. 
 PLATYRHINA (Gr. platus, broad ; rhines, nostrils). A group of the Quadrumana. 
 PLATYSOMUS (Gr. platus, wide ; soma, body). A genus of Ganoid Fishes. 
 PLEISTOCENE (Gr. pleistos, most ; kainos, new). Often used as synonymous 
 
 with "Post-Pliocene."
 
 GLOSSARY. 391 
 
 PLEUROTOMARIA (Gr. pleura, the side ; tomt, notch). A genus of Univalve 
 shells. 
 
 PLIOCENE (Gr. pleion, more ; kainos, new). The later Tertiary period. 
 
 PLIOPITHECUS (Gr. pleion, more ; pithekos, ape). An extinct genus of Monkeys. 
 
 PLIOSAURUS (Gr. pleion, more ; saura, lizard). A genus of Plesiosaurian 
 Reptiles. 
 
 POLYCYSTINA (Gr. polus, many ; and kustis, a cyst). An order of Protozoa 
 with foraminated siliceous shells. 
 
 POLYPARY. The hard chitinous covering secreted by many of the Hydrozoa. 
 
 POLYPE (Gr. polus, many ; pous, foot). Restricted to the single individual of 
 a simple Actinozoon, such as a Sea -anemone, or to the separate zooids of a 
 compound Actinozoon. Often applied indiscriminately to any of the Ccelen- 
 terata, or even to the Polyzoa. 
 
 POLYPORA (Gr. polus, many; poros, a passage). A genus of Lace-corals 
 (Fenestellidce). 
 
 POLYTHALAMOUS (Gr. polus ; and thalamos, chamber). Having many chambers ; 
 applied to the shells of Foraminifera and C'epJialopoda. 
 
 POLYZOA (Gr. polus; and zoon, animal). A division of the Molluscoida com- 
 prising compound animals, such as the Sea-mat sometimes called Bryozoa. 
 
 PORIFERA (Lat. poms, a pore ; and fero, I carry). Sometimes used to desig- 
 nate the Foraminifera, or the Sponges. 
 
 PRJBMOLABS (Lat. prce, before ; molares, the grinders). The molar teeth of 
 Mammals which succeed the molars of the milk-set of teeth. In man, the 
 bicuspid teeth. 
 
 PROBOSCIDEA (Lat. proboscis, the snout). The order of Mammals comprising 
 the Elephants. 
 
 PROCCKLOUS (Gr. -f.ro, before ; koilps, hollow). Applied to vertebrae the bodies 
 of which are hollow or concave in front. 
 
 PRODUCTA (Lat. productus, drawn out or extended). An extinct genus of 
 Brachiopods, in which the shell is " eared," or has its lateral angles drawn 
 out. 
 
 PROTICHNITES (Gr. protos, first ; iehnos, footprint). Applied to certain im- 
 .pressions in the Potsdam sandstone of North America, believed to have 
 been produced by large Crustaceans. 
 
 PROTOPHYTA (Gr. protos ; and phuton, plant). The lowest division of plants. 
 
 PROTOPLASM (Gr. protos ; and plusso, I mould). The elementary basis of or- 
 ganised tissues. Sometimes used synonymously for the "sarcode" of the 
 
 PROTOROSAURUS or PROTEROSAURUS (Gr. protos, first ; orao, I see or discover ; 
 
 saura, lizard : or proteros, earlier ; saura, lizard). A genus of Permian 
 
 lizards. 
 PROTOZOA (Gr. protos; and zoon, animal). The lowest division of the animal 
 
 kingdom. 
 PSAMMOHUS (Gr. psammos, sand ; odous, tooth). An extinct genus of Cestra- 
 
 ciont Sharks. 
 PSEUDOPODIA (Gr. pseudos, falsity ; and pous, foot). The extensions of the 
 
 body-substance which are put forth by the Rhizopoda at will, and which 
 
 serve for locomotion and prehension. 
 PSILOPHYTON (Gr. psilos, bare ; phuton, plant). An extinct genus of Lyco- 
 
 podiaceous plants. 
 PTERANODON (Gr. pteron, wing ; a, without ; odous, tooth). A genus of Ptero- 
 
 saurian Reptiles. 
 
 PTKRASPIS (Gr. pteron, wing ; aspis, shield). A genus of Ganoid Fishes. 
 PTERICITTHYS (Gr. pteron, wing ; ichthus, fish). A genus of Ganoid Fishes. 
 PTERODACTYLDS (Gr. pteron, wing ; daktulos, linger). A genus of Pterosaurian 
 
 Reptiles. 
 PTEROPOUA (Gr. pteron, wing ; and pous, foot). A class of the Mollu-sca which 
 
 swim by means of tins attached near the head. 
 
 PTEROSAURIA (Gr. pteron, wing ; saura, lizard). An extinct order of Reptiles. 
 PTILODICTYA (Gr. ptilon, a feather ; diktuon, a net). An extinct genus of 
 
 Polyzoa.
 
 392 GLOSSARY. 
 
 PTYCHOCERAS (Gr. ptucM, a fold ; keras, a horn). A genus of Ammonitidce. 
 
 PULMONATE. Possessing lungs. 
 
 PYRIFOHM (Lat. pyrus, a pear; and. forma, form). Pear-shaped. 
 
 QUADRUMANA (Lat. quatuor, four ; manus, hand). The order of Mammals 
 comprising the Apes, Monkeys, Baboons, Lemurs, &c. 
 
 RADIATA (Lat. radius, a ray). Formerly applied to a large number of animals 
 which are now placed in separate sub-kingdoms (e.g., the Cwlentemta, the 
 Echinodermata, the Infusoria, &c.) 
 
 RADIOLARIA (Lat. radius, a ray). A division of Protozoa. 
 
 RAMUS (Lat. a branch). Applied to each half or branch of the lower jaw, or 
 mandible, of Vertebrates. 
 
 RAPTORES (Lat. rapto, I plunder). The order of the Birds of Prey. 
 
 RASORES (Lat. rado, I scratch). The order of the Scratching Birds (Fowls, 
 Pigeons, &c.) 
 
 RECEPTACULITES (Lat. receptaculum, a storehouse). An extinct genus of 
 Protozoa. 
 
 REPTILIA (Lat. repto, I crawl). The class of the Vertebrata comprising the 
 Tortoises, Snakes, Lizards, Crocodiles, &c. 
 
 RETEPORA (Lat. retS, a net ; poms, a pore). A genus of Lace-corals (Polyzoa}. 
 
 RHAMPHORHYNCHUS (Gr. rhamphos, beak ; rhugchos, nose). A genus of 
 Pterosaurian Reptiles. 
 
 RHINOCEROS (Gr. rhis, the nose ; keras, horn). A genus of Hoofed Quadru- 
 peds. 
 
 RHIZOPODA (Gr. rMza, a root ; and pous, foot). The division of Protozoa com- 
 prising all those which are capable of emitting pseudopodia. 
 
 RHYNCHOLITES (Gr. rhugchos, beak ; and lithos, stone). Beak-shaped fossils 
 consisting of the mandibles of Cephalopoda. 
 
 RHYNCHONELLA (Gr. rhugchos, nose or beak). A genus of Brachiopods. 
 
 RODENTIA (Lat. rodo, I gnaw). An order of the Mammals ; often called Glires 
 (Lat. glis, a dormouse). 
 
 ROTALIA (Lat. rota, a wheel). -A genus of Foraminifera. 
 
 RUGOSA (Lat rugosus, wrinkled). An order of Corals. 
 
 RUMINANTIA (Lat. ruminor, I chew the cud). The group of Hoofed Quadru- 
 peds (Ungulata) which " ruminate" or chew the cud. 
 
 SARCODE (Gr. sarx, flesh ; eidos, form). The jelly-like substance of which the 
 bodies of the Protozoa are composed. It is an albuminous body containing 
 oil-granules, and is sometimes called "animal protoplasm." 
 
 SAURIA (Gr. saura, a lizard). Any lizard-like Reptile is often spoken of as a 
 "Saurian;" but the term is sometimes restricted to the Crocodiles alone, 
 or to the Crocodiles and Lacertilians. 
 
 SAUROPTERYQIA (Gr. saura ; ptertix, wing). An extinct order of Reptiles, 
 called by Huxley Plesiosauria,. from the typical genus Plesiosaurus. 
 
 SAURURJS (Gr. saura; oura, tail). The extinct order of Birds comprising 
 only the Archceopteryx. 
 
 SCANSORES (Lat. scando, I climb). The order of the Climbing Birds (Parrots, 
 Woodpeckers, &c.) 
 
 SCAPHITES (Lat. scapha, a boat). A genus of the A mmonitidce. 
 
 SCOLITHUS (Gr. skolex, a worm ; lithos, a stone). The vertical burrows of sea- 
 worms in rocks. 
 
 SCUTA (Lat. scutum, a shield). Applied to any shield-like plates ; especially to 
 those which are developed in the integument of many Reptiles. 
 
 SELACHIA or SELACHII (Gr. selar.hos, a cartilaginous fish, probably a shark). 
 The sub-order of Elasmobranchii comprising the Sharks and Dog-fishes. 
 
 SEPIOSTAIRE. The internal shell of the Sepia, commonly known as the 
 "cuttle-bone." 
 
 SEPTA. Partitions. 
 
 SERPENTIFORM. Resembling a serpent in shape. 
 
 SERTULARIDA (Lat. sertum, a wreath). An order of Hydrozoa.
 
 GLOSSARY. 393 
 
 SESSILE (Lat. sedo, I sit). Not supported upon a stalk or peduncle; attached 
 
 by a base. 
 
 SET'^E (Lat. bristles). Bristles or long stiff hairs. 
 SIGILLARIOIDS (Lat. sigilla, little images). A group of extinct plants of which 
 
 Sigillaria is 1 the type, so called from the seal-like markings on the bark 
 SILICEOUS (Lat. silex, ftint). Composed of flint. 
 
 SINISTRAL (Lat. sinistra, the left hand). Left-handed; applied to the direc- 
 tion of the spiral in certain shells, which are said to be "reversed." 
 SIPHON (Gr. a tube). Applied to the respiratory tubes in the Mottusca ; 
 
 also to other tubes of different functions. 
 SIPHONIA (Gr. siphon, a tube). A genus of fossil Sponges. 
 SIPHONOSTOMATA (Gr. siphon ; and stoma, mouth). The division of Gastero- 
 
 podous Molluscs in which the aperture of the shell is not " entire," but 
 
 possesses a notch or tube for the emission of the respiratory siphon. 
 SIPHUNCLE (Lat. siphunculus, a little tube). The tube which connects to- 
 gether the various chambers of the shell of certain Cephalopoda (e.g., the 
 
 Pearly Nautilus). 
 SIBENIA (Gr. seiren, a mermaid). The order of Mammalia, comprising the 
 
 Dugongs and Manatees. 
 SIVATHERIUM (Sira, a Hindoo deity ; Gr. therion, beast). An extinct genus 
 
 of Hoofed Quadrupeds. 
 SOLIDUNGDLA (Lat. solidus, solid ; ungula, a hoof). The group of Hoofed 
 
 Quadrupeds comprising the Horse, Ass, and Zebra, in which each foot has 
 
 only a single solid hoof. Often called Solipedia. 
 SPHENOPTERIS (Gr. sphen, a wedge ; pteris, a fern). An extinct genus of 
 
 ferns. 
 
 SPICULA (Lat. spiculum, a point). Pointed needle-shaped bodies. 
 SPIRIFERA (Lat. spira, a spire or coil ; fero, I carry). An extinct genus of 
 
 Brachiopods, with large spiral supports for the "arms." 
 SPIRORBIS (Lat. spira, a spire ; orbis, a circle). A genus of tube-inhabiting 
 
 Annelides, in which the shelly tube is coiled into a spiral disc. 
 SPONGIDA (Gr. spoggos, a sponge). The division of Protozoa commonly known 
 
 as sponges. 
 STALACTITES (Gr. stalasso, I drop). Icicle-like encrustations and deposits of 
 
 lime, which hang from the roof of caverns in limestone. 
 STALAGMITE (Gr. stalagma, a drop). Encrustations of lime formed on the floor 
 
 of caverns which are hollowed out of limestone. 
 STIGMARIA (Gr. stigma, a mark made with a pointed instrument). A genus 
 
 founded on the roots of various species of Sigillaria. 
 STRATUM (Lat. stratus, spread out ; or stratum, a thing spread out). A layer 
 
 of rock. 
 STROMATOPORA (Gr. stroma, a thing spread out ; poros, a passage or pore). A 
 
 Palaeozoic genus of Protozoa. 
 STROPHOMENA (Gr. strophao, I twist ; ment, moon). An extinct genus of 
 
 Brachiopods. 
 
