UNIVERSITY OF CALIFORNIA.; 
 
 FROM THE LIBRARY OF 
 
 DR. JOSEPH LeCONTE. 
 
 GIFT OF MRS. LECONTE. 
 No. 
 
 I 
 
km 
 
 1 *fcli 
 
 
 i? 
 
 9, 
 
 ELEMENTARY SCIENCES 
 
CHAMBERS' EDUCATIONAL COURSE 
 
 NUMBER Til. 
 
 ELEMENTS 
 
 OF 
 
 GEOLOGY, 
 
 BY DAVID PAGE. 
 
 EDITED BY D. M. REESE, M. D., LL. D. 
 
 NEW-YORK: 
 
 PUBLISHED BY A. S. BARNES & CO, 
 PHILADELPHIA: JOHN BALL. 
 H. W. DERBY & CO. 
 
 CINCINNATI. 
 
 1849. 
 
CHAMBERS' EDUCATIONAL COURSE. 
 
 Tlif> object of the following works is to furnish the friends of HU improved 
 system of education with the hooks required fur carrying out their views, in 
 the actual business of the school-room, and the family circle. 
 
 The Messrs. Chambers (whose works are so favorably known in the different 
 departments of literature, throughout this country as well as Europe) have 
 employed the first professors in Scotland in the preparation of these works. 
 They are now offered to the schools of the United States, under the American 
 revision of D. M. REKSE, M. D.. LL. D., late superintendent of public schools 
 of the city and county of New- York. 
 
 I. CHAMBERS' TR E ASUR Y OF K NOWLEDG E. (3 parts in one.) 
 
 BY W. & R. CHAMBERS. 
 
 PART 1 Embrace) Elementary Lessons in Gammon Things or things which lie most imme 
 diately around us, and first attract the attention of the young mind. PART -I Embrace 
 Practical Lessons on Common Objects such as articles or objects from the Mineral. Vege 
 table, and Animal Kingdoms, manufactured articles, miscellaneous substances and objects, &c 
 PART 3 Embraces Introduction to the Sciences. This presents a systematic view of nature 
 under the various sciences. Care is taken that the information given should not be a 
 superficial view of a lew unconnected phenomena, but a chain of principles calculated, in 
 combination, to impress a distinct and comprehensive idea to the mind of the very young child 
 
 This volume is designed for an early reading book, that the scholar may be exercised in reading. 
 and at the same time acquire knowledge of such subjects as his capacity will enable him t 
 understand. It contains much useful information upon common objects of life. 
 
 II. CHAMBERS' E LF M E NTS OF DR AWI NG. (2 parts in one.) 
 
 BY JOHN CLARK. 
 
 PART 1 Embraces Exercises, for the Slate. PART -2 Embrace! the Principle} of Drawing 
 and Perspective. 
 
 With but very few exceptions, children are fond of making efforts in Drawing. Furnished with 
 a black-lead pencil and sheet of paper, or slate and pencil, they are delighted to scribble 
 whatever their fancy suggests. Followed up methodically by the teacher, their infant 
 aspirations may lead to the development of much valuable talent. Illustrated by Engravings. 
 
 III. CHAMBERS' ELEMENTS OF NATURAL PHILOSOPHY. 
 
 THREE PARTS IX ONE. 
 
 PART 1 Embraces Laws of Matter and M'>fi'>n. PART 2 Embrace) Mechanic). PART 3 
 
 Embraces Hydrostatics, 'Hy Iraulics, and Pneumatics. 
 In the treatment of the several subjects great care has been taken to render the language simple 
 
 and intelligible. Illustrated by ' Wood Engravings- 
 
 IV CHAMBERS' CHEMISTRY AND ELECTRICITY. 
 
 PART 1 Embraces Illustrations. and experiments of the Chemical Phenomena of Daily Life. 
 By D. B. REID, M. D., F. R. S. E. PART -1 Embraces Electricity, (statical and current.) 
 By ALEXANDER BAIN, the original inventor of Electric and Telegraphic clocks. 
 
 This work is designed to facilitate the introduction of Chemistry as an elementary branch oj 
 education in schools. Illustrated by Engravings. 
 
 V. CHAMBERS' VEGETABLE AND ANIMAL PHYSIOLOGY. 
 
 BY O. HAMILTON, M. D. 
 
 PART 1 Embraces the General Structure and Functions of Plant*. PART 2 Embraces tht 
 
 Organization of Animals. 
 The object of this work is to unite Vegetable and Animal Physiology, and bring both systems 
 
 under one head, as properly connected and adapted to the mind of the student. 
 
 VI CHAMBERS' ELEMENTS OF ZOOLOGY. (Illustrated;, 
 
 Presenting a complete view of the Animal Kingdom as a portion of external nature. As the 
 composition of one of the most eminent physiologists of our age, it possesses an authority not 
 attributable to such treatises in general. 
 
 VII. CHAMBERS' E LE M E NTS OF GEOLOGY. (Illustrated.) 
 
 BY DAVID PAGE. 
 
 The subject is here presented in its two aspects of interesting and important. Interesting, 
 inasmuch as it exhibits the progressive conditions of the earth from the remotest periods, and 
 reveals the character of the plants and animals which have successively adorned and peopled 
 its surface ; and important, as it determines the position of those metals and minerals upon 
 which the arts and manufactures so intimately depend. 
 
 Entered 
 
 . S. BARNES & CO., 
 in the Clerk> Office of the District Court of the Southern District of New- York. 
 
i 
 
 Q 
 
 
 \o 
 
 
 INTRODUCTORY OBSERVATIONS, 
 
 THE AMERICAN EDITOR. 
 
 ss 
 
 IT is only within the present century, that the subject of 
 this volume has been recognised as a science, and hence not- 
 withstanding the ardour with which it has been cultivated, 
 and the rapid advances it has made, it must still be considered 
 in its infancy. There are two objects included in the inves- 
 tigations of this science, viz.: 1. The present condition of 
 the earth's surface; and 2. The changes to which it has 
 been subjected. The former may be called positive geology, 
 and imbodies the facts of the science; the latter is speculative 
 geology, and includes the theories which are proposed to 
 explain and account for the changes which have occurred in 
 the structure of the globe during past ages. Hence it has 
 been proposed to call the former geognosy, including our 
 absolute knowledge ; and the latter geology, comprising spe- 
 culative reasoning; but as they are jointly cultivated, the 
 latter term is employed to embrace both, and has been very 
 generally adopted. 
 
 Of the certainty which attaches to much of the speculative 
 department of geology, and of its claims to the character of 
 an inductive science, and the comparative rank to which it is 
 entitled, there is still a diversity of opinion among philoso- 
 phers. Sir John Herschel, however, in view of its recent 
 developments has declared his opinion that in point of dignity 
 and the extensive range of its subjects, it deservedly ranks 
 
 101296 
 
VI INTRODUCTORY OBSERVATIONS. 
 
 second to astronomy. This is certainly high praise, and from 
 great authority. Indeed, the facts of the science which have 
 been already established, and which are rapidly accumulating, 
 are of themselves full of interest, and many of them of the 
 highest practical importance. The speculative reasoning on 
 these facts may or may not be worthy of equal confidence; 
 but very much of it will be found to be rational and satisfac- 
 tory, and will continue to be held in high esteem until some 
 better solution shall be given to the problems, which the 
 absence of historical or geological records have left unex- 
 plained. 
 
 But with the facts of the science we have chiefly to do in 
 this elementary volume, and the author has presented these 
 in a form of simplicity and attractiveness which admirably 
 adapts the subject to the young, rendering it a most agreeable 
 and useful study. The latest discoveries are here stated, and 
 very little improvement of the text has been called for by the 
 editor, who has contented himself mainly by the adaptation 
 of analytical questions which will be found on every page, 
 and it is hoped will be useful both to the teachers and the 
 pupils of those schools in which this work may be intro- 
 duced. 
 
 In a science so new, and with a nomenclature not yet per- 
 fected, it has been obviously impracticable to dispense with 
 the technicalities of the science ; for the most of which, 
 indeed, there are neither substitutes nor synonymes in our 
 language. They will all be found accompanied by explana- 
 tory notes at the end of each section in which they first occur, 
 and which render them perfectly intelligible. 
 
 In using this book in schools, it is recommended that each 
 section be made a lesson for study and recitation. The read- 
 ing of each paragraph to be followed by proposing the ques- 
 tions in the order they are numbered, an answer being required 
 in the language of the book ; and afterwards, if need t>e, in 
 other terms, and accompanied by other illustrations when 
 practicable. In the speculative department, touching the 
 
INTRODUCTORY OBSERVATIONS. Vll 
 
 periods and eras of past ages, and the chronological hypo- 
 theses which are hazarded, may be made the topic of collo- 
 quial and familiar conversation, or of an oral lecture. 
 
 In this way, it is confidently believed that a very good 
 knowledge of this new science and its important practical 
 and economical uses may be readily imparted. And in its 
 adaptation to the use of schools, there can be little doubt that 
 among practical teachers, this volume will be esteemed to 
 possess very superior advantages. As such it is recom- 
 mended to public favour. D. M. R. 
 
PREFACE. 
 
 GEOLOGY, in its aim to describe the materials composing 
 the earth's crust, their mode of arrangement, and the causes 
 which seem to have produced that arrangement, constitutes 
 one of the most interesting and important of the natural sci- 
 ences. Interesting, inasmuch as it exhibits the progressive 
 conditions of the world from the remotest periods, and reveals 
 the character of the plants and animals which have succes- 
 sively adorned and peopled its surface ; and important, as it 
 determines the position of those metals and minerals upon 
 which the arts and manufactures so intimately depend. Va- 
 luable as are its deductions, Geology is comparatively of 
 recent growth, it being only within the present century that 
 accurate data have been collected, and those absurd specula- 
 tions respecting the origin of the globe eschewed, which had 
 so long impeded the legitimate prosecution of the subject. 
 If, however, long repressed by the imprudence of its early 
 cultivators, no branch of human knowledge has made more 
 rapid progress since right modes of investigation were adopted 
 none attracted a greater degree of attention, or been more 
 generally applicable to the economical purposes of life. To 
 furnish an outline of the science in its present state of ad- 
 vancement is the object of the following treatise, in which 
 the leading facts are stated in as simple a manner as is con- 
 sistent with accuracy. Technical terms, often so ignorantly 
 inveighed against, have not been avoided, but have been gra- 
 dually introduced with their explanations, to familiarize the 
 learner with Geological language, and thus prepare him for 
 the study of more advanced works, as well as for the prac- 
 1* 
 
X PREFACE. 
 
 tical prosecution of the subject. A uniform arrangement of 
 the topics has been strictly adhered to, so as at once to assist 
 the memory and facilitate reference ; theoretical disquisitions 
 have been studiously avoided ; and a plain record of facts and 
 observations presented, in order that the treatise might answer 
 the end intended namely, for Use in Schools and for Private 
 Instruction. 
 
CONTENTS. 
 
 OBJECTS OF GEOLOGY . 11 
 
 GENERAL STRUCTURE AND CONDITIONS OF THE GLOBE 
 
 Figure . 18 
 
 Density 19 
 
 Temperature 20 
 
 Surface Configuration . 25 
 
 Distribution of Land and Water 26 
 
 , Constitution of the Ocean 29 
 
 The Atmosphere 31 
 
 Planetary Relations ....*.. 32 
 
 CAUSES MODIFYING THE STRUCTURE & CONDITIONS OF THE GLOBE 
 
 Atmospheric Agencies 36 
 
 Aqueous Agencies 44 
 
 Igneous Agencies 52 
 
 Organic Agencies ........ 59 
 
 Recapitulation of Modifying Causes .... 65 
 
 MINERAL SUBSTANCES COMPOSING THE EARTH'S CRUST . 66 
 
 MEANS OF GEOLOGICAL INVESTIGATION . ... 73 
 
 Forms of Stratification . . . . * . . 76 
 
 Positions of Unstratified Rocks 78 
 
 ORYCTOLOGY .SCIENQE OF FOSSILS . . . . .80 
 
 Petrifaction, Bituminization, Metallization ... 81 
 Fossil Botany and Zoology . . .84 
 
 CLASSIFICATION OF ROCK FORMATIONS .... . 88 
 
 Table of British Deposits .* 90 
 
 Section of Existing Arrangement of Rocks . . 94 
 
 GRANITIC BASIS OF PRIMARY STRATA * . . . . 97 
 GNEISS AND MICA SCHIST SYSTEMS >'*, . . 101 
 CLAY-SLATE, GRAUWACKE, AND SILURIAN SYSTEMS . . 108 
 
 OLD RED SANDSTONE SYSTEM . . " , * 21 
 Classification of Fossil Fishes '>. ".*'.. .130 
 
 CARBONIFEROUS SYSTEM . ' 134 
 
 Mountain Limestone . . . . . ' . . . . 135 
 Coal Measures . ." 141 
 
Xll CONTENTS. 
 
 Page 
 NEW RED SANDSTONE SYSTEM 158 
 
 OOLITIC SYSTEM 
 
 Lias, Oolite, and Wealden Groups 166 
 
 CKETACEOUS OR CHALK SYSTEM 179 
 
 TERTIARY STRATA 186 
 
 SUPERFICIAL ACCUMULATIONS ..'... 198 
 
 Erratic Block, or Boulder Group 201 
 
 Ossiferous Sands and Gravel ...... 205 
 
 Ossiferous Caves, Fissures, and Breccia .... 208 
 
 Raised Beaches Submarine Forests . . . .211 
 
 Marine Silt, Sand-drift, Shingle Beaches, &,c. . . . 215 
 
 Submarine Deposits and Accumulations . . . 218 
 
 Terraces in Valleys 219 
 
 Deposits in Valleys 221 
 
 Deltas and Estuary Deposits ...... 222 
 
 Lacustrine, or Lake Deposits ...... 228 
 
 Chemical and Mineral Deposits 231 
 
 Peat-Mosses, Jungle, Vegetable Drift . . . .235 
 Shell-Beds, Coral- Reels, "&c. ..'... 242 
 
 Soils 251 
 
 Earthquakes and Volcanoes 254 
 
 RECAPITULATION OF THE STRATIFIED SYSTEMS . . . 262 
 IMPORTANCE OF GEOLOGICAL SCIENCE . 274 
 
 GEOGRAPHICAL GEOLOGY. 
 
 ASIA . . 281 
 
 AFRICA 289 
 
 EUROPE t 292 
 
 NORTH AMERICA 300 
 
 SOUTH AMERICA . . . . . . t 18 
 
 APPENDK 323 
 
 INDEX ...... . 827 
 
ORYCTOLOGICAL CHART. 
 
 I I ' 1)M> 
 
 3- OrtliocerciUtes 
 
 -| p>v,^sc_- f: ^_ .L^r: 
 
 The aeological Distribution of Fossil Organic Remains. 
 
THE ORYCTOLOGICAL CHART. This is a representation of the 
 leading facts in Oryctology, exhibiting all the important organic 
 remains of the different formations. The greater or less space occu- 
 pied by the various tribes of animals and plants on the chart shows 
 their comparative abundance or paucity. The branches designate 
 the species. When one entirely disappears during some formation, 
 but afterward reappears, a line is drawn where it is wanting. The 
 whole brings under a glance of the eye the rise, developement, rami- 
 fication, and extirpation of the different tribes. 
 
GEOLOGY. 
 
 OBJECTS OF GEOLOGY. 
 
 1. GEOLOGY is that science which treats of the mate- 
 rials composing the earth's crust, their mode of arrange- 
 ment, and the causes which seem to have produced that 
 arrangement. (See Appendix.) 
 
 2. By the earth's crust is meant that external shell or 
 covering of solid matter which is accessible to man's inves- 
 tigation. The highest mountains do not rise five miles 
 above the level of the sea, and the deepest mines descend 
 only about a third part of a mile, so that, even were we 
 perfectly acquainted with the entire space between the top 
 of the highest mountain and the bottom of the deepest 
 mine, it would form but a very insignificant fraction of 
 the distance between the surface and centre of the globe, 
 which is nearly 4000 miles. Thin as this crust may seem, 
 it nevertheless presents innumerable objects for investiga- 
 tion ; hence the magnitude of this science, which has been 
 ranked, in point of importance, second only to that of 
 astronomy. 
 
 3. The materials which compose the crust of the globe are 
 exceedingly varied. For instance, one part of the surface 
 is covered with sand, another with clay, and a third with 
 gravel. How were these materials formed, whence were 
 they derived, and by what agency were they laid down in 
 
 1. Define Geology. 
 
 2. What is the earth's crust 1 
 
 3. What of the highest mountains, and deepest mines ? 
 
 4. What of the semi-diameter of the earth f 
 6. How does the surface of the earth vary f 
 
1*2 GF.OLOGY. 
 
 their present position? Again, shells and bones may be 
 found in the sand arid clay, plants and trees in the peat- 
 earth. How came these remains to be buried there, and 
 are they similar to those animals and vegetables now living 
 arid growing upon the earth? As we dig through the 
 sands, gravels, and clays, we come upon rocks, some in 
 layers, others in masses; some are hard and sparkling, 
 others soft and earthy; and most of them differ in colour. 
 Many of them differ also in the kind of matter of which 
 they are composed, such as sandstone, limestone, coal, 
 roofing-slate, &c. How were these rocks formed, and by 
 what means were they laid down in their present positions? 
 for rocks so different in kind as limestone, coal, and sand- 
 stone, must have been formed under different circumstances. 
 Further, we find petrified shells, fishes, bones, and plants 
 imbedded in these rocks; and different rocks contain dif- 
 ferent kinds of these remains. How were they imbedded 
 there? Are they similar to shells, fishes, and plants now 
 existing? Do they seem to have lived and grown in the 
 sea, in fresh water, or on dry land ? Such are a few of 
 the questions which it is the province of the geologist to 
 consider; and in doing so, he must ground his reasoning 
 upon the analogy of the changes now going forward on the 
 face of the globe, endeavouring to discover what relation 
 they bear to former changes, and whether both may be 
 ascribed to similar causes. 
 
 4. The causes which modify the crust of the globe are 
 very numerous, differing in power, as well as in their mode 
 of action. At present we find rivers bearing down mud, 
 sand, and gravel, and depositing the same either along their 
 banks, in lakes, or in the sea these deposits form ing layers 
 of mud, sand, or gravel, which in some cases become con- 
 solidated, and assume a rocky appearance. If plants, shells, 
 
 fo. What else is found under these materials ? 
 
 7. What variety in these rocks ? 
 
 8. What is imbedded in many rocks ? 
 
 9. What questions, and how solved ? 
 
 10. What of rivers and their deposits ? 
 
 11. What of rains, frosts, winds, &c. ? 
 
 12. How do plants and animals modify the earth's crust 1 
 
OBJECTS OF GEOLOGY. 13 
 
 or dead animals be carried down at the same time by these 
 rivers, they will be imbedded in the layers so formed, and 
 will in course of time become petrified, or converted into 
 stony matter. Rains, frosts, winds, and the like, act upon 
 all rocks, and make them crumble down, thus leaving the 
 decayed matter to form additional surface soil, or to be 
 borne down by rivers and other currents of water. Plants 
 and animals also modify the crust of the globe : plants grow 
 and decay, either adding matter to the soil, or forming 
 accumulations in marshes, in the character of peat-moss : 
 animals also yield their remains to the surface ; and some 
 of them, as shell-fish and corals, form vast accumulations 
 of solid matter. Earthquakes break up the earth's crust, 
 elevating some places, and sinking others ; raising the bot- 
 tom of the sea to become dry land, and sinking dry land 
 under the ocean. Volcanoes are sometimes accompanied 
 with similar effects, and generally throw out liquid lava, 
 which, when cooled down, forms rocks ; and repetitions of 
 these discharges gradually form mountains. 
 
 [In this general summary of the causes which modify the 
 crust of the globe, no reference is made to the geological 
 agency of man, and that of animals in general is but 
 slightly alluded to. "By the destruction of animals; by 
 the distribution of both plants and animals ; by altering the 
 climate of large tracts of country by means of cultivation ; 
 by resisting the encroachments of rivers and of the ocean ; 
 by reducing hills and mountains ; by furnishing the spoils 
 of his own power, and of the products of his art, to make 
 up portions of soil ; man has exerted no small influence in 
 changing the earth's surface." But in the language of the 
 author of the "Wonders of Geology," the labours of the 
 human race, in a geological view, sink into utter insignifi- 
 cance, when compared with the achievements of animals 
 invisible to the naked eye, of beings which live, flourish, 
 and die without the notice of the lord of creation. Of the 
 geological agency of various kinds of animals, the same 
 author names the following, viz : " The infusoria in the 
 
 13. What of earthquakes ? 
 
 14. What changes are produced by volcanoes 1 
 
14 GEOLOGY. 
 
 formation of immense beds of marl; the polyparia in 
 the creation of vast coral islands; marine and fresh water 
 shell-fish, in producing the beds of limestone, which are 
 supposed to constitute one-seventh part of the crust of the 
 globe; the shells, reptiles, and fishes which have formed 
 various kinds of marble; the corals, sponges, and radiata 
 that have formed the beds of chalk and flint; and many 
 others which have caused the whole surface of our earth to 
 pass through the wonderful laboratory of life."] 
 
 5. The causes enumerated in the preceding paragraph are 
 those which mainly contribute to the modification of the 
 crust of the globe. In general they act gently, and within 
 limited spaces; occasionally with great violence, and over 
 a large extent of country. These forces have always ex- 
 erted themselves with greater or less intensity, and have 
 always produced corresponding results. In reference to 
 the masses of sand, gravel, and clay, now far removed from 
 waters, and to the various rocks which are found at great 
 depths in the earth's crust, it is the object of geology to dis- 
 cover whether they are to be ascribed to the operation of 
 forces similar in kind, but greater in degree, than those 
 above-described ; and whether the plants and animals found 
 petrified within them be or be not of the same kinds as 
 those now existing. If they are of the same races, did 
 they exist under similar circumstances? and if not, what 
 seem to have been the conditions of the world under which 
 they flourished? 
 
 6. To solve the numerous problems which geology thus em- 
 braces, a vast amount of research and knowledge is neces- 
 sary. To account for the aggregation of positions of many 
 rock masses, the geologist requires to be acquainted with 
 the principles of mechanics ; to treat of their composition 
 and formation, the aid of chemistry must be called in ; to 
 describe and classify the remains of plants and animals, he 
 must have recourse to botany and zoology; while, generally 
 speaking, there are many of his problems, for the successful 
 
 15. What variety in the action of these several agencies? 
 
 16. How does Geology investigate these, and for what purposes T 
 
 17. Which of the natural sciences is in requisition here f 
 
OBJECTS OP GEOLOGY. 15 
 
 solution of which the assistance of almost every branch of 
 natural science is necessary. An amount of acquirements 
 so varied is beyond the compass of many minds ; hence 
 geology has been divided into several departments, which, 
 while ultimately depending on each other for their pro- 
 gress, can be studied as individual sciences. These are 
 Physical Geography, which limits itself to the mere sur- 
 face and configuration of the earth as occupied by land and 
 water, mountains and valleys, and other external appear- 
 ances; Mineralogy, which treats of the individual crystals 
 or minerals of which rock masses are composed; and 
 Oryctology, or Paleontology , which directs itself exclu- 
 sively to the consideration of the fossil plants and animals 
 that may be discovered in the crust of the globe. 
 
 7. Abstract or speculative geology comprehends all these 
 branches, and, were it a perfect science, would present a 
 history of the globe from its origin and formation, through 
 all the changes it has undergone, up to the present time ; 
 describing its external appearance, its plants and animals, 
 at each successive period. As yet, geology is the mere 
 aim to arrive at such knowledge ; and when we consider 
 how difficult it is to trace the history of a nation even over 
 a few centuries, we cannot be surprised at the small pro- 
 gress geologists have made in tracing the history of the 
 earth through the lapse of ages. To ascertain the history 
 of a nation possessed of written records, is a task compara- 
 tively easy ; but when these are wanting, we must examine 
 the ruins of their cities and monuments, and judge of them 
 as a people from the size and structure of their buildings, 
 and from the remains of art found therein. This is often 
 a difficult, a'nd all but impracticable task ; much more so is 
 it to decipher the earth's history. It is true that certain 
 geological facts are recorded; but the record is neither dis- 
 tinct nor of much antiquity. We learn that earthquakes 
 
 18. Define Physical Geology, Mineralogy, Oryctology, &c. 
 
 19. What of the objects of speculative geology I 
 
 20. Why does it fail to do all this ? 
 
 21. How is a nation's history studied ? 
 
 22. What geological records exist t 
 
16 GEOLOGY. 
 
 have raised land above, or sunk it beneath, the sea ; that 
 volcanoes have formed mountains and buried cities, such as 
 Herculaneum and Pompeii; that the mud of rivers has 
 formed vast plains like the Deltas of the Nile and Ganges; 
 that cities once on the sea-shore are now several miles 
 inland; and that cities once removed from the sea have 
 oeen washed away by its inroads, their sites now forming 
 the bed of the ocean. Beyond a few facts like these, we 
 have no written geological record ; and, for the earlier his- 
 tory of the earth, must descend into the gravels, clays, and 
 rocks which form its crust ; judge of past changes by the 
 character of these masses ; and reason as to the kind of 
 plants and animals which formerly peopled its surface, 
 from the petrified remains which are entombed in the strata 
 beneath. 
 
 8. The practical utility of geology is alike varied and 
 extensive. The metals so indispensable to the purposes of 
 civilized life are all dug in the shape of ores from the rocky 
 crust, certain metals being found in certain rocks, and in 
 certain positions. As with metals, so with coal, building- 
 stone, limestone, and other minerals; and it is the duty of 
 practical geology to direct the miner in his search for these 
 valuable metals and minerals, and to point out to him by 
 what means they can be most economically obtained. In a 
 country like ours, where railroads, canals, reservoirs, tun- 
 nels, and harbours are in constant requirement, the deduc- 
 tions of geology must be of first importance in pointing out 
 the kind of rocks through which these operations have to 
 be conducted, as also in ascertaining the strength and du- 
 rability of the building material required by the engineer 
 and architect. Soils being in many cases composed of the 
 decayed materials, as well as influenced by the porous or 
 compact texture of the underlying rocks, there must sub- 
 sist an intimate connexion between them ; an acquaintance 
 with the prevalent characters of rock formations will, there- 
 fore, greatly assist the agriculturist in his endeavours to 
 
 23. How then do our researches extend beyond these 1 
 
 24. In what is the practical utility of geology seen 1 
 
 25. What of great public works, and buildings ? 
 
 26. How is it important to the agriculture of the country? 
 
OBJECTS OF GKOLOOIT. 17 
 
 improve the fertility of the soil. Other practical advantages 
 to be derived from the study of geology might be pointed 
 out : but these will be best considered in a subsequent part 
 of the treatise, when, as may be supposed, the student will 
 be better able to judge of their importance. 
 
 i. EXPLANATORY NOTE. 
 
 GEOLOGY (Greek, ge, the earth, and logos, a discourse) reasoning 
 about the structure of the earth. The term Geognosy (from ge, and 
 gnosis, knowledge) is sometimes used instead of geology, the former 
 signifying absolute knowledge, and the latter implying speculative 
 reasoning. Geology, however, is the term most frequently in use, and 
 is likely to continue so. 
 
 CRUST the outer or solid covering of any body, such as the crust of 
 a loaf, the shell of an egg, &c. The crust generally differs in quality 
 from the internal parts, which it covers ; hence the term " crust of the 
 earth" is used to distinguish it from the interior of the globe, concerning 
 which we have no certain knowledge. 
 