 SUB-CALCAREOUS. Somewhat calcareous. 
 SUB-CENTRAL. Nearly central, but not quite. 
 
 SUTURE (Lat. suo, I sew). The line of junction of two parts which are immov- 
 ably connected together. Applied to the line where the whorls of a univalve 
 
 shell join one another ; also to the lines made upon the exterior of the shell 
 
 of a chambered Cephalopod by the margins of the septa. 
 SYRINGOPORA (Gr. surigx, a pipe ; poros, a pore). A genus of Tabulate Corals. 
 
 TABULAE (Lat. tabula, a tablet). Horizontal plates or floors found in some 
 Corals, extending across the cavity of the " theca " from side to side. 
 
 TEGUMENTAHT (Lat. tegumentum, a covering). Connected with the integu- 
 ment or skin. 
 
 TELEOSAUROS \Gr. teleios, perfect ; saura, lizard). An extinct genus of Cro- 
 codilian Reptiles. 
 
 TELEOSTEI (Gr. teleios, perfect; osleon, bone). The order of the "Bony 
 Fishes."
 
 394 GLOSSARY. 
 
 TELSON (Gr. a limit). The last joint in the abdomen of Crustacea; va- 
 riously regarded as a segment without appendages, or as an azygous 
 appendage. 
 
 TE.STACULITES (Lat. tentaculum, a feeler). A genus of Pteropoda. 
 
 TEREBRATULA (Lat. terebratu*, bored or pierced). A geutis of Bmchiopoda, so 
 called in allusion to the perforated beak of the ventral valve. 
 
 TEST (Lat. testa, shell). The shell of Mollusca, which are for this reason 
 sometimes called "Testacea;" also, the calcareous case of Echinoderms ; 
 also, the thick leathery outer tunic in the Tunicata. 
 
 TESTACEOUS. Provided with a shell or hard covering. 
 
 TESTUDIXID^E (Lat. testudo, a tortoise). The family of the Tortoises. 
 
 TETRABRANCHIATA (Gr. tetra, four ; bragchia, gill). The order of Cep/ialopoda 
 characterised by the possession of four gills. 
 
 TEXTULARIA (Lat. texttlis, woven). A genus of Foraminifera. 
 
 THECA (Gr. theke, a sheath). A genus of Pteropods. 
 
 THECODONTOSAURUS (Gr. theke, & sheath; odous, tooth; saura, lizard). A 
 genus of "Thecodout " Reptiles, so named in allusion to the fact that the 
 teeth are sunk in distinct sockets. 
 
 THERIODONT (Gr. therion, a beast ; odous, tooth). A group of Reptiles so 
 named by Owen in allusion to the Mammalian character of their teeth. 
 
 THORAX (Gr. a breastplate). The region of the chest. 
 
 THYLACOLEO (Gr. thulakos, a pouch ; leo, a lion). An extinct genus of Mar- 
 supials. 
 
 TRIGONIA (Gr. treis, three ; gonia, angle). A genus of Bivalve Molluscs. 
 
 TRIGONOCARPON (Gr. treis, three ; gonia. angle ; karpos, fruit). A genus 
 founded on fossil fruits of a three-angled form. 
 
 TRILOBITA (Gr. treis, three ; lobos, a lobe). An extinct order of Crustaceans. 
 
 TRINUCLEUS (Lat. tris, three ; nucleus, a kernel). A genus of Trilobites. 
 
 TROGOXTHERIUM (Gr. troyo, I gnaw ; therion, beast). An extinct genus of 
 Beavers. 
 
 TUBICOLA (Lat. tuba, a tube; and colo, I inhabit). The order of Annelida, 
 which construct a tubular case in which they protect themselves. 
 
 TUBICOLOUS. Inhabiting a tube. 
 
 TUNICATA (Lat. tunica, a cloak). A class of Molhtscoida which are enveloped 
 in a tough leathery case or " test." 
 
 TURBINATED (Lat. turbo, a top). Top-shaped ; conical with a round base. 
 
 TURRILITES (Lat, turris, a tower). A genus of the Ammonitidce. 
 
 UMBO (Lat. the boss of a shield). The beak of a bivalve shell 
 
 UNGUICDLATK (Lat. unguis, nail). Furnished with claws. 
 
 UNGULATA (Lat. unaula, hoof). The order of Mammals comprising the Hoofed 
 
 Quadrupeds. 
 
 UNGULATE. Furnished with expanded nails constituting hoofs. 
 UNILOCULAR (Lat. unus, one ; and loculus. a little purse). Possessing a single 
 
 cavity or chamber. Applied to the shells of Foraminifera and Mollusca. 
 UNIVALVE (Lat. unus, one ; valvce, folding-doors). A shell composed of a 
 
 single piece or valve. 
 URODELA (Gr. oura, tail ; delos, visible). The order of the Tailed Amphibians 
 
 (Newts, &c.) 
 
 VENTRAL (Lat. venter, the stomach). Relating to the inferior surface of the 
 
 body. 
 VENTRICULITES (Lat. ventriculum, a little stomach). A genus of siliceous 
 
 Sponges. 
 
 opouges. 
 
 VERMIFORM (Lat. vermis, worm ; and forma, form). Worm-like. 
 VERTEBRA (Lat. verto, 1 turn). One of the bony segments of the vertebral 
 ^ column or backbone. 
 VKKTEBRATA (Lat. vertebra, a bone of the back, from vertere, to turn). The 
 
 division of the Animal Kingdom roughly characterised by the possession of 
 
 n "Ko/L-KrvT 
 
 backbone. 
 
 (Lat. vesica, a bladder). A little sac or cyst.
 
 GLOSSARY. 395 
 
 WHORL. The spiral turn of a univalve shell. 
 
 XIPHOSURA (Gr. xiphos, a sword ; and oura, tail). An order of Crustacea, 
 comprising the Limuli or King-Crabs, characterised by their long sword- 
 like tails. , 
 
 XvLOBirs (Gr. xulon, wood; bios, life). An extinct genus ot Myriapods, 
 named in allusion to the fact that the animal lived on decaying wood. 
 
 ZAPHRENTIS (proper name). A genus of Rugose Corals. 
 
 ZEUGI.ODONTIDJE (Gr. zevgle, a yoke; odous, a tooth). An extinct family of 
 
 Cetaceans, in which the moiar teeth are two-fanged, and look as if composed 
 
 of two parts united by a neck. 
 ZOOPHYTE (Gr. zoon, animal ; phuton, plant). Loosely aj ^ 
 
 like animals, such as Sponges, Corals, Sea-anemones, Sea-mats, &c.
 
 INDEX. 
 
 Acadian Group, 79. 
 
 Acer, 308. 
 
 Aceroulana, 119, 173. 
 
 Acidaspis, 123. 
 
 Acorn-shells, 267. 
 
 Aoroculia, 128. 
 
 Acrodus, 214, 212, 275; nobilis, 242. 
 
 Acrotreta, 11U 
 
 Acroura, 120. 
 
 Actinocrinus, 175. 
 
 jEglina, 108. 
 
 ^Epiornis, 348. 
 
 Agiiostus, 85-87, 108 ; rex, 85. 
 
 .4 tees malchis, 354. 
 
 ^Itecfo, 108. 
 
 Alethopteris, 136, 165,196. 
 
 Algae (see Sea-weeds). 
 
 Alligators, 218, 297. 
 
 ^.'nws, 262. 
 
 Amblypterus, 188; macropterus, 188. 
 
 Ambonychia, 111. 
 
 Ammonites, 187, 212-214, 237-239. 272; 
 Humpliresianus, 238 ; bi/rons, 238. 
 
 AmmonUidce, 239, 272, 285, 294. 
 
 Amphibia, 189; of the Carboniferous, 
 189-191 ; of the Permian, 200 ; of the 
 Trias, 215-217; of the Jurassic, 242; of 
 the Miocene, 313. 
 
 Amphicyon, 322. 
 
 A mphilestes, 253. 
 
 Amphiffpongia, 118. 
 
 Amphintegina, 311. 
 
 AmphMierium, 253 255; Prevostii, 254. 
 
 Amphitragulus, 317. 
 
 Amplexus, 173; curalloides, 174. 
 
 Ampyx, 108. 
 
 Ananehy'es, 266 
 
 Anchitherium, 3'U, 302. 
 
 Ancyliceraa, 272, 273; Mather onianus, 
 273 
 
 Ancylitherium Pen'elici, 315. 
 
 ^Indr.a.; Scheuch&ri, 313, 314. 
 
 Ang'ospeniis, 261, 202. 
 
 Animal Kingdom, divisions of, 375-378. 
 
 Anisupm, 20b. 
 
 Annelida, of the Cambrian period, 82, 
 83; of the Lower Silurian, Iu7; of the 
 Upper Silurian, 122, 123 ; of the De- 
 vonian, 143, 144 ; of the Carboniferous, 
 178. 
 
 Annularia, 137, 196, 207. 
 
 Anomodontia, 220. 
 
 Anoplot/teridce, 302. 
 
 Anoplotherium, 302, 303; commune. 303. 
 
 Ant-eaters, 299, 315, 349, 350, 353. 
 
 Antelopes, 317. 
 
 Anthracnsaurus Husssllt, 190. 
 
 Anthrnpalcemon gracdis, 180. 
 
 An'Moaapra, 318. 
 
 ^ ntilope rjuadricornis, 318. 
 
 Antwerp drag, 325. 
 
 Apes, 32.5. 
 
 Apiucrinus, 231. 
 
 Apteryx, 346, 348. 
 
 Aqueous locks, 15. 
 
 ^r;(c/mid of the Coal-measures, 181. 
 
 Avalo-Ciispian Beds, 326. 
 
 ^.ratMxtria, 2^2. 
 
 Araucarinxylon, 170. 
 
 ^4rca, 198 ; antiqua, 199. 
 
 Archcenc daria, 178. 
 
 Archceocyathus, 82. 
 
 Archceupteryx, 252, 281; macrura, 252, 
 
 Archceosphcerince, 75 
 
 Archimedes, 184; Wortheni, 183. 
 
 ^rcAiMitw, 1S2. 
 
 Arctic regions, Miocene flora of, 310. 
 
 Arctucyon, 3"4. 
 
 Arenaceous rocks, 20. 
 
 Arenicolites, 83 ; didymus, 88. 
 
 Arenig nu-ks, 92, 94. 
 
 Argillacfoiis rocks. 20. 
 
 Armadillos, 2i'9, 351, 353. 
 
 Arti'idactyle Ungulates, 300, 317. 
 
 Asaphua, 108; tyrannus, 107, 108. 
 
 Ascocera*, 130. 
 
 Aspidella, 76. 
 
 Aspidura loricata, 210. 
 
 Astarte bnreali, 338. 
 
 Asterophylli'es, 137, 196. 
 
 Asterus'eus, 152. 
 
 Astrceidm 231. 
 
 As'rceospi>ng_ia, 118, 139. 
 
 Astylospongia, 98 ; prcu-nwrsa, 98. 
 
 Athyris, 11 , 127, 147, 198 ; ttubtilita, 185. 
 
 Atlantic Ooze, 2J, 23. 
 
 Atrypa, 127; congesta. 127; hemisphce- 
 
 rica, 127 ; reticularis, 147, 148. 
 Auger-shells, 293. 
 Aurochs, 356. 
 Aves (.see Birds).
 
 INDEX. 
 
 397 
 
 Avieula, 235 ; contorta, 211, 212 ; socialis 
 
 211. 
 
 " Avieula contorta Beds," 204, 212. 
 Aviculidce, 198, 269. 
 A viculopecten, 186. 
 Axophyllum, 173. 
 Aymestry Limestone, 116, 117. 
 Azoic rocks, 67. 
 
 Baculites, 273 ; anceps, 274. 
 
 Bagshot and Bracklesham Beds, 287. 
 
 Bakewellia, 198. 
 
 BaUena, 315. 
 
 Bala Group, 93, 94. 
 
 Bala Limestone, 93. 
 
 JBalan 'dee, 267. 
 
 Ban/csia, 262, 308. 
 
 Barbadoes Earth, 33. 
 
 Barnacles, 267. 
 