 PETRIFIED, PETRIFACTIONS (Latin, pet ra, a stone, and facere, to make) 
 to make or change into stone. When a shell, bone, or piece of plant, 
 by being enclosed in rocky matter, becomes hard and heavy like stone, 
 yet retains its shape, it is said to be petrified. Petrification is thus 
 caused by the particles of stony matter entering into, and filling the 
 pores of the animal or vegetable structure ; lime-water, for instance, 
 entering int6 the pores, and between the fibres of a piece of wood, 
 makes it a limy petrifaction. 
 
 FOSSIL (Lat., fossus, dug up) anything dug up out of the earth is 
 fossil ; but the term " fossils," or " fossil remains " is now generally 
 applied to petrified vegetable or animal remains dug out of the earth's 
 crust. 
 
 ORYCTOLOGY (Gr., orusso, to dig, and logos, a discourse) a discourse 
 or reasoning about things dug up. PALEONTOLOGY (from palaios, 
 ancient, on/a, beings, logos, a discourse) a discourse or reasoning about 
 ancient beings. Both of these terms are used by geogolists to signify 
 the science of fossil remains ; some objecting to oryctology as merely 
 referring to things dug up, while common stones are dug up as well as 
 remains of plants and animals ; others objecting to palaeontology, be- 
 cause, though it refers to ancient beings, it does not imply that they are 
 fossil. 
 
 STRATUM, plural STRATA (Lat., stratus, strewn, or spread out). When 
 different rocks lie in succession upon each other, each individual forms 
 
 27. Define Geognosy, as distinguished from Geology. 
 
 28. How is the crust of the earth illustrated ? 
 
 29. From what is it contradistinguished, and why 1 
 
 30. Define petrifaction, and explain by example. 
 
 31. What is understood by fossils ? 
 
 32. Distinguish Oryctology from Palaeontology. 
 
 33. What objections to these terms ? 
 
 34. Define stratum, stratified, &c. 
 
18 GEOLOGY. 
 
 a stratum; and is so termed from its appearing to have been laid, or 
 npread out in order. Rocks arranged in parallel layers are thus said to 
 be stratified ; and those among which there is no appearance of this 
 parallel arrangement, unstratified. 
 
 GENERAL STRUCTURE AND CONDITIONS OF 
 THE GLOBE. 
 
 9. Before entering upon the consideration of the mate- 
 rials which compose the externaf crust, there are certain 
 facts concerning the general structure and conditions of the 
 globe itself, a knowledge of which is necessary to the prose- 
 cution of geological research. These are its Figure, Den- 
 sity, Temperature, and Surface Configuration ; the distri- 
 bution of Land and Water, Constitution of the Sea, the 
 Atmosphere, and Planetary Relations. 
 
 FIGURE. 
 
 10. THE FIGURE OF THE EARTH is nearly that of a sphere 
 or globe. A diameter (measure through) from north to 
 south is said to be polar ; one from east to west, equatorial. 
 If the earth were perfectly spherical, these diameters should 
 be of the same measure ; but it has been found by accurate 
 investigation that the polar is less than the equatorial by 
 about 26J miles. According to Herschel 
 
 The Equatorial is . . 7925-648 miles. 
 The Polar is . 7899-170 miles. 
 
 Difference, . . . 26-478 miles. 
 
 This gives a flattening or compression at each pole of about 
 13^ miles ; so that the figure of the earth is, strictly speak- 
 ing, that of an oblate spheroid. 
 
 1 1 . This polar compression may be artificially illustrated 
 by twirling with rapidity a ball of any yielding material, such 
 as putty, round a spit thrust through it for an axis, when a 
 
 35. What preliminary subjects are cited for inquiry ? 
 
 36. Define the polar and equatorial diameters of the globe. 
 
 37. How, and why do they differ, and to what extent 1 
 
 38. How is it illustrated and explained 7 
 
DENSITY OF THE EARTH. 19 
 
 bulging at the outer surface will take place, causing the ball 
 to lose its original globular shape. This bulging takes place 
 through what is called centrifugal (flying from the centre) 
 force, and creates a difference between the two diameters 
 of the ball similar to that which exists in the terrestrial globe. 
 
 12. From this spheroidal Jigure, and what we know of 
 the law of centrifugal force acting upon a body of yielding 
 material, it is concluded that the earth was in a soft or 
 yielding state at the time when it assumed its present form. 
 This is obviously a point of considerable importance in the 
 physical history of our planet, and therefore demands the 
 especial attention of the geologist. 
 
 DENSITY. 
 
 13. THE DENSITY OF THE EARTH has also been computed 
 with considerable accuracy. By weighing the most preva- 
 lent rocks, it has been found that the solid crust composed 
 of them is about two and a-half times heavier than water; 
 but from experiments made on the attraction of mountains 
 of known bulk, compared with the attraction and bulk of 
 the globe, it has been inferred that the density of the whole 
 mass is five times that of water. In other words, the earth, 
 as at present constituted, is Jive times heavier than a globe 
 of water of similar dimensions, and twice that of the rocks 
 at its surface. 
 
 14. The interior or central material of the earth being 
 thus necessarily heavier than the rocks which form its crust, 
 numerous speculations have been indulged in as to what 
 the nature of thase materials may be. It has been said that 
 air, water, or stone, as known at the surface, cannot com- 
 pose the interior parts; for if the law of gravitation exert 
 itself uniformly towards the centre, either of these would be 
 so compressed as to give the earth's mass a mean density 
 
 39. What then is the true figure of the earth ? 
 
 40. What inference is thence drawn t 
 
 41. What of the density of the earth, and how computed T 
 
 42. Wh* of the interior of the earth T 
 
 43. Whj '.B it denied that it is either air, water, or stone t 
 
20 GEOLOGY. 
 
 greater than the Jaws of attraction will allow. Water, for 
 instance, would, at the depth of 362 miles, be as heavy as 
 quicksilver, and air as heavy as water at 34 miles; while at 
 the centre, the density of marble would be increased 119 
 times! To make their suppositions accord with the mean 
 density of the earth, that is, to reconcile the forces of gravi- 
 tation and attraction, theorists have successively proposed 
 gaseous fluids, heated matter, arid even light itself, as the 
 central material. 
 
 15. Laying aside all hypotheses, our knowledge respect- 
 ing the density arid internal structure of the earth may be 
 thus summarily stated: 1. The density of the rocky crust 
 is, on an average, two and a-half times that of water ; 2. The 
 mean density of the whole mass is five times that of water; 
 3. The central parts cannot be composed of similar material 
 with the crust, otherwise their compression would become 
 so great towards the centre, that the mean density of the 
 earth would be much greater than it is ; and 4. That the 
 condensation of the central masses must be counteracted 
 by some expansive influence, such as heat, or have a con- 
 stitution unlike any substance with which we are acquainted 
 at the surface. 
 
 TEMPERATURE. 
 
 16. THE TEMPERATURE OF THE EARTH is 3 Subject the 
 
 consideration of which exercises a most important influence 
 on the reasonings of geologists. There is, first, the surface 
 temperature, which affects the growth and distribution of 
 plants and animals; second, the temperature of the crust, 
 which may give rise to gaseous exhalations, thermal springs, 
 mineral and metallic transformations ; and, third, there ap- 
 pears to be an. internal or central temperature, having its 
 seat beneath the solid crust, and which seems to be the 
 
 44. What hypotheses have been started on this subject T 
 
 45. How far may it be said that our knowledge extends on this subject ? 
 
 46. What agency is supposed to oppose gravitation and attraction in 
 
 the masses of the earth's centre ? 
 
 47. What three divisions are made in the temperature of the earth? 
 
 48. What is ascribed to each ? 
 
TEMPERATURE OP THE EARTH. 21 
 
 cause of volcanoes, earthquakes, and other similar phe- 
 nomena. 
 
 17. Of the surface temperature^ we know that it is influ- 
 enced, first, from day to day, and from season to season, 
 by the heat of the sun ; second, by the degree of latitude, 
 being warmest at the equator, and gradually diminishing 
 towards either pole; third, by the distribution of land 
 and water, the sea being less liable to sudden fluctuations 
 of temperature than the land; fourtfi, by the nature of the 
 surface, the kind and colour of matter variously absorbing 
 and retaining the heat derived from the sun ; and lastly, by 
 the elevation of the land above the mean level of the sea, 
 the more elevated being the colder regions. All these in- 
 fluences are at present in active force, affecting more or less 
 the growth and distribution of animal and vegetable life; 
 and iu like manner must they have exerted themselves at 
 former periods, though perhaps increased or counteracted 
 by certain conditions not now existing. 
 
 18. The temperature of the crust may be affected either 
 by heat from the sun, by heat created by chemical action 
 among its materials, or by heat from the interior. During 
 summer, the surface is heated by the sun, and this heat is 
 communicated to a certain depth; during winter it is again 
 given off to the surrounding atmosphere more or less, ac- 
 cording to the severity of the winter. This alternate re- 
 ceiving and parting with heat may differ considerably in any 
 particular summer or winter, but over a number of years it 
 is found to be nearly stationary; that is, the amount of heat 
 received arid given off may be said to balance each other. 
 According to this doctrine, the earth in summer will be 
 warmer near the surface than it is at small depths; and in 
 winter will be colder at the surface than at depths beyond 
 the influence of the passing cold. 
 
 19. The heat of the sun can only affect the earth to a 
 Umittd d+pth; for, as the heat of summer proceeds down- 
 
 49 What influences modify the surface temperature T 
 
 50. To what is the temperature of the crust ascribed f 
 
 51. How does it vary 1 
 
 52 Explain thin phenomena. 
 
 2 
 
GEOLOGY. 
 
 wards, it is arrested by the cold of winter, and thus con- 
 tinually kept within a given limit. By actual experiment, 
 it has been ascertained that, at a given depth beneath the 
 surface of the earth, there is a point at which the tempera- 
 ture remains constantly the same, being uninfluenced by 
 any causes which affect the surface. This depth will vary 
 according to the kind of material of which the crust at any 
 given place is composed, be these materials rocks, sand, or 
 water; but in no instance has it been found to be less than 
 60, or more than 100 feet. A series of these depths, as 
 represented by the white line in the subjoined diagram, is 
 called by geologists the stratum of invariable temperature. 
 
 Section, showing the stratum of invariable temperature, and relative 
 thickness of the solid crust. 
 
 20. Proceeding- beyond this invariable stratum, towards 
 the centre (c), it has been found that the temperature gra- 
 dually increases; a circumstance which attracted the atten- 
 tion of philosophers more than a century ago. In 1802 
 D'Aubuisson revived the investigation, and since that time, 
 observations have been made in the principal mines of 
 Europe and America. The greatest depths at which expe- 
 
 53. Does the material of which the crust is composed affect its tempe- 
 
 rature ? 
 
 54. To what depth does the stratum of invariable temperature extend ? 
 65. Does the temperature increase at greater depths ? 
 
TEMPERATURE OF THE EARTH. 23 
 
 riments have been conducted, are 1713 feet in Mexico, 1584 
 in England, and about 1300 in Germany; and in all of 
 these the temperature has been found to increase according 
 to the depth. In 1827 M. Cordier published a memoir on 
 this interesting subject, in which he collected the observa- 
 tions of others together with his own ; and having made 
 allowance for the heat arising from the breathing of miners, 
 for the combustion of lamps, and communication with the 
 atmosphere, he drew the following general conclusions: 
 
 1. Below the invariable stratum, the temperature at any 
 given depth remains perfectly constant for several years; 
 
 2. That below the invariable stratum the temperature goes 
 on increasing with the depth; and, 3. That, taking the 
 average of observations, this increase of temperature goes 
 on at the rate of one degree of Fahrenheit's thermometer 
 for every 45 feet. Others haye allowed 60 feet for the rise 
 of one degree; but even taking this lower estimate, it must 
 follow, if the increase go on in the sarrte ratio, that a tem- 
 perature equal to 100 degrees of Wedgewood's pyrometer 
 would be found at the depth of 160 miles. But, 100 de- 
 grees of VVedgewood is sufficient to keep in fusion any of 
 the known rocks, so that, according to this estimate, the 
 solid crust of the earth cannot be more than 61) or 80 miles 
 in thickness a mere fractional film of the distance from 
 the surface to the centre. 
 
 21. Of the internal or central heat of the globe, we know 
 nothing by actual experiment ; but are left to infer as to its 
 amount from the descending increase of temperature ob- 
 servable in the solid crust, and from the occurrence of hot- 
 springs, vapour fissures, and volcanoes. That the heat of 
 the crust increases as we descend, has been fully established 
 by experiments in mines, in Artesian wells, and in the 
 waters of other deep-seated springs; and if this tempera- 
 
 56. What of the experiments ? 
 
 57. Does not this prove that very great heat would be found in the deep 
 
 interior of the globe ? 
 
 58. In what ratio does the temperature increase ? 
 
 59. At this rate, what would be the heat 160 miles below the surface T 
 
 60. What inference is authorized from this fact ? 
 
 (j 1 . What other facts go to prove the central heat of the globe to be 
 great ? 
 
54 GEOLOGY. 
 
 ture goes on increasing at the ratio above-mentioned, then 
 the interior parts must be heated to an enormous degree ; 
 so much so, indeed, as fully to counteract that law of com- 
 pression formerly adverted to, and which would render all 
 known matter, if placed at the centre, so dense as to be 
 inconsistent with the mean density of the globe. 
 
 22. Taking all circumstances into account, the following 
 conclusions seem warrantable: first, that the interior parts 
 of the earth are heated to intensity; second, that this heat 
 is the apparent cause of volcanoes, hot-springs, and other 
 thermal phenomena; third, that the solid crust derives part 
 of its heat from this source; fourth, that this solid crust has 
 partly been formed by the cooling of an original igneous 
 mass; fifth, that if volcanoes, hot-springs, &c. take place at 
 the expense of this internal heat, the globe must be gradu- 
 ally cooling; but, lastly, that from the bad conducting nature 
 of the rocky crust, this gradual refrigeration is not percep- 
 tible within any given time. 
 
 EXPLANATORY NOTE. 
 
 DENSITY (Lat. densus, thick) thickness or compactness. Density is 
 a comparative term; gold, for instance, being denser than iron, iron 
 than granite, granite than sandstone, sandstone than water, and water 
 than gas ; that is, a cubic inch of any one of these bodies would differ 
 in weight from a cubic inch of any of the others. To render this idea 
 of density more definite, water at the temperature of 60 degrees has 
 been taken as the standard or measure ; hence, if water be assumed as 
 weighing 1, the rdcky materials composing the earth's crust will be 2, 
 or two and a-half times heavier than water. 
 
 ARTESIAN WELLS (Artois, a district in France) a term applied to 
 wells sunk by digging or boring perpendicularly through various strata, 
 from the circumstance that this mode was first practised in the district 
 above referred to. 
 
 THERMAL (Greek, therme, heat) warm or hot. Thermal and igne- 
 ous nre sometimes used indiscriminately; but it is more accurate to 
 make a distinction. Thus, in treating of volcanoes, we speak of igne- 
 ous agency; in treating of hot-springs, thermal is the more appropriate 
 term. 
 
 TEMPERATURE OF THE EARTH. The chief of those who have con- 
 
 62. What conclusions are thus reached 7 
 
 63. Define density, and give illustrations. 
 
 64. What of Artesian wells 7 
 
 65. Define thermal and igneous. 
 
 66. What classes of experiments have been made, and by whom 7 
 
SURFACE CONFIGURATION. 25 
 
 ducted experiments relative to this subject are Gemanne, Saussure, 
 D'Aubuisson, Fourier, Cordier, Quetelet, and Arago, in France, Ger- 
 many, &c. ; Sir John Leslie, Fox, Forbes, &c. in Britain ; and Hum- 
 boldt, in Mexico. Their experiments present a wonderful degree of 
 coincidence, and are chiefly of three classes : 1. Those made in mine- 
 ral veins, 01 in mountain masses, such as granite ; 2. Those made in 
 stratified rocks, as in coal mines ; and, 3. Those made in Artesian 
 wells and other deep-seated springs. 
 
 SURFACE CONFIGURATION. 
 
 23. THE SURFACE CONFIGURATION OF THE EARTH is more 
 the study of physical geography than of geology proper ; 
 but it is necessary to observe in what manner it influences 
 the geological changes now in progress. The surface of 
 the earth is extremely irregular, being diversified by hills 
 and valleys, rivers, lakes, seas, &c. Portions of it are 
 covered with woods and forests; other portions are elevated 
 above the limits of vegetable or animal life, and covered 
 with eternal snows. Some parts of the exposed surfa'ce 
 are so hard, that no sensible decay is experienced for ages; 
 others so soft and loose, that scarcely a shower falls with- 
 out carrying away a portion to some lower level. These 
 differences of surface material are also influenced by steep- 
 ness and irregularity of position ; the- transporting power 
 of streams and rivers being proportioned to the rapidity of 
 their descent. These are familiar instances of the numerous 
 changes effected by diversity of surface configuration ; but 
 the student has only to cast his eye over his own district, 
 to be convinced haw many geological results depend upon 
 .^this cause. Those immense plains the steppes of North- 
 ern Asia, the prairies of North arid the pampas of South 
 America must affect and be affected in a different manner 
 from the Himmaleh, Alps, Andes, and other mountain 
 ranges. The showers and snows which produce torrents 
 and avalanches on the Alps, form merely springs and harm- 
 less streams on the Apennines; .and while the sluggish 
 river is forming inland plains with its mud, the rapid tor- 
 
 67. Name the varieties of surface. 
 
 68- How do these modify the configuration of the globe 1 
 
 69. What illustrations are here cited 1 
 
20 GEOLOGY. 
 
 rent is carrying its burden forward to the bottom of the 
 ocean. 
 
 24. The surface outline of the earth is so irregular that 
 even physical geography, with all the facilities afforded by 
 modern intercourse, has yet presented us with a very gene- 
 ral description ; and before we can estimate the full force 
 of this configuration as a geological agent, we must know 
 more of the relative elevations and depressions of the land, 
 and the nature of the rocky substances so elevated and 
 depressed. Of the surface configuration of the world in 
 its earlier ages, we have no positive knowledge; but we are 
 certain that whatever it might be, it would materially influ- 
 ence the changes then going forward, just as the same 
 cause is operating at the present moment. 
 
 DISTRIBUTION OP LAND AND WATER. 
 
 25. THE DISTRIBUTION OF LAND AND WATER, upon which 
 so many geological phenomena depend, is influenced by 
 this principle alone : namely, that so long as the same quan- 
 tity of water remains on the globe, a fixed amount of space 
 will be required to contain it. If the difference between the 
 elevations and depressions of the solid crust be small in 
 other words, if the hollows in which lakes and seas are 
 spread out be shallow their waters must extend over a 
 greater space : and if these hollows be deep, the waters will 
 occupy less extensive areas. The operation of this principle 
 the student should bear in mind; for if, in the earlier ages 
 of the world, the elevation of the land was less general, the 
 waters would occupy larger spaces, and this more extended 
 area of shallow water would act in various ways. It would 
 render the climate more genial and uniform, and extending a 
 greater surface to the evaporating power of the sun, rains 
 and atmospheric moisture would be more prevalent. These, 
 
 70. What obscurity still rests on this subject ? 
 
 71. How is the distribution of land and water regulated ? 
 
 72. How illustrated ? 
 
 73. What hypothesis is suggested ? 
 
 74. What effect would result upon the climate ? 
 
 75. How would it affect animal and vegetable life 1 
 
DISTRIBUTION OF LAND AND WATER. 
 
 27 
 
28 GFOLOOY. 
 
 again, would operate on the amount and kind of animal 
 and vegetable life on dry land ; while the shallow waters 
 themselves would be more productive of life, it being a well- 
 known fact, that shell-fishes and aquatic plants flourish only 
 at limited depths around the shores. Of the distribution 
 of land and water at any former period of the world, we can 
 only infer from the appearances which the surface and rocky 
 strata present; but of the present distribution, we have 
 pretty accurate information, with the exception of those 
 regions surrounding either pole. 
 
 26. TJie proportion of dry land to water, as at present 
 existing, is about one to three ; that is, three-fourths of the 
 whole surface of the globe may be assigned to water. The 
 dry land presents itself in islands and continents variously 
 situated; but the student has only to cast his eye over a map 
 of the world, to observe that the greater portion is placed 
 in the northern hemisphere, while the walers occupy the 
 greater portion of the equatorial and southern regions. The 
 relative configuration of land and sea is extremely irregular, 
 and no conception can be formed of it, unless from the 
 study of a well-constructed nmp. 
 
 27. This configuration exercises a most important influ- 
 ence in geological operations by determining the direction 
 of oceanic and tidal currents, and by modifying the direc- 
 tion and force of waves. Ocean-currents carry along with 
 them plants, trees, and other floating materials, which will 
 be arrested wherever the land presents an obstruction. 
 Tides exercise a powerful transporting influence : they rise 
 to greater or less heights, according as they are obstructed 
 by the outline of the land; and while they sweep headlands 
 and promontories bare, they lay down sand and gravel in 
 sheltered bays. Waves also wear away the land, according 
 as the line of coast obstructs or favours the violence of their 
 
 76. What data have we of the ancient state of things ? 
 
 77. Where is our knowledge defective of the present ? 
 
 78. What are the proportions ? 
 
 79. How is the land distributed chiefly ? 
 
 80. Where are the waters most abundant ? 
 
 81. How are the oceanic and tidal currents directeu I 
 
 82. What is said of the effect of these ? 
 
CONSTITUTION OF THE OCEAN. 29 
 
 progress. If, therefore, these oceanic agents be wearing 
 away dry land in one quarter, and filling up shallow bays 
 and creeks in another; if springs and rivers be wearing 
 down inland countries, and carrying the material to the sea; 
 and if, moreover, earthquakes and volcanoes be here sub- 
 merging land, and there elevating the bottom of the ocean, 
 the relative distribution of land and water must be continu- 
 ally fluctuating 
 
 '28. Of the depth of the sea little is known from actual 
 soundings ; but some geologists, taking the mean elevation 
 of land at between two and three miles, have supposed the 
 mean depth of ocean not to exceed that extent. As the 
 land, however, rises variously from a few feet to more than 
 five miles, others, attributing the same irregularities to the 
 bottom of the ocean as are seen on the surface of the land, 
 have assigned various depths, from a few feet to five or six 
 miles. From calculations which have been recently made 
 on the velocity of tidal waves, which are found to proceed 
 according to the depth of the channel, it is estimated that 
 the extreme depths of the Atlantic are about 50,000 feet, 
 or more than nine miles. 
 
 29. Besides the Pacific, Atlantic, and other regions of 
 the great ocean, there are large inland seas, such as the 
 Baltic and Mediterranean, as also extensive lakes of fresh 
 and salt water, all of which exercise important and varied 
 functions in modifying the surface of the globe. From the 
 existing arrangement, we are naturally led to entertain the 
 opinion, that conditions similar in kind, though differing 
 in degree, have at all times been imposed upon land and 
 water. 
 
 CONSTITUTION OP THE OCEAN. 
 
 3D. OP THE CONSTITUTION OF THE OCEAN chemical re- 
 search affords us pretty accurate data. Water, whether fresh 
 
 83. To what causes is to be ascribed the fluctuation in the relative dis- 
 
 tribution of land and water 1 
 
 84. How is the depth of the sea calculated t 
 
 85. What of its extreme depth ? 
 
 b6. What bodies of water are named, other than the great oceans T 
 2* 
 
30 GEOLOGY. 
 
 or salt, may contain impurities such as clay, sand, gravel, 
 animal and vegetable matter; but if left at rest, these by 
 their own weight soon fall to the bottom. Such substances 
 are said to be mechanically suspended ; and when deposited 
 at the bottom, they form sediment. Besides impurities of 
 this description, water may contain matter which will not 
 fall down, and which is said to be held in chemical solution . 
 Sea water of the Atlantic, according to Dr. Marcet, contains 
 4 3-lUth grains of saline matter in every hundredth ; while, 
 according to Dr. Murray, the water of the German Ocean 
 contains only 3 3-100th grains. This saline matter con- 
 sists chiefly of muriate of soda (common salt), sulphate of 
 s'oda, muriate of lime, and muriate of magnesia. It has been 
 also ascertained that the southern ocean contains more salt 
 than the northern; that small inland seas, though communi- 
 cating with the ocean, are less salt than the ocean ; that the 
 Mediterranean contains a greater proportion of saline matter 
 than the Atlantic; and though the saltness of the sea be 
 pretty uniform at great depths, still, at the surface, owing 
 to the admixture of rain, river, and iceberg water, it is not 
 quite so salt. 
 
 31. A knowledge of the constitution of the ocean is ne- 
 cessary to the explanation of numerous facts in geology. 
 The saline constituents must influence more or less all 
 chemical changes, rock deposits, and animal and vegetable 
 life, which take place in the ocean. From these constitu- 
 ents shell-fish and coral animals derive the matter of which 
 shell-beds and coral-reefs are constructed ; and by this same 
 constitution, marine animals and plants are made to assume 
 a character which distinguishes them from the inhabitants 
 of fresh waters. 
 
 32. The pressure of the sea (which depends on its depth) 
 also exerts an important influence, as what takes place near 
 
 87. What impurities are found in water T 
 
 88. How are they suspended ? 
 
 89. What salts are found in sea water ? 
 
 90. How are they held in combination ? 
 
 91. What variety in the proportion of salts? 
 
 92. How does the constitution r the ocean influence geological phe- 
 
 nomena ? 
 
 93. What of the pressure of the seat 
 
THE ATMOSPHERE. 31 
 
 the surface would be impossible at greater depths. There, 
 animal and vegetable life, as known to us, cannot exist; 
 sand and mud, which remain loose near the shore, would 
 become much consolidated if subjected to this pressure; 
 and, accoiding to the experiments ot' Sir James Hall, even 
 limestone could be fused without the loss of its carbonic 
 acid. Other results, depending upon the present constitution 
 of the ocean, might be pointed out ; but enough, we trust, 
 has been stated to impress the student with a conviction of 
 its geological importance. 
 
 THE ATMOSPHERE. 
 
 33. THE ATMOSPHERE, which everywhere surrounds the 
 globe, is either of itself the immediate cause of numerous 
 terrestrial changes, or it is the medium through which they 
 are effected. The air is a gaseous fluid, produced by the 
 combination of 79 parts of nitrogen with 21 of oxygen, _ 
 every 100 such parts containing a small portion of carbonic ' 
 acid and other extraneous impurities. It is indispensable 
 to the life of plants and animals, and an alteration of its 
 constitution would completely change the relations of ani- 
 mated nature ; for, while a greater proportion of carbonic 
 acid would be highly favourable to vegetation, it would be 
 utterly destructive to animals. The proportion of nitrogen 
 and oxygen in the atmosphere is at present, nearly as 4 to \q 
 1 ; change this, and 5 of oxygen with 1 of nitrogen forms a 1 * 
 compound (nitric acid, or aquafortis) so corrosive, that even / 
 the metals are dissolved by it. The air is an elastic or 
 compressible medium; and, consequently, the lower strata 
 near the earth will be compressed by the weight of those 
 above them, and thus the air will become rarer as we as- 
 cend. From measuring the rate at which this rarity takes 
 place, it has been calculated that at the height of forty-five 
 miles the atmosphere would become so rare as to be inappre- 
 
 94. What of the constitution of the atmosphere? 
 
 95. How would a change in its composition or properties affect living 
 
 beings T 
 
 96. How is this illustrated T 
 
 97. What of atmospSeric pressure upon the rarity of the air ? 
 
32 GEOLOGY. 
 
 ciable. Forty five miles has, therefore been assumed as the 
 limit of the atmosphere. 
 