 Bath Oolite, 227. 
 
 Bats, 304, 322. 
 
 Bears, 330, 359. 
 
 Beaver, 322, 336. 
 
 Beetles, 182, 811. 
 
 Belemnitella mucronata, 275. 
 
 Belemnites, 214, 240, 274; canaliculatus, 
 241. 
 
 Belemnitidce, 240, 285. 
 
 Belemnoteuthig, 240. 
 
 Belinurus, 179. 
 
 Bellerophon, 111, 129, 148, 186; Argo, 111. 
 
 Belodon, 218; Carolinensis, 219. 
 
 Belosepia, 295. 
 
 Beloteuthis subcostata, 239, 240. 
 
 Bembridge Beds, 288. 
 
 Beryz, 276 ; Lewesiensis, 276. 
 
 Beyrichia, 107 ; complicata, 107. 
 
 Bird's-eye Limestone, 95, 96. 
 
 Birds, of the Trias, 222 ; of the Jurassic, 
 251-253 ; of the Cretaceous, 281, 282 ; of 
 the Eocene, 297 ; of the Post-Pliocene, 
 345-348. 
 
 Bison priscus, 356. 
 
 Bituminous Schists of Caithness, 36. 
 
 Bivalves (see Lamellibranchiata). 
 
 Black-lead (see Graphite). 
 
 Black-River Limestone, 95, 96. 
 
 Blastoidea, 176; of the Devonian, 143; 
 of the Carboniferous, 176. 
 
 Boidce, 296. 
 
 Bolderberg Beds, 307. 
 
 Bone-bed, of the Upper Ludlow, 116; of 
 the Trias, 224. 
 
 Bony Fishes (see Teleostean Fishes). 
 
 Bos primigenius, 356 ; taunts, 356. 
 
 Boulder-clay, 337. 
 
 Bourgueticrinus, 266. 
 
 Bovey-Tracy Beds, 305, 309. 
 
 Brachiopoda, 125; of the Cambrian rocks, 
 87; of the Lower Silurian, 108-110; of 
 the Upper Silurian, 125-128 ; of the De- 
 vonian, 147, 148 ; of the Carboniferous, 
 184-186 ; of the Permian, 198 ; of the 
 Trias, 211 ; of the Jurassic, 234; of the 
 Cretaceous, 268 ; of the Eocene, 292. 
 
 Brachymetopus, 179. 
 
 Brachyurous Crustaceans, 180, 197. 
 
 Bradford Clay, 227. 
 
 Breaks in the Geological and Palseonto- 
 logical record, 44-52. 
 
 Breccia, 19. 
 
 Brick-earths, 339. 
 
 27 
 
 Bridlington Crag, 325, 326, 336. 
 Brittle-stars (nee Ophiuroidea). 
 Bronteus, 145. 
 Brontotheridee, 316. 
 Brontotherium ingens, 316. 
 Brontozoum, 206. 
 Buceinum, 237. 
 Bucklandia, 230. 
 Bulimus, 294. 
 
 Bunter Sandstein, 203, 204, 206. 
 Butterflies, 233, 311. 
 Byssoarca, 198. 
 
 Cainozoic (see Kainozoic). 
 
 Calamaries, 239. 
 
 Calamites, 163, 166, 196; canrueformw, 
 
 Calcaire Grossier, 287, 288. 
 
 Calcareous rocks, 20-32 ; Tufa, 21. 
 
 Calciferous Sand-rock, 95, 96. 
 
 Calveria, 178. 
 
 Calymene, 108, 123; Blumenbachii, 107. 
 
 Camarophoria globulina, 198. 
 
 Cambrian period, 77-90; rocks of, in 
 Britain, 77, 78; in Bohemia, 79; in 
 North America, 79 ; life of, 80-90. 
 
 Camelopardalidce, 317. 
 
 Camels, 317, 354. 
 
 Canis lupus, 336 ; Parisunsis, 304. 
 
 Caradoc rocks, 93, 94, 96. 
 
 Carbon, origin of, 36. 
 
 Carboniferous Limestone, 157, 158. 
 
 Carboniferous period, 157-192; rocks of, 
 157-160 ; life of, 160-191. 
 
 Carboniferous Slates of Ireland, 135, 158, 
 159. 
 
 Carcharias, 275. 
 
 Carcharodon, 295, 312 ; product, 313. 
 
 Cardinia, 235. 
 
 Cardiocarpon, 137. 
 
 Cardiola, 128; fibrosa, 128; interrupta, 
 128. 
 
 Cardita, 213, 292; planicosta, 292, 293. 
 
 Cardium, 292; Rhceticum, 211, 212. 
 
 Caribou, 355. 
 
 Carnivora, of the Eocene, 304; of the 
 Miocene, 322 ; of the Pliocene, 330, 331 ; 
 of the Post-Pliocene, 359-361. 
 
 Caryocaris, 107, 108. 
 
 Caryocrinus ornatus, 106. 
 
 Castor fiber, 336. 
 
 Castoroides Ohioensis, 361. 
 
 Catastrophism, theory of, 3. 
 
 Catopterus, 214. 
 
 Cauda-Galli Grit, 135, 137. 
 
 Caulopteris, 136, 164. 
 
 Cave-bear, 360. 
 
 Cave-deposits, 337, 339, 341-344. 
 
 Cave-hvaena, 360. 
 
 Cave-lion, 361. 
 
 Caves, formation of, 341 ; deposits in, 342. 
 
 Cavicomia, 317. 
 
 Cement-stones, 31. 
 
 Cephalaxpis, 152. 
 
 Cephalopoda, of the Cambrian period, 88 ; 
 of the Lower Silurian, 111-114 ; of the 
 Upper Silurian, 130; of the Devonian. 
 149 ; of the Carboniferous. 186, 187; of 
 the Permian, 199; of the Trias, 212 ; of 
 the Jurassic, 237-240 ; of the Cretaceous, 
 272-275; of the Eocene, 294; of the 
 Miocene, 312.
 
 398 
 
 INDEX. 
 
 Ceratiocaris, 108. 
 
 Ceratites, 212-214; nodosus, 212. 
 
 Ceratodus, 214; altw, 214; fosteri, 214, 
 215, 255; serratus, 214. 
 
 Ceriopora, 145; flainUtonensis, 146. 
 
 Cerithium, 213, 293; hexagonum, 294. 
 
 Cenidce, of the Miocene period, 317; of 
 the Pliocene, 329 ; of the Post-Pliocene, 
 354, 355. 
 
 Cervus, 317 ; capreolus, 336, 354 ; elaphus, 
 336, 354; megaceros, 354, 355; tara/i- 
 dws, 354. 
 
 Cestraclon Philippi, 188, 255. 
 
 Cestracionts, of the Devonian, 154 ; of the 
 Carboniferous, 188 ; of the Permian, 
 199; of the Trias, 214 ; of the Jurassic, 
 242 ; of the Cretaceous, 275. 
 
 Cetacea, 299 ; of the Eocene, 299 ; of the 
 Miocene, 315. 
 
 Cetiosaurus, 249, 25 
 
 Chceropotamus, 302. 
 
 Chasietes, 105, 173 ; tumidus, 174. 
 
 Chain-coral, 119. 
 
 Chalk, 259 ; structure of, 21-23 ; Foramin- 
 ifera of, 22, 263; origin of, 23; with 
 flints, 259 ; without flints, 259. 
 
 Chama, 236. 
 
 Charncerops, 308 ; Helvetica, 309. 
 
 Chazy Limestone, 95, 96. 
 
 Cheiroptera, of the Eocene, 304, 305 ; of 
 the Miocene, 322. 
 
 Cheirotherium, 215, 216. 
 
 Cheirurus, 108, 123 ; bimwronatus, 124. 
 
 Chelichnm Duncani, 202. 
 
 Chelone Benstedi, 280 ; planiceps, 251. 
 
 Chelonia, of the Permian, 202; of the 
 Jurassic, 251 ; of the Cretaceous, 280 ; 
 of the Eocene, 296 ; of the Miocene, 213. 
 
 Chemnitzia, 213. 
 
 Chemung Group, 135, 136, 137. 
 
 Chert, 34. 
 
 Chillesford Beds, 325, 326, 336. 
 
 Chonetes, 127, 147, 184; Hardrensis, 185. 
 
 Chonophyllum, 178. 
 
 Cidaris, 266. 
 
 Cincinnati Group7 95, 96. 
 
 Cinnamomuin polymorphum, 309. 
 
 Cinnamon -trees, 262, 290, 306, 308, 309. 
 
 Cladodus, 188. 
 
 Claiborne Beds, 289. 
 
 Clathropora, 145; intertexta, 146. 
 
 Clay, 20 ; Red, origin of, 35. 
 
 Clay-ironstone, nodules of, 31. 
 
 Cleidophoms, 111. 
 
 Cleodora, 312. 
 
 Climaeograptus, 101, 119. 
 
 Clinton Formation, 116, 117. 
 
 Clisivphyllum, 173. 
 
 Clupeidce, 276. 
 
 Clymenia, 149 ; SedgwicUi, 149. 
 
 Coal, 36 ; structure of, 163 ; mode of for- 
 mation of, 162. 
 
 Coal-measures, 159, 160; mineral char- 
 acters of, 159; mode of formation of, 
 160, 162 ; plants of, 162-170. 
 
 Coccoliths, 261. 
 
 Coccosteus, 151, 152. 
 
 Cochlwdus, 188 ; contortus, 189. 
 
 Coleoptera, 182, 311. 
 
 Colossochelys Atlas, 313. 
 
 Columnaria, 105 ; alveolata, 105. 
 
 Comatula, 232, 266. 
 
 Conclusions to be drawn from Fossils, 
 
 52-56. 
 Concretions, calcareous, 29; phosphatic, 
 
 31 ; of clay-ironstone, 31 ; of manganese, 
 
 Conglomerate, 18. 
 
 Coniferce, 262 ; wood of, 13 ; of Devonian 
 period, 13S; of the Carboniferous, 170; 
 of the Permian, 196 ; of the Trias, 208 ; 
 of the Jurassic period, 230. 
 
 Coniston Flags and Grits, 116. 
 
 Connecticut Sandstones, footprints of, 
 222, 346. 
 
 Conoeoryphe Mathewi, 85; Sultzeri, 85. 
 
 Conodonts, 114, 131. 
 
 Constellaria, 105. 
 
 Constricting serpents of the Eocene, 296. 
 
 Contemporaneity of strata, 44-46. 
 
 Continuity, theory of, 5-7. 
 
 Conularia, 111, 129, 148, 186, 199, 237; 
 ornata, 149. 
 
 Conulus, 186. 
 
 Conus, 293. 
 
 Coomhola Grits, 158, 159. 
 
 Coprolites, 31, 243. 
 
 Coralline Crag, 324. 
 
 Corallines, 25. 
 
 Corallium, 311. 
 
 Coral-rag, 227, 229, 230. 
 
 Coral-reefs, 24-26. 
 
 Coral-rock, 26. 
 
 Coral-sand, 19, 26. 
 
 Corals, 103 ; of the Lower Silurian, 104, 
 105 ; of the Upper Silurian, 119 ; of the 
 Devonian, 140-143 ; of the Carbonifer- 
 ous, 172-175 ; of the Permian, 197 ; of 
 the Trias, 209 ; of the Jurassic, 230, 231 ; 
 of the Cretaceous, 266 ; of the Eocene, 
 292; of the Miocene, 311. 
 
 Corbula, 235. 
 
 Cornbrash, 227, 229. 
 
 Corniferous Limestone, 135, 137. 
 
 Cornulites, 123. 
 
 Cornus, 262. 
 
 Coryphodvn, 300. 
 
 Cowries, 259, 271, 293. 
 
 Crabs, 180, 197, 233, 267. 
 
 Crag, Red, 324; White, 324; Norwich, 
 324; Antwerp, 325; Bridlington, 325; 
 Coralline, 324. 
 
 Crania, 110, 127, 198, 269 ; Ignabergensis, 
 269. 
 
 Crassatella, 292. 
 
 Crepidophyllum, 142; Archiaci, 142. 
 
 Cretaceous period, 256-283 ; rocks of, in 
 Britain, 257-259; in North America, 
 260, 261 ; life of, 261-283. 
 
 Crinoidal Limestone, 24, 25. 
 