 34. This aerial medium is the laboratory in which nume- 
 rous operations are effected. Vapours, rains, snows, clouds, 
 winds, and electricity, are among the most apparent of 
 these, and are continually influencing the earth's surface; 
 either mechanically, as by rains and winds ; chemically, as 
 by carbonic acid; electrically, as by electrical phenomena 
 during thunder ; or vitally, as in the support of plants and 
 animals. So far as we can learn from human history, the 
 constitution of the atmosphere has continued without sen- 
 sible change ; but of its primeval constitution we know 
 nothing, but are left to infer of its conditions from the 
 character of the plants and animals imbedded in the rocky 
 strata. At present, atmospheric agency is exerted in a 
 thousand ways, and analogy warrants us to conclude that 
 such has always been the case; this agency being the same 
 in kind, though perhaps differing in degree. 
 
 PLANETARY RELATIONS. 
 
 35. THE PLANETARY RELATIONS OP THE GLOBE exert a 
 permanent, and, it may be, sometimes a temporary and pe 
 culiar influence on the changes which have been effected, 
 or are now going forward, on its surface. From the sun 
 it derives light and heat, those agencies so indispensable to 
 animal and vegetable existence ; on its relation to the sun 
 and moon depend those important tidal influences already 
 adverted to ; while to the same relation it owes its daily and 
 annual revolutions, with all their attendant results. A per- 
 manent increase or diminution of the sun's heat would 
 change the whole vegetable and animal economy; the ap- 
 proach of a comet might derange the present order of the 
 
 98. What atmospheric phenomena are named ? 
 
 99. In how many ways do these influence the earth's surface ? 
 
 100. What of the permanence of the atmospheric constitution? 
 
 101. What of the planetary relations? 
 
 102. What of the influence of the sun and moon ? 
 
 103. How would a change in our relation to the sun affect us ? 
 
 104. What if a comet should approach us ? 
 
PLANETARY RELATIONS <>F THE GLOBE. 33 
 
 globe's rotations; and a slight shifting of the earth's axis, \ 
 so as to displace the present planetary position of its poles u t 
 and equator, would so alter the distribution of plants and/ 
 animals, would so derange its surface configuration, and 
 change the distribution of land and sea, that the face of 
 nature would then present an entirely different picture. So 
 far as history or the calculations of astronomy over a space 
 of 3000 years will permit us to infer, no such revolutions 
 have taken place; nor do the tides, the sun's heat or light, 
 seem to have been in the least affected. But while this is 
 true, it does not prevent the possibility of such changes ; 
 and certain geological appearances present themselves in 
 the earth's crust, which cannot be accounted -fur unless by 
 the supposition of such revolutions. 
 
 36. The daily and annual rotations of the earthy the 
 sun's light and heat, the ebb and flow of the tides, &c. are 
 permanent occurrences, dependent on the planetary relations 
 of the globe; catastrophes, such as would arise from the 
 contact of a comet, a change in the position of the earth's 
 axis, or the like, would be temporary and peculiar. 
 
 EXPLANATORY NOTE. 
 
 ELEVATIONS AND DEPRESSIONS. These are terms applied to the 
 risings and fallings of the surface of the earth from the slightest un- 
 dulation to the highest mountain, and from the gentlest hollow to the 
 greatest depth of ocean. The greatest heights with which we are 
 acquainted are those of the Himmaleh range in Asia, the Dhawalagiri 
 Peak being 28,077 feet, and the Jewahir 25,747. The Andes, in South 
 America, are the next in order, the Nevado di Sorato being 25,250 feet, 
 and Illimani 24,450. In Europe, the Alps rise (in Mont Blanc) to 
 lo,668 feet, the Pyrenees to 1 1 ,283 ; and in Africa, Geesh, in Abyssinia, 
 is 15,000, and the Peak of Teyde (Tenerifle) gives 12,180. As some 
 parts of the dry land are above the level of the sea, so also some por- 
 tions are beneath such as the central regions of Asia around the Cas- 
 pian and the Aral seas, where the surface has been ascertained to be 
 from 80 to 100 feet actually lower than the level of the ocean. But the 
 greatest depressions in the solid crust, are those occupied by the sea, 
 where actual soundings have reached depths of nearly a thousand 
 
 105. Suppose the axis of the earth slightly shifted T 
 
 106. Is there any proof of any of these changes within 3000 years T 
 
 107. What are permanent occurrences ? 
 
 108. What of the elevations and depressions of the surface of the globe f 
 
 109. Name the examples here ci'.ed. 
 
34 GEOLOGY. 
 
 fathoms ; and to which other calculations have assigned a depth of no 
 less than nine miles. 
 
 AVALANCHES (French, lavanches, avalanges) are accumulations of 
 enow, or of snow and ice, which descend from lofty mountains, like the 
 Alps, into the valleys beneath. They originate in the higher regions 
 of mountains, and begin to descend when the gravity of the mass be- 
 comes too great for the slope on which it rests, or when fresh weather 
 destroys its adherence to the surface. Avalanches are generally dis- 
 tinguished as drift, rolling, sliding, and glacier or ice avalanches. 
 Drift are those caused by the action' of the wind on the snow while 
 loose and powdery ; rolling, when a detached piece of snow begins to 
 roll down the steep it licks up the snow over which it passes, and 
 thus acquires bulk and force as it descends ; sliding when the mass 
 looses its adherence to the surface, and descends, carrying every thing 
 before it which is unable to resist its pressure ; and glacier or ice, when 
 pieces of frozen snow and ice are loosened by the heat of summer, and 
 precipitated into the plains below. 
 
 ICEBERG (German eis, ice, and berg, mountain) the name given to 
 the masses of ice resembling mountains, often found floating in the 
 polar seas. They are sometimes formed in the sea itself by the accu- 
 mulation of ice and snow ; at other times they seem to be glaciers 
 which have been piling up on a precipitous shore, till broken off and 
 launched into the ocean by their own weight. Masses of this kind have 
 been found in Baffin's Bay two miles long and half a mile in breadth, 
 rising from 40 to 200 feet above the water, and loaded with beds of 
 earth, gravel, and rocks. Some idea of the size of these icebergs may 
 be formed from the fact, that the mass of ice below the level of the 
 water is about eight times greater than that above. As they float to- 
 wards warmer regions, they gradually dissolve, dropping their burden 
 of rock debris, and thus strewing the bottom of the ocean with clay, 
 gravel, and boulder stones, some of which are many tons in weight. 
 
 PROPORTION OF LAND AND SEA. The proportion of land to sea is, 
 accurately, as 266 to 734. If, therefore, the whole superficies of the 
 globe be taken at 196,816,658 square miles, it follows that the dryland 
 occupies 52, 353,231 square miles, and the ocean an area of 144,463,427 
 square miles. 
 
 PRESSURE OF THE ATMOSPHERE. If the density of air at the surface 
 of the earth be represented by one, at seven miles above the earth it 
 will be l-4th, at fourteen miles l-l6th, at twenty-one miles it will be 
 l-64th, and so on. This property of air would lead to the idea of an 
 indefinite extension of the atmosphere, but there is evidently an ap- 
 preciable limit to this ; and hence, by calculations relative to the pro- 
 gress of the sun's light, and other astronomical phenomena, forty-five 
 miles has been fixed as the altitude of the atmosphere. Air is pon- 
 derable 100 cubic inches at the temperature of 60 degrees weighing 
 
 110. Define avalanches, and explain their variety. 
 
 111. What are icebergs, and how formed ? 
 
 112. What of their size and depth ? 
 
 113. How is the proportion of land to sea stated in figures 1 
 
 114. How is it that forty-five miles have been fixed upon as the altitude 
 
 of our atmosphere ? 
 
 115. Is air ponderable, and what is its weight T 
 
CAUSES MODIFYING THE STRUCTURE OF THE GLOBE. 35 
 
 30 grains. A perpendicular column of the whole atmosphere is balanced ; 
 by one of mercury rising to 30 inches ; hence the atmosphere presses on ' 
 every ciibic inch of surface with a weight equal to 16 pounds. 
 
 PRESSURE OF THE OCEAN Water being slightly compressible, it 
 follows, as in the atmosphere, that water at great depths in the ocean 
 will be denser than at the surface. According to calculations by . 
 Oersted, water at the depth of 100 feet is compressed l-340th part of i 
 its own bulk. 
 
 CAUSES MODIFYING THE STRUCTURE AND 
 CONDITIONS OF THE GLOBE. 
 
 37. Had the general structure and conditions of the globe, 
 as described in the foregoing section, been subjected to no 
 modifying causes, they would have remained unchanged 
 from the beginning of time, and the earth would have pre- 
 sented now the same appearance as at any former period. 
 But these very conditions are themselves the causes of 
 change, for they mutually act upon each other, and give 
 rise to innumerable agents, which have continued through 
 all time to modify the face of nature. Thus, for example, 
 the planetary relations of the earth enable it to derive heat 
 from the sun ; this heat vaporizes the water of the ocean, the 
 vapour produces rains, these rains form springs and rivers, 
 the rivers wear down the land, and thus change the surface 
 configuration ; the matter borne down by the rivers forms 
 new land along the sea-shore, altering the distribution of 
 land and water; and this distribution of land and water 
 materially affects the kind and distribution of plants and 
 animals. This is a simple instance of the changes pro- 
 duced by the action and reaction which takes place among 
 the general conditions of the globe ; and the student would 
 do well, at this stage of his progress, to familiarize himself 
 with such trains of cause and effect, as it is only by the 
 ready application of similar reasoning that he will be able 
 to comprehend many of the phenomena hereafter described. 
 
 38. The modifying causes produced by the mutual influ- 
 
 116. What is the pressure of the atmosphere upon a cubic inch ? 
 
 117. What of the pressure of the ocean t 
 
 118. What causes modify the structure and conditions of the globe ? 
 
 119. Describe the effect of the sun's heat on the ocean t 
 
 120. What of rivers, and the changes they produce 1 
 
36 GEOLOGY. 
 
 ence of the general conditions already considered are ex- 
 ceedingly numerous and varied. At present, it is necessary 
 to notice only such as seern to account for the principal 
 facts connected with the solid materials which form the 
 crust of the globe, and the order and manner of their ar- 
 rangement. These causes, or agents, may be divided into 
 four great classes; namely, ATMOSPHERIC, AQUEOUS, IG- 
 NEOUS, and ORGANIC ; and their modes of action may be 
 either mechanical, chemical, electrical, or vital. 
 
 ATMOSPHERIC AGENCIES. 
 
 39. ATMOSPHERIC AGENTS act either mechanically or 
 chemically : the action of wind in drifting loose sand 13 
 mechanical, the action of the air in weathering the surface 
 of rocks is chemical. The atmosphere may either act di- 
 rectly, as in the case of winds, or indirectly, as in the pro- 
 duction of waves, the effects of which on the sea-coast are 
 often destructive and extensive. The changes produced 
 on the earth's crust by atmospheric agency are sometimes 
 slow and gradual, such as in the crumbling down of rocks; 
 or immediate, as in the uprooting of forests by tempests, 
 and the covering of green valleys by barren sand-drift. 
 The air, or atmosphere, is one of the most important ele- 
 ments, and is more or less connected with every operation 
 in nature. By it the sun's light and heat are equally dif- 
 fused ; it is indispensable to the existence of plants and 
 animals; and it is the great laboratory in which the waters 
 of the ocean are purified and distributed over the face of 
 the globe. These may be said to be universal functions 
 of the atmosphere. It also acts peculiarly, and over limited 
 extent, as in the production of winds, frost, heat, electricity, 
 and gaseous admixtures. 
 
 121. What four great classes of agency are named ? 
 
 122. What of their modes of action ? 
 
 123. How do atmospheric agents act ? 
 
 124. Give examples of each. 
 
 125. What of direct and indirect action ? 
 
 126. Name instances of gradual and immediate action. 
 
 127. What of the universal functions of the atmosphere? 
 
 128. In what phenomena does it act peculiarly ? 
 
ATMOSPHERIC AGENCIES. 37 
 
 40. Winds are aerial currents. When the air of one 
 region becomes heated or rarefied, the colder and heavier air 
 of the surrounding regions rushes in to restore the balance, 
 and thus atmospheric currents are produced. These cur- 
 rents are extremely unstable, blowing without regard to 
 time or direction, and modified and obstructed in a thousand 
 ways by hills, valleys, and other surface irregularities. They 
 are equally unstable in their velocity, varying from the 
 gentlest breeze to the fiercest hurricane which overturns 
 cities and uproots forests. But though characterized by 
 these irregularities over the greater portion of the globe, 
 there are regions over which they pass with wonderful 
 steadiness for months together. The trade-winds which 
 take place within the tropics possess this character, and 
 blow Irom east to west with little variation of direction or 
 force. The monsoons, which are connected with the trade- 
 winds, are also preity regular; and in most countries an 
 east, a south, or a west wind, is found to prevail over other 
 directions, and* that at particular periods of the year. Of 
 the phenomena of winds in the earlier eras of the world we 
 have no knowledge; but we are warranted to conclude, 
 that since the elevation of dry land, and the distribution of 
 land and water, they have been analogous to what is now 
 in daily occurrence. 
 
 41. Wind acts on all loose material, bearing it from ex- 
 posed to sheltered places. Sand, gravel, and loose shells 
 are most frequently shifted by its force, and blown into hil- 
 locks, or scooped out into hollows, without order or regu- 
 larity. All those extensive tracts of sand found along the 
 sea-coast known in Scotland as links, and as downs in 
 England owe their surface formation to the wind. The 
 sand collected in bays and creeks by the waves and tides 
 of the ocean, is no sooner left dry by the tide, and exposed 
 to the sun, than it becomes light, and easily acted upon by 
 the wind, which raises it into knolls and ridges beyond the 
 
 129. Define winds, when and how produced t 
 
 130. How modified and varied ? 
 
 131. What of trade-winds T 
 
 132. What are monsoons ? 
 
 133. Upon what materials do winds act, and what examples ajc cited T 
 
38 GEOLOGY. 
 
 influence of the returning tide. By and by a scanty herbage 
 gathers over the sand, arid thus, in course of ages, extensive 
 downs are formed. In a similar manner the wind acts 
 upon the sandy deserts of Arabia and Egypt, continually 
 shifting their surface ; and if it sets in from any prevailing 
 direction, these sands are carried forward, year after year, 
 burying trees, fields and villages, and thus converting fertile 
 districts into barren wastes. When a river enters the sea 
 through a sandy district, it has a tendency frequently to shift 
 its channel ; and this tendency is greatly increased by winds 
 damming up the current with drifted sand. Volcanoes oc- 
 casionally discharge showers of dust and ashes, which, 
 during high winds, are carried over many leagues of surface, 
 or borne out to the ocean. During calm weather volcanic 
 dust and ashes would fall in the neighbourhood of the 
 crater ; during high winds they may be deposited at vast 
 distances from their original sources. Such examples as 
 the above are the ordinary actions of wind: the uprooting of 
 forests, the destruction of cities, and the like, are extraordi- 
 nary, and are caused by whirlwinds and hurricanes. 
 
 42. Frost exercises a slow but permanent influence in mo- 
 difying the surface configuration of the globe. When the 
 heat of the surrounding atmosphere falls below 32 degrees 
 of the thermometer, water begins to freeze, and in this state 
 expands. During winter or moist weather, water enters 
 between the particles of all rocky matter at the surface of 
 the earth, and also into the larger fissures; and the expan- 
 sion of this water by frost separates these particles, and 
 leaves them to fall asunder when the ice is dissolved. This 
 takes place more or less every winter ; and there is not a 
 cliff or hill side but bears evidence of this kind of action. 
 The effect of frost in crumbling down rocky material has 
 been long observed; the farmer takes advantage of it to 
 pulverize his soil ; and in some districts slate and flagstone 
 are split into thin lamina? by being exposed to the frost. 
 
 43. Of the amount of change produced by frost, it would 
 
 134. Name the changes produced by the winds upon sand. 
 
 135. What instances are cited of ordinary and extraordinary winds ? 
 
 136. How does frost modify the earth's surface ? 
 
 137. Give the examples and illustrations in the text. 
 
ATMOSPHERIC AGENCIES. 39 
 
 be difficult to form an estimate ; but, taking it over a lapse 
 of ages, there can be little doubt that it has been an impor- 
 tant agent. In mountain regions, such s the Alps, its 
 effects are strikingly apparent in the formation of ava- 
 lanches; and in northern latitudes the iceberg is one of its 
 familiar productions. The action of frost in crumbling 
 down a rocky surface seems slow and insignificant, but 
 when we look upon the avalanche carrying rocks, gravel, 
 trees, and houses before it, and burying them in one com- 
 mon ruin ; when we look upon the iceberg laden with huge 
 stones, and dropping them into the ocean as it dissolves, 
 we are more impressed with its importance, and are ena- 
 bled to account for certain geological appearances which no 
 other agency could have produced. (See note, p. 34.) 
 
 44. Solar heat and light may, without much impropriety, 
 be classed as atmospheric agents, as the atmosphere is the 
 medium through which they act, and by which they are 
 modified. Water conducts heat faster than air, and -air, at 
 the surface of the earth, faster than highly rarefied air at 
 great heights; hence different conditions of the atmosphere 
 may have hitherto conducted more heat to the earth's sur- 
 face. The quantity of light which reaches the earth de- 
 pends upon the serenity of the atmosphere, and the height 
 of the sun above the horizon ; hence, also, a different con- 
 dition of atmosphere would produce a different amount of 
 light. 
 
 45. Heat and light are indispensable to vegetable and 
 animal existence ; and the kind and number of plants and 
 animals depend, in a great measure, upon the degree and 
 uniformity of their influence. Heat converts water into 
 vapour, and vapour forms dews, rains, &c. The amount 
 of vapour, and consequently the amount of rain, will de- 
 pend upon the degree of heat ; and hence the heavy peri- 
 odical rains of the tropics. A higher degree of heat all 
 over the earth would greatly increase the amount of rains, 
 these rains would form more gigantic rivers, and geological 
 effects of corresponding magnitude would follow. 
 
 138. How is the power of frost shown ? 
 
 139. How are solar heat and light modified by the atmosphere 7 
 
 140. What effects are ascribed to heat and light ? 
 
43 CEOLOGY. 
 
 46. Of the amount of solar heat received by the earth at 
 any former period, we are left to infer from the kind of 
 plants and animals which are found imbedded in the rocky 
 strata ; a scantiness and peculiar character of these remains 
 indicating a temperature analogous to that of the polar 
 regions, and numerical amount and external form indicating 
 a climate similar to that of the tropics. 
 
 47. Electricity is only ranked among atmospheric agents, 
 though electric, galvanic, and magnetic influences may be 
 going on in the crust of the globe totally independent of 
 the atmosphere. The effects of these subtle forces are not 
 easily calculated ; and what connexion they may have with 
 earthquakes, with the formation of metallic veins, and simi- 
 lar phenomena, geology has not been able to determine. We 
 know that the hardest and most untractable substances in 
 nature can be artificially dissolved and reconstructed by the 
 aid of electricity; this force sometimes acting slowly and 
 insensibly, and other times with rapidity and violence. We 
 know, also, that what the chemist has not been able to effect 
 by the most powerful charges of electricity, has been ac- 
 complished by the slow and almost insensible effects of the 
 same agent. What takes place in the laboratory of the che- 
 mist may be daily occurring in nature. We occasionally 
 perceive the violent effects of electricity during a thunder- 
 storm ; but these may be trifling in comparison with what 
 is hourly, but insensibly, taking place among the materials 
 which compose the crust of the earth. We often hear of 
 the disasters of a tropical thunder-storm, where the electric 
 fluid demolishes houses, rends trees, sets fire to forests, or 
 shivers rocks ; but these consequences, though startling, 
 produce no extensive terrestrial changes ; so that it is to 
 the slow and unseen agency of this power in producing 
 peculiar transformations of metallic and other matter, that 
 its importance in geological reasoning is mainly to be 
 ascribed. 
 
 141. What indications of solar heat are found in fossil remains 1 
 
 142. Is electricity always an atmospheric agent ? 
 
 143. What phenomena may depend on this agent? 
 
 144. What is said of the variable actions of electricity ? 
 
 145. Which kind of electrical agency is regarded chiefly in geological 
 
 inquiries ? 
 
ATMOSPHERIC AGENCIES. 4 I 
 
 48. The gaseous constitution of the atmosphere acts che- 
 mically, not mechanically. In its ordinary state, as we 
 have already seen, every 100 parts are composed of 79 
 nitrogen and 21 oxygen, with a small proportion of carbo- 
 nic acid, amounting to little more than one part in a thou- 
 sand. This constitution is essential to animal and vegeta- 
 ble life; hence the student can readily conceive how any 
 extensive alteration of this mixture would operate. Car- 
 bonic acid gas is given off by some springs, by volcanic 
 fissures, and by similar sources both in the sea and on dry 
 land. This gas is destructive to life; and consequently 
 shoals of fishes, or herds of animals, coming in contact 
 with any extensive exhalation of it, would be instantly suf- 
 focated. Other gaseous fumes are also destructive to life ; 
 and bearing these facts in mind, we may be enabled to ac- 
 count for peculiar accumulations of animal remains in cer- 
 tain situations in the rocky strata. 
 
 49. Rocks exposed to the atmosphere absorb air and mois- 
 ture, and the action of this air and moisture weathers, or 
 dissolves the union of the outer particles. These outer 
 particles fall off by the force of gravity; another set of par- 
 ticles are exposed to the same wasting influence; and thus, 
 year after year, every rock and mountain is losing more or 
 less of its material. 
 
 50. Oxygen and carbonic acid are the principal agents 
 in this operation. All metallic substances are acted on by 
 oxygen ; it tarnishes their surface, gradually eats into their 
 mass, and in time converts them into a loose powdery sub- 
 stance. Iron affords a similar illustration of this fact : 
 however well polished, if exposed to air and damp, it be- 
 gins to rust, film after film, till the whole is in time con- 
 verted into a reddish powder, called rust, or oxide of iron. 
 All the igneous rocks, and most of the aqueous, contain 
 iron disseminated in minute particles through their mass, 
 and are therefore liable to be acted upon by oxygen. It is 
 
 146. What of the gases of the atmosphere T 
 
 147. Whence may carbonic acid be given off" in quantities 1 
 
 148. What fossil remains may be thus accounted for ? 
 
 149. What of weathering rocks T 
 
 150. What action is ascribed to the oxygen- of tho atmosphere T 
 
42 GEOLOGY. 
 
 this oxide of iron which gives the reddish colour to many 
 rocks and mineral waters. 
 
 51. The formation of many soils is owing to this pulver- 
 izing power of the atmosphere; and as their loose matter is 
 washed down by rains and rivers, a new supply is formed 
 by further disintegration of the rocks beneath. We have 
 no means of ascertaining the amount of change produced 
 by the chemical constitution of the atmosphere ; but this 
 we know, that it must hav-e exerted itself through all time 
 most powerfully in warm damp climates, and least where 
 the air was clear and arid. Soft clays and shales are easily 
 weathered down; so, also, are all kinds of volcanic rocks; 
 and even granite has been known to be pulverized to the 
 depth of three inches in six years. 
 
 52. The atmospheric agents chiejly instrumental in modi- 
 fying the crust of the globe, all, more or less exert a de- 
 grading or wasting influence; that is, a tendency to wear 
 down the surface to a lower level. Wind occasionally pre- 
 sents an exception to this statement, and tends to raise the 
 surface; as in the formation of downs and sand-hills, of 
 considerable elevation, like those of Barry at the mouth of the 
 Tay. Atmospheric forces act either mechanically, chemically, 
 or vitally; are universal in their operations, with perhaps the 
 exception of frost in the tropics; and must have exercised 
 an important influence on the geological conditions of the 
 earth from the beginning of time. 
 
 EXPLANATORY NOTE. 
 
 ATMOSPHERIC, AQUEOUS, IGNEOUS, AND ORGANIC. The student 
 should make himself perfectly familiar with the application of these 
 terms. Wind, for example, is a purely atmospheric agent ; springs, 
 rivers, and waves, are aqueous agents ; volcanoes are igneous agents, 
 and, geologically speaking, the term is chiefly applied to forces or 
 
 151. What is said of the rust of iron ? 
 
 152. How may soils be thus formed ? 
 
 153. What instances are cited of the pulverizing power of the atmos- 
 
 phere ? 
 
 154. To what kind of action is this to be ascribed ? 
 
 155. What exception to the wasting effects of this class of agents ? 
 
 156. What exception is admitted to their universal action ? 
 
 157. Name the illustrations in the Note. 
 
ATMOSPHERIC AGENCIES. 43 
 
 results depending upon the internal heat of the earth ; and organic 
 agents ire such as arise from animal or vegetable life. Organic (Greek, 
 organen, an instrument or machine) is applied to vegetable or animal 
 structures, as being made up of parts nicely adapted to each other. All 
 matter resulting from the growth or decay of plants and animals is said 
 to be organic. 
 
 MECHANICAL, CHEMICAL, ELECTRICAL, AND VITAL. A piece of 
 chalk may be brayed to powder by pounding it in a mortar ; it may 
 also be reduced to powder by dissolving it in sulphuric acid ; in the 
 former instance the action is mechanical, in the latter chemical. In 
 whatever manner electricity acts, the action is said to be electrical ; the 
 reconversion of blue vitriol (sulphate. of copper) into metallic copper, 
 as is done in electrotyping, is an example of this kind of action. Vital 
 is applied to any sort of action depending on life, whether in animals or 
 vegetables. 
 
 WINDS. Besides the trade-winds, blowing within the 25th degree 
 of latitude on either side the equator, there are the monsoons, which 
 are merely the trade- winds diverted north or south by the land that -- 
 lies within these parallels ; the simoom, a burning pestilential blast, 4 
 which rushes with fury over the sandy deserts of Arabia ; the harmat- 
 tan, a cold dry wind, frequent in Africa and in Eastern countries ; 
 the sirocco, a hot, moist, and relaxing wind, which visits Italy from the 
 opposite shores of the Mediterranean ; the bize, a cold frosty wind, 
 which descends from snow-covered mountains, such as the Alps ; and 
 whirlwinds and tornados, that are common to all countries, but most 
 destructive in warm regions. 
 
 FREEZING. Water, at the temperature of 40 degrees, may be said 
 to be stationary as to bulk ; but if the temperature be reduced, it be- 
 gins to expand, till, at 32 degrees, it freezes, and is converted into solid 
 ice, in which state it is 1-1 4th larger than its original volume. On the 
 other hand, if the temperature be increased, the water is gradually con- 
 verted into vapour, till, at 212 degrees, it boils, and is rapidly expanded 
 into steam, in which state it is 1700 times its original bulk. Steam 
 can be still further expanded, till almost no known force is able to 
 resist it. 
 
 PULVERIZE (Lat., pulvus, dust) to reduce to dust or powder. Soil, 
 which is reduced to small particles by the action of frost, is said to be 
 pulverized. So also of rocks. 
 
 DISINTEGRATE (Lat., dis, asunder, integer, whole) to break asunder 
 any whole or solid matter. The disintegration of rocks is caused by 
 the slow action of the atmosphere or by frosts, &c. 
 
 DEGRADING, DEGRADATION (Lat.,cte, down, gradus, a step) to take 
 down from one level to another. The degradation of hills and cliffs is 
 caused by rains and rivers ; hence water is said to degrade, or to exer- 
 cise a degrading influence on the land. Degradation and elevation of 
 land are opposite terms. 
 
 153. Give an example of each mode. 
 
 1 ?9. Name the variety of winds and their peculiarities. 
 
 160. What of the expansion of water in freezing T 
 
 161. What is the extent of expansion in water by boiling ? 
 
 162. Is this the limit of its expansion 1 
 
 63. Define Pulverize; Disintegrate; Degradation; Denudation, 8tc- 
 

 44 
 
 GEOLOGY. 
 
 DENUDATION (Lat., denudo, I lay bare) a term sometimes employed 
 as synonymous with degradation, but inaccurately so. For example, 
 disintegration, strictly applies to that action by which the materials 
 of solid rocks are loosened or separated from each other ; degradation 
 to the carrying of these materials from a higher to a lower level ; and 
 denudation to the removal of superficial matter by water, so as to lay 
 bare the inferior strata. 
 
 AQUEOUS AGENCIES. 
 
 53. AQUEOUS AGENTS, or those arising from the power 
 and force of water, are perhaps not so universal or so com- 
 plex in their operations as atmospheric ; but they are more 
 powerful, and consequently exert a more obvious influence 
 in modifying the crust of the globe. Their mode of action 
 is either mechanical or chemical ; mechanical, as when a 
 river wears away its banks, and carries the material to the 
 sea; and chemical, when, from gaseous admixture, water 
 is enabled to dissolve certain rocks and metals. The ac- 
 tion of water is sometimes slow and gradual, as in the 
 wearing down of rocks by rain ; or rapid and violent, as in 
 the case of river-floods and sea-storms. The effects of rain 
 upon a cliff may not amount to one inch in a hundred 
 years, while hundreds of acres of alluvial land may be 
 swept to the ocean by one river flood. Water operates vari- 
 ously : sometimes by itself, as in rivers; sometimes in union 
 with the atmosphere, as during land and sea-storms. Its 
 power as a geological agent is most obvious in the case of 
 rains, springs, rivers, lakes, waves, currents, and tides ; and the 
 results of these agents are distinguished as meteoric, fuvi- 
 atile, lacustrine, or oceanic. 
 
 54. Rain, hail, snow, and all atmospheric vapours, exer- 
 cise a degrading influence on the earth's surface. By en- 
 tering the pores and fissures of rocks, they soften and grad- 
 ually dissolve their surface, and thus materially assist the 
 
 164. What of aqueous agents ? 
 
 165. Name an instance of mechanical and one of chemical action. 
 
 166. How is aqueous action varied? 
 
 167. How may it be complicated ? 
 
 168. In what instances is its power most obvious ? 
 
 169. By what names are these results designated 7 
 
 170. Explain the action of rain and wind. 
 
AQl tOE S AGfeStil Eft. 
 
 operations of frosts, winds, &,c. Rain, accompanied by 
 high winds, acts with greater force; snow, from accumu- 
 lating during frost, and suddenly dissolving during fresh 
 weather, sometimes occasions violent floods and inunda- 
 tions. Floods arising from the melting of snow are gene- 
 rally very destructive, for, during the season when they 
 occur, the surface is soft and loose, and much more liable 
 to be carried away. Rain and other vapours are indispens- 
 able to the growth of vegetables, and when accompanied 
 with sufficient warmth, a luxuriant and gigantic vegetation, 
 like that of the tropics, is the result. The amount of rain 
 which falls on the earth's surface is exceedingly varied, 
 ranging from 20 or 30 inches to several feet per annum. In 
 tropical regions, rains are periodical ; that is, fall for weeks 
 together at certain seasons. This gives rise to inundations; 
 hence the peculiar phenomena attending the floodings of 
 such rivers as the Nile, Ganges, &c. 
 
 55. Of the quantity of rain which f til during past periods 
 of the world we have no positive knowledge: but if we are 
 able to discover evidence of a higher temperature, we are 
 warranted in concluding that the quantity of rain was much 
 greater. A greater fall of rain would produce larger rivers, 
 and larger livers would carry down a greater quantity of 
 silt and debris ; this would form more extensive plains and 
 deltas ; and these, again, would sustain a more gigantic race 
 of plants arid animals. From this example, the student 
 will readily perceive the connection and influence of these 
 allied causes. Rain water generally contains carbonic 
 acid, ammonia, and other substances ; and, consequently, 
 acts chemically as well as mechanically. 
 
 56. Springs art discharges of water from the crust of the 
 earth either by rents, fissures, or other openings in the stir- 
 face. The water which falls in rain, snow, &c. partly runs 
 off, and partly sinks into the crust, where it collects in vast 
 
 171. How does snow operate ? 
 
 172. How is the vegetation of the tropics acounted for f 
 
 173. What of the amount of rain T 
 
 174. What connection between temperature and rain 1 
 
 175. N'ime the chemical agent found ia rain. 
 !"6. Whence are springs derived T 
 
46 GEOLOGY. 
 
 quantites, and ultimately finds its way again to the surface 
 by springs. Springs issuing from strata at great depths are 
 said to be deep-seated; those from clay or gravel are shal- 
 low. Some only flow during or shortly after rains, and are 
 said to be temporary; some flow always, and are perennial ; 
 while others flow and ebb, and are said to be intermittent. 
 
 57. The characters in which geologists have principally 
 to consider springs are cold, thermal, and mineral. Cold 
 springs have a mechanical action when they cut out chan- 
 nels for themselves; and they act chemically when, for 
 example, they contain carbonic acid, and dissolve portions 
 of the rocks through which they pass. All petrifying springs 
 that is, such as convert wood and bones into stony matter 
 act chemically. Thermal, or hot springs, occur in nu- 
 merous parts of the world (England, Iceland, Germany, 
 Switzerland, Italy, Hindostan, &c.), and also act mechani- 
 cally and chemically, but with much greater chemical force 
 than cold springs. Mineral springs may be either cold or 
 hot, and take their name from the circumstance of their 
 waters holding some mineral or earthy substance in solution. 
 
 58. Mineral springs, geologically speaking, are by far 
 the most important, as, from their composition, they indicate 
 the kind of rocks through which they pass, while they more 
 or less influence all deposits or waters into which they flow. 
 Thus, some contain iron, and are said to be ferruginous, or 
 chalybeate; some copper (cupriferous), some lime (calca- 
 reous), some salt (saline), while others give off sulphureous 
 vapours; and so on with almost every known mineral. 
 Those issuing from strata containing iron or lime are more 
 or less impregnated with these substances; and when they 
 arrive at the surface of the earth, and their waters become 
 exposed to the air, the ferruginous or limy matter is depo- 
 sited along their courses, or is carried down to the nearest 
 
 177. What variety of springs are named ? 
 
 178. In what character do geologists consider them 7 
 
 179. How do cold springs act ? 
 
 180. Where are thermal springs, and what is their action ? 
 
 181. Define mineral springs. 
 
 182. By what names are they called when they contain iron ? copper I 
 
 -lime t salt ? or sulphur ? 
 
, - 
 
 AQUEOUS AGENCIES. 47 
 
 river or lake. If layers of mud, sand, or gravel be forming 
 in such a lake, these layers will be impregnated with the 
 matter of the springs; hence geologists speak of ferruginous, 
 calcareous, or saliferous strata. Mineral springs may there- 
 fore be said to exert a two-fold influence : first, by dissolving 
 and carrying away matter from the strata beneath ; and, 
 second, by adding that matter to the strata which are now 
 being formed on the surface. The student will thus per- 
 ceive the manner in which springs act in modifying the 
 crust of the earth ; and in proportion to their size, the soft- 
 ness of the strata through which they passed, and the de- 
 gree of heat they had acquired, so must the extent of their 
 influence have been at any former period. 
 
 59. Rivers are the most important aqueous agents em- 
 ployed in modifying the surface of the globe. Springs, as 
 they issue into open day, naturally seek a lower level ; and 
 numbers of them meeting in one channel, form streams, 
 which again join in some still lower valley, where their 
 union produces rivers of various sizes. Rivers may be said 
 to be a species of natural drainings, by which the supera- 
 bundant moisture which falls on the land is again returned 
 to the sea. They are of all dimensions; in breadth from a 
 few feet to several miles, so shallow that a boy might wade 
 them, or so deep as to float the largest ships, and ranging 
 in length of course from fifty or sixty miles to as many hun- 
 dreds. 
 
 60. The geological action of rivers is twofold; first, by 
 wearing down the land through which they pass, and then 
 by carrying down the material to lakes and seas. Both their 
 degrading and transporting force depends upon their velocity. 
 For example, it has been calculated that a force of 3 inches 
 per second will tear up fine clay, 6 inches will lift fine sand, 
 8 inches sand as course as linseed, and 12 inches fine gravel ; 
 
 183. What double influence is ascribed to mineral springs ? 
 
 184. How may the extent of their influence be estimated ? 
 
 185. Into what do springs and their streams flow ? 
 
 186. What of the variety and extent of rivers ? 
 
 1ST. Upon whit do the degrading and transporting effects of rivers de- 
 pend 1 
 188. How is comparative velocity measured I 
 
48 GEOLOGY. 
 
 while it requires a velocity of 24 inches per second to roll 
 along rounded pebbles an inch in diameter, and 36 inches 
 per second to sweep angular stones of the size of a hen's 
 egg. Rivers, during floods, often acquire a much greater 
 velocity than this, and stories of considerable weight are 
 then borne down by their currents. The degrading .power 
 of running-water depends also upon the kind of material 
 through which it flows; loose soil, clay, and sandstone being 
 easily worn down, while granite or basalt will suffer little 
 loss for centuries. The mere flowing of pure water would 
 exert little influence on hard rocks; but all rivers carry down 
 sand and gravel; and these, by rubbing and striking against 
 the sides and bottoms of the channel, assist in scooping out 
 those channels which everywhere present themselves. The 
 Nerbuddah, a river of India, has scooped out a channel in 
 basaltic rock 100 feet deep. Messrs. Sedgwick and Mur- 
 chison give an account of gorges scooped out in beds of the 
 rock called conglomerate, in the valleys of the Eastern Alps, 
 600 or 700 feet deep. A stream of lava, which was vomited 
 from ^Etna in 1603, happened to flow across the channel of 
 the river Simeto. Since that time the stream has cut a pas- 
 sage through the compact rock to the depth of between 40 
 and 59 feet, and to the breadth of between 50 and several 
 hundred feet. The cataract of Niagara, in North America, 
 has receded nearly 50 yards during the last 40 years. Below 
 the Falls, the river flows in a channel upwards of 150 feet 
 deep and 160 yards wide, for a distance of seven miles; and 
 this channel has evidently been produced by the action of 
 the river. Such effects as the above are produced by the 
 general or ordinary action of water; but when rivers are 
 swollen by heavy rains, by the sudden melting of snow, and 
 the like, then they act with extraordinary violence. In 
 these cases they overflow their banks, rush with a velocity 
 of 20 or 30 feet per second, tear up the soil, and sweep be- 
 fore them trees, animals, houses, and bridges. The water 
 of all rivers which exert a degrading influence is more or 
 
 189. What remarkable examples are cited I 
 
 190. What of the falls at Niagara ? 
 
 191. What of the velocity and force of freshets T 
 
iCQUEOUS AGENCIES. 
 
 49 
 
 less turbid, and an idea of their power may be formed by 
 observing this fact. 
 
 61. The matter which rivers carry down is either depo- 
 sited Hong their banks, in lakes or in the ocean. If .they 
 flow sluggishly along a flat valley, the mud and sand which 
 their waters contain gradually falls to the bottom and there 
 rests as sediment. This sedimentary matter forms what is 
 called alluvial land, and most of the flat and fertile valleys 
 in the world have been so produced. Again, when a lake 
 occurs in the course of rivers, the sediment is there col- 
 lected, and the water issues from the lake as if it had been 
 filtered. In progress of time, lakes are filled or silted up 
 with this sediment, and their basins appear first as marshes, 
 and latterly as alluvial land. But whatever quantity of 
 matter may be deposited in valleys or lakes, the greatest 
 amount will always be carried down to the ocean, and de- 
 posited at the mouth 
 
 of the river or along 
 the shores. The hea- 
 viest material, such 
 as gravel, will fall 
 down first, then the 
 lighter sand, and ulti- 
 mately the finest mud. 
 The mud of the Gan- 
 ges discolours the 
 Bay of Bengal to a 
 distance of 60 miles 
 from its mouth ; and 
 according to Captain Sabine, the muddy waters of the 
 Amazon may be distinguished 300 miles from the shore. 
 
 62. The consequence of this continual seaward-carriage 
 of stdimcntary matter is, that at the mouths of most rivers 
 there are alluvial formations, known by the name of deltas; 
 such as those of the Nile, the Ganges, the Niger, &-c. 
 
 192. How is alluvial land formed ? 
 
 193. What of lakes? 
 
 194. What instances are named of rivers emptying their sediment into 
 
 the ocean T 
 
 195. What are deltas, and where found 1 
 
50 GEOLOGY. 
 
 They take their name from their resemblance in shape to 
 the Greek letter A (delta) ; and frequently extend over vasi 
 surfaces that of the Ganges being about 200 miles in one 
 direction by 220 in another. They consist of alternate 
 layers of sand, gravel, or mud, according to the kind of 
 material the river carries down. The foregoing cut repre 
 sents the Delta of the Nile, which is generally regarded aa 
 the type of all similar deposits. 
 
 63. The geological results effected by the agency of run- 
 ning water are ceaseless and universal. Rivers are gradually 
 wearing down the hills and higher lands, and as gradually 
 silting up lakes and low tracts of valley land. They lay 
 down beds of gravel, sand, or mud ; and these beds, again, 
 enclose trees, plants, the bones and shells of animals, in 
 greater or less abundance. As rivers now act, so must 
 they have always acted, and to this kind of agency must 
 we ascribe the formation of many of the rocks (with their 
 fossils) which now form the crust of the earth both at great 
 depths and at distances now far removed from the sea. We 
 have no actual knowledge of the rivers of the ancient 
 world ; but judging from the extent of sedimentary rocks, 
 they must have been much more gigantic than most of 
 those now existing. 
 
 64. Waves, currents, and tides are also power ful geologi- 
 cal agents. Waves are continually in action; and according 
 to their violence, and the materials composing the sea-coast, 
 so is the amount of change produced. Cliffs of sandstone, 
 chalk, clay, or other soft rock, are, year after year, under- 
 mined by their force; masses fall down, are soon ground to 
 pieces, and swept off by every tide; new underminings take 
 place, new masses fall down, and thus thousands of acres 
 of land have been reduced to a level with the sea. What 
 the waves batter down, the tides and currents transport to 
 sheltered bays and creeks along the shore ; so that, while 
 
 196. Whence is this name derived ? 
 
 197. Of what do they consist ? 
 
 198. What of the uniform and universal action of rivers? 
 
 199. What geological inferences are made concerning ancient rivers ? 
 
 200. What instances are cited of the effects of waves, currents, and tides} 
 
 201. What geological reasoning is thence authorized ? 
 
AQUEOUS AGENCIES' 51 
 
 in one quarter the sea is making encroachments on the 
 land, in another it is accumulating sand and gravel to form 
 new land. The power of waves and currents is much in- 
 creased by the fact, that rocks are more easily moved in 
 water, and thus gravel beaches are piled up or swept away 
 with apparent facility. The ordinary action of the sea is 
 small, however, compared with what is sometimes accom- 
 plished during storms and high inundations; and those who 
 have witnessed the effects of a few successive tides at such 
 periods, will readily form an estimate of what may be ac- 
 complished during the lapse of ages. 
 
 65. The action of waves, currents, and tides, is varied and 
 complicated; but it may be stated generally, that waves 
 batter down the sea-cliffs, or raise up loose matter from the 
 bottom ; that tidal currents convey the disintegrated matter 
 to more sheltered bays and creeks; and that oceanic cur- 
 rents convey floating material, such as drift-wood, plants, 
 and dead animals, from one part of the ocean to another. 
 Tides rise and ebb from 4 to 40 feet ; they enter into cer- 
 tain rivers for many miles; and thus a mingling of fresh 
 water and marine, deposits takes place. As at present, so 
 in ages past; and by diligently studying the effects pro- 
 duced by waves and tides, the student will be enabled to 
 account for many appearances which the sedimentary rocks 
 present. 
 
 EXPLANATORY NOTES. 
 
 THE ACTION OF WATER is said be meteoric when it acts through 
 the atmosphere ; fluviatile (Jluvius, a river) when it acts by running 
 streams or rivers ; lacustrine (locus, a lake), by pools or lakes ; and 
 oceanic, when by the ocean. 
 
 SILT Mud or sand carried down by any river, and deposited either 
 along its banks or in lakes, is called silt ; and when a lake becomes 
 filled with this matter, it is said to be silted up. Silt is generally ap- 
 plied to matter calmly or slowly deposited. 
 
 202. What work is ascribed to waves T 
 
 203. What do tidal currents effect? 
 
 204. How do oceanic currents operate ? 
 
 205. What is the varied extent of the ebb and flow of tides f 
 
 206. Define the italicised terms in the first Notes. 
 
 207. What is tilt , and debris >> 
 
52 OEOLOGY. 
 
 DEBRIS (French) a term applied to the loose material arising from 
 the disintegration of rocks. 
 
 ALLUVIAL (Lat., luere, to wash, and ad, together). Land washed or 
 brought together by the action of water ia said to be alluvial. Most 
 of the straths and car'ses in Scotland, and the dales in England, are 
 alluvial ; as are also the deltas of all such rivers as the Nile, Ganges, 
 Niger, Mississippi, &c. 
 
 SEDIMENT (Lat., sedere, to sit or settle down) matter settled down 
 from solution in water. If water containing mud be allowed to stand 
 without agitation, the mud will gradually fall to the bottom, and be- 
 come sediment. Rocks which have been deposited after this manner, 
 such as sandstone, are said to be sedimentary. 
 
 DEPOSIT (Lat., de, down, and positus, placed) applied to matter 
 which has settled down from water. Mud, sand, gravel, &c. are all 
 deposits, and are distinguished by the kind of agency which produced 
 them ; such as fluviatile (river) deposits, lacustrine (lake) deposits, 
 marine (sea) deposits, and littoral (sea-shore) deposits. 
 
 IGNEOUS AGENCIES. 
 
 6ti. Atmospheric and aqueous agencies may be said to 
 exert themselves similarly in modifying the crust of the 
 globe. Both have a tendency to wear down the dry land ; 
 and if this influence went on year after year, without any 
 counteracting force, a time might arrive when hills and 
 plains would be reduced to one uniform level. But the 
 system of nature is beautifully balanced in all its parts, and 
 as one set of agents degrade, another are employed to ele- 
 vate. Thus the layers of loose material which are at one 
 time spread out in the bottom of lakes and seas, is at an- 
 other raised into open day, to form new lands for the sup- 
 port of vegetable and animal existence. The principal 
 agent employed in this elevating process is the Igneous, 01 
 that which depends upon some deep-seated source of fire 
 Hereafter we shall notice the opinions which have been ad 
 vanced concerning the origin of subterranean fire ; at pre 
 sent we have merely to do with its sensible effects. 
 
 67. Igneous agency may exert itself either chemically ot 
 mechanically ; chemically, as in the production of new com- 
 pounds, gaseous admixtures, &.c. ; t mechanically, as when 
 
 208. Define alluvial with examples, as also sediment and deposit. 
 
 209. What are the antagonist agencies called, which elevate the crus 
 
 of the globe ? 
 
 210. How do igneous agencies act 'chemically and mechanically f 
 
IGXF.OUS AGI.NC1ES. 
 
 53 
 
 it elevates and fractures the solid crust of the earth. Its 
 mode of action may be considered under three heads, 
 namely, Volcanoes, Earthquakes, and Gradually Elevating 
 Forces. 
 
 68. Volcanoes may be described as vents of subterrane- 
 ous fire, through which smoke, gaseous vapours, cinders, 
 ashes, stones, and rocky matter in a state of fusion, are dis- 
 charged. The explosive or expansive force of the internal 
 fire forms a vent for itself in the first instance; this 
 opening is termed the crater, and the matter discharged, 
 gradually collecting around it, produces a mountain of a 
 towering or conical form, like that described by the follow- 
 ing figure. 
 
 View of Mount jEtna. 
 
 60. Such is the general appearance of isolated volcanoes; 
 but they frequently occur in ranges, producing, by the 
 union of their forces, elevated mountain chains like those 
 
 211. Define a volcano. 
 
 212. What is its spontaneous opening called ? 
 
 213. How is their mountainous structure produced 1 
 
 214. What of volcanic ranges? 
 
 3* 
 
54 
 
 GEOLOGY. 
 
 of South America. In these ranges, some of the vents are 
 in active operation, and others have become dormant; so that 
 we are insensibly led from the crater vomiting forth smoke 
 and lava to those now cold and dormant, and thence again 
 back to distant eras when all mountain chains were pro- 
 duced by the same kind of forces. Indeed no one can 
 look upon the mere outward appearance of ^Etna and 
 Vesuvius on the one hand, the Alps, the hills of central 
 France, and the hills of the Scottish Lowlands on the other, 
 without at once assigning their origin to similar causes. 
 
 70. Volcanic forces not only elevate but fracture and con- 
 tort the originally plane strata, at the same time that they 
 throw up rocky matter which is not arranged in distinct 
 layers. It has been already stated that water has a ten- 
 dency to lay down the material which it transports in 
 flat or level strata; hence the sedimentary rocks will 
 originally partake of this level character. Suppose, then, 
 that the following engraving represents a part of the earth's 
 
 crust not broken or upheaved by volcanic forces, the same 
 portion will present a very different appearance when frac- 
 
 tured and elevated by these causes. Here the sedimentary 
 strata are not only thrown out of their original level posi- 
 
 215. Are all the vents in actual operation 7 
 
 216. What geological inference is thence derived ? 
 
 217. How then are mountains and hills to be accounted for T 
 
 218. Explain the two diagrams, and the origin of each. 
 
IGNEOUS AGENCIES. 55 
 
 tion, but are bent, broken asunder, and in many places 
 overlaid by discharges of volcanic matter; hence a very ob- 
 vious distinction exists between rocks of aqueous and rocks 
 of igneous origin. 
 
 71. A volcano may at one time discharge ashes, at an- 
 other time rock fragments, and at a third molten lava ; and 
 it is true that these different materials may be found on its 
 sides arranged in something like strata; but they do not 
 present this regularity for any distance. Sedimentary 
 strata, on the other hand, preserve their character and con- 
 tinuity over many miles of country, showing a calm and 
 tranquil origin in comparison with those masses produced 
 by volcanic fusion. Other distinctions between aqueous and 
 igneous rocks will hereafter be pointed out to the student; 
 but at present he cannot fail to perceive that sand, clay, 
 mud, and other matter deposited from water, must be more 
 equally and flatly laid down than cinders, ashes, and lava, 
 which are vomited forth without order or arrangement. 
 
 72. There are at present upwards of two hundred volca- 
 noes in active operation. The greater number of these are 
 to be found in the mountain ranges of South America, along 
 the western coast of North America, and in the Southern Pa- 
 cific. In central Asia there are also several vents; and ^Etna, 
 Vesuvius, and Ilecla, are well known examples in Europe. 
 The number of active volcanoes is nothing, however, in com- 
 parison with what once existed; for there is scarcely a coun- 
 try (Italy, France, Britain, West India Islands, the Azores, 
 Iceland, &c.) that does not give evidence of innumerable 
 volcanic craters which have long since ceased to modify the 
 crust of the globe. Even these dormant vents are insignifi- 
 cant in comparison with the still older mountain ranges of the 
 Grampians, Pyrenees, Uralian, Himmaleh, Andes, and other 
 chains which must have been upheaved by the same sub- 
 terranean forces. 
 
 73. Of the elevating power of volcanoes we have many 
 
 219. What variety in the volcanic discharges? 
 
 220. How \re aqueous and igneous rocks distinguished ? 
 
 221. Wher i are active volcanoes and how many ? 
 
 222. What proportion do these bear to those now dormant? 
 
 223. Name some of the examples of the elevating power of volcanoes. 
 
56 GEOLOGY. 
 
 examples within the historical period, and comparing active 
 volcanic hills with ancient ranges, we may arrive at some 
 idea of the enormous power exerted by igneous forces in 
 the earlier ages of the world. During an eruption of 
 ^Etna, a space around the mountain, 150 miles in circum- 
 ference, was covered with a layer of sand and ashes, gene- 
 rally about 12 feet thick. In the first century, the cities 
 of Herculaneum and Pompeii were buried beneath such a 
 layer of matter by Vesuvius. In 1660, the philosopher 
 Kircher, after accurately examining ^Etna, and the ground 
 adjoining its base, calculated that the whole matter thrown 
 out by it at its various active periods would form a mass 
 twenty times as large as the mountain itself, which is 10,870 
 feet high, and 30 miles in diameter at the base. From 
 this mountain, in 1775, there issued a stream of lava a 
 mile and a-half in breadth, 12 miles long, and 200 feet 
 thick. At an earlier period, there was a stream which 
 covered 84 square miles. In 1538, a large hill, since 
 named Monte Nuovo, was thrown up in the neighbourhood 
 of Naples in one night; and in 1759, in a district of Mex- 
 ico, previously covered by plantations, a sudden outburst 
 of volcanic action, which lasted several months, terminated 
 in leaving six hills, varying from 300 to 1600 feet in height 
 above the old plain. As on land, so also in the ocean ; and 
 the student will hereafter find that many volcanoes have 
 been known to arise from the sea, that the bottom of the 
 sea has been upheaved by the same influence, and that 
 many islands, such as those of the Pacific and Atlantic, are 
 mere accumulations of volcanic matter. " Owhyhee," says 
 De la Beche, " is a magnificent example of such an island; 
 the whole mass, estimated as exposing a surface of 4000 
 square miles, is composed of lava, or other volcanic matter, 
 which rises in the peaks of Mouria Roa and Mouna Kaa 
 to the height of between 15,000 and 16,000 feet above the 
 level of the sea." (See Appendix-) 
 
 74. Earthquakes are most important geological agents, 
 though their origin and mode of action is scarcely so ob- 
 
 224. What islands are known to have this origin ? 
 
 225. Have earthquakes any relation to volcanoes T 
 
IGNEOUS AUENCIFS. 57 
 
 vious as those of volcanoes. The theories which have 
 been advanced to account for such phenomena will be else- 
 where adverted to; here it is sufficient to state, that, though 
 they occur in all parts of the, world, they are much more 
 frequent and violent in the region of active volcanoes. 
 Earthquakes are strictly mechanical in their mode of action, 
 upheaving some portions of the crust and depressing others, 
 causing rents and fissures, altering the course of fivers, ele- 
 vating the bottom of the sea to open day, and submerging 
 dry land beneath the ocean. They are sometimes so gen- 
 tle in their operations, that a slight tremulous motion of 
 the earth is all that is perceived ; at other times the shock 
 is so violent, that the surface configuration of wide districts 
 is completely altered, and the works of man become masses 
 of ruin. Volumes might be filled with accounts of earth- 
 quakes and their disastrous consequences; we shall simply 
 notice a few historical facts to show their importance. In 
 1596 several towns in Japan were covered by the sea; in 
 1638 St. Euphemia became a lake ; in 1692 Port Royal, 
 in Jamaica, was submerged ; in 1775, the great earthquake 
 of Lisbon, sank many parts of the Portuguese and African 
 shores 100 fathoms under water; in 1819, at the mouth 
 o. the Indus, a large tract of country, with villages, was 
 submerged, while a new tract was elevated, called the 
 *' Ullah Bund;" in 1822 about 103 miles of the Chili coast 
 was elevated to the height of four or six I'eet ; and in 1843 
 several of the West India Islands were fearfully convulsed, 
 and a vast amount of lile and property destroyed. 
 