 Crinoidea, 120 ; of the Cambrian, 82 ; of 
 the Lower Silurian, 105 ; of the Upper 
 Silurian, 120-1J2; of the Devonian, 143; 
 of the Carboniferous. 175 ; of the Per- 
 mian, 197; of the Trias, 209; of the 
 Jurassic, 231 ; of the Cretaceous, 266 ; 
 of the Eocene, 292. 
 
 Crwceras, 273 ; cristaturn, 274. 
 
 Crocodilia, 218 ; of the Trias, 21S ; of the 
 Jurassic, 251 ; of the Cretaceous, 280 ; 
 of the Eocene, 296,297. 
 
 Cromer Forest-bed, 336. 
 
 Crossozamites, 230. 
 
 Crotalocrinus, 122.
 
 INDEX. 
 
 399 
 
 Crustacea, of the Cambrian, 83-87 ; of the- 
 Lower Silurian, Iu7, 108; of the Upper 
 Silurian, 123-125; of the Devonian, 144, 
 145, of the Carboniferous, 178-181; of 
 the Permian, 197; of the Trias, 210; of 
 the Jurassic, 233; of the Cretaceous, 
 267. 
 
 Cryptogams, 164, 262. 
 
 Ctenacanthus, 188. 
 
 Ctenodonta, 111. 
 
 Cupressus, 262. 
 
 Cursores, 297, 346. 
 
 Cuttle-fishes (see Dibranchiate Cephalo- 
 pod*). 
 
 Cya'hoerinus, 175. 
 
 Cyathophyllum, 119, 142, 173. 
 
 Cycadoptertg, 262. 
 
 Cycads, 208; of the Carboniferous, 170; 
 of the Permian, 197; of the Trias, 208; 
 of the Jurassic, 230; of the Cretaceous, 
 261. 
 
 Cijclas, 268. 
 
 Cyclonema, 129. 
 
 Cyclophtkalmug senior, 181. 
 
 Cyclostoma, 294 ; Arnoudii, 294. 
 
 Cynodraco, 220. 
 
 Cyprcea, 271, 293 ; elegans, 393. 
 
 Cypress, -262, 308, 311. 
 
 Ci/prltlina, 145. 
 
 Cvpridina Slates, 145. 
 
 Cyrena, 235, 268, 292. 
 
 Cyrtina, 213, 214. 
 
 Cyrtoceras, 114. 
 
 Cystiphyllum, 119, 142, 173; vesiculosum, 
 141. 
 
 Cystoidea, 105-107 ; of the Cambrian, 82 ; 
 of the Lower Silurian, 106; of the 
 Upper Silurian, 120. 
 
 Dachstein Beds, 205, 206. 
 
 Dadoxyhn, 138, 170. 
 
 Daonella, 211; Lammelli, 211. 
 
 Dasornis Londinensis, 297. 
 
 Decapod Crustaceans, 180. 
 
 Deer, 317, 329, 354. 
 
 Deinosauria, 248 ; of the Trias, 221 ; of 
 the Jurassic, 248-251 ; of the Cretaceous, 
 277-279. 
 
 Deinotheriirm, 319, 320 ; giganteum, 320. 
 
 Denbighshire Flags and Grits, 115. 
 
 Dendrocrinm, 82. 
 
 Dendrograptus, 100. 
 
 Desmids, 138, 261. 
 
 Devonian Formation, 133-136; origin of 
 name, 133; relation to Old Red Sand- 
 stone, 133, 134; of Devonshire, 134; 
 of North America, 135, 136; life of, 
 136-156. 
 
 Diadcma, 266. 
 
 Diatoms, 33; of the Devonian, 138; of 
 the Carboniferous, 164 ; of flints, 261 ; 
 of Richmond Earth, 33, 307. 
 
 Dibrnnchiate Cephalopoda, 112; of the 
 Trias, 212; of the Jurassic, 239-241; 
 of the Cretaceous, 274, 275; of the 
 Eocene, 294; of the Miocene, 312. 
 
 Diceras, 236 ; arietina, 236. 
 
 Diceras Limestone, 227, 236. 
 
 Dichobune, 303. 
 
 Dichograptits, 101 ; octobrachiatus, 101. 
 
 Dicotyledonous plants. 262. 
 
 Dimtyles antiqims, 317. 
 
 Dicrdnograptus, 101, 119. 
 
 DMyonema, 89, 100, 119; soeiale, 89. 
 Dicynodon, 220 ; lacerticepg, 221. 
 Didelphyg, 254, 315; gypsurum, 299. 
 Dulux ineptux, 348. 
 
 JJiilnm.-yraptus, 101; divaricate, 102. 
 Dikellvcephalus Celticw, 84; Afinneso- 
 
 tenkis, 84. 
 Dimorphodon, 247. 
 Dinichthyx, 153; Uertzeri, 151. 
 Dincceras, 303 ; mirabilis, 304. 
 Dinocerata, 303, 304. 
 Dinophis, 296. 
 Dinornis, 346, 348; elephantopus, 346, 
 
 347; giganteus. 346. 
 Dinosauria (see Deinosauria). 
 Dinotherium (see Deinotherium). 
 
 ' hyphyUum, 142. 
 
 Dvplograptw, 101, 119; pristis, 102. 
 
 Dipnoi, 153, 187, 215. 
 
 Diprotodon, 348, 349 ; australis, 348. 
 
 Diptera, 311. 
 
 Discina, 87, 110, 127, 198. 
 
 niscoidea, 266 ; cylindrica, 267. 
 
 Dithyrocaris, 179 ; Scouleri, 180. 
 
 Dodo, 348. 
 
 Dog whelks, 293. 
 
 Dolomite, 27, 28. 
 
 Dolomitic Conglomerate of Bristol, 201, 
 
 219. 
 
 Dolphins, 299, 315. 
 Dorcatherium, 317. 
 Downton Sandstone, 116. 
 Draco volans, 245. 
 Dragon-flies, 311. 
 Drift, Glacial, 337. 
 Dremotherium, 317. 
 Dromatherium sylvestre, 223, 224. 
 Dryandra, 262. 
 Dryopithecus, 323. 
 Dugongs, 299. 
 
 Echinodermata, of the Cambrian, 82 ; of 
 the Lower Silurian, 105; of the Upper 
 Silurian, 120; of the Devonian, 143 ; of 
 the Carboniferous, 175 ; of the Permian, 
 197 ; of the Trias, 209 ; of the Jurassic, 
 231; of the Cretaceous, 266; of the 
 Eocene, 292. 
 
 Echinoidea, 177; of the Upper Silurian, 
 120 ; of the Devonian, 143 ; of the Car- 
 boniferous, 177; of the Permian, 197; 
 of the Jurassic, 233 ; of the Cretaceous, 
 266. 
 
 Edentata, 349 ; of the Eocene, 299 ; of the 
 Miocene, 315; of the Post-Pliocene, 
 349-353. 
 
 Edriocrinus, 122. 
 
 Eifel Limestone, 185. 
 
 Elasmobranchii (see Placoid Fishes). 
 
 Elagmosanrus, 276. 
 
 Elephants, 319, 320, 330. 
 
 Elephas, 320; Americantts, 357; anti- 
 quus, 329, 830, 336, 341, 357 ; Falcuneri, 
 359 ; Melitensis, 359 ; meridionalis, 329, 
 330, 336, 357 ; planifrong, 321 ; primi- 
 aenius, 339, 841, 357, 358. 
 
 Elk, 354 ; Irish, 354, 355. 
 
 EUipsocephalus Itofi, 84. 
 
 Elotherium, 317. 
 
 Emydidce, 296. 
 
 Emys, 280. 
 
 Enaliosaurians, 219, 242, 276. 
 
 Encrinital marble, 24.
 
 400 
 
 INDEX. 
 
 Encrinurus, 123. 
 
 Enerinus liliiformis, 209, 210. 
 
 Endogenous plants, 261. 
 
 Endnphyllum, 173. 
 
 Endothyra, 171; Bailyi, 172. 
 
 Engis skull, 364. 
 
 Entomis, 145. 
 
 Entomoconchus Scouleri, 179, 180. 
 
 Eocene period, 284 ; rocks of, in Britain, 
 
 287, 288; in France, 2S8; in North 
 
 America, 288, 289 ; life of, 289-305. 
 Eocidaris, 197. 
 
 Eophyton., SO ; Linneanum, 81. 
 Eophyton Sandstone, 79. 
 Eosaurus Acadianus, 191. 
 Eozoic rocks, 67 
 Eozoon Bavaricum, 76. 
 Eoz'Mn Cana dense, 68, 76 ; appearance of, 
 
 in mass, 69 ; minute structure of, 70, 71 ; 
 
 affinities of, with Foraminifera, 71-74. 
 Ephemeridce, 145, 183. 
 Equisetacece., 166. 
 Equisetites, 196. 
 Equidce, 301, 302, 316, 328. 
 Equus, 302 ; cabaltvs, 354 ; excelsus, 328 ; 
 
 fossilis, 336, 354 
 Eridophyllum, 142. 
 Eryon arctiformis, 233, 234. 
 Eschara, 267. 
 Escharidce, 267. 
 Escharina, 267 ; Oceani, 268. 
 Estheria, 145, 179, 210; tenella, 180. 
 Eucalyptocrinus, 122; polydactylus, 122. 
 
 ompkaJws,'l28, 148, 186, 199, 213; dis- 
 cors, 129. 
 
 Euplectella, 265. 
 
 Euproiips, 179. 
 
 European Bison, 356. 
 
 Eurypterida, 124, 179 ; of the Upper Silu- 
 rian, 124 ; of the Devonian, 144. 
 
 Even-toed Ungulates, 300, 317, 354. 
 
 Exogenous plants, 266. 
 
 Exogyra, 236 ; virgula, 236. 
 
 Extinction of species, 57, 58. 
 
 Fagus, 262. 
 
 Faluns, 306. 
 
 Fan-palms, 308. 
 
 Favistella, 105. 
 
 Favosites, 119, 142; Gothlandica, 143; 
 hemisphcerica, 143. 
 
 Faxoe Limestone, 259, 286. 
 
 Felisangustus, 330 ; leo, 361 ; spelcea, 361. 
 
 Fenestella, 108, 125, 145, 184, 198, 210; 
 cribrosa, 146; magnified, 146 ; retiformis, 
 198. 
 
 Fenestellidce, 183. 
 
 Ferns, of the Devonian, 136 ; of the Car- 
 boniferous, 164; of the Permian, 196; 
 of the Trias, 207 ; of the Jurassic, 229 ; 
 of the Cretaceous, 261. 
 
 Fig-shells, 293. 
 
 Fishes, 350; of the Upper Silurian, 130, 
 131 ; of the Devonian, 150-155 ; of the 
 Carboniferous, 187, 188 ; of the Permian, 
 199, 200 ; of the Trias, 214, 215 ; of the 
 Jurassic, 240-242 ; of the Cretaceous, 275, 
 276 ; of the Eocene, 295, 296 ; of the 
 Miocene, 312, 313. 
 
 Flint, 33 ; structure of, 34 ; origin of, 34 ; 
 organisms of, 34, 138, 263 ; of Chalk, 34, 
 239, 261. 
 
 Human implements associated with bones 
 of extinct Mammals, 363, 364. 
 
 Flora (see Plants). 
 
 Footprints of Cheirotherium, 215, 216; 
 of the T riassic sandstones of Connecti- 
 cut, 222. 
 
 Foraminifera, 22-24, 71-74 ; of the Cam- 
 brian, 82; of the Lower Silurian, 98; 
 of the Carboniferous, 171, 172; of the 
 Permian, 197 ; of the Trias, 209 ; of the 
 Jurassic, 230 ; of the Cretaceous, 21, 
 22, 263 ; of the Eocene, 290 ; of the 
 Miocene, 311 ; of the Post-Pliocene, 
 338 ; of Atlantic ooze, 22, 23 ; as build- 
 ers of limestone, 24, 25, 28 ; as forming 
 green sands, 34. 
 
 Forbnsiocrinus, 175. 
 
 Forest-bed of Cromer, 336. 
 
 Forest-bugs, 811. 
 
 Forest-marble, 227. 
 
 Formation, definition of, 18 ; succession 
 of, 42. 
 
 Fossiliferous rocks, 14-37; chronological 
 succession of, 37-44. 
 
 Fossilisation, processes of, 11-14. 
 
 Fossils, definition of, 11 ; distinctive, of 
 rock-groups, 38; conclusions to be 
 drawn from, 52-56; biological relations 
 of, 57-61. 
 
 Foxes, 304. 
 
 Fringe-finned Ganoids, 153. 
 