 75. The gentral efftct of earthquakes, like that of volcanic 
 forces, is to render the crust of the earth irregular in sur- 
 face, by depressing some portions and by elevating others. 
 It requires little effort of imagination to conceive how a 
 level tract of country might by a few shocks, be converted 
 
 226. What geological changes have been thus occasioned 1 
 
 227. What variety has been observed in this agency ? 
 22H. What instances are cited ? 
 
 229. What resemblance in their general effects to volcanoes t 
 
 230. What geological changes would obviously result from an earth- 
 
 qua te. 
 
58 
 
 GEOLOGV. 
 
 into abrupt heights, rents, chasms, and hollows, or even 
 sunk many fathoms beneath the ocean. Earthquakes in 
 the vicinity of the sea are generally accompanied with vio- 
 lent agitation of the water, and waves of enormous height 
 are rolled upon the land (60 feet in the Lisbon earthquake), 
 tearing up the surface, and forming masses of loose material. 
 
 76. As earthquakes now act, so must they have done in 
 all time past; and if the great mountain ranges prove the 
 existence of more extensive volcanic agency, we are war- 
 ranted to conclude that earthquakes were also more frequent 
 and disastrous in the earlier ages of the world. If fissures, 
 chasms, and subsidences be at present produced by earth- 
 quakes, the student will have little difficulty in accounting 
 for the numerous rents and breakings which occur in the 
 solid strata in regions where volcanoes and earthquakes have 
 
 ong since ceased to exert their agency. 
 
 77. Gradually elevating forces appear to be intimately 
 connected with those which produce volcanic eruptions and 
 earthquakes. The term is applied where we find tracts of 
 country and shores of the sea undergoing a slow process of 
 elevation, without being accompanied with any perceptible 
 violence. Mr. Lyell has discovered instances of this kind 
 of elevation along the shores of the Baltic, where places, 
 which a century ago were on a level with the sea, are now 
 several feet above it, and where even a change of a few 
 inches has taken place since 1820. 
 
 78. To what extent such jorces may have operated in 
 times past we have no knowledge; and even at the present 
 moment, differences in the relative level of sea and land 
 may be occurring in certain districts so gradually, that they 
 escape our observation. Wherever the sea has acted upon 
 the land for any length of time, it forms a shore or beach, 
 generally an inclined plane, along which the tide rises and 
 falls. If the land be raised up, or the sea depressed, the 
 form of this beach will be preserved, and easily traceable 
 both from its level appearance and Irom the nature of the 
 
 231. Is it not rational then to ascribe such to this cause? 
 
 232. Maj not gradual elevations be accounted for in the same way 1 
 
 233. What evidence is furnished of such changes upon the sea-shore ? 
 
ORGANIC AGENCIES. 5^ 
 
 gravel, sand, and shells of which it is composed. Such 
 ancient beaches have been found in various parts of the 
 world, at elevations from 8 to 60 feet, clearly showing that 
 changes in the relative level of sea and land have often 
 taken place over vast areas, but affording little evidence 
 whether the changes have been suddenly or gradually ac- 
 complished. Along the shores of the Forth and Clyde in 
 Scotland, the east coast of England, and the coast of 
 France, Portugal, and America, there is a very remarkable 
 beach of this description, from 40 to 50 feet above the 
 present sea-level, and presenting a sort of step or terrace, 
 which is easily traceable sometimes for miles together. 
 This terrace is composed of rounded pebbles, gravel, sand, 
 and sea-shells, and such material as usually compose the 
 beaches at the present day. 
 
 79. As some parts of the land may be elevated, so others 
 may be depressed; and consequently we find stumps of 
 trees under the present sea-level, clearly showing that the 
 land on which they grew had been submerged. But whether 
 these ancient elevations and depressions have been accom- 
 plished in one hour, or in many years, whether quietly or 
 with violence, geologists have not yet been able to determine. 
 
 EXPLANATORY NOTE. 
 
 VOLCANO, from Vulcan, the god of fire, who was supposed by the 
 ancients to reside in a cavern under Mount ^Etna, and to forge thun- 
 derbolts for Jupiter. 
 
 LAVA, an Italian term, now universally applied to those masses of 
 melted matter which are discharged by volcanoes during an eruption. 
 Loose fragments of rocks, cinders, dust, and ashes, are comprehended 
 under the term scoria. 
 
 CRATER ((Jr., krater, a cup or bowl) the mouth or vent of a volcano, 
 so called from the resemblance which its shape bears to an ancient 
 drinking bowl. The craters of volcanoes have, in general, one edge 
 a little lower than the other, owing to the prevailing winds carrying 
 the greater portion of the light material to the opposite side. 
 
 ORGANIC AGENCIES. 
 
 80. Compared with the other classes of agents which 
 have been described, the Organic are comparatively unim- 
 
 234. Whence is the term volcano derived 1 
 
 235. Define lava and scoria. 
 
 236. What of craters? 
 
63 GEOLOGY. 
 
 portant in modifying the crust of the globe. They exert an 
 elevating or accumulnting influence, and may act either on 
 the dry land, in fresh or in salt water, according to the na- 
 ture of the vegetables or animals from which they result. 
 They are comparatively slow in their operations, but pro- 
 duce the most interesting class of phenomena with which 
 geological research has made us acquainted. Organic 
 agency presents itself under two great heads namely, 
 Vegetable and Animal. 
 
 81. Vegetable growth acts in two ways : first, by forming 
 accumulations of matter, such as peat; or, second, by pro- 
 tecting the soil from the degrading power of rains and 
 winds. Extensive areas of sand-drift would be continually 
 shifting, were it not for the vegetable sward which gathers 
 over their surface; and all soils, during seasons of drought 
 or rain, would be liable to be blown or washed away, were 
 it not for the grassy turf which covers them. Marine plants 
 are extremely perishable, and exert no perceptible influence 
 on the earth's crust. Terrestrial plants are of a very differ- 
 ent character both in point of size, number, and material ; 
 and to them are chiefly owing the vegetable deposits in all 
 ages of the world. 
 
 82. Trees and plants are annually carried down by rivers, 
 and deposited along with the layers of sand and mud which 
 have already been noticed. The rafts of the Mississippi 
 are frequently several miles in length, and from 6 to 10 feet 
 thick, being composed of trees, roots, and brushwood. All 
 marshes and shallow waters give birth to innumerable 
 aquatic plants, which grow and decay from year to year, 
 till, in the course of centuries, their remains form thick 
 accumulations of peat. Peat bogs, of many miles in sur- 
 face, and from 4 to 20 feet in thickness, are frequent in 
 Scotland, Ireland, and other countries, and contain trees 
 and the remains of animals which once inhabited the coun- 
 
 237. What two classes of organic agency are named ? 
 
 238. How does vegetable growth act ? 
 
 239. Wherein do marine and terrestrial plants differ ? 
 
 240. What of the rafts of the Mississippi ? 
 
 241. How does peat accumulate ? 
 
ORGANIC AGEWIE*. ' 61 
 
 try. Vegetable growth is greatly influenced by climate, 
 being more prolific and gigantic in warm than in cold re- 
 gions, and being also entirely different in character. While, 
 therefore^ peat is forming in the bogs of Ireland, the Missis- 
 sippi is carrying down the pines of America, and the Gan- 
 ges the palms, canes, and tree-ferns of the Indian jungle. 
 [In consequence of some obstruction in the arm of the 
 river, called the Atchafalaya, supposed to have been formerly 
 the bed of the Red river, a raft had accumulated in 35 
 years, which in 1816, was 10 miles long, 220 yards wide, 
 and 8 feet thick! Although floating, it is covered with 
 living plants, and of course with soil.] 
 
 b3. Of the vegetation of past eras we can only judge 
 from the fossil remains found in the solid rocks; and, 
 comparing that of the coal strata with what now exists, we 
 are warranted in concluding that the earth has at certain 
 times nourished a more luxuriant and gigantic vegetation. 
 Indeed coal, as wilT hereafter be shown, is just as much .a 
 mass of altered plants and trees as peat is; and when the 
 student is told of many beds of coal lying one above another, 
 some of which are ten, fifteen, arid twenty feet in thickness, 
 he may readily conjecture, what an immense mass of vege- 
 tation has been compressed into this one formation. The 
 present formation of vegetable deposits, and the dependence 
 of plants upon temperature and climate, are facts which it 
 is necessary to bear in mind; otherwise it will be impossi- 
 ble to account for many appearances which are presented 
 in the stratified crust of the globe. 
 
 84. Animal life is also an active agent in adding to the 
 solid material of the globe. Generally speaking, the remains 
 of animals are very perishable; hence, though their bones, 
 teeth, and scaly coverings are numerously found as fossils, 
 yet these form a mere fraction of the rocks in which they 
 are imbedded. It is not in this light, therefore, that animal 
 
 242. What difference does climate produce in vegetation ? 
 
 243. What of fossil remains ? 
 
 244. What of coal strata ? 
 
 245. In what way does animnl life add to the solid material of the globe 
 
 to a limited extent ? 
 
GEOLOGY. 
 
 existence may be said to be influential in modifying the 
 crust of the earth ; and we may reckon of slight importance 
 all the skeletons of the larger animals which are deposited 
 along with the mud, sand, and gravel in the bottoms of ex- 
 isting lakes and seas. It is the minutest forms of life which 
 are mainly instrumental in forming deposits of this class; 
 such as the coral-insect, shell-fish, and some crustaceous 
 animals. 
 
 85. By the labours of the coral animalcule are formed 
 those extensive reefs of solid coral, or limestone, well 
 known to the navigators of the Pacific. These reefs rise in 
 masses of various shapes ; sometimes as islets, at other 
 times as circular belts enclosing a lagoon or lake of salt 
 water, but more frequently in long abrupt ridges from 23 
 to 100 feet in thickness. The great reef, which follows 
 the line of the northern coast of New Holland, is more than 
 1000 miles in length, in the course of which there is one 
 continued portion exceeding 353 miles, without a break or 
 passage through it. The animalcule is scarcely so large as 
 a pin's head ; it is star-shaped, is of a soft gelatinous struc- 
 ture, and myriads, of them unite in their operations to form 
 a single branch of coral. By examining a piece of coral, 
 its surface will be found dotted with small star-like openings, 
 each of these contains a single animal, and the space be- 
 tween them is covered by the membrane above referred to. 
 These animalcules have the power of secreting limy mat- 
 ter from the waters of the ocean ; they are incessantly at 
 action, and many of the reefs rise several feet in the course 
 of a few years. They do not commence their labours at 
 great depths, but attach their structures to rocks from 60 
 to 100 feet below the surface; and thus the coral reefs 
 partake of the shape of the submarine ridges on which they 
 are founded. As their structures approach the surface, the 
 waves and currents of the ocean detach large pieces, which 
 are either drifted on the land, and form coral beaches, 01 
 
 246. What are the principal forms of animal life which are of impor 
 
 tance geologically ? 
 
 247. What remarkable reefs of coral are named ? 
 
 248. What of these animalculae and their labours ? 
 
 249. How are these reefs elevated above the' surface ? 
 
ORGANIC AGENCIF.8. 63 
 
 are piled upon the surface of the growing reef, till it rises 
 above the sea. When the animal readies the surface it 
 ceases its operations, and the subsequent elevation into 
 islands and dry land is performed by the waves and tides, 
 and by the elevating forces described in the preceding sec- 
 tion. 
 
 86. Coral is almost entirely composed of pure limestone, 
 and is found in all stages of solidity, from an open porous 
 mass, with the live animal upon it, to a hard and compact 
 limestone, with scarcely a trace of its animal origin discern- 
 ible. There are many species of the coral animalcule, 
 each variety rearing its structure after a different form; and 
 from this fact such names have been given as tree coral, 
 fan coral, organ-pipe coral, brain coral, &c. Whatever be 
 the shape, the substance formed, and their mode of action, 
 is the same. They are found largely over the Southern 
 Pacific, in the Indian Sea, the Red Sea, and other por- 
 tions of the ocean. As at present, so in former ages of 
 the world ; and the student will hereafter find that many 
 of the beds of limestone now deep in the crust of the 
 globe, have been formed by the same kind of organic 
 agency. 
 
 87. Shtll-Jish, like the coral animal, have the power of 
 secreting limy matter from the ocean. In the former case, 
 the secreted matter forms a covering or enclosure for the 
 animal ; in the latter, the animal is external, and the struc- 
 ture forms a mere groundwork for its operations, and a 
 wider field for the increase of its kind. There is an immense 
 variety of shell-fish, but only a few varieties exist in great 
 numbers, and it is by the agency of these that shell-beds 
 are formed. The oyster, muscle, and cockle, are familiar 
 examples; they live in great shoals or beds, covering from a 
 few acres to many miles of the bottom of our seas and friths. 
 Zoologists have found that most shell-fish live in shallow 
 waters around the shores; and from this habit they are 
 
 250. What of the nature and variety of coral ? 
 
 251. Are there different species of animalculae t 
 
 252. Where are they most numerous ? 
 
 253. In what particulars does the labour of shell-fish differ from these ? 
 
 254. Name some examples of shell-fish who make these beds. 
 
64 
 
 GEOLOGY. 
 
 more liable to be covered by the material borne down by 
 floods and rivers. In raised beaches, and in deltas, we 
 actually find such accumulations of shells, sometimes seve- 
 ral feet in thickness, and presenting the same appearance 
 as when they Jived and multiplied in the waters. If, then, 
 extensive layers of shell-fish now exist, and if they are 
 sometimes found imbedded in the alluvial matter of deltas 
 and lakes, the student will be better enabled to account for 
 the occurrence of thick masses of shells, or limestone 
 wholly composed of shells, among the solid rocky strata. 
 
 88. Although corals and shell-fish are the most important 
 animal agents in adding to the material of the earth's crust, 
 yet the exuviae of other animals must not be overlooked , 
 for, it is often from the occurrence of these alone, that we 
 are enabled to infer as to the former conditions of the 
 world. Thus, the remains of elephants, lions, and tigers, 
 may be carried down by the waters of the Ganges, and de- 
 posited in its delta; those of the rhinoceros, hippopotamus, 
 and ostrich, by the Niger; and those of the buffalo, elk, 
 and reindeer, by the Mississippi ; while the rivers of Bri- 
 tain convey no such remains to the ocean. The sand, 
 mud, and gravel of all these deltas are very much alike ; 
 and if they should hereafter form rocks, the geologist 
 could tell of the condition of the country in which they 
 were formed only by the kind of fossils which these rocks 
 contained. 
 
 89. The formation of coral-reef s and shell-beds is a grad- 
 ual and ordinary operation ; but shoals of other fishes may 
 be entombed during violent storms, or during submarine 
 volcanic eruptions, which are attended by noxious vapours, 
 heat, and a suffocating agitation of the mud of the ocean. 
 The modes in which vegetable and animal life may affect 
 the crust of the globe are extremely complex and varied, 
 but the above are the most obvious and important 
 
 255. What of the exuviae of other animals ? 
 
 256. Of what use are these in geological researches ? 
 
 257. What of shoals of fishes, and how entombed ? 
 
RECAPITULATION. DO 
 
 RECAPITULATION. 
 
 90. As detailed in the preceding section, the causes chiefly- 
 employed in modifying the structure of the globe may be 
 divided into four classes ATMOSPHERIC, AQUEOUS, IGNE- 
 OUS, and ORGANIC. The former two exert a degrading or 
 wasting influence, and if not counterbalanced by other 
 forces, would ultimately wear down the dry land to a level 
 with the ocean ; the latter exert an elevating or accumu- 
 lating influence, and thus maintain that elevation and diver- 
 sity of dry land essential to animal and vegetable life. To 
 assist the memory, these agents may be briefly arranged as 
 follows : 
 
 DEGRADING CAUSES. 
 
 Atmospheric. Aqueous. 
 
 Winds, Rains, Snow, &c. 
 
 Frosts, Springs, 
 
 Heat and Light, Rivers, 
 Gaseous Admix- Waves, Currents, 
 tures. Tides. 
 
 ELEVATING CAUSES. 
 
 Igneous. Organic. 
 
 Volcanoes, Vegetable accu- 
 
 Earthqnakes, mulations, as 
 
 Gradually ele vat- peat, &c. 
 ing forces. Animal, as co- 
 ral-reefs, shell- 
 beds, &c. 
 
 91. If, then, on the one hand, winds, frosts, rains, rivers, 
 and reaves be continually wasting down the solid crust, and 
 depositing the debris in layeis along the bottom of lakes 
 and seas ; and if, on the other, these layers be consolidated 
 by pressure, by chemical processes, or by heat, and be then 
 elevated into dry land by volcanoes and earthquakes^ it 
 must be obvious that the surface of the globe is in a state 
 of perpetual change. These changes may be slow and im- 
 perceptible, or sudden and obvious; but in either way the 
 appearances exhibited by the earth's surface must be very 
 different now from what it was many thousand years ago. 
 "What was then coveied by the ocean, may now be dryland; 
 and what was dry land, may have since been ocean, and 
 may now be dry land again. These changes will be mani- 
 
 258. Recapitulate the four classes of agencies modifying the structure 
 
 of the globe. 
 
 259. Repeat the table in which they are arranged. 
 
 260. How is it proved that the mrface is perpetually changing T 
 
 261. How must these changes be manifested ? 
 
66 GEOLOGY. 
 
 Tested by the kind of layers or rocks deposited at each sue, 
 cessive period in the bottom of the sea ; hence the geolo- 
 gical history of the world can only be discovered by the 
 study of these strata. But as these strata were upheaved 
 by volcanic agency, rocky masses of igneous or volcanic 
 origin are frequently mingled with them ; hence we find 
 not only stratified rocks from deposition in water, but un- 
 stratified, the result of igneous fusion. Again, all* strata 
 originally deposited by water will contain more or less the 
 remains of plants and animals which flourished during the 
 period they were deposited ; and the consideration of these 
 petrifactions affords the geologist an idea of the kind of life 
 which then peopled the surface of the earth, or inhabited 
 the waters. These unstratified and stratified rocks, with 
 the animal and vegetable remains which they contain, form 
 the solid crust of the globe the structure, composition, and 
 formation of which it is the province of geology to consider. 
 
 EXPLANATORY NOTE. 
 
 SECRETION (Lat., secretus, separated or set aside). Both animals 
 and vegetables are said to secrete certain substances. Coral, for ex- 
 ample, is an animal secretion composed of lime, which the animalcule 
 has the power of separating from the water of the ocean ; resin and 
 gum are vegetable secretions. 
 
 EXUVI.E (Lat., cast clothes). In Zoology this term is applied to the 
 ejctermd integuments of animals which are periodically shed or cast off, 
 such as the skin of the snake, the crustaceous covering of the crab, 
 &c. ; but in geology it is employed to designate fossil animal remains 
 of whatever description. 
 
 MINERAL SUBSTANCES COMPOSING THE 
 EARTH'S CRUST. 
 
 92. THE MINERAL OR ROCKY SUBSTANCES which com- 
 pose the crust of the globe are exceedingly numerous and 
 varied. They are commonly known by the name of rocks, 
 minerals, metals, earths, and salts; but, geologically, are all 
 
 262. How must the geological history be discovered ? 
 
 263. What variety of strata are found, and why ? 
 
 264. What do we learn from the petrifactions 1 
 
 265. Define secretion and exuvia. 
 
 266. What minerals are included in the term rock ? 
 
SUBSTANCES COMFUSINttTHE EARTHS CRUST. 
 
 67 
 
 comprehended under the general appellation rock. The 
 individual minerals and elementary substances of which 
 rocks are composed, come more appropriately under the 
 sciences of mineralogy, metallurgy, and chemistry. Pass- 
 ing over the mere surface soil, and proceeding downwards 
 to the greatest known depth, the solid crust may be said 
 to be composed of two great classes of rocks those ar- 
 ranged in layers, and those occurring in irregular masses; 
 in other words, the STRATIFIED and UNSTRATIFIED. The 
 stratified are those which have been formed from deposition 
 in water; hence they are also known by the terms aqueous 
 and sedimentary. The unstratified are those which have 
 been formed by fire, and are also known by the terms igne- 
 ous and volcanic. The following engraving represents the 
 appearance which the stratified and unstratified rocks pre- 
 sent in a section of the earth's crust. 
 
 Unstratified. 
 
 Stratified. 
 
 93. All rocks, whatever be th$ir origin, have three charac- 
 ters under which they are viewed by the geologist namely, 
 the Mechanical, Mineral, and Chemical; and though it is 
 impossible, in an elementary work of this kind, to enter 
 fully into the consideration of these characters, still it is 
 necessary that the student should be in some degree ac- 
 quainted with the technical terms which are employed to 
 designate these characters. 
 
 267. By what sciences are they analyzed ? 
 288. What two great classes of rocks ? 
 
 269. How are the stratified divided T 
 
 270. How are the unstratified divided 1 
 
 271. Under what three characters are all rocks regarded by geolo- 
 
 gists l 
 
f>3 GEOLOGY. 
 
 94. The mechanical structure of rucks is that which pre- 
 sents itself in the general appearance of the mass as it 
 occurs in the earth, or in portions of the mass when it is 
 broken up by artificial means. It has nothing to do with 
 the composition, arid merely considers the appearances pre- 
 sented, whether the rock be roofing-slate, chalk, or coal. 
 For example, some rocks are arranged in layers, and these 
 layers can be split up into still thinner plates, as slate; 
 others occur in columns, like the basalt of Staffa and the 
 Giant's Causeway ; and these columns can be broken up 
 into small prismatic pieces. This structure is purely me- 
 chanical, and has been divided by geologists into the ex- 
 ternal and internal the former having reference to the 
 mere outward form, and the latter to the shape of the smaller 
 fragments into which the mass can be broken. The ex- 
 ternal structure of coal, for instance, is stratified, but the 
 internal structure varies : caking coal breaking up into small 
 cubes or square pieces, split coal into thin slaty divisions, 
 and cannel coal into irregular fragments, having a shell- 
 like surface. 
 
 95. The terms employed to describe these varieties of 
 structure are useful, in as far as they enable one writer to 
 make himself understood by another. The following are 
 those of most frequent occurrence : 
 
 Massive) occurring in large masses of no determinate form, as gra- 
 nite. 
 
 Amorphous, without any regular shape ; amorphous and massive are 
 very similar terms. 
 
 Cuboidal, in square masses resembling cubes, as some greenstones. 
 
 Prismatic, occurring in masses, with faces and angles like a prism 
 
 Columnar, in columns or pillars, like basalt. Where the pillars are 
 not very distinct and regular, the term sub-columnar is used. 
 
 Stratum, bed, seam, and layer. These are nearly synonymous terms, 
 all conveying the idea of being spread or laid out in parallel masses, as 
 sandstone, slate, &c. 
 
 Schistoze. fissile, slaty, laminar, are employed to describe rocks capa- 
 ble of being split up into thin plates or divisions like slate. 
 
 foliated, when the laminae or slates split up into still thinner leaves. 
 
 272. Describe the varieties included in mechanical structure. 
 
 273. Define external and internal structure as exemplified in coal. 
 
 274. Explain massive and amorphous. 
 
 275. Explain the italicised terms as defined. 
 
COMPOS) NI; Tiit EARTH'S CRUST. 60 
 
 Squatnose, when the fragments have a scaly appearance, like mica* 
 
 Fibrous, having a fibrous texture, like asbestus ; acicular) when the 
 fibres have a distinct needle-shaped appearance. 
 
 Vesicular, cdlular, when the texture of the rock is full of small cells 
 er vesicles. 
 
 Granular, when the texture is made of distinct grains, as granite. 
 
 Saccharoid, when the grains have a uniform crystalline aspect, like 
 loaf-sugar. 
 
 Porous, of an open texture, or full of pores, as pumicestone. 
 
 Friable, when easily broken down; earthy, of a soft dull texture; and 
 compact, when of a close and firm texture. 
 
 96. The mineral character of rocks has reference to the 
 number and aggregation of the simple minerals of which 
 they are composed. A piece of granite, for example, is 
 composed of distinct crystals of felspar, quartz, and mica, 
 which are said to be simple minerals. In general, mine- 
 rals occur in fixed shapes, as cubes, prisms, &c. in the 
 igneous rocks ; while in the aqueous, their edges and an- 
 gles are broken and water-worn. Some rocks are simple 
 that is, composed only of one mineral, such as limestone; 
 others compound, or formed of several minerals, as granite; 
 and some, apparently simple, are in reality compounds of 
 several minerals minutely blended together, as certain kinds 
 of sandstone, 
 
 97. There are many hundreds of simple minerals differ- 
 ing from each other in shape, colour, lustre, hardness, com- 
 position, &c. The consideration of these characteristics 
 more properly constitute the science of mineralogy; but it 
 is imposible for the student in geology to make much use- 
 ful progress without being acquainted with those minerals 
 which enter most largely into the composition of rocks. 
 These are the following : 
 
 Quartz; the hard white crystals of granite, and the white grains of 
 sandstone, are of quartz. 
 
 Felspar; the soft grayish crystals of granite, which can be easily 
 scratched, are of felspar. 
 
 Mica; the glistening, scaly, and transparent portions of granite 
 
 276. What are the simple minerals, as in granite 
 
 277. What difference in shape, and why f 
 
 278. What examples of simple and compound ? 
 
 279. How do simple minerals differ 1 
 
 280. Define the names of the simple minerals at her* explained. 
 
 4 
 
70 GEOLOGY. 
 
 are of mica ; it occurs in minute scales in many sandstones, giving to 
 them a silvery aspect. 
 
 Hornblende, a black or dark-green mineral found in some granites 
 in the room of mica; granite is then called syenite. Hornblende is so 
 named from its horny fracture. 
 
 Actynolite, so called from the pointed or thorny appearance of its 
 crystals ; it is of a greenish-gray colour, and found in some of the early 
 slates. 
 
 Augite, a greenish mineral found in many igneous rocks ; it is the 
 type of a class to which the hornblende and actynolite belong'. 
 
 Diallage, also called Schiller Spar, an olive, blackish, or yellowish- 
 green mineral of a foliated structure, and having a metallic lustre. 
 
 Schorl, occurs in black prismatic crystals ; is brittle and lustrous, 
 and becomes elastic by heat and friction 
 
 Chlorite, so called from its greenish-black colour; it is either of 
 a crystallized or foliated structure ; and in the latter state it forms the 
 greater portion of that greenish slate called chlorite slate. 
 
 Green-earth, a greenish earthy mineral allied to chlorite, which 
 enters largely into the composition of many trap-rocks. 
 
 Talc, a transparent mineral resembling mica, but softer, and not 
 elastic. 
 
 Steatite; all rocks containing this mineral feel greasy or soapy, and 
 are thus easily distinguished ; they are sometimes called soap-stones. 
 
 Garnet, a reddish or wine-coloured mineral found in some mica 
 slates and volcanic rocks. 
 
 Carbonate of lime; pure marble, chalk, &c.are carbonates of lime. 
 
 Carbonate of magnesia; lithographic limestone is a compound of car- 
 bonate of magnesia and carbonate of lime. 
 
 Sulphate of lime; gypsum, or plaster of Paris, is sulphate of lime. 
 
 Chloride of sodium; common salt is chloride of sodium; it is found 
 in sea-water, and in masses constituting rock-salt. 
 
 Bitumen, an inflammable mineral, found either liquid, or in petro- 
 leum or rock-oil ; solid, as in asphalte ; or mixed, as in common coal. 
 
 Iron, oxide and snlphurets of; rust is an oxide of iron; pyrites, or 
 those little yellow cubes found"in roofing-slate, are sulphurets. 
 
 98. The most abundant rocks are formed by the aggre- 
 gation of the above minerals. It would be impossible to 
 convey an adequate idea of these rocks by a mere verbal 
 description : and at this stage the student should endeavour 
 to make himself familiar with the following rocks (of 
 which there are many varieties), by the inspection of actual 
 specimens : 
 
 GRANITE, FELSPAR ROCK, QUARTZ ROCK, 
 
 SYENITE, CLAYSTONE, SANDSTONE, 
 
 281. Repeat the definitions of minerals here given. 
 
 282. Enumerate the names of the rocks, formed of these simple mine- 
 - rals variously compounded. 
 
SUBSTANCES COMPOSING THK EARTH*S CRUST. 71 
 
 GRENESTONE, ORNSTONE, CLAY-SHALE, 
 
 BASALT, TCHSTONE, SLATE, 
 
 HYFERSTHENE ROCK, GNEISS, FLITTT, 
 
 DIALLAGE ROCK, MICA SCHIST. CHERT, 
 
 SERPENTINE, CHLORITE SCHIST, LIMESTONE, 
 
 WACKE, HORNBLENDE SCHIST, COAL. 
 
 99. The chemical character of rocks has no reference 
 either to their mechanical structure or mineral aggregation. 
 According to the deductions of chemistry, all bodies in 
 nature, whatever their structure or appearance, are com- 
 posed of fifty-four simple or elementary substances. Gra- 
 nite, mineralogically speaking, is composed of quartz, 
 felspar, and mica ; but these three minerals are each com- 
 posed of several chemical elements quartz, for example, 
 being a compound of the gaseous body oxygen, and a metal 
 called silicum. 
 
 100. Of the elementary bodies, under the ordinary pres- 
 sure and temperature of the atmosphere, there are 
 
 Five gaseous hydrogen, oxygen, nitrogen, chlorine, and fluorine; 
 
 Seven non-metallic-, liquids and solids bromine, iodine, sulphur, 
 phosphorus, selenium, carbon, and boron ; 
 
 Thirteen solid metalloids, which unite with oxygen to form the 
 earths and alkalies sodium, potassium, lithium, aluminum, silicium, 
 yttrium, glucium, thorium*, calcium, magnesium, zirconium, stron- 
 tium, barium ; 
 
 Twenty-nine metals, which are all solid save mercury manganese, 
 zinc, iron, tin, cadmium, arsenic, antimony, copper, molybdenum, 
 uranium, tellurium, chromium, cerium, nickel, vanadium, cobalt, lead, 
 tungsten, titanium, mercury, columbium, bismuth, osmium, silver, 
 palladium, rhodium, platinum, gold, and iridium. 
 
 101. Only a few of the fifty-four so-called elements enter 
 largely into the composition or the rocky masses which 
 constitute the crust of the globe. The most prevalent are 
 oxygen, carbon, sulphur, aluminum, silicium, potassium, 
 sodium, calcium, magnesium, and iron. Of these, oxygen 
 
 283. What of the chemical character of rocks T 
 
 284. How many chemical elements T 
 
 285. State an example of the difference between these, and mineralo- 
 
 gical elements. 
 
 286 Into how many classes are the elementary bodies divided 1 
 287. Name the most prevalent in rocks. 
 
72 GEOLOGY. 
 
 is by far the most prevalent; it is found in combination 
 with every other substance, and is supposed to constitute 
 fully one-half of the ponderable matter of the globe. 
 
 102. From what has been staled in the foregoing para- 
 graphs respecting the mechanical, mineral, and chemical 
 characters of rocks, it will be seen how necessary a know- 
 ledge of these is to the right investigation of the constitu- 
 tion of the earth. It is true that geological research may 
 be carried on without an intimate knowledge of mineralogy 
 or chemistry, but it is evident that a certain amount of 
 mineralogical and chemical information will greatly assist 
 the pursuit. To illustrate this by a familiar example: 
 Granite, geologically speaking, is unstratified, massive, gra- 
 nular, composed of several ingredients ; from its general 
 structure, it is regarded as arising from igneous fusion, and 
 is considered as the basis of all the stratified rocks. To 
 the mineralogist these facts are of little importance; he 
 proceeds to consider it as composed of three distinct mine- 
 rals quartz, felspar, and mica and to arrange these mine- 
 rals into classes according to their shape, colour, lustre, 
 hardness, &c. But a knowledge of these minerals greatly 
 assists the geologist; for, while he finds them regularly 
 crystallized in granite, he finds them broken and water- 
 worn in gneiss, and concludes that gneiss must have been 
 formed of the disintegrated particles of granite. Again, to 
 the chemist, geological conclusions and mineral classifica- 
 tion are but secondary objects; he takes up the simple 
 minerals, and resolves them into their simplest elements, 
 and finds that quartz consists of silicium and oxygen; fel- 
 spar of silica, alumina, lime, potash, oxide of iron, and 
 water; mica of silica, alumina, magnesia, potash, oxide of 
 iron, and oxide of magnesia. A knowledge of these che- 
 mical facts also greatly assists the geologist; as they enable 
 him to account for many changes which take place among 
 rocks, and from whence their minerals have been derived. 
 For instance, iron and clay-slate are not perceptible in gra- 
 
 288. How is mineralogy shown to be important to the geologist ? 
 
 289. What illustration is cited 1 
 
 2190. What of chemical analogies of quartz, felspar, and mica"? 
 291. How is chemistry shown to be important to the geologist ? 
 
MEANS OF GEUfTUUlCAL INVES i'lGATlON. 73 
 
 nite; yet, by chemical means, the ores of iron and clay- 
 slate may both be derived from the felspar and mica which 
 constitute the granite. 
 
 EXPLANATORY NOTE. 
 
 CHARACTERS OF ROCKS. The student will readily learn to distinguish 
 the mechanical characters of rocks, that is, that which relates to their 
 external forms and internal texture. For example, he can have little 
 difficulty in determining whether a rock be columnar or massive, 
 granular or fibrous ; he may, however, frequently be puzzled to decide 
 as to its mineral composition. Certain simple minerals, as quartz, 
 mica, iron pyrites, &c. are easily recognised ; but in the majority of 
 cases many tests are required, such as taste, smell, adhesion to the 
 tongue, colour, lustre, form, hardness, and so on. For this purpose a 
 knowledge of mineralogy is necessary ; an acquirement which, at this 
 stage, the student is not expected to possess. It will therefore be ad- 
 visable that he familiarize himself with the most prevalent minerals and 
 rocks by the inspection of actual specimens, cabinets of which can be 
 obtained from the dealers for a trifling sum. To ascertain the precise 
 chemical constitution of any rock, is a matter requiring considerable ex- 
 perience in the laboratory ; but possessed of a retort and spirit-lamp, 
 a blowpipe, a few test-tubes, and acids, the student may readily de- 
 tect the presence of such substances as lime, iron, copper, lead, sul- 
 phur, soda, potash, &c. 
 
 MEANS OF GEOLOGICAL INVESTIGATION. 
 
 103. The means placed within man's reach for investi- 
 gating the history of the globe, are of a very satisfactory de- 
 scription. The accessible crust being for the most part 
 formed of stratified rocks occurring in definite order one 
 above another, each composed of certain minerals, and 
 containing different kinds of fossil plants and animals, it 
 enables us to determine the relative time required for the 
 formation of certain strata, and to predict, from the kind 
 of fossils, what must have been the state of the earth as to 
 climate and other geographical features at the period when 
 these remains were imbedded. Strata, for example, which 
 
 292. What tests are necessary in deciding the mineral composition of 
 
 rocks T 
 
 293. To what science do these belong ? 
 
 294'. What apparatus is necessary for the chemical analysis of rocks? 
 
 295. What are our means of geological investigation T 
 
 296. What are instances of geological inferences t 
 
74 OF.OLOGY; 
 
 contain the remains of marine shells and fishes, indicate 
 that they have been deposited in seas; those containing 
 freshwater shells and plants, that they have been formed in 
 lakes and estuaries ; and as certain plants and animals now 
 flourish in a tropical climate, so will similar fossil remains 
 indicate that they have lived under a similar temperature. 
 Fine-grained and thinly-laminated beds, such as clay slate, 
 must have been deposited under different conditions from 
 a bed of gravelly conglomerate ; and the circumstances 
 which went to the formation of coal, must have been widely 
 different from those under which chalk was formed. Fur- 
 ther, some strata lie in a slanting position; and as we know 
 that all matter deposited from water arranges itself in nearly 
 horizontal beds, these strata must have been turned up by 
 some elevating cause. No extensive elevation of the crust, 
 however, can take place without causing rents and fractures, 
 contortions, and oiher dislocations of the strata ; and from 
 the magnitude of these, some idea may be formed of the 
 volcanic forces which caused them. Thus it is, by the 
 stratified rocks, the order in which they occur, the kind of 
 material of which they are composed, and the organic re- 
 mains imbedded in them, that the geologist is enabled to 
 proceed with his investigations. 
 
 104. Had the stratified rocks lain in regular undisturbed 
 succession, like the coats of an onion, man would have made 
 but little progress in deciphering their history, as the 
 greatest perpendicular descent he has yet made into the 
 crust of the earth does not extend to half-a-mile. But as 
 these rocks are thrown up into slRnting and irregular posi- 
 tions, so that the lowest are brought to the surface equally 
 with those most recently formed, geologists have been able 
 t ) collect a regular series of stratified rocks, from those de- 
 posited, as it were, but yesterday, downwards to the unstra- 
 tified granite which forms their basis. There are two great 
 means of investigation : artificial sections, as exhibited in 
 coal-pits, quarries, and tunnels ; and natural sections, as 
 
 297. What peculiarities in the stratified rocks are relied on ? 
 
 29S. How are w e enabled to investigate the deep unstratified rocks ? 
 
 299. Define the two kinds of sections. 
 
MEANS OF GEOLOGICAL INVESTIGATION. 7/ 
 
 occasionally exposed by the sea-shore, by ravines, and by 
 river channels. 
 
 105. Artificial sections assist geological inquiry in Jhi3 
 manner: Suppose a series of strata, , 6, c, d, should occur 
 in a horizontal position (fig. 'A), we may become acquainted 
 
 Fig. A. 
 
 with their composition and order by a shaft or pit piercing 
 them; but by this means we cannot arrive at any great depth 
 into the earth's crust, from the expense of working deep 
 shafts, and the difficulty of carrying off their water. Were 
 the same series of rocks, however, thrown up in a slanting 
 position (fig. B), then every shaft that pierced them would 
 *add to the amount of our information. For example, the 
 shaft No. 1 pierces the coal-beds a, 6, and c ; No. 2 the 
 coal-beds, c, d, and e.; and No. 3 the coal-beds e,f, and g. 
 Now, by adding the results of these comparatively shallow 
 shafts, they would /urnish us with information respecting 
 the whole series of strata from a to g, and which, in a 
 horizontal position, human means never could have reached. 
 By collecting and comparing the results of many shafts and 
 borings, geologists are enabled to map out sections of ex- 
 tensive districts, and so become acquainted with the struc- 
 ture of the earth to enormous depths. 
 
 1 OH. The most extensive and satisfactory sections of stra- 
 tified rocks are those presented by ravines, and by the sea- 
 shore. Thus, in tracing the course of a river, as repre- 
 sented by the following engraving, the geologist would 
 
 100. How may we examine horizontal strata 1 
 J01. What do figures A and B illustrate ? 
 
 302. Is there any more extensive and satisfactory mode by a natural 
 section 1 
 
res 
 
 GF.OI..C-CV. 
 
 become acquainted wi.h several series of rocks, an d see 
 their mineral and fossil characters much more distinctly than 
 
 by any shaft or boring. Here the river bank exposes the strata 
 from C to D in regular succession, where it is obvious, had 
 they been in a horizontal position, only two or three beds 
 would have been cut through by the action of the water. 
 Such sections are numerous in hilly countries and along 
 the sea-coast ; and in these situations should the student 
 make himself familiar not only with the succession of strata, 
 but with the modes and peculiarities of stratification, which 
 can never be perfectly understood unless from actual ob- 
 servation. 
 
 FORMS OF STRATIFICATION. 
 
 107. The stratified rocks being, as it were, the key to the* 
 structure and history of the earth, it will be necessary to 
 
 C B A 
 
 advert to some of the more common forms in which strati- 
 
 303. What does figure C and D exhibit? 
 
 304. Where may such natural sections be sought? 
 
 305. Explain the variety of strata in the first diagram. 
 
 306. By what names are they designated ? 
 
 307. Describe the second diagram* 
 
FORMS OF STRATIFICATION. 
 
 77 
 
 ficition is presented. When strata lie in a flat or level 
 position, they are said to be plane or horizontal, as at A in 
 the subjoined figure ; when they slant, as at B, they are said 
 to be inclined, and the angle which they form with the hori- 
 zon is called the dip, or angle of inclination; when highly 
 inclined, as at C, they are termed vertical, or edge strata, 
 as appearing to be set on edge; when bent and twisted, as 
 at D, contorted; and when suddenly bent up by subterra- 
 nean forces, as at E, they are said to be tilted up. 
 
 108. Strata which dip in two opposite directions from a 
 common ridge, as at a, are said to form an anticlinal axis, 
 or saddle-back; when dipping to a common point, as at 5, 
 the axis is termed synclinal, and the hollow so formed a 
 trough or basin. The headland, or bluff, formed by the 
 abrupt termination of a series of strata, is called an escarp- 
 ment, as at e ; and beds, lying apart from the main series to 
 
 which they belong (0), outliers. Where a stratum comes to 
 the surface, as at c, it is said to crop out; and the part ex- 
 posed forms the crop or outcrop. Strata are said to be con- 
 formable, when they are arranged parallel to each other; 
 but unconformable when one set of beds overlie a lower 
 series, without any conformity to the position of the latter. 
 The strata at x are unconformable to those upon which 
 they rest. There are several other terms applied to the po- 
 sition and inclination of stratified masses, but the above 
 are those which most frequently occur. 
 
 308. Define the italicised technicals. 
 
 309. Define conformable and inconformable. 
 
73 GBOLOGY. 
 
 POSITIONS OF UNST RATIFIED ROCKS. 
 
 1 09. As all stratified rocks irere originally laid down in 
 a position nearly horizontal, the different inclinations and 
 contortions described above must have been produced by 
 elevating or igneous causes. Whether the upheaving forces 
 exerted themselves through volcanic vents, accompanied 
 by discharges of unstratified or igneous rock, or simply as 
 earthquakes, they would produce other appearances than 
 mere change of position in strata. These appearances are 
 generally known by the name of fractures, or disruptions, 
 and may or may not be accompanied by discharges of igne- 
 ous rock. 
 
 1 10. Discharges ofingneous rock present themselves either 
 as disrupting, inter stratified, or overlying masses. In the 
 accompanying section, A is simply a disrupting mass, or 
 mountain range, by which the original strata are broken 
 asunder; B is partly a disrupting mass, and partly overly- 
 ing, as it overlies the strata at d; and C is both disrupting 
 
 and interstratified, part of the fused mass appearing between 
 the strata at e. Disrupting masses are caused by the ex- 
 pansive force of the fused material from beneath ; overly 
 ing masses by the rock spreading itself, when in a liquid 
 
 310. How must these various strata have been formed ? 
 
 311. What of fractures and disruptions? 
 
 312. What variety in the discharges of igneous rock ? 
 
 3 1 3. Explain the diagram. 
 
 314. How are disrupting masses produced ? 
 
 31. "i. WltHt of ovorlving masses, and iiiterstratified ? 
 
POSITIONS OP UNSTRATIF1EI) ROCKS. ?'.) 
 
 state, over the surface of the strata : and interstratified by 
 overlying masses being covered by a new deposition of 
 strata. Sometimes there is a pseudo or false inter stratifica- 
 tion; that is, when the expansive force of the igneous rock 
 has raised one set of strata from another, and inserted itself 
 for some distance between them. In either case the inter- 
 stratified igneous rock presents no regularity or continuity 
 of stratification, and is easily distinguished from rocks 
 formed from sediment in water. 
 
 1 1 1. Fractures of the strata caused by subterranean 
 forcts are known by the terms veins, faults, dykes, slips, 
 hitches, &c. In the subsequent figure, a is a suite of veins 
 traversing unstratified and stratified rocks; 6 a fault, or 
 dislocation, on each side of which the strata are thrown at 
 different inclinations; c a dyke, composed either of igne- 
 ous rock injected from below, or of clay and gravel washed 
 in from above, also accompanied by an alteration of the 
 dip ; and d a hitch or slip arising from a portion of the 
 
 strata having been thrown down to a lower level without 
 any change in the inclination. Of course the phrase thrown 
 down is merely relative: for while the strata on the right of 
 d appear to be thrown down, those on the left seem to be 
 thrown up. The mining terms, up-throw and down-throw, 
 t here f re, refer to the same phenomenon, and are used 
 nccording to the position from which the strata happen to 
 be viewed. 
 
 316. What are instances of pseudo or false interstratification T 
 
 317. How are fractures of strata designated T 
 
 318. Exolain the diagram, and define the terms. 
 
80 GEOLOGY. 
 
 EXPLANATORY NOTE. 
 
 ANTICLINAL (Greek, anti, on opposite sides, and clino, I bend) 
 bending towards opposite sides, such as strata from a common axis. 
 Strata bending south and north from one ridge form an anticline, or 
 saddle-back ; but when they dip in every direction from one point, they 
 are said to be quaquaversal, 
 
 SYNCLINAL (Gr., syn, together, and clino, I bend) bending together, 
 or towards one point, such as the sides of a basin towards the bot- 
 tom. 
 
 DISRUPTING (Lat.,<Ks, asunder, ruptits, broken) breaking or forcing 
 asunder. 
 
 DISLOCATION (Lat., dis, asunder, locus, a place) displaced, or put 
 out of its original or regular position. 
 
 DYKE (Scottish, dyke, a wall or fence) applied to those interruptions 
 which the miner meets with in his progress, from their appearing to 
 wall off one part of a coal-field from another. Sometimes these dykes 
 are only a few r eet in thickness ; at other times they are as many 
 yards. 
 
 ORYCTOLOGY SCIENCE OF FOSSILS. 
 
 (See Oryctological Chart.) 
 
 { \'2. Fossils, whether vegetable or animal, generally par- 
 take of the character of the rocky substances in which they 
 are imbedded; that is, if occurring in limestone, they will 
 be more or less calcareous; if in coal, more or less bitu- 
 minous; and so on of other substances. It must not be 
 supposed, however, because a plant or animal is found in 
 limestone, that it will be always wholly calcareous, or be- 
 cause it is found in coal, that it will be bituminous; the 
 fact is, that fossils often present very irregular characters, the 
 organic substance being sometimes entirely destroyed, 
 leaving only its cast or impression. But whatever changes 
 they have undergone, they may, for the sake of convenience, 
 be arranged into three classes; namely, petrifactions, con- 
 verted into stony matter; bituminizations, converted into 
 bituminous matter; and metallizations, where the substance 
 of the fossil, whether stony or bituminous, is pervaded by 
 some metallic substance. (See Appendix.) 
 
 319. What of anticlinal and quaquaversal ? 
 
 320. Describe disruption, dislocation, and dyke. 
 
 321. What determines the nature of fossils? 
 
 322. Into how manv elapses are thev divided t 
 
PETRIFACTION, ETC. 81 
 
 PETRIFACTION, BITLMINIZAT1ON, AND METALLIZATION. 
 
 113. THE PROCESS OF PETRIFACTION consists in the infil- 
 tration of stony matter into the pores of bone or vegeta- 
 bles. In some instances, the animal or vegetable substance 
 has been almost entirely dissolved, and the stony matter 
 so gradually substituted, that the petrifaction presents a 
 perfect resemblance in its minutest parts to the original 
 structure. Petrifaction has been artificially attempted, by 
 burying bones in mud, clay, and lime; when it was found 
 that at the end of one year the bones had become harder 
 and heavier, and scarcely distinguishable from true fossils. 
 Springs containing lime in a state of chemical solution are 
 familiar examples of petrifying agents, when they convert 
 pieces of moss, straw, twigs, and other bodies, into limy or 
 calcareous matter. Lime is one of the most prevalent petri- 
 fying agencies; but wood is often found converted into 
 flint, or silicified ; and many fossil trees are mere masses of 
 fine-grained sand or quartz. 
 
 114. The organic structure of plants and animals is not 
 destroyed by petrifaction, as has been proved by many ex- 
 periments. For example, slices of fossil trees have been 
 made so thin as to be semi-transparent, and thus show the 
 traces of vegetable fibre ; and fossil zoophytes have been 
 suspended in acids till the whole of the lime was dissolved, 
 leaving the animal tissue distinct in its original form, and 
 sometimes in its original colour. From this it will be per- 
 ceived that the structure of the organism always more or 
 less remains, and forms a basis for the petrifying solution 
 which thoroughly pervades it, without disturbing the ar- 
 rangement of those parts on which its characteristic form 
 depends. It is this form or external character which ena- 
 bles geologists to compare and classify fossils with existing 
 plants and animals. 
 
 323. In what does petrifaction consist T 
 
 324. What success has attended artificial petrifactions 1 
 
 325. What kind of springs will petrify 1 
 
 326. Name some varieties. 
 
 327. Is the organic structure preserved in these petrifaction* ? 
 32S. Name the examples which prove this. 
 
 329. Is the chai *cteristic form important to geologists T 
 
SiJ GEOLOGY. 
 
 115. Bituminization is that process by which vegetables 
 insensibly lose their organic structure, and pass by chemi- 
 cal process into bitumens; that is, into inflammable sub- 
 stances, of which coal, mineral pitch, asphalte, &c. are ex- 
 amples. Bituminization may sometimes be regarded as a 
 sort of petrifaction, as when substances not originally vege- 
 table are impregnated with bituminous matter, such as 
 fossil fishes found in bituminous slate. But bituminization 
 proper is totally different, and refers only to a certain 
 change which vegetables undergo, by which they more or 
 less lose their vegetable texture, and are converted into 
 solid or liquid bitumen. To render this more evident by 
 analogy: If a piece of animal muscle be buried in the 
 earth, where it obtains sufficient moisture and warmth, and 
 is wholly excluded from the air, it is soon changed into a 
 fatty wax-like mass (called adipocere, from the Latin, adeps, 
 fat, and cera, wax), in which no trace of animal fibre is 
 present. In like manner, if vegetable matter be*excluded 
 from the air, and subjected to heat and moisture, it is grad- 
 ually converted into a black viscous and inflammable sub- 
 stance, called bitumen. This bitumen is found in all states 
 of purity: pure and limpid as naphtha, oily as petroleum, 
 viscous or slaggy as in mineral pitch or asphalte, elastic as 
 in mineral caoutchouc, and solid as in jet, cannel, and 
 common coal; the latter of which varies according to the 
 quantity of earthy matter mixed up with it. Amber and 
 certain mineral resins are also the results of bituminiza- 
 tion. 
 
 116. The process of bituminization cannot be fully un- 
 derstood without a considerable knowledge of chemistry : 
 a few of the changes which decomposing vegetables under- 
 go may, however, be enumerated. If vegetables are left 
 on the surface of the earth exposed to air arid moisture 
 they soon putrefy, and fall down into a black pulverulent 
 matter, called vegetable mould. Again, if they are sub- 
 
 330. Define bituminization with an example. 
 
 331. What is adipocere ? 
 
 332. What varieties of bitumen are named ? 
 
 333. What varieties in the process, and the different results f 
 
PETRIFACTION, ETC. 83 
 
 jected to moisture, and partially excluded from the atmos- 
 phere, petrifaction does not take place; but a half-bitumin- 
 ous substance is formed analogous to peat-moss. Lastly, 
 if vegetable matter be buried at depths beyond the influence 
 of the air, neither mould nor peat is formed, but bituminous 
 matter in various degrees of purity and perfection is ob- 
 tained. This process of bituminization has been defined 
 as " a fermentation peculiar to vegetable matter placed in 
 such situations as not only to exclude the external air, and 
 secure the presence of moisture, but prevent the escape of 
 the more volatile principles." Every one is familiar with 
 the kind of fermentation which takes place when half-dried 
 hay is thrown into a heap ; it gives off heat, becomes black 
 in colour, and frequently takes fire and is consumed. It is 
 this heating process which produces the bituminous fer- 
 mentation when the vegetable mass is excluded from the air, 
 and subjected to moisture and pressure. Animal remains 
 may be impregnated with bitumen; but it is vegetables 
 alone which can be converted into mineral pitch, jet, and 
 common coal ; and these substances are more or less pure, 
 according as earthy matter may be mingled with them. 
 
 1 17. Metallization is that process by which fossil remains 
 become impregnated with, or wholly converted into, metal- 
 lic substances. The student must be aware that metals 
 can be dissolved or held in a state of solution, as well as 
 in a state of fusion. In this state of solution they are 
 borne about by the waters which hold them: and these 
 waters either percolate through the earth, or mingle inti- 
 mately with the substances which compose it. The strata 
 which imbed fossils generally contain metallic substances, 
 such as iron ; animals and vegetables, when in a state of 
 decay, give off certain gases; water is always present in 
 greater or less abundance; and thus the metallic sub- 
 stances, the gases and water, by chemical union, form com- 
 pounds, which enter thoroughly into the pores of the fos- 
 
 334. Is this process analogous to fermentation ? 
 
 335. Is it peculiar to vegetables ? 
 
 336. What of metallization 7 
 
 337. How is it accounted for 1 
 
 338. Describe the chemical agents. 
 
84 
 
 sils, and so convert them into a metallic, instead of ston) 
 or bituminous state. The changes thus effected are some- 
 times partial, the external parts of the fossil being metal- 
 lized, whilst the interior remains stony or bituminous; 
 sometimes the fossil is simply covered ever with an incrust- 
 ation of metallic salts, such as iron pyrites; at other times 
 the original elements of the fossil remain thoroughly im- 
 bued with the metal; while not unfrequently the whole sub- 
 stance is rendered metallic, every trace of organic structure 
 being obliterated. 
 
 1 18. By thf.se three processes Petrifaction, Bituminiza- 
 tion, and Metallization have the remains of plants and 
 animals, which once lived and grew on the face of the 
 globe, been preserved in the strata which compose its crust. 
 So complete in many cases is this system of preservation, 
 that the geologist is enabled not only to discover their form 
 and structure, but to decide with certainty as to their habits, 
 and to say whether they were fresh-water or marine, whether 
 terrestrial or aquatic, whether they lived and flourished 
 under a tropical or under a temperate climate. 
 
 FOSSIL BOTANY AND ZOOLOGY. 
 
 1 19. Before the geologist be qualified to decide as to the 
 nature of fossil plants and animals; before he can classify 
 them and compare them with those now existing, or deter- 
 mine all the conditions under which they must have flou- 
 rished, he would require to be acquainted with the leading 
 facts of botany and zoology. In an elementary work of 
 this kind, it would be out of place to enter largely into the 
 characteristics of these sciences; but as a certain amount 
 of knowledge is necessary to the understanding of subse- 
 quent details, we may shortly recapitulate the classification 
 of plants and animals as generally received among botanists 
 and zoologists. (See Appendix.) 
 
 120. VEGETABLES may be arranged under two grand 
 divisions CELLULAR and VASCULAR : (Appendix.) 
 
 339. How are these fossils varied ? 
 
 340. How are these processes and their products important to geolo- 
 
 gists 7 
 
FOSSIL BOTANY AND ZOOLOG*. 85 
 
 I. Cellular without regular Teasels, but composed of fibres which 
 sometimes cross and interlace each other. Conferva;, lichens, fungi, 
 alge (sea-weeds), and mosses, belong to this division. In some of 
 these families there are no apparent seed organs. 
 