 Fucoidal Sandstone, 79, 80. 
 
 Fucoids, 80, 97. 
 
 Fuller's Earth, 227, 229. 
 
 Fusulina, 172 ; cylindrica, 172. 
 
 Fusus, 237, 293. 
 
 Galeocerdo, 312. 
 
 Galerites, 266 ; albo-galerus, 267. 
 
 Galentes, 254. 
 
 Ganoid Fishes, 150 ; of the Upper Silurian, 
 130 ; of the Devonian, 150-153 ; of the 
 Carboniferous, 187, 188; of the Permian, 
 199 ; of the Trias, 214 ; of the Jurassic, 
 241; of the Cretaceous, 275; of the 
 Eocene, 295. 
 
 Gaspg Beds, 134. 
 
 Gasteropoda, of the Cambrian, 88 ; of the 
 Lower Silurian, 111; of the Upper Silu- 
 rian, 128, 129 ; of the Devonian, 148 ; of 
 the Carboniferous, 186; of the Permian, 
 199; of the Trias, 213 ; of the Jurassic, 
 236, 237 ; of the Cretaceous, 271 ; of the 
 Eocene, 292, 293. 
 
 Gastornis Parisiensis, 297. 
 
 Gault, 257, 258. 
 
 Gavial, 251, 297. 
 
 Genesee Slates, 135. 
 
 Geological record, breaks in the, 47-52. 
 
 Giraffes, 317. 
 
 Glacial period, 335 ; deposits of, 337, 338. 
 
 Glandulina, 311. 
 
 Glauconite, 34, 74, 98, 263. 
 
 Glavconome, 12H, 184 ; pulcherrima, 183. 
 
 Globe Crinoids (see Cystoidea). 
 
 Gl-ibigerina, 22, 23, 2(54. 
 
 Glutton, 360. 
 
 Glyptasier, 120. 
 
 Glyptocrinus, 122. 
 
 Gliiptodon, 351, 352 ; dampen. 352. 
 Giypl - 
 
 Glyptolcemm, 153. 
 
 Goats, 318. 
 
 Goniatites, 130, 149, 187, 214 ; Jossce, 187.
 
 INDEX. 
 
 4OI 
 
 Gorgonidce, 292. 
 Grallatores. 297. 
 Graphite, 36 ; mode of occurrence of, 36, 
 
 68 ; origin of, 36. 
 Qraptolites, 89, 100; structure of, 100; 
 
 of the Lower Silurian, 100-103; of the 
 
 Upper Silurian, 118, 119. 
 Great Oolite, 2i7, 229; Upper, 257, 258, 
 
 260 
 
 Greenland, Miocene plants of, 311. 
 Greeusand, Lower, 257, 260. 
 Green sands, origin of, 44, 263. 
 Grevittea, 262, 308. 
 Qrijftthides, 179. 
 Grizzly Bear, 359 
 Ground Sloths, S51. 
 Gi-<//>!ir<'a, 236; incurva, 236. 
 Guelph Limestone, 117. 
 Gulo luxcus, 360 ; spelccus, 360. 
 Guttenstein Beds, 205, 206. 
 Gymnospermous Exogens, 262. 
 Gypsum, 32, 193, 204. 
 Gyracanthus, 188. 
 Gyroceras, 130. 
 
 Hadrosaurus, 278. 
 
 Ualitherinm, 299. 
 
 Hallstadt Beds, 205, 206. 
 
 Halobia, 211. 
 
 Halysites, 119 ; agglomerata, 120 ; caten- 
 
 ularia, 120. 
 
 Hamilton formation, 135, 137. 
 Hamites, 273 ; rotundus, 274. 
 Haplophlebium Barnesi, 182. 
 Harlech Grits, 78, 79. 
 Harpes, 108, 123 ; 
 Hastings Sands, 257. 
 Headon and Osborne series, 287, 288. 
 Heart-urchins, 311. 
 Heliolites, 105, 119, 266. 
 Heliophyllvm, 142, 173; exiguum, 141. 
 Helix, 294. 
 Helladotherium, 317. 
 Heloporafragilis, 126. 
 Hemicidarig crenularis, 233. 
 Hemiptera, 311. 
 
 Hemitrochiscus paradoxus, 197. 
 Hempstead Beds, 306. 
 Hesperornis, 281, 282 ; regalis, 282. 
 Heteropoda, 111 ; of the Lower Silurian, 
 
 111 ; of the Upper Silurian, 129 ; of the 
 
 Devonian, 148 ; of the Carboniferous, 
 
 186. 
 
 Hinnites, 213. 
 Hipparion, 301, . _ 
 Hippopodium, 235. 
 Hippopotamus, 302; amphibhts, 317, 329; 
 
 major, 329, 336, 354 ; Sivalensis, 318. 
 
 " - 108. 
 
 <thoa, 1( 
 Hippurite Marble, 270. 
 Hippurites, 270; Toucasiana, 271. 
 Hippitritid<e, 270, 285. 
 Hitstioderma, 82. 
 Hollow-horned Ruminants, 317. 
 Holoci/ftis elegans, 266. 
 Holopea, 129 ; subconica, 129. 
 Holopella, 129, 213; obsoleta, 129. 
 Holoptychius, 153 ; nobilissimus, 154. 
 Holostbmatous Univalves, 236, 293. 
 Holothurians, 120. 
 Holtenia, 264. 
 Homacanthus, 188. 
 
 Homalonotus, 123, 145 ; armatus, 144. 
 
 Homo diluvii testis, 313. 
 
 Honeycomb Corals, 142. 
 
 Hoofed Quadrupeds, 300. 
 
 Hudson River Group, 95. 
 
 Huronian Period, 75, 76 ; rocks of, 75. 
 
 Hycena crocuta, 360; spelcea, 360; flip- 
 
 parionum, 330. 
 Hyanictis, 322. 
 Hycenodon, 304. 
 Hyalea D'Orbignyana, 312. 
 Hybodus. 214, 242, 275. 
 Bydractinia, 265. 
 Hydroid Zoophytes, 103, 265. 
 Hymenocaris vcrmicauda, 84, 88. 
 Hymenophyllites, 165. 
 Hymenoptera, 811. 
 Hyopotamus, 302. 
 Hyperodapedon, 218. 
 Hypsiprymnopxis, 224. 
 Hystnx primigenius, 322. 
 
 Ichthyocrinus Icevis, 122. 
 
 Ichthyornis, 281, 282; di'spar, 281, 282. 
 
 Ichthyosaurus, 242, 243, 276; commwrsis, 
 242. 
 
 Ictitherium, 322. 
 
 Igtuma, 277. 
 
 Iguanodun, 277, 278 ; ifantelli, 278. 
 
 Ilfracombe Group, 134. 
 
 Illcenus, 108, 123 , 
 
 Imperfection of the palseontological re- 
 cord, 50, 51. 
 
 Inferior Oolite, 227, 229. 
 
 Infusorial Earth, 33. 
 
 Inoceramus, 269 ; sulcatus, 270. 
 
 Insectivora, of the Eocene, 305; of the 
 Miocene, 322. 
 
 Insects, of the Devonian, 145; of the 
 Carboniferous, 182; of the Jurassic, 
 233 ; of the Miocene, 311, 312. 
 
 Irish Elk, 354, 355. 
 
 Ischadites, 99, 118. 
 
 Isopod Crustaceans, 84. 
 
 Jackson Beds, 289 
 
 Jurassic period, 226; rocks of, 226-229; 
 life of, V 29-255. 
 
 Kaidacarpum, 230. 
 Kainozoic period, 44, 284-287. 
 Kangaroo, 348. 
 Kelloway Rock, 227. 
 Kent's Cavern, deposits in, 343. 
 Keuper, 204, 206. 
 Kimmeridge Clay, 227, 229. 
 King-crabs, 84, 124, 125, 179. 
 Kniiinckia, 213, 214. 
 Kossen Beds, 205, 206. 
 
 Labyrinthodon Jcegeri, 217. 
 
 Labi/rinthodontia, 190; of the Carbon- 
 iferous, 189-191; of the Permian, 200; 
 of the Trias, 215-217. 
 
 Lace-corals, 108, 125, 145, 183, 198, 210. 
 
 Laci-.rtiUa. 202; of the Permian, 201, 202; 
 of the Trias, 217, 218 ; of the Jurassic, 
 251 ; of the Cretaceous, 280. 
 
 Lcelaps, 278. 
 
 Lamellibmnchiata, of the Cambrian, 88 ; 
 of the Lower Silurian, 110; of tlic 
 Upper Silurian, 128 ; of the Devonian,
 
 402 
 
 INDEX. 
 
 148 ; of the Carboniferous, 186 ; of the 
 Permian, 198 ; of the Trias, 211 ; of the 
 Jurassic, 234-236 ; of the Cretaceous, 
 268-270 ; of the Eocene, 292. 
 
 Lamna, 275, 312. 
 
 Lamp-shells (see Brachiopoda). 
 
 Land-tortoises, 313. 
 
 Lauracece, 308. 
 
 Laurentian period, 65; rocks of, 65, 66; 
 Lower Laurentian, 66 ; Upper Lau- 
 rentian, 66 ; areas occupied bjr Lau- 
 rentian rocks, 66 ; limestones of, 66, 
 6" ; iron-ores of, 68 ; phosphate of lime 
 of, 68 ; graphite of, 68 ; life of, 67-75. 
 
 Leaf-beds of the Isle of Mull, 306. 
 
 Leda, 292 ; trwieata, 338. 
 
 Leguminogitei Marcouanus, 263. 
 
 Lemming, 344, 345. 
 
 Lepadidce, 267. 
 
 Lepadocrinus Gebhardi, 106. 
 
 Leperditia, 108; canadensis, 107. 
 
 Lepidaster, 120. 
 
 Lepidechmus, 178. 
 
 Lepidesthes, 178. 
 
 Lepidodendroids, 166, 167, 207. 
 
 Lepidodendron, 118, 136, 166, 196; Stern- 
 bergi, 167. 
 
 Lepidoptera, 311. 
 
 Lepidosiren, 153. 
 
 Lepidustem, 188. 
 
 Lepidostrobus, 166. 
 
 Lepidotus, 275. 
 
 Leptcena, 109, 110, 125, 234; Liassica, 
 235; sericea, 110. 
 
 Leptocaelia, 127 ; plano-convexa, 127. 
 
 Lias, 226, 227, 229. 
 
 Lichas, 108. 
 
 Licrophycus Ottawaensis, 97. 
 
 Lignitic Formation of North America, 
 288, 294. 
 
 Lily-encrinite, 209, 210. 
 
 Lima, 235. 
 
 Lime, phosphate of, 30, 31. 
 
 Limestone, 23-27 ; varieties of, 27-30 ; 
 origin of, 21; microscopical structure 
 of, 26; Crinoidal, 24; Forarniniferal, 
 24, 26; coralline, 24; magnesian, 27; 
 metamorphic, 27 ; oolitic, 28-30 ; piso- 
 litic, 29 ; bituminous, 36 ; Laurentian, 
 67. 
 
 Limncea, 294 ; pyramidalis, 294. 
 
 Limulus, 84, 124, 125, 179. 
 
 Lingula, 87, 88, 110, 127, 147, 198 : Cred- 
 nen, 198. 
 
 Lingula Flags, 77, 78, 79, 88. 
 
 Lingulella, 87, 88 ; Davisii, 88 ; ferru- 
 ginea, 88. 
 
 Linodendron, 262, 308 ; Meeki, 263. 
 
 Lithostrotion, 173 ; irregulare, 174. 
 
 Lituites, 130. 
 
 Lizards (see Lacertilia). 
 
 Llama, 354. 
 
 Llanberis Slates, 79. 
 
 Llandeilo rocks, 92, 94, 96. 
 
 Llandovery rocks, 93; Lower, 93; Upper, 
 115. 
 
 Lobsters, 180, 210, 233, 267. 
 
 Loess, 339. 
 
 London Clay, 287, 288. 
 
 Longmynd rocks, 77-SO, 83. 
 
 Lonsdakia, 173. 
 
 Lophiodon, 316. 
 
 Lophophijllum, 173. 
 
 Lower Cambrian, 77-79 ; Chalk, 259 ; Cre- 
 taceous, 257, 258 ; Devonian, 134 ; 
 Eocene, 287, 288; Greensand, 257. 258; 
 Helderberg, 117, 118; Laurentian rocks, 
 66; Ludlow rock, 116; Miocene, 305; 
 Old Red Sandstone, 134 ; Oolites, 227, 
 229: Silurian period, 90-114; rocks of, 
 in Britain, 92-94; in North America, 
 94-96; life of, 97-114'. 
 
 Loxonema, 186, 199, 213. 
 
 Ludlow rocks, 116, 117. 
 
 Lycopodiacece, 118, 136, 167. 
 
 Lynton Group, 134. 
 
 Lyrodesina, 111. 
 
 Macaques, 323, 331. 
 
 Machcer -acanthus major, 151, 155. 
 
 Machairodus, 221, 249, 322, 331, 360; 
 cul/ridens, 331. 
 
 Maclurea, 111; crenulata, 112. 
 
 Macrocheilus, 186, 199, 213 
 
 Macropetalichthya, 152; SuWvanti, 151. 
 
 Macrotherium giganteum, 315. 
 
 Macrurous Crustaceans, 180. 
 
 Maclra, 292. 
 
 Maestricht Chalk, 259, 279, 286. 
 
 Magnesian Lifhestone, 27; nature and 
 structure of, 28 ; of the Permian series, 
 194, 196. 
 
 Magnolia, 262. 290, 31ft. 
 
 Mammalia, of the Trias, 223, 224 ; of the 
 Jurassic, 253, 254; of the Eocene, 
 299-305; of the Miocene, 313-323; of 
 the Pliocene, 327-331; of the Post- 
 Pliocene, 348-362. 
 
 Mammoth, 339, 341, 344, 357-359. 
 
 Man, remains of, in Post-Pliocene de- 
 posits, 341, 344. 
 
 Manatee, 299. 
 
 Mantellia, 230 ; megalophylla, 230. 
 
 Maple, 290, 308, 310. 
 
 Marble, 28; encrinital, 24; statuary, 27. 
 
 Marcellus Shales, 135. 
 
 Mariacrinua, 122. 
 
 Marmots, 322. 
 
 Marsupials, 299 ; of the Trias, 223 ; of the 
 Jurassic. 253, 254 ; of the Eocene, 299 ; 
 of the Miocene, 315 ; of the Post-Plio- 
 cene, 348, 319. 
 
 Marniipwcrinus, 122. 
 
 Marsupites, 266. 
 
 Mastodon, 319, 321, 322; Americanus, 
 angustidens, 322; Arvenensis, 329; 
 longirostris, 322 ; Ohioticus, 357 ; Siva- 
 lensis, 321. 
 
 Medina Sandstone, 116. 
 
 Mcgalichthys, 188. 
 
 Megalodon, 148. 
 
 Megalomua, 128. 
 
 Megalonyx, 351. 
 
 Megalosaurus, 249, 278. 
 
 Megatherium, 350, 351 ; Cuvieri, 350. 
 
 Melania, 294. 
 
 Melinites, 178. 
 
 Menevian Group, 77-79. 
 
 Menobranchus, 189. 
 
 Meristella, 127; cylindrica, 127; inter- 
 media, 127 ; naviformti, 127. 
 
 Mesopithecus, 323. 
 
 Mesozoic Period, 44. 
 
 Sfichelini-a, 142. 
 
 Micraster, 266. 
 
 Microlestes, 224 ; antiquus, 223.
 
 INDEX. 
 
 403 
 
 Middle Devonian, 134 ; Eocene, 287 288, 
 289; Oolites, 227; Silurian, 91. 
 
 Miliolite Limestone, 290. 
 
 M Me para, 230. 
 
 Millstone Grit, 159, 161. 
 
 Miocene period, 305 ; rocks of, in Britain, 
 305, 306; in Fiance, 306; in Belgium, 
 307; in Switzerland, 306; in Austria, 
 307; in Germany, 307; in Italy, 307; in 
 India, 307; in North America, 307; life 
 of, 308-323. 
 
 Mitre-shells, 271, 293. 
 
 if lira, 271, 293. 
 
 Moas of New Zealand, 346-348. 
 
 Moiholopsis, 111 ; Solvcnsis, 88. 
 
 Molasse, 306. 
 
 Mole, 322, 336. 
 
 Monkeys, 305, 331. 
 
 Moiiocotyledonous plants, 262. 
 
 Moiioyraptus, 100, 119 ; priodon, 119. 
 
 Monotis, 211. 
 
 Monte Bolea, fishes of, 295. 
 
 Montlivaltta, 209. 
 
 Mosasauroids, 279, 280. 
 
 Mosasaurm, 279; Camperi, 279; prin- 
 ceps, 279. 
 
 Mountain Limestone, 108, 161. 
 
 Mud-fishes, 153, 215. 
 
 Mud-turtles, 280. 
 
 Mull, Miocene strata of, 306. 
 
 Murchisonia, 111, 129, 199,213; gracilis, 
 
 Murex, 237, 293. 
 Muschelkalk, 203, 204, 206. 
 Musk-deer, 317. 
 Musk-ox, 344, 345, 356. 
 Musk-sheep, 356. 
 Myiiobatii JMinmJaii, 296. 
 Mylndon, 351 ; robmtm, 352. 
 Xyophona, 211; lineata, 211. 
 Mijriapoda, of the Coal, 181, 182. 
 
 Nassa, 293. 
 
 tfatatores, 297. 
 
 Natica, 271, 293. 
 
 Nautilus, 112-114, 130, 149, 186, 199, 237, 
 
 272, 294 ; Danicus, 272 ; pompilius, 237. 
 Neanderthal skull, 364. 
 Neocomian series, 257, 260. 
 Neolimulus, 125. 
 
 Merinoea, 237, 271 ; Goodhallh, 237. 
 Nf.rita, 393. 
 Neuroptera, 311. 
 Neuropteris, 136, 165, 196. 
 Newer Pliocene, 323, 324. 
 New Red Sandstone, 193, 203. 
 Newts, 189, 200, 217. 
 Niagara Limestone, 117. 
 Nipaditf.s, 290 ; ellipticus, 290. 
 JV 'oeggerathia, 197. 
 Nonvich Crag, 324. 
 Nothosaurus, 219 ; mirabilis, 219. 
 Notidanm, 241. 
 Numenius gypsorum, 297. 
 Nummulina, 172, 290; latviyata, 290 ; 
 
 pristina, 172. 
 Nummulitic Limestone, 24, 287, 291. 
 
 Oak, 262, 310. 
 
 Obnlella, 87 ; sagiUalis, 88. 
 
 Odd-toed Ungulates, 300, 315, 327, 353. 
 
 Odontaxpis, 275. 
 
 Odunioptens, 105; Schlotheimi, 104. 
 
 Odontopteryx, 297 ; toliapicus, 297, 298. 
 
 Odontornithes, 282. 
 
 Ogygia, 108 ; Buchii, 107. 
 
 Older Pliocene, 323, 324. 
 
 Oldhamia, 81; antiqua, 82; slates of 
 
 Ireland, 79, 80. 
 
 Old Red Sandstone, 133 ; origin of name, 
 133 ; of Scotland, 134 ; relations of, to 
 Devonian, 133, 134, 155. 
 Olenus, 108 ; micrurus, 88. 
 Oligocene, 305. 
 OUgoponis, 178. 
 Olive-shells, 293. - 
 Omphyma, 119. 
 
 Onchus, 130 ; tenuistriatus, 181. 
 Oneida Conglomerate, 116. 
 Onychodus, 153 ; xigmoides, 151. 
 Oolitic limestone, structure of, 28 ; mode 
 
 of formation of, 30. 
 Oolitic rocks (.see Jurassic). 
 Ooze, Atlantic, 22, 33. 
 Ophidla, 251 ; of the Eocene, 296. 
 Ophiuroidea, of the Lower Silurian, 105 : 
 of the Upper Silurian, 120; of the Car- 
 boniferous, 177 ; of the Trias, 210 ; of 
 the Jurassic, 233. 
 Opossum, 299, 315. 
 Orbitoides, 291. 
 Oriskany Sandstone, 135. 
 Ormoxylon, 138. 
 Orohippus, 302. 
 
 Orthis, 38, 109, 125, 147, 184, 199 ; biforata, 
 109 ; Davidsoni, 127 ; elegantula, 127 ; 
 Jlabellulum, 109; llicksti, 38; lenticu- 
 larls, 38; plicatella, 110; resupinata, 
 185; subquadrata, 109; testudinaria, 
 110. 
 Orthoceras, 89, 112, 113, 130, 149, 186, 
 
 213 ; crebriseptum, 113. 
 Orthonola, 111. 
 Orthoptera, 182, 311. 
 Osmeroidcs, 276 ; Mantelli, 276. 
 Osmerus, 276. 
 Osteolepis, 153. 
 
 Ostracode Crustaceans of the Cambrian, 
 83; of the Lower Silurian, 107; of the 
 Upper Silurian, 123 ; of the Devonian, 
 145; of the Carboniferous, 179 ; of the 
 Permian, 197 ; of the Trias, 210 ; of the 
 Jurassic, 233; of the Cretaceous, 267. 
 Ostrea acuminata, 235 ; Couloni, 269 ; 
 deltoidea, 235 ; distorla, 235 ; expansa, 
 gregarea, 235 : Marshii, 235, 236. 
 OtMlit*, 295 ; nbliquus, 296. 
 Otozamites, 230. 
 Otozown, 206. 
 
 Oudenodm, 220; Bainii, 221. 
 Oeibos moschatus, 356. 
 Oxford Clay, 227, 229. 
 Oxyrhina, 312 ; xiphodon, 313. 
 Oysters, 235, 236, 269. 
 
 Pachyphyllum, 173. 
 
 Pala-arca, 111. 
 
 Palceaster, 120 ; Ruthveni, 121. 
 
 Palasterina, 120; primcuva, 121. 
 
 PaUechimis, 120, 17S ; elUjiticws, 177. 
 
 Pultun*, isn; typus, 180. 
 
 Palmocvma, 120; Colvini, 121. 
 
 ra'a'olit'hicm'an, remains of, 363-365. 
 Pnlceomanon. 118. 
 Palceoniscuv, 188, 200.
 
 404 
 
 INDEX. 
 
 Pcdceontina Oolitica, 233. 
 Palseontological evidence as to Evolution, 
 
 60, 372-374. 
 Pateontological record, imperfection of 
 
 the, 50, 51. 
 
 Palaeontology, definition of, 10. 
 Palceonyctis, 304 
 Palceophis, 296 ; toliapicus, 296 ; typhceus, 
 
 296. 
 
 PaloBoreas, 318. 
 Palceosaurus, 200, 218, 219 ; platyodon, 
 
 219. 
 
 Palceosiren Beine-rti, 200. 
 Palceotherium, 300 ; magnum, 301. 
 Palceoxylon, 170. 
 Palseozoio period, 44. 
 Palms, 230, 263, 290, 308, 309 
 Paludina, 257, 294. 
 Pandanece, 230. 
 Pandanus, 262. 
 
 Paradoxides, 86, 87, 108 ; Bohemicus, 85. 
 Parasmilia, 266. 
 Parkeria, 264. 
 Pear Encrinite, 231. 
 Pearly Nautilus, 58, 111, 112, 237. 
 Peccaries, 317. 
 Pecopteris, 136, 165, 196. 
 Pectew Grcenlandicus , 338 ; Islandicus, 
 
 338 ; FaZonimsis, 211, 212, 204. 
 Penarth Beds, 204. 
 Pennatulidas, 292. 
 Pentacrinus, 231 ; caput-medusce, 231 ; 
 
 fasciculosiis, 232. 
 Pentamerus, 125, 126; galeatus, 126; 
 
 KnighM, 128. 
 
 Pentremites (see Blastoidea). 
 Pentremltes conoideus, 176; pyri/ormis, 
 
 176. 
 
 Perching Birds, 297. 
 Percidce, 276. 
 Periechocriims, 122. 
 Perissodactyle Ungulates, 300, 315, 327. 
 Permian period, 192-202; rocks of, in 
 Britain, 194; in North America, 194; 
 life of, 195-302. 
 
 Persistent types of life, 58, 371. 
 Petalodus, 188. 
 Petraster, 120. 
 Petroleum, origin of, 36. - 
 Pezophaps, 348. 
 