 II. Vascular with vessels which form organs of nutrition and re- 
 pro luction. According to the arrangement of these organs, vascular 
 plants have been divided into four classes: 1. Without perfect flow- 
 ers, and with no visible seed organs (crypt ogamia). To this class many 
 fossil plants belong ; such as gigantic tree ferns, horse tails, and others 
 resembling ferns. 2. With flowers, but having the seeds naked (pAa- 
 nerogamia gymnospermous). To this class belong the cycades, or pine- 
 apple tribe, and the conifers, or firs. 3. Flowering plants with one 
 cotyledon or seed-lobe (phaner ogamia monocotyledonous). This class 
 comprises water-lilies, palms, lilies, the sedge, iris, and canes. 4. 
 Flowering plants with two cotyledons (phanerogamia dicotyledonous). 
 This class comprises all forest trees and shrubs. None of the families 
 of plants, but those in thi$ last class, have the true woody structure, 
 or produce perfect wood, except the coniferae, or firs ; but the wood of 
 these is easily distinguishable from true dicotyledonous wood. 
 
 121. ANIMALS, according to Cuvier, may be arranged into 
 four great divisions VERTEBRATED, MOLLUSCOUS, ARTI- 
 CULATED, and RADIATED : 
 
 I. Vertebrated animals which have a skull containing the brain, 
 and a spine or back-bone containing the principal trunk of the nervous 
 system, commonly called the "spinal marrow. They have red blood. 
 This division comprehends the Mammalia (those animals which suckle 
 their young), Birds, Reptiles, and Fishes. 
 
 II. Molluscous animals in this division have no internal skeleton ; 
 the muscles are attached to the skin, which in many species is covered 
 with a shell. The nervous system and viscera are composed of de- 
 tached masses, united by nervous filaments. They have a complete 
 system of circulation, and particular organs for breathing by. Animals 
 with Bivalve, Univalve, and Chambered shells, belonging to this divi- 
 sion ; though many molluscs, like the common snail, have no shell. 
 
 III. Articulated to this division belong Worms, Crustaceous animals 
 like the lobster, and all insects. Their nervous system consists of two 
 long cords, ranging along the body, and swelling out in different parts 
 into knots or ganglions. Worms having their bodies composed of rings 
 are called annelides, and have red blood : some species of worms in- 
 habit a calcareous tube, supposed to be formed by exudation. 
 
 IV. Radiated comprises all those animals formerly called Zoophytes, 
 or animal-plants, as corallines, &c. In animals of this division, the 
 
 341. What sciences are important in the study of fossils 1 
 
 342. How are vegetables divided 1 
 
 343. Define the technicals used in both divisions. 
 3->4. How are animals classed 7 
 
 345. Define and explain these terms. 
 34t>. Define and explain the technicals. 
 
86 
 
 GEOLOGY. 
 
 organs of sense and motion are circularly disposed around a centre or 
 axis ; hence the term radiated, or disposed in rays. They have no 
 distinctly-marked nervous system, and the traces of circulation in 
 many species can hardly be discerned. Many of the radiata are fixed, 
 such as the corals ; others move and float about, as the star-fish and 
 sea-urchin. 
 
 122. Besides the above distinctions, which depend on the 
 structure and form of plants and animals, there are others 
 which should constantly be kept in view ; namely, those 
 depending upon mode of life, climate, and situation. The 
 plants of the tropics are very unlike those of polar regions, 
 both in number, size, and character; marine plants and 
 animals are essentially different from those inhabiting fresh 
 waters; and aquatic plants and amphibious animals present 
 a very different appearance from those constantly existing 
 upon dry land. Each race of plants and animals is, more- 
 over, perfectly adapted for the functions it has to perform 
 in the economy of nature; and is furnished with peculiar 
 organs, according to the kind of food upon which it lives, 
 and the other habits it displays. Thus, one set of organs 
 indicates swiftness, another strength, a third prehensile or 
 seizing powers, a fourth climbing, leaping, or swimming 
 powers, a fifth that the animal lives on roots, on herbage, 
 or on the flesh of others. 
 
 123. As in the vegetable and animal economy of the pre- 
 sent day, so in all times past; and thus the geologist, by 
 analogy and comparison, is able to decide as to the cha- 
 racter of the fossil plants and animals which he discovers. 
 He finds in their characters and skeletons a key to the modes 
 of their existence, and can tell with precision whether they 
 lived in the waters or on dry land, in fresh or in salt water, in 
 a cold or in a hot climate ; whether animals browsed upon 
 plants or lived upon other animals, whether they are fur- 
 nished with organs indicating an amphibious existence; 
 and in general can determine their character and modes of 
 existence. Moreover, as certain classes of plants and ani- 
 
 347. What other distinctions are important 1 
 
 348. How are the varieties illustrated ? 
 
 349. What of the permanence of their economy ? 
 
 350. What are the points of geological discovery in these fossils ? 
 
FOSSIL BOTANY AND ZOOLOGY. 87 
 
 mals indicate certain conditions of the worJd, the geologist 
 will be enabled by their remains to decipher the past his- 
 tory of our globe, and so arrive at that which is the aim 
 and object of all true geological research. 
 
 EXPLANATORY NOTE. 
 
 PETRIFACTIONS are, in general, described according to the mineral 
 substance which enters most abundantly into their composition. If 
 it be lime, then they are designated calcareous (Lat., calx, lime); if 
 flint, silecious or silicified (silex, flint) ; and so on of other minerals. 
 
 BITUMEN (Gr., pilus, the pitch tree) a variety of inflammable mine- 
 ral substances, which, like pitch, "burn with flame in the open air. 
 Naphtha, petroleum, and asphaltum, are familiar examples; and all sub. 
 stances impregnated with these bitumens are said to be bituminous. As 
 mentioned in the text, it is the prevalent opinion that all bituminous 
 matter is of organic or vegetable origin. 
 
 BITUMINOUS FERMENTATION. All vegetable matter is liable to cer- 
 tain states of fermentation, according to the degree of heat, air, and 
 moisture to which it is subjected. These states have been successively 
 described as the saccharine, vinous, acetous, septic, and bituminous. 
 For example, the saccharine is that which manifests itself in the opera- 
 tion of malting and in the ripening of fruits ; if water and heat be ap- 
 plied, it passes into the vinous, or that by which wine and spirituous 
 liquors are formed. Again, if, while the vinous is going on, air be par- 
 tially admitted, the acetous, or vinegar-forming fermentation, will be 
 produced ; and by further exposure of the vegetable matter to the air, 
 it will pass into a mass of earth and carbon : this fits it for the septic, 
 or putrefying process; but if air be excluded, and heat, moisture, and 
 pressure be present, the bituminous will be the result. By a knowledge 
 of these processes, it is easy to understand how malt, wine, vinegar, 
 vegetable mould, and coal, are respectively formed. 
 
 ADIPOCEHE (Lat., adeps, fat, cera, wax) a fatty substance produced 
 by the decomposition of the flesh of animals in moist situations, or 
 under water, resembling, in some of its properties, a mixture of fat and 
 wax. It is found in damp grave-yards, in peat-bogs, where animals 
 have been accidentally entombed, and it is also occasionally thrown up 
 on the sea-shore after a storm. It has a chalky aspect, a soapy feel, is 
 inflammable, and swims in water. 
 
 FOSSIL BOTANY AND ZOOLOGY. The animals peculiar to a country 
 constitute its Fauna, and the plants its Flora. The terms are respec- 
 tively derived from the Latin Fauni, rural deities, and Flora, the god- 
 dess of flowers. As naturalists speak of the existing Fauna and Flora 
 of any country, so geologists speak of the fossil Fauna and fossil Flora 
 of certain geological epochs and formations. 
 
 351. What of petrifactions 1 
 
 352. Give examples of bitumen. 
 
 3o3. Name the varieties of fermentation, and explain them. 
 
 354. Describe adipocere, its nature. and source. 
 
 355. What of the fossil Fauna and Flora ? 
 
88 GEOLOGY. 
 
 CLASSIFICATION OF ROCK FORMATIONS. 
 
 124. The subjects treated in the preceding sections may 
 be regarded as introductory to the study of Descriptive 
 Geology; for, without a knowledge of them, it would be 
 impossible to comprehend the nature of the changes which 
 our planet has hitherto undergone. Those changes are in- 
 dicated by certain characters stamped upon the rocks which 
 constitute its crust characters obviously analogous to such 
 as are now produced by causes in active operation around 
 us. It was necessary, therefore, to learn something of the 
 existing structure and conditions of the globe, and of the 
 causes mechanical, chemical, and vital which are modi- 
 fying these conditions, in order that we might be enabled 
 to reason from what is recent and apparent, to that which 
 has taken place at more remote periods. 
 
 125. The term rock is applied by geologists not only to 
 those hard substances usually called so, but also to all sands, 
 clays, gravels, and marls which occur in beds, strata, or 
 masses. It is also used to denote a collection of such sub- 
 stances: thus, we say the "rocks of a country;" or, speak- 
 ing more definitely of any mineral series, we say the Chalk 
 rocks, the Carboniferous rocks, and so on. The rocks 
 which compose the crust of the earth, though varying much 
 in mineral character, as well as external appearance, occur 
 either in masses, or in series having a close resemblance to 
 each other ; so much so, that geologists conclude that cer- 
 tain series have been formed under similar circumstances. 
 This opinion is further confirmed by the fact, that certain 
 series of strata always imbed fossils of a different character 
 from those contained in other series; hence the origin of 
 rock classification. 
 
 126. Leibnitz, in 1680, divided rocks into two great 
 classes STRATIFIED and UNSTRATIFIED the latter being 
 the result of igneous fusion, and the former that of aque- 
 ous solution. This distinction, though of importance at 
 
 356. How extensively is the term rock applied 
 
 357. What is the orisrin of rock classification ? 
 
 358. Name that of Leibnitz. 
 
CLASSIFICATION OF KOCK FORMATIONS. 83 
 
 the period to which we refer, was still of little avail in de- 
 ciphering the history of the earth, as unstratified rocks are 
 mingled with the highest as well as with the lowest strata; 
 and as, moreover, the stratified, rocks differ essentially from 
 each other, and often contain very different fossil remains. 
 Lehman, a German mineralogist, next proposed to divide 
 the stratified rocks into 
 
 PRIMITIVE those containing no fossil organic remains. 
 SECONDARY those containing remains of animals and vegetables. 
 LOCAL those but partially occurring in different districts. 
 
 127. Werner, the great German geologist, improved upon 
 this classification, and divided all rocks into Primary, Tran- 
 sition, Secondary, and Local. The term Transition was 
 added by Werner, as implying that the rocks so called ex- 
 hibited a passage from the primary into the secondary in 
 regard to their mineral character, and also that the earth 
 was changing from an uninhabitable to an inhabitable state 
 during the period of their formation. Subsequently, from 
 the fossil discoveries of Cuvier and others, a more definite 
 idea was attached to the term Local, and the word Tertiary 
 was employed to denote all those regularly stratified beds 
 which occur" above the Chalk strata. These divisions 
 Primary, Transition, Secondary, and Tertiary though lia- 
 ble to many objections, are still more or less in use by ge- 
 ologists ; hence the following classification of the stratified 
 rocks which compose the crust of the earth : 
 
 f SUPERFICIAL ACCUMULATIONS all loose and irregularly deposited 
 
 masses of clay, sand, gravel, and boulder stones. 
 I TERTIARY local deposits of regular strata, containing remains 
 0; | of plants and animals, not differing widely from those now in- 
 habiting the globe. 
 
 SECONDARY strata of chalk, clay, and shale, red and white sand- 
 stones, coal, ironstone, and limestone occurring in many parts 
 of the world, and containing fossil plants and animals of different 
 species from those now existing. 
 
 TRANSITION strata of sandstones, shales, slates, and limestones 
 containing few or no fossil plants, and the remains of no higher 
 animals than Crustacea, shell-fish, corals, and corallines. 
 PRIMARY slaty and crystalline strata, very hard and compact, and 
 totally void of organic remains. 
 
99 GEOLOGY. 
 
 1 28. As geologists became better acquainted with the suc- 
 cession of the stratified rocks, a more minute subdivision 
 took place, and these formations have been found to con- 
 sist of systems, series, and groups of strata differing con- 
 siderably from each other. Thus the term formation is 
 applied to designate strata which seern to have been formed 
 under nearly similar circumstances. A formation may con- 
 sist of several systems that is, strata having nearly the 
 same mineral and fossil character; and there may be seve- 
 ral groups in a system, such as sandstone or limestone 
 group. All these groups consist of strata which, accord- 
 ing to their thickness or external appearance, are desig- 
 nated beds, seams, layers, schists, or slates. Bearing these 
 terms in mind, the student will be prepared to understand 
 the following table of stratified rocks as they occur in the 
 British islands : 
 
 TABLE OF BRITISH DEPOSITS. 
 
 pSoiL decomposed vegetable and animal matter, 
 SUPERFICIAL I w ith earthy admixtures. 
 
 A rrrnvrTTT A J ALLUVIUM deposits of sand, gravel, and clay, 
 TIONS I formed b y the ordinary action of water. 
 
 DILUVIUM deposits of gravel and clay with bould- 
 ers, formed by unusual operations of water. 
 ("CRAG calcareous conglomerate of marine shells and 
 
 gravel ; beds of marl. 
 
 TFRTTAR.V < FRESH- WATER, OR ESTUARY BEDS consisting of 
 ' ] marls, imperfect limestones, and clays. 
 
 I MARINE BEDS consisting of blue and plastic clays 
 (^ thin beds of sand, lignite, &c. 
 
 359. What was Lehman's ? 
 
 360. How did Werner improve it ? 
 
 361. For what purposes did he apply the term Transition ? 
 
 362. Why was tertiary substituted for local ? 
 
 363. How is this term now employed ? 
 
 364. What classification is here adopted ? 
 
 365. What of systems, series, and groups? 
 
 366. How are the strata of different groups designated ? 
 
 367 Define every term used in this table of British deposits 1 
 
CLASSIFICATION OF ROCK FORMATIONS. 
 
 91 
 
 soft and white, with layers of flint ; chalk, 
 hard, and without flints. 
 
 Chalk J GAULT, or beds of bluish marly clays, with green 
 System. j sand. 
 
 1 GREEN-SAND beds of green ferruginous sands, 
 
 L with chert nodules. 
 
 (WEALDEN GROUP beds of clay, argillaceous lime- 
 
 stones, and sands. 
 
 Oolitic J OOLITE beds of oolite limestone, calcareous grits, 
 System. | sands, and clays, all calcareous. 
 
 I LIAS GROUP bluish clays, alum shales, marls, and 
 p limestones, all finely stratified. 
 j SALIFEROUS MARLS variegated shales and shell 
 New Red limestone, with bands of sandstone. 
 
 Sandstone, orJ RED SANDSTONE GROUP fine-grained, sometimes 
 
 Saliferotu 
 System. 
 
 Old Red 
 
 Sandstone 
 r, f 
 
 Silurian 
 System. 
 
 j conglomerate. 
 
 I MAGNESIAN LIMESTONE thick-bedded limestones 
 
 *- and calcareous conglomerates. 
 
 [COAL MEASURES alternating beds of coal, shale, 
 
 ironstone, and sandstone. 
 
 Carboniferous} CARBONIFEROUS, OR MOUNTAIN LIMESTONE thick- 
 System. bedded grayish limestones and shales. 
 
 J CALCIFEROUS SANDSTONE white, thick-bedded 
 
 v. sandstones, and calcareous shales. 
 
 f YELLOW SANDSTONES, with beds of mettled shales 
 
 ant ^ mar ^ s - 
 4 RED S ANDSTONES sometimes fine-grained, some- 
 
 times quartzose and conglomerate. 
 j GRAY OR RUSTY-COLOURED SANDSTONES micace- 
 V. ous, and often iu flags or thin-bedded. 
 f UPPER SILURIAN rocks gray and bluish lime- 
 J stones, with coloured micaceous shales. 
 j LOWER. SIEURIAN rocks impure shelly limestone, 
 L mottled sandstones, dark calcareous flags. 
 ^HARD ARGILLACEOUS rocks thick-bedded sand- 
 Grduwacke j stones, slaty sandstones, and limestones. 
 System. j FINE AND COARSE-GRAINED slaty rocks gray mica- 
 ( ceous slates. 
 
 ^CLAY-SLATE finely laminated ; dark, liver, and 
 Clay-Slate I purplish-coloured. 
 
 System. 
 
 Mica Schist 
 System. 
 
 Gneiss 
 System. 
 
 j HORNBLENDE AND CHIASTOLITB slates, finely lami- 
 
 (^ nated. 
 
 ( CHLORITE SLATES greenish-coloured slates, with 
 
 ^ mica, mica schist, talc schist, crystalline lime- 
 
 ( stone, and quartz rock. 
 
 ( GNEISS ROCKS intermingled with irregular beds of 
 
 \ quartz rock, crystalline limestone, and mica schist. 
 
 To assist the student in forming an idea of the succession 
 of these formations and systems, the stratified rocks are 
 more summarily arranged in the following diagram : 
 
 368. Distinguish between formations, systems, series and groups. 
 
 369. Explain all the technicals of this table. 
 
 370. Observe the order of this classification of the stratified rocks. 
 
GEOLOGY. 
 
 Vegetable Soil. 
 Alluvial Clay, Sand, and Gravel. 
 Diluvial Clay with Boulders. 
 Sandstone and Calcareous Grits. 
 Estuary Marls, Limestones, &c. 
 Blue and Plastic Clays, Marls, &c.( 
 
 Chalk Beds and Green-sand. 
 Oolite Limestones and Grits. 
 Lias Limestone and Shales. 
 
 Saliferous Marls, Shell Lime- 
 stone. 
 
 New Red Sandstone. 
 Magnesian Limestone. 
 
 Coal Beds alternating with 
 Sandstones, Clay-shale, 
 Ironstone, and impure 
 Limestones. 
 
 Mountain Limestone. 
 
 
 Old Red Sandstone. 
 Silurian Limestones, &c. 
 Grauwacke, Sandy Slates. 
 
 Clay Slates. 
 
 Mica and Talc Schists. 
 
 Gneiss Rocks, &c. 
 
 371. Repeat the order of these formations and systems until the di- 
 gram becomes familiar. 
 
CLASSIFICATION OF ROTX FORMATIONS. 93 
 
 129. The unstratified or igneous rocks occur in no regu- 
 lar succession, but appear amidst the stratified without order 
 or arrangement; heaving them out of their original hori- 
 zontal positions, breaking up through them in volcanic 
 masses, and sometimes overrunning them after the manner 
 of liquid lava. From these circumstances, they are in gen- 
 eral better known by their mineial composition than by 
 their order of occurrence. Still, it may be convenient to 
 divide them into three great classes; granitic, trappean, 
 and volcanic granitic being the basis of all known rocks, 
 and occurring along with the primary and transition strata ; 
 the trappean of a darker and less crystalline structure than 
 the granitic, and occurring along with the secondary and 
 tertiary rocks; and the volcanic still less crystalline and 
 compact, and of comparatively recent origin, or still in 
 process of formation. Classifying the stratified and un- 
 stratified rocks after this idea, they would present the fol- 
 lowing tabular arrangement: 
 
 Unstratified. Associated with, 
 
 VOLCANIC {SUPERFICIAL ACCUMULATIONS soil, alluvium, dilu- 
 ( vium. 
 ^TERTIARY crag, fresh-water marls, London and 
 
 plastic clay. 
 
 TRAPPEAN. ^ SECONDARY chalk, oolite, Has, new red sandstone, 
 I coal measures, mountain limestone, old red sand- 
 ^ stone. 
 
 C TRANSITION silurian and grauwacke rocks, concre- 
 te A vrrin J tionary limestones. 
 
 1U " ', PRIMARY clay-slate, crystalline limestone, mica 
 (^ schist, quartz, and gneiss rocks* 
 
 This division of the igneous unstratified rocks subserves 
 many useful purposes in geology; at the same time that it 
 is a distinction warranted by the nature, aggregation, and 
 aspect of their component minerals. The granitic, so 
 named from their distinctly granular and crystalline tex- 
 
 372. What of the order of the unstratified rocks T 
 
 373. How then are they known t 
 
 374. Into what three classes have they been divided T 
 
 375. Describe each of these. 
 
 376. Repeat the tabular arrangement. 
 
 377. What rocks are comprised in the granitic T 
 
 5 
 
94 
 
 GEOLOGY. 
 
CLASSIFICATION OF~ ROCK FORMATION*. 95 
 
 ture, comprise granite, syenite, protogine, primitive green- 
 stone, serpentine, porphyritic, and other varieties of gra- 
 nite. The troppean (Swedish, " trappa," a stair) are so 
 called from the step-like or terraced sides of the hills formed 
 by these- rocks, which include basalt, green-stone, clink- 
 stone, claystone, trachyte, porphyry, and amygdaloid. The 
 volcanic, as the name implies, are those products discharged 
 by recent or active volcanoes, such as lava, obsidian, scori, 
 pnmice, and tufa. As associated in the crust of the 
 earth, the Unstratified and Stratified rocks would present 
 something like the opposite section : 
 
 130. It must not be supposed, however, that the stratified 
 rocks always occur in any proportion of the earth's crust 
 in full and complete succession, as represented above ; all 
 that is meant is, that such would be their order if every 
 group and formation were present. But whatever number 
 of groups may be present, they never happen out of their 
 regular order of succession ; that is, clay-slate never oc- 
 curs above coal, nor coal above chalk. Thus at London, 
 tertiary strata occupy the surface ; in Durham, magnesian 
 limestone; in Fife, the coal measures; and in Perthshire, 
 the old red-stone and clay-slate; so that it would be fruit- 
 less to dig for chalk in Durham, for magnesian limestone 
 in Fife, or for coal in Perthshire. It would not be absurd, 
 however, to dig for coal in Durham, because that mineral 
 underlies the magnesian limestone; or for old red sand- 
 stone in Fife, because that formation might be naturally 
 expected to occur under the coal strata of that county, in 
 the regular order of succession. To make this order of 
 succession still plainer, suppose the rock systems to be re- 
 presented by series of figures, we might have 
 
 379. Whafcin the trappeanT 
 
 380. What in the volcanic ? 
 
 381. Do the strati6ed rocks always occur in full and complete succes- 
 
 sion, or only in this order when present I 
 
 382. What variety in illustrated T 
 
96 GFOI.OOT. 
 
 7" 
 
 6 
 
 5 
 
 4 
 
 3 
 
 2 
 
 U LI. 
 
 Any member of the series may be absent ; but those that 
 remain never occur out of their natural order of suprapo- 
 sition. 
 
 EXPLANATORY NOTE. 
 
 CLASSIFICATION OF ROCKS. Other " Systems of Classification" than 
 the above have from time to time been advanced by geologists ; but 
 as most of them are founded upon some favourite theory, or upon 
 mere local data, they have not met with any thing like a general re- 
 ception. It may be necessary, however, to notice some of the dis- 
 tinctions which occur in the works of certain modern authors. Cony- 
 beare and Phillips, in their Geology of England and Wales, divide the 
 stratified crust into the following orders : 
 
 1. Superior containing the Tertiary deposits. 
 
 2. Supermedial comprising the chalk, oolite, and new red sand- 
 stone. 
 
 3. Medial comprising the coal measures, mountain limestone, and 
 old red sandstone. 
 
 4. Submedial~conta.in\ng the Transition strata. 
 
 5. Inferior embracing all the Primitive formations. 
 
 Others have proposed to divide the crust into five great formations ; 
 namely, Colluvial, Cretaceous, Carboniferous, Schistose, and Crystal- 
 line ; each of these formations being subdivided into three systems. 
 Subdivided in this manner, the carboniferous and cretaceous would 
 present the foil owing arrangement : 
 
 Super cretaceous plastic clays, marls, and lignite beds (Tertiary). 
 Cretaceous chalk, chalk marls, and green-sand. 
 Subcretaceous weald, oolite, and lias strata. 
 
 Super carboniferous variegated marls, red sandstone, and magne- 
 sian limestone. 
 
 Carboniferous coal measures, millstone, and mountain limestone. 
 Subcarboniferous old red sandstone. 
 
 The rocks of the stratified crust, divided and subdivided in this man- 
 ner, are easily remembered ; the arrangement, moreover, being one 
 
 383. Explain the series of figures. 
 
 384. What of supraposition, and its value to the geologist } 
 
 385. What other classifications have been proposed I 
 
GRANITIC BASIS OF PRIMARY STRATA. 97 
 
 which is warranted by actual observation. The term fossiliferoiu is 
 commonly employed to denote all those formations in which fossils 
 have been found ; and non-fossil if 'erous, those, like the mica schist and 
 gneiss, in which no organic remains have yet been discovered. Meta- 
 morphic is sometimes applied to those non-fossiliferous systems, imply- 
 ing that the strata have been so metamorphosed by heat, as to oblite- 
 rate all traces of fossil exuviae. Mr. Lyell divides the tertiary strata 
 into foar groups; namely, Eocene, Meiocene, Pleiocene, and Pleistoctnt; 
 these terms indicating the approach which the imbedded fossils make 
 to existing nature. For example, Eocene (Gr., eos, the dawn, and kai- 
 *o*, recent), indicates those strata in which the dawn or commence- 
 ment of recent animals takes place; Meiocene (melon, less), less 
 recent ; Pleiocene (pleion, more), more recent; and Pleistocene (pleis- 
 ton, most recent,) or approaching nearly to existing orders. Instead of 
 Stratified and Unstratined, or Sedimentary and igneous, some geolo- 
 gists make use of the terms Neptunian and Plutonic the former being 
 derived from Neptune, the god of the sea or water, and the latter from 
 Pluto, the god of fire. 
 
 GRANITIC BASIS OF PRIMARY STRATA. 
 
 .131. We commence our investigation of the earth's 
 crust, by describing the lowest or earliest formations of 
 strata. Some geologists in their descriptions begin at the 
 surface, and proceed downwards; but it is certainly the 
 more natural and intelligible method to commence with 
 the lowest, and proceed upwards seeing that the lowest 
 have been deposited first, and that each succeeding forma- 
 tion must have been formed from the disintegrated mate- 
 rials of those which preceded it. 
 
 1 32. Whatever may have been th* origin of the globe, 
 we are warranted in stating that GRANITIC ROCKS form a 
 solid crust or basis upon which all the systems of strata 
 rest These granitic rocks show no traces of stratification; 
 they are all highly crystalline; none of their crystals are 
 water-worn ; and from these circumstances, as well as from 
 the fact that we find them bursting up through, and displac- 
 ing the primary strata, it is concluded that they are of ig- 
 neous origin. If ever this globe was in a fused state, as 
 
 3^6. What additional classifications are spoken of? 
 
 3>7. Why do we begin at the lowest strata and proceed upward f 
 
 3S8. What may be regarded as the basis of the earth's crust f 
 
 389. Whence have we the evidence of their igneous origin f 
 
98 GEOLOGY. 
 
 has been supposed by many philosophers, the granitic crust 
 is such as would be formed by cooling down of the igneous 
 matter. Cooling and contracting irregularly, it would 
 assume an unequal surface; here forcing itself up into 
 considerable heights, and there sinking into hollows; the 
 highest granitic mountains bearing no greater proportion 
 to the size of the globe, than the blisters and scorias on a 
 smelting furnace do to the liquid mass upon which they are 
 formed. 
 