 Phacops, 108, 123, 145 ; Downingite, 124 ; 
 granulalus, 144 ; farois, 144 ; latifrons, 
 144, 145; longicaudatus, 124; rana, 145. 
 Phcenopora entriformis, 126. 
 Phalaugers, 348. 
 Phanerogams, 164. 
 Phaneropleuron, 153. 
 Phascolotherium, 253, 254. 
 Pheronema, 264. 
 Phillipsastrcea, 142. 
 Phillipsia, 179 ; semtni/era, 180. 
 Pholadomya, 235. 
 Phormosuma, 178. 
 Phorus, 271. 
 
 Phosphate of lime, concretions of, 30 ; 
 disseminated iu rocks, 30 ; origin of, 31. 
 Phyllograptus, 102; <?/F"*, 102. 
 Phyllopoda, of the Cambrian, 83 ; of the 
 Lower Silurian, 108 ; of the Upper Silu- 
 rian, 123; of the Devonian, 145; of the 
 Carboniferous, 179; of the Permian, 
 197 ; of the Trias, 210. 
 
 Phyllopora, 210. 
 
 Physa, 294 ; columnaris, 294. 
 
 Pigs, 302, 317, 329, 354. 
 
 Pilton Group, 135. 
 
 Pinites, 170. 
 
 Pisces (see Fishes). 
 
 Pisolite, 29. 
 
 Pisolitic Limestone of France, 259, 286. 
 
 Placodus, 220 ; giyas, 220. 
 
 Placoid Fishes, 150; of the Upper Silurian, 
 130, 131; of the Devonian, 153-155; of 
 the Carboniferous, 1S8 ; of the Permian, 
 199 ; of the Trias, 214 ; of the Jurassic, 
 241 ; of the Cretaceous, 275 ; of the 
 Eocene, 295 ; of the Miocene, 312. 
 
 Plagiaulax, 254. 
 
 Planoht.es, 122 ; vulgaris, 123. 
 
 Planorbis, 294. 
 
 Plants, of the Cambrian, 80, 81 ; of the 
 Lower Silurian, 97, 98 ; of the Upper 
 Silurian, 118 ; of the Devonian, 136-139 ; 
 of the Carboniferous, 163-170; of the 
 Permian, 196 ; of the Trias, 207, 208 ; 
 of the Jurassic, 229, 230; of the Cre- 
 taceous, 261-263 ; of the Eocene, 289, 
 290 ; of the Miocene, 308-311. 
 
 Platrmopora, 119. 
 
 Platanus, 262, 3"8 ; aceroides, 309. 
 
 Platephemera antiqua, 145. 
 
 Platyceras, 128, 148; dumosum, 148; 
 multisinuatum, 129 ; ventrieosum, 129. 
 
 Platycrinus, 122, 175; tricontadactylus, 
 175. 
 
 Platyostoma, 129 ; Niagarense, 129. 
 
 Platyrhine Monkeys, 362. 
 
 Platyschisma helicites, 129. 
 
 Platysomus, 200 ; yibbosus, 199. 
 
 Platystoma, 213. 
 
 Pleistocene period, 334 ; climate of, 362. 
 
 Plesiosaunis, 219, 243-245, 276; dolicho- 
 deirus, 244. 
 
 Pleurocystites squamosus, 106. 
 
 Pleurotoma, 293. 
 
 Pleuntomaria, 111, 129, 186, 199, 236, 271. 
 
 Plicatula, 213. 
 
 Pliocene period, 323; rocks of, in Britain, 
 324; in Belgium, 325; in Italy, 325; 
 in North America, 326 ; life of, 326-331. 
 
 Pliopithecus, 322 ; antiquus, 323. 
 
 Pliosaurus, 245. 
 
 Podocarya, 230. 
 
 Podozarmtes, 208 ; lanceolatus, 209. 
 
 Polir-schiefer, 33. 
 
 Polycystina, 31 ; of Barbadoes-earth, 33. 
 
 Polypora, 145, 184 ; dendroides, 183. 
 
 Polypterus, 153, 188. 
 
 Polystomella, 311. 
 
 Polytremacix, 266. 
 
 Polyzoa, of the Cambrian, 81, 89 ; of the 
 Lower Silurian, 108; of the Upper 
 Silurian, 125; of the Devonian, 145, 
 146; of the Carboniferous, 183, 184; 
 of the Permian, 198 ; of the Trias, 210 ; 
 of the Cretaceous, 267 ; of the Miocene, 
 312. 
 
 Populus, 262. 
 
 Porcellia, 186. 
 
 Porcupines, 322. 
 
 Portage Group, 135. 
 
 Port-Jackson Shark, 154, 188, 242. 
 
 Portland beds, 227, 229. 
 
 Post-Glacial deposits, 336, 338. .
 
 INDEX. 
 
 405 
 
 Post-Pliocene period, 334. 
 
 Post-Tertiary period, 286. 
 
 Poteriocrinus, 175. 
 
 Potsdam Sandstone, 79. 
 
 Pre-Glaeial deposits, 336. 
 
 Prestwichia, 179 ; rotundata, 179. 
 
 Primitta, 107; strangulata, 107. 
 
 Primordial Trilubites, 85. 
 
 Primordial zone, 79. 
 
 Proboseidea, of the Miocene, 319, 322; of 
 the Pliocene, 329, 330; of the Post- 
 Pliocene, 357-359. 
 
 Produeta, 147, 184, 198; horrida, 198; 
 Ir-ngispina, 185; semireticulata, 185. 
 
 Productella, 147, 184. 
 
 Productida', 147, 211. 
 
 Proetus, 123. 
 
 Prong-buck, 318. 
 
 Protaster, 120; Sedgwickii, 121. 
 
 Proteacece, 262, 308) 309. 
 
 Proteus, 189. 
 
 Protichniles, 87. 
 
 Protocyntites, 82. 
 
 Protornis Glarisiensis, 297. 
 
 Protorosaurus, 201, 202 ; Speneri, 201. 
 
 Protospongia, 81 ; fenestrata, 88. 
 ' Prototaxites, J18, 138; Logani, 139. 
 
 Psammobia, 292. 
 
 Psammodus, 188. 
 
 Psaronius, 136, 164. 
 
 Pseudocrinus bifasciatus, 106. 
 
 Psilophyhm, 118, 137, 138 ; princeps, 138. 
 
 Pteranodon, 247. 277; longiceps, 277. 
 
 Pleraspw, 130, 152 ; Ban/csii, 130. 
 
 Pterichthys, 152 ; cornutus, 153. 
 
 Ptenncea, 128; subfalcata, 128. 
 
 Pteroceras, 237, 271. 
 
 Pterodactylus, 245, 277; crassirostris, 246. 
 
 Pterophyllum, 208, 230 ; Jcegeri, 209. 
 
 Pteropoda, of the Cambrian, 88 ; of the 
 Lower Silurian, 111; of the Upper 
 Silurian, 129; of the Devonian, 148; 
 of the Carboniferous, 186; of the Per- 
 mian, 199; of the Jurassic, 237. 
 
 Pterosauria, 245; of the Jurassic, 245-248; 
 of the Cretaceous, 277. 
 
 Pterygotus Anglicus, 124, 125. 
 
 PUlodictya, 108, 125 ; acwto, 109;/aZci- 
 formis, 109 ; raripora, 126 ; Schafferi, 
 109. 
 
 Ptychoceras, 273 ; Emericianum, 274. 
 
 Ptychodus, 275. 
 
 Pupa vetusta, 186. 
 
 Purbeck Beds, 228; Mammals of, 254. 
 
 Purpuroidea, 237. 
 
 Pycnodua, 275. 
 
 Pyrula, 293. 
 
 Quadrumana, of the Eocene, 305 ; of the 
 Miocene, 322, 323 ; of the Pliocene, 331 ; 
 of the Post-Pliocene, 361. 
 
 Quadrupeds (e Mammalia). 
 
 Quaternary period, 334. 
 
 Quebec Group, 95, 96, 101. 
 
 Quercus, 262. 
 
 Rabbits, 322. 
 #<roa, 313. 
 Raptores, 297. 
 Rasores, 297. 
 Recent period, 286, 334. 
 Receptaculites, 99. 
 
 Red clays, origin of, 35. 
 
 Red Coral, 311. 
 
 Red Crag, 324. 
 
 Red Deer, 336, 354. 
 
 Reindeer, 314, 345, 354, 855. 
 
 Remopleurides, 188. 
 
 Reptiles, 200; of the Permian, 200-202; 
 of the Trias, 217-221 ; of the Jurassic, 
 242-251; of the Cretaceous, 276-281; of 
 the Eocene, 296, 297. 
 
 Retepora, 108, 125, 145, 184, 198, 210; 
 Ehrenbergi, 198 ; Phillipsi, 146. 
 
 Retiolites, 119. 
 
 Retzia, 127. 
 
 Rheetic Beds, 204-206. 
 
 Rhamphorhyncltus, 247; Buclclandi, 248. 
 
 Rhmoceridce, 315. 
 
 Rhinocerot Etruscus, 327, 328, 336, 353; 
 leptorhinm, 328 ; megarhinug, 327-329, 
 336, 353 ; tichorhinus, 353, 354. 
 
 Rhi-nopora verrucosa, 126. 
 
 Rhizodus, 188. 
 
 Rhombus minimus, 295. 
 
 Rhyncholites, 239. 
 
 Rhynchonella, 110, 127, 147, 184, 234, 268, 
 292 ; cuneata, 127 ; neglecta, 127 ; pleu- 
 rodon, 185 ; varians, i35. 
 
 Rhynchosaurus, 218 ; articeps, 218. 
 
 Rice-shells, 293. 
 
 Richmond Earth, 33, 307. 
 
 Ringed Worms (see Annelida). 
 
 River-gravels, high-level and low-level, 
 340, 341. 
 
 Robulina, 311. 
 
 Rocks, definition of, 14; divisions of, 
 14, 15; igneous, 14; aqueous, 15-18; 
 mechanically-formed, 18-20; chemically- 
 formed, 20; organieally-fonned, 20-37; 
 arenaceous, 20 ; argillaceous, 20 ; cal- 
 careous, 20-32 ; siliceous, 20, 32-34. 
 
 Rodentia, of the Eocene, 305; of the 
 Miocene, 322; of the Post-Pliocene, 361. 
 
 Roebuck, 336, 354. 
 
 Rostellana, 237, 293. 
 
 Rotalia, 22, 98, 171, 24; Boueana, 264. 
 
 Rugose Corals, 104; of the Lower Silurian, 
 104, 105; of the Upper Silurian, 119; 
 of the Devonian, 141 ; of the Carbon- 
 iferous, 172-174; of the Permian, 197; 
 of the Upper Greensand, 266. 
 
 Rupelian Clay, 307. 
 
 Sabal major, 300. 
 
 Sabre-toothed Tiger, 322, 331. 
 
 Saccammina, 172. 
 
 Saccosoma, 232. 
 
 Salamanders, 189, 313. 
 
 Salina Group, 117. 
 
 Salix, 262 ; Meeki, 263. 
 
 Salmonidcf, 276. 
 
 Steo hirsuta, 85. 
 
 Sassafras cretacea, 263. 
 
 Sauropten/gia, 219. 
 
 Scalar ia, 271, 293; Graenlandica, 338. 
 
 Scaphites, 272, 273 ; aequalis, 274. 
 
 .SV//>'ius, 198, 211. 
 
 Schoharie Grit, 135, 137. 
 
 Scolecoderma, 82. 
 
 Scoliostoma, 213. 
 
 Scolith us, 82 ; Canadensis, 83. 
 
 Scon-ions of the Coal-measures, 181. 
 
 Scorpion-shells, 271.
 
 406 
 
 INDEX. 
 
 Screw-pines, 230. 
 
 Seutella, 311 ; subrotunda, 312. 
 
 Sea-cows (see Sirenia). 
 
 Sea-lilies (see Crinoidea). 
 
 Sea-lizards (see Enaliosaurians). 
 
 Seals, 322. 
 
 Sea-mats and Sea-mosses (see Polyzoa). 
 
 Sea-shrubs (see Gorgonidae). 
 
 Sea-urchins (see Echinoidea). 
 
 Sea-weeds, 80, 81, 83, 97, 136, 164, 261. 
 
 Secondary period, 44 
 
 Sedimentary rocks, 15. 
 
 Semnopithecus, 322, 331. 
 
 Septaria, 31. 
 
 Sequoia, 306, 309, 310; Couttsice, 309; 
 gigantea, 309 ; Langsdorjfti, 309. 
 
 Scrolls, 84. 
 
 Serpents (see Ophidia). 
 
 Serpulites, 123. 
 
 Sewalik Hills (see Siwalik Hills). 
 
 Sheep, 355. 
 
 Shell-sands, 19. 
 
 Sigillaria, 168, 169 ; Grceseri, 168. 
 
 Sigillarioids, 136, 168, 170, 196. 
 
 Silicates, infiltration of the shells of For- 
 aminifera by, 34, 74. 
 
 Siliceous rocks, 20, 32. 
 
 Siliceous Sponges, 265. 
 
 Siliciflcation, 13, K. 
 
 Silurian period (see Lower Silurian and 
 Upper Silurian), 90-114, 115-132. 
 
 Simosaurus, 219 ; Gaillardoti, 219. 
 
 Siphonia, 264 ; ftcus, 265. 
 
 Siphonostomatous Univalves, 237, 271, 293. 
 
 Siphnnotreta, 110. 
 
 Sirenia, 299, 320 ; of the Eocene, 299 ; of 
 the Miocene, 315. 
 
 Siren lacertina, 200. 
 
 Sivatherium, 318 ; giganteum, 319. 
 
 Siwalik Hills, Miocene strata of, 307. 
 
 Skiddaw Slates, 101. 
 
 Sloths, 315, 349-351. 
 
 Smilax, 308. 
 
 Smithia, 173. 
 
 Snakes (see Ophidia). 
 
 Soft Tortoises, 296. 
 
 Solarium, 271. 
 
 Solenhofen Slates, 228. 
 
 Solitaire, 346, 348. 
 
 Spalacotherium, 254. 
 
 Spatangus, 311. 
 
 Sphcerospongia, 139. 
 
 Sphagodus, 130. 
 
 Spkenodon, 218. 
 
 Sphenoptens, 136, 165, 196. 
 
 Spiders of the Coal-measures, 181. 
 
 Spider-shells, 237. 
 
 Spindle-shells, 237. 
 
 Spirifera, 125, 147, 184, 19S, 234 ; crispa, 
 127; disjuncta, 147; hysterica, 126; 
 mucronata, 147; Niagarensis, 127; ros- 
 trata,235; sculptilis,Ul ; trigonalis,lS5. 
 
 Spiri/eridce, 147. 
 
 Spirophyton cauda-Gatti, 135, 164. 
 
 Spimrbis, 123, 143, 178 ; Arkonensis, 144 ; 
 Carbonanus, 178; laxus, 144; Lewtsii, 
 123 ; omphalodes, 144 ; spinulifera, 144. 
 
 Spiruhrostra, 31 2. 
 
 Spondylus, 269 ; spinosus, 270. 
 
 Sponges, of the Cambrian, 81 ; of the 
 Lower Silurian, 98 ; of the Upper Silu- 
 rian, 119 ; of the Devonian, 139 ; of the 
 
 Carboniferous, 171 ; of the Permian, 
 197 ; of the Trias, 209 ; of the Jurassic, 
 230; of the Cretaceous, 264, 265. 
 jilla, 197. 
 'illopsis, 197. 
 . . hyllum, 173. 
 
 Spore-cases, of Cryptogams in the Ludlow 
 rocks, 118 ; in the Coal, 163. 
 
 Squirrels, 322. 
 
 Stagonoleplx, 218. 
 
 Staircase-shells, 271. 
 
 Stalactite, 21. 
 
 Stalagmite, 21. 
 
 Star-corals, 231. 
 
 Star-fishes, 105, 120, 210. 
 
 St Cassian Beds, 205, 206. 
 
 Stephanophtjllia, 266. 
 
 Stereognathus, 253, 254. 
 
 Stigmaria, 169 ; ficoides, 169. 
 
 Stonesfield Slate, 227; Mammals of, 253. 
 
 Strata, contemporaneity of, 44. 
 
 Stratified rocks, 15-18. 
 
 Streptelaama, 105. 
 
 Streptorhynchus, 198. 
 
 Stromatopora, 98, 99, 118, 139 ; rugosa, 99; 
 tuberculata, 140. 
 
 Strombodes, 119; pentagonus, 104. 
 
 Strombus, 271. 
 
 Strophalnsia, 198. 
 
 Strophodus, 255. 
 
 Strophomena, 109, 110, 125, 147, 184 ; 
 alternata, 110 ; deltoidea, 109 ; filitexta, 
 110; rhomboidalis, 147, 148; subplana, 
 127. 
 
 Sub-Apennine Beds, 325. 
 
 Sub-Carboniferous rocks, 158, 161. 
 
 Succession of life upon the globe, 367-374. 
 
 Suida, 302, 317, 329. 
 
 Sulphate of lime, 22. 
 
 SMS Erymanthius, 317 ; scrofa, 354. 
 
 SynastroM, 209. 
 
 Synhelia Sharpeana, 266. 
 
 Synocladia, 198 ; virgulacea, 198. 
 
 Syringopora, 119, 173 ; ramulosa, 174. 
 
 Tabulate Corals, 104; of the Lower Silu- 
 rian, 105 ; of the Upper Silurian, 119; 
 of the Devonian, 142; of the Carbon- 
 iferous, 172; of the Permian, 197. 
 
 Talpa Europcea, 336. 
 
 Taplridce, 300. 
 
 Tapirs, 300. 
 
 Tapirus Arvernensis, 327. 
 
 Taxocrimis tuberculatus, 122. 
 
 Taxodium, 262, 3u8, 310. 
 
 Teleosaurus, 251. 
 
 Teleostean Fishes, 150; of the Cretaceous, 
 276. 
 
 Telerpeton Elginense, 218. 
 
 Tellina proximo,, 338. 
 
 Tentaculites. 129, 148 ; ornatus, 129. 
 
 Terebra, 293. 
 
 Terebratella, 268 ; Astieriana, 268. 
 
 Terebratula, 184, 234 ; digona, 235 ; elon- 
 gata, 168 ; hastata, 185 ; quadrifida, 
 235 ; sphceroidalis, 235. 
 
 TerebratuUna, 268 ; caput-serpentis, 268 ; 
 striata, 268. 
 
 Termites, 311. 
 
 Terrapins, 280, 296. 
 
 Tertiary period, 44, 284-287. 
 
 Tertiary rocks, classification of,
 
 INDEX. 
 
 407 
 
 Testudinidce, 313. 
 
 Tetrabranehiate Cephalopods, 112 ; of the 
 Cambrian, 89 ; of the Lower Silurian, 
 112-114 ; of the Upper Silurian, 130 ; of 
 the Devonian, lift; of the Carboniferous, 
 186, 187 ; of tlie Permian, 199 ; of the 
 Trias, 212; of the Jurassic, 237-239; of 
 the Cretaceous, 272-274 ; of the Eocene, 
 294 ; of the Miocene, 312 
 
 Texlulana, 22, 264, 311 ; Meyeriana 311. 
 
 Thanet Sands, 287, 288. 
 
 Theca, 88. Ill, 129. 
 
 Theca Dandii, 88. 
 
 Thecidium, 213. 
 
 Thecodont Reptiles, 218. 
 
 Thecodontosaurus, 200, 218 ; antiquus, 219. 
 
 Thecoxmiha annularis, 231. 
 
 Thelodus, 131. 
 
 Theriodont ReptHes, 202, 220. 
 
 Thylacoleo, 349. 
 
 Tile-stones, 116. 
 
 Titanothenum, 316. 
 
 Toothed Birds, 281-283. 
 
 Tortoises, 202, 296. 
 
 Tragoceras, 318. 
 
 Travertine, 21. 
 
 Tree-Ferns, of the Devonian, 136; of the 
 Coal-measures, 164. . 
 
 Tremadoc Slates, 77-79. 
 
 Treinatis, 110. 
 
 Trenton Limestone, 95, 96. 
 
 Trianthrus Beckii, 107. 
 
 Triassie period, 203; rocks of, in Britain, 
 204 ; in Germany, 204 ; in the Austrian 
 Alps, 205; in North America, 205; life 
 of, 206-224 
 
 Trlconodon, 254. 
 
 Trigonia, 235, 255, 269. 
 
 Tngmiiudce, 198, 211. 
 
 Trigonocarpitm. 170 ; ovatum, 170. 
 
 Trilobites, 84-87; of the Cambrian, 85, 87; 
 
 . of the Lower Silurian, 107, 108; of the 
 Upper Silurian, 123, 124 , of the De- 
 vonian, 144, 145 ; of the Carboniferous, 
 179. 
 
 Trimerellidce, 127. 
 
 Trinucleus, 108 ; concentricus, 107. 
 
 Trionyodce, 296. 
 
 Triton, 293 
 
 Trochocyathwt, 266. 
 
 Trochonema, 129. 
 
 Trogontherium. 361 ; Cuvieri, 336, 361. 
 
 Trumpet-shells, 293. 
 
 Tulip-tree, 262, 308. 
 
 TurUnolia sulcata, 292. 
 
 Turbinohdce, 292. 
 
 Turrilites, 272, 273 ; catenulatus, 274. 
 
 Turritella, 271, 293. 
 
 Turtles, 202, 251, 280, 296. 
 
 Typhis tuUfer, 293. 
 
 Ullmania setaginoides, 197. 
 
 Unconformability of strata, 48. 
 
 Under-clay of coal, lf>2. 
 
 Ungulata, of the Eocene, 300-303 ; of the 
 Miocene, 315-319; of the Pliocene, 327- 
 329 ; of the Post-Pliocene, 353-357. 
 
 Uniformity, doctrine of, 5-7. 
 
 Unio, 250. 
 
 Univalves (see Gasteropoda). 
 
 Upper Cambrita, 77 - 79 ; Chalk, 259 ; 
 Cretaceous, 257, 260 ; Devonian, 135 ; 
 Eocene, 287, 288; Greensaud, 258; 
 Helderberg, 135 ; Laurent fan, 66 ; Llan- 
 dovery, 115 ; Ludlow rock, 116 ; Mio- 
 cene, 305 ; Oolites, 227 : Silurian period, 
 115; rocks of, in Britain, 115, 116; in 
 North America, 116-118 ; life of, 118-131. 
 
 Ursus arctos, 359 ; A rvernensis, 330 ; fe- 
 rox, 359 ; gpelcva, 360. 
 
 Urus, 336, 356. 
 
 Valley-gravels, high-level and low-level, 
 
 339-341. 
 
 Vanessa. Pluto, 312. 
 Varamdce, 202. 
 Vegetation (see Plants). 
 Ventricitlites, 264, 265 ; simplex, 265. 
 Venus's Flower-basket, 265. 
 Vennilia, 197. 
 
 Vespertilw Parisiensis, 304, 305. 
 Vicksburg Beds, 289. 
 Vines, 306, 309, 310. 
 Vitreous Sponges, 264. 
 Voltzia, 208 ; heterophylla, 209. 
 Valuta, 271, 293 ; elonaala, 271. 
 Volutes, 271, 23, 312. 
 
 Walchia, 196, 197; piniformis, 196. 
 
 Walrus, 322. 
 
 Wealden Beds, 257. 
 
 Wellingtoma, 309, 310. 
 
 Wenlock Beds, 115, 117; Limestone, 115; 
 
 Shale, 115. 
 Wentle-traps, 271. 
 Werfen Beds, 205, 2<>6. 
 Whalebone Whales, 299, 315. 
 Whales, 299, 315. 
 Whelks, 237. 
 White Chalk, 259; structure of, 21, 22; 
 
 origin of, 23, 263. 
 White Crag, 324. 
 White River Beds, 307. 
 Wild Boar, 354. 
 Williamsonia, 230. 
 Winged Lizards (xee Pterosauria). 
 Winged Snails (see Pteropoda). 
 Wing-shells, 271. 
 Wolf, 336, 360. 
 Wolverine, 360. 
 Wombats, 348. 
 Woolhope Limestone, 115. 
 Woolly Rhinoceros, 339, 341, 344, 353. 
 Woolwich and Reading Beds, 287. 
 Worm-burrows, 82, 83, 123. 
 
 Xanthidia, 138, 161. 
 Xenoneura antiquorum, 145. 
 Xiphodon, 303. 
 Xylobius, 182 ; Sigillariai, 182. 
 
 Zamia gpiralix, 208. 
 
 Zamites, 208, 230, 310. 
 
 Zaphrentis, 105, 119, 142, 173; cornicula, 
 
 141 ; Stokesi, 104 ; vennicularis, 174. 
 Zeacrinus, 175. 
 Zechstein, 194. 
 Zeuglodon, 299, 315 ; cetoides, 299, 300.
 
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