 1 33. The composition of granitic rocks is somewhat varied. 
 Granite proper is composed of crystals of felspar, quartz, 
 and mica; is generally of a grayish colour; but is some- 
 times reddish, from the oxide of iron contained in the fel- 
 spar. When the dark glistening mineral hornblende takes 
 the place of the mica, the rock is known by the name of 
 Syenite, from Syene in Egypt, where it is found in great 
 abundance; arid when talc supplants the mica, the admix- 
 ture of felspar, quarlz, and talc, forms the Protogine of 
 French geologists. Sometimes it is formed by an admix- 
 ture of quartz and hypersthene, with scattered crystals of 
 mica, and is then called hyprrsthenic granite; or it may 
 assume a speckled and mottled appearance, from the pre- 
 sence of variously-coloured minerals, such as chlorite, and 
 is then called serpentine, from the fanciful resemblance it 
 bears to the serpent's skin. [At New Haven and Milford, 
 in Connecticut, a beautiful variety of this rock is found, 
 which is called verd-antique marble. It is a mixture of 
 serpentine with limestone, talc, hornblende, and felspar, and 
 exists in several varieties.] Porphyritic granite is also of 
 common occurrence ; that is, when, in addition to the crys- 
 tals which compose the general mass, larger crystals of 
 felspar are indiscriminately mingled through it. Occasion- 
 ally, the minerals in granite are so arranged as to bear a 
 resemblance to the lines in Arabic writing; hence this 
 variety is known by the name of graphic granite. 
 
 390. How do the granitic rocks render it probable that the globe was 
 
 once in a state of fusion, or liquefaction by heat J 
 
 391. Of what elements is granite composed? 
 
 392. When does it become Syenite ? 
 
 393. What is Protogine 7 
 
GRANITIC BASIS OF PR1MAKV STRATA. 99 
 
 134. Besides the above varieties, there are other distinc- 
 tions in use among geologists, according to the colour and 
 composition of granitic rocks. Felspar, quartz, mica, horn- 
 blende, and hypersthene, are the most abundant constitu- 
 ents; but the aspect of the mass is sometimes modified by 
 the partial admixture of other minerals, especially actyno- 
 lite, chlorite, talc, sch'orl, and steatite. When only two 
 minerals form a granitic rock (as felspar and mica), it is 
 called a binary granite. ; when three (felspar, quartz, and 
 mica), a ternary granite; and when four (quartz, mica, fel- 
 spar, and hornblende), a quaternary granite. 
 
 135. The structure of granite is always massive and 
 irregular; its texture is of various degrees of fineness, from 
 a hard and close-grained rock, to a coarse and loose aggre- 
 gation of primary crystals. 
 
 136. The position and relation of granite to the primary 
 strata is exceedingly irregular. Sometimes it rises up in 
 mountain masses (ra w), at other times spreads out as an 
 undulating floor or basis (6 6), and not unfrequently breaks 
 through the unstratified rocks in veins (v v v v v) of the 
 
 b b 
 
 Relative Positions of Granite. 
 
 most fantastic description. From these facts, there can be 
 no doubt of its igneous origin ; and the student will there- 
 fore be prepared to find it, like all other igneous rocks, 
 occurring amid the stratified formations at various periods 
 of the earth's history. Generally speaking, it is associated 
 with the primary and transition formations, just as trap 
 
 394. What is the nature of other varieties, and how designated ? 
 
 395. Give examples of binary, ternary, &c. 
 
 396. Explain how the diagram proves the igneous origin of granite. 
 
 397. Is it ever found associated with all the formations J 
 
109 GEOLOGY. 
 
 rocks are usually associated with secondary and tertiary 
 strata, or as volcanic products are mingled up with the 
 superficial accumulations now in progress ; but the student 
 is not on this account to suppose that granite may not also 
 be found in conjunction with secondary or tertiary strata. 
 
 1 37. The geographical distribution of granitic rocks is 
 very general ; they form many of the most extensive moun- 
 tain ranges in the world. The Grampians in Scotland, the 
 Cumberland and Cornwall hills in England, the Wicklow 
 mountains in Ireland, the Alps in Switzerland, the Pyrenees 
 in Spain, the Dofrafelds in Norway, the Abyssinian and 
 other A'rican ranges, and the Andes in South America, 
 are all more or less composed of rocks partaking of a gra- 
 nitic character. 
 
 138. The physical geography of a granitic district is by 
 no means remarkable for its fine scenery. Where the rock 
 is soft, the hills have a heavy rounded appearance, and are 
 only peaked and irregular in outline where it is hard, and 
 flanked by stratified rocks. Forming, in general, very lofty 
 hills and elevated table-lands, granitic districts present a 
 bleak and barren landscape, which is rendered still more so 
 by the snow-clad peaks of the loftier mountains. 
 
 13i). The economical uses to which granitic rocks arid 
 their products are applied are by no means unimportant. 
 Compact granite, from its extreme hardness, is largely 
 etnployed in the construction of docks, lighthouses, foun- 
 dations, bridges, and other structures where durability is 
 the object in view. Waterloo Bridge in London, the Liver- 
 pool and other English docks, are built of Aberdeen gra- 
 nite. It is the ordinary building stone in the city of 
 Aberdeen. The pyramids, Pompey's pillar, and other 
 ancient Egyptian structures, are composed of it, as are also 
 many monumental erections in our own country. Within 
 these few years, the red granite of Peterhead, in Scotland, 
 has been brought into use as an ornamental stone ; and 
 machinery has been erected to polish it like marble, to 
 
 398. What of the localities of granite T 
 
 399. What of its physical geography ? 
 
 400. What of its economical uses 7 
 
GNEISS AND MICA SCHIST SYSTEMS. 101 
 
 which many prefer it for chimney slabs, vases, pedestals, 
 &c. Mica and talc are sometimes found in crystals more 
 than a foot square; when of this size, they are split up into 
 thin plates, and, from their transparency, used in some 
 countries as a substitute for glass. Talc, by the Russians, 
 is thought preferable to glass for ship light, as it is not apt 
 to be broken by the firing of cannon ; it also stands a 
 higher degree of heat than glass without splintering. Some 
 varieties of felspathic and talcose granites are easily decom- 
 posed by exposure to the atmosphere, and in this state pro- 
 duce a fine impalpable powder of silica and clay, of great 
 use in the manufacture of porcelain, Mosaic tesserae, but- 
 tons, and artificial gems. The clay from decomposed fel- 
 spar is known in China by the name of kaolin, and is used 
 by that nation in the manufacture of their finest china. 
 According to Dr. Boase, upwards of 12,000 tons of decom- 
 posed felspar (Cornith clay) are annually exported from 
 Cornwall to the English potteries. 
 
 EXPLANATORY NOTE. 
 
 GRANITIC GROUP. To the many varieties of this group Mr. Lyell 
 applies the term hypogene rocks (Or., hypo, under, and ginomai, I am 
 formed) ; that is, nether, or under-formed rocks. This term he em- 
 ploys to avoid any theory as to the origin of granite ; but it has not 
 been generally adopted, the prevalent belief being, as mentioned above, 
 that granite is of igneous origin ; that it has resulted from the gradual 
 cooling down of the globe while in an incandescent state ; and that it 
 therefore forms a basis for all the stratified systems. 
 
 GNEISS AND MICA SCHIST SYSTEMS. 
 
 140. Before describing the primary rocks, it is necessary 
 to advert to a general fact, applicable to the character of all 
 stratified formations. Silir.eoita, argilfacfons, calcareous, and 
 carboniferous compounds, may be said to constitute the 
 solid crust of the globe ; and these compounds differ in 
 their appearance and mode of aggregation according to the 
 
 401. What of mica and talc ? 
 
 402. What species are used for manufactures T 
 
 403. What two systems are next considered T 
 
 404. What four compound* are said to form the crust of the globe I 
 
132 GEOLOGY. 
 
 order of their occurrence. For instance, the siliceous 
 rocks of the primary strata are compact and crystalline; in 
 the secondary they are less compact, lose their crystalline 
 appearance, and become sandstones of various degrees of 
 fineness ; in the tertiary they are often so soft in their tex- 
 ture as to be called sands: while in the superficial they are 
 merely loose accumulations of sand and gravel. So it is 
 with the argillaceous rocks from the compact and glisten- 
 ing clay-slates of the primary, through the slaty shales of 
 the secondary, and the laminated clays of the tertiary rocks, 
 up to the soft plastic clays of our alluvial valleys. As with 
 the siliceous and argillaceous, so with calcareous and car- 
 boniferous ; hence a table may be formed exhibiting these 
 gradations : 
 
 Siliceous. Argillaceous. Calcareous. Carboniferous. 
 
 Sand, Alluvial Clay, Marl, Peat, 
 
 Sandstone, Laminated Clay, Chalk, Lignite, 
 
 Grauwacke, Slaty Shale, Limestone, Brown Coal, 
 
 Quartz Rock. Clay-Slate. Crystalline Marble. Common Coal. 
 
 Thus, as we descend into the crust, the mineral ingredients 
 of the stratified rocks assume different degrees of aggrega- 
 tion, gradually becoming harder and more compact, till 
 ultimately they present a crystalline texture scarcely dis- 
 tinguishable from the granitic basis. 
 
 141. The composition of the. primary strata, like that of 
 the granite on which they rest, is often modified by the pre- 
 sence of peculiar minerals; though felspar, quartz, mica, 
 talc, hornblende, and chlorite, constitute the greater portion 
 of their mass. Gneiss, or the oldest system of stratified 
 rocks, differs little from true granite in its mineral compo- 
 sition, except in as far as regards the aggregation of the 
 simple minerals. In granite, the crystals of felspar, quartz, 
 mica, and hornblende, are entire and distinct; in gneiss, 
 their angles and frees are broken and water-worn. In 
 granite, there are no traces of a laminated or stratified 
 structure ; in gneiss, this structure is evident, even where 
 
 405. Describe the varieties of each according to the table. 
 
 406. How do they vary as we descend into the crust? 
 
 407. What minerals constitute the chief portion of primary strata 7 
 
 408. Wherein does gneiss ditfer from granite ? 
 
GNEISS AND MICA SCHIST SYSTEMS. 133 
 
 the strata are most indurated and contorted. All this attests 
 the aqueous origin of gneiss that it must have been de- 
 posited in water, and that it is composed of the disintegrated 
 minerals of unstratified granite. 
 
 14*2. The stratified structure which is sometimes confused 
 and indistinct in gneiss t is much more apparent and regular 
 in mica schist The particles of the latter are more water- 
 worn, and the abundance of fragmented mica gives its lami- 
 nation a degree of parallelism not to be found in the former. 
 Both, however, are frequently seen passing into each other, 
 thus rendering it difficult to distinguish where the one sys- 
 tem ends and the other begins. Passing over these dubious 
 strata, the mica schist system is composed of alternations of 
 mica schist, talcose schist, chlorite schist, hornblende schist, 
 quartz rock, primitive or crystalline limestone, with occa- 
 sional beds of clay-slate in the upper part of the system. 
 Independently of their stratification, the mica schist rocks 
 distinctly indicate, by their texture, that they have been 
 formed by the action of water. The particles of which 
 they are composed are more broken and rounded than those 
 of gneiss a circumstance arising from the fact, that they 
 were partly derived from granite and partly from gneiss, 
 which must thus have undergone a double process of attri- 
 tion. The following engravings are intended to represent 
 the external appearance of granite, gneiss, and mica schist 
 the first composed of distinct crystals, and showing no 
 traces of lamination ; the second irregularly laminated ; and 
 the third finely and regularly laminated. 
 
 Granite. Gneiss. Mica Schist. 
 
 143. Gneiss and mica schist differ little from granite, 
 
 409. Whit origin is hence ascribed to gneiss 1 
 
 410 What of mica schist? 
 
 41 1 Of what minerals is the mica schist system comoosed 1 
 
 412 Point out the distinctions of the diagrams. 
 
1 34 GEOLOGY. 
 
 and still less from one another, in their mineral composi- 
 tion ; showing clearly that it is chiefly in the degree of 
 attrition which the original minerals have undergone, that 
 their external differences consist: 
 
 GRANITE of felspar, quartz, and mica ; felspar, quartz, hornblende ; 
 felspar and hornblende ; or it may be of various combinations of these 
 simple minerals. 
 
 GNEISS of felspar, quartz, and mica; occasionally with hornblende 
 and garnets in it. 
 
 MICA SCHIST of mica and quartz, with hornblende and garnets con- 
 tained in it. 
 
 TALCOSE SCHIST of talc and quartz, and differs only in this respect 
 from mica schist. 
 
 CHLORITE SCHIST of chlorite and quartz. 
 
 HORNBLENDE SCHIST of quartz and hornblende, occasionally with 
 actynolite. 
 
 QUARTZ ROCK generally contains hornblende or mica irregularly im- 
 bedded in it. 
 
 The particles of the primary strata are indefinite both as to 
 srze and arrangement some are fine and close-grained, 
 others are conglomerate and coarse; but all bear evident 
 trace.- of t'leir aqueous origin. 
 
 144. There is nothing like a regular order of succession 
 among the primary strata. It may be stated generally, how- 
 ever, that gneiss underlies the mica schist ; that mica and 
 other crystalline schists are the lowest in the system ; and 
 that quartz rock, primitive limestone, and clay schist, make 
 their appearance towards the upper part of the series. 
 Stratification is sometimes obscure, and not very persistent ; 
 that is, any one stratum is not ibund stretching over a great 
 extent of country, as is the case with the secondary rocks. 
 A seam of coal will often be found stretching over ten or 
 twelve miles of country, without much difference either in 
 quality or thickness; but in the primary systems, the strata 
 thicken, thin out, and disappear in a very capricious man- 
 ner. In absence of any thing like a characteristic section, 
 
 413. What is argued from the slight differences in their mineral com- 
 
 position ? 
 
 414. Define each of the terms by their composition. 
 
 415. What of the particles of the primary strata 7 
 
 416. What of the order of succession in'the primary strata T 
 
 417. How is thfiir stratification 1 
 
GNEISS AND MICA SCHIST SYSTEMS. 105 
 
 the following rocks may be mentioned as constituting the 
 great bulk of the primary formation : Gneiss, mica schist, 
 talc schist, chlorite schist, shorlaceous schist, stea schist, 
 hornblende schist, actynolite schist, quartz rock, crystalline 
 limestone, hornstone, and protogine. Most of these rocks 
 pass insensibly into each other, and thus many compounds 
 are formed of which the student can only obtain a know- 
 ledge by the study of actual specimens. 
 
 145. No organic remains have yei been discovered in the 
 gneiss or mica schist systems ; and if life, either in a vege- 
 table or animal form, existed at the time these rocks were 
 deposited, it must have been exceedingly rare, and confined 
 to a few limited points on the earth's surface. (See note, 
 p. 108.) 
 
 14(3. As to the origin of the gneiss and mica schist sys- 
 tems, it is abundantly evident that the materials of which 
 they are composed were derived from the underlying gra- 
 nite. It has been stated that this rock forms a solid and 
 irregular basis, on which all the sedimentary strata rest; 
 and if this be true, it is evident that its surface must have 
 been partly under and partly above water, and subject to 
 the degrading influence of atmospheric, aqueous, and che- 
 mical agencies. Moreover, if the granitic crust was formed 
 by the cooling of an originally fused globe, the waters rest- 
 ing in the hollows must have been heated to a high degree, 
 and the air must have been loaded with vapours. All this 
 would further tend to hasten the degradation of the granite; 
 the runnels and streams would carry down the loose parti- 
 cles, laying down the heavier first, and carrying out the 
 lighter and smaller to deeper water. In process of time 
 the loose matter would get consolidated by the pressure of 
 its own mass ; the high temperature then pervading the 
 globe, together with chemical agency, would assist in pro- 
 ducing the crystalline texture; and thus a variety of schis- 
 tose rocks might be formed at one and the same time. 
 
 418. \\ hat roeks form the great bulk of the primary strata ? 
 
 419. Are they distinct or do they blend into each other 1 
 
 420. What is the inference from the absence of organic remains ? 
 
 421. Whence were the materials of the piimary strata derived, and 
 
 how accounted for f 
 
106 GEOLOGY. 
 
 That a high temperature 'existed during the formation of 
 the primary rocks, we have ample evidence, not only in 
 their hard and crystalline texture, and in the absence of all 
 organic remains, but in the occurrence of certain minerals, 
 such as garnet, whose presence denotes that the rocks in 
 which it is found have experienced a degree of heat 
 sufficiently light to form such a fusible mineral, but not 
 enough to melt the other constituents of which they are 
 composed. 
 
 147. The igneous rocks associated with the gneiss and 
 mica schist systems are, as may be anticipated, the granitic 
 on which they rest, and from which their materials have 
 been directly derived. Sometimes the granite is in imme- 
 diate contact with the gneiss, so much so, as to render it 
 matter of difficulty to say where the one ends and the other 
 begins ; at other times it touches the mica schist, or, it may 
 be, passes through both in the form of dykes and veins. 
 Later igneous rocks, such as porphyry, greenstone, and ser- 
 pentine, are frequently found traversing the gneiss and 
 mica schist in dykes and protruding masses; and occa- 
 sionally, still more recent effusions of trap are found pass- 
 ing through the primary strata, with their associated dykes 
 and veins of granite. Metalliferous veins are not of fre- 
 quent occurrence in the primary strata of the British isles, 
 though they are found in those of central and northern 
 Europe. Thermal springs are perhaps still more rare, 
 though abundant enough in the gneiss and mica schists of 
 other countries. 
 
 148. The extent of country occupied by the primary strata 
 is very great, although as yet but imperfectly ascertained. 
 They occur abundantly in the Highlands and islands of 
 Scotland, in the north of Ireland, along the flanks of the 
 Pyrenees, the Alps, the great mountain chains of northern 
 Europe, in Asia, in Ceylon, in Africa, and in America, 
 particularly in the Brazils and the United States. 
 
 422. What is inferred from the occurrence of garnet? 
 
 423. What igneous rocks are found in the gneiss and mica schist 
 
 systems ? 
 
 424. What of metals and thermal springs ? 
 
 425. To v.<ia extent are the primary strata ascertained? 
 
GNEISS AND MICA SCHIST SYSTEMS. 107 
 
 140. The physical aspect of primitive districts is bold, 
 rugged, and unfertile. Thrown into lofty mountains by 
 the granite, and into abrupt and vertical positions, it is 
 chiefly among gneiss and mica schist that those deep glens 
 and abrupt precipices occur which give the well-known 
 picturesque effect to Highland scenery. The student will 
 readily perceive how this effect is produced, when he con- 
 siders the hardness of the rocks, and the highly vertical 
 and contorted positions into which they are thrown ; where- 
 as in secondary formations, the position is in general flatter, 
 and the strata so soft, that they cannot present the same 
 rugged and abrupt appearance. 
 
 150. The minerals of commerce derived from these systems 
 are by no means numerous. Several of the metallic ores, 
 such as tin and copper, occur in veins traversing these 
 strata. The limestones, from their highly crystalline tex- 
 ture, in general produce valuable marbles ; but none of the 
 other rocks are of use for architectural purposes. Potstone, 
 or the lapis ollaris of the ancients, of which very pretty jars 
 and vases are manufactured, is found in stea schist. Ami- 
 anthus, or flexible asbestus, occurs among the mica schisis, 
 and is sometimes used in the manufacture of fabrics which 
 are indestructible by fire. The garnet is a well-known pre- 
 cious stone ; and many of the most valuable are found in 
 the rocks of this system. 
 
 151. It may be stated generally ofgnriss and mica schist t 
 that they are the oldest sedimentary rocks, and rest upon 
 masses which owe their origin to heat; that they are totally 
 different from other stratified rocks, inasmuch as their par- 
 ticles have not undergone so much attrition, and likewise 
 as they have been subjected to a higher degree of heat ; 
 that they are destitute of organic remains, arid therefore 
 afford no evidence of habitable dry land ; and lastly, that 
 they are spread over so great an extent, as to be considered 
 almost universal. 
 
 426. What of the physical aspect and peculiarities of these primitive 
 
 districts ? 
 
 427. What of the minerals of commerce in these systems? 
 
 428. Describe their jreneral characteristics. 
 
103 GEOLOGY. 
 
 EXPLANATORY NOTE. 
 
 SILICEOUS (Lat., silex, flint) all rocks having a flinty texture are said 
 to be siliceous. Quartz is the purest form in which silex occurs. When 
 grains of quartz are loosely aggregated, as in some sandstones, the 
 locks are said to be quart zose, or gritty. 
 
 ARGILLACEOUS (Lat., argilla, clay) rocks composed of clay, or hav- 
 ing a considerable portion of clay in their composition, are said to be 
 argillaceous. 
 
 CALCAREOUS (Lat., calx, lime) composed of, or containing a con- 
 siderable portion of lime. 
 
 CARBOMFEROUS (Lat., carbo, coal, or charcoal) rocks containing 
 conl, or associated with coal, are said to be carboniferous. Carbon- 
 aceous is applied when traces of carbon appear intermingled with their 
 texture. 
 
 SCHIST (Gr., schisma, a splitting or division) applied to rocks easily 
 split up into slaty-like plates or divisions, as mica schist. 
 
 GNEISS AND MICA SCHIST. It has been already stated, that to these 
 systems Mr. Lyell applies the term met amor phi c, meaning thereby that 
 they have undergone a metamorphosis, or change, in their sedimentary 
 character, so as frequently to be mistaken for true igneous or granitic 
 rocks. According to this opinion, gneiss and mica schist may have 
 contained organic remains, the traces of which havo since been obli- 
 terated by heat ; even granite itself may be a highly metamorphic 
 rock in other words, that it may be altered or metamorphosed sedi- 
 mentary strata. By this theory all stratified systems may in time become 
 metamorphic, so that geology can never hope to arrive at any thing 
 like a continuous history of the globe from its origin upwards the 
 older strata and their remains being thus successively obliterated. 
 This theory, however, has not been generally adopted, and, from the 
 plain evidences which most strata afford of their formation, it is not 
 likely to be so. 
 
 CLAY-SLATE, GRAUWACKE, AND SILURIAN SYSTEMS. 
 
 152. It has been stated that the four great types of all 
 stratified rocks are siliceous, argillaceous, calcareous, and 
 carboniferous ; and that, in general, each system is charac- 
 terized by some prevailing type. The gneiss and mica 
 schists have been described as eminently siliceous: we shall 
 now learn that in the clay-slate, grauwacke, and silurian 
 systems, argillaceous compounds prevail almost wholly so 
 in the first system, mingled with arenaceous strata in the 
 
 429. Define the several terms of the note. 
 
 430. Why does Mr. Lyell use the term metamorphic ? 
 
 431. What systems are next considered ? 
 
 432. To which type of stratified rocks do these belong 7 
 
CLAY-SLATE, GRALWACKE, AND SILURIAN SYSTEMS. l'J3 
 
 second, and with calcareous and arenaceous beds in the 
 third. 
 
 L>3. The clay-slate system presents a vast thickness of 
 fine-grained fissile argillaceous rock, of considerable hard- 
 ness, varying in colour, and of glistening aspect. The 
 prevalent colours of sjate are black, green, bluish, purplish, 
 and mottled; some varieties being hard and splintery, 
 others soft and perishable. The character of any particu- 
 lar slate is, however, very persistent; the accidental or 
 imbedded minerals are few these being chiefly cubic-iron 
 pyrites, and crystals of chiastolite and hornblende. 
 
 154. The, composition of the grauwacke, is much more 
 varied and irregular. As sandstone may be said to be con- 
 solidated sand, and conglomerate consolidated gravel, so 
 may grauwacke be defined to be an aggregate of clay, grains 
 of quartz, felspar, and mica, with fragments of jasper and 
 other minerals. The cementing material is clay, which 
 often constitutes the greater portion of the rock, and in 
 such cases the texture differs little from that of clay-slate; 
 but in many strata fragmentary ingredients prevail, so that 
 the texture varies in fineness from that of a coarse slate to 
 a conglomerate of pebbles more than an inch in diameter. 
 Like clay-slate, grauwacke presents various degrees of hard- 
 ness, though, generally speaking, it may be described as a 
 highly indurated conglomerate indicating most clearly its 
 origin from the waste of earlier siliceous and argillaceous 
 formations. Associated with the slates and grauwackes 
 are occasional beds of concretionary limestone, which par- 
 take of the argillaceous character of the rocks with which 
 they are associated. 
 
 155. In the silurian system, limestones occur more fre- 
 quently, so that the calcareous type, or, at all events, an 
 intimate blending of argillaceous and calcareous com- 
 pounds, may be said to prevail. Until a recent period, this 
 system was considered as a portion of the grauwacke 
 group, and as marking its passage into the gray micaceous 
 
 433. What of the varieties and composition of the clay slate ? 
 4J4. Ho'.v does grauwacke diler from this 1 
 
 435. What of its composition and varieties? 
 
 436. What is peculiar in the silurian system ? 
 
1 1 GEOLOGY. 
 
 beds of the old red sandstone. Merely looking at cabinet 
 specimens, it would be impossible to distinguish between 
 many of the giauwacke and silurian rocks, but taking them 
 in the mass they are readily distinguishable. In the first 
 place, their sedimentary character is very marked; they 
 present more rapid alternations from one kind of strata to 
 another; they have undergone fewer* changes by heat; and 
 are generally looser and more earthy in their texture. The 
 limestones are less crystalline than those of the early grau- 
 wackes; the arenaceous beds are also less siliceous, and 
 more closely resemble ordinary sandstones, while the abun- 
 dance of organic remains justifies their arrangement into a 
 separate system. 
 
 156. From this description of these systems, it will be 
 seen that their main type is argillaceous; eminently so in 
 the clay-slates; abundantly enough in the grauwackes, 
 which pass, in texture, from slate to a coarse quartzose 
 conglomerate ; and perceptibly in the silurian limestones, 
 which are all of a dark argillaceous character. It is also 
 worthy of notice, that the crystalline aspect which charac- 
 terized the Primary Rocks disappears with the clay-slates, 
 and gradually passes into an earthy or arenaceous texture 
 in the grauwacke and silurian. It is true that some of the 
 lower slates have a glistening semi-crystalline appearance; 
 but, taken, in the mass, arid in conjunction with the grau- 
 wacke and silurian rocks, the whole materials of these sys- 
 tems are more loosely arranged, and more decidedly sedi- 
 mentary, than the gneiss and mica schists. The term 
 Transition has been applied to the series, as not only indi- 
 cating a change in the causes of formation, but implying 
 that the world was then passing from an uninhabitable to 
 an inhabitable state. 
 
 157. The stratified structure is abundantly obvious in 
 the rocks of the transition series. The occurrence of inter- 
 stratified limestones, and the bands of different colour and 
 hardness in the slates, all point to deposition in water; 
 
 437. Wherein do they differ from grauwacke ? 
 
 438. Of what type are these three systems t 
 
 439. Why is the term transition applied to this series 1 
 
 440. What proves their aqueous origin 1 
 
CLAY-SLATE, GRAUWACKE, AND SILURIAN SYSTEMS. I I I 
 
 while the succession of fine and coarse-grained grauwackes, 
 of siiurian limestones and shales, is as decisive of stratifi- 
 cation as alternations of sandstone, shale, and coal. From 
 this statement, the student must not, however, expect to 
 find the sedimentary structure very distinctly marked in the 
 chy-slatcs; it is only in the grauwacke and siiurian that 
 this is decided. Lamination may be said to prevail in the 
 rocks of fine texture, and stratification in those of an are- 
 naceous or calcareous character. The laminated structure 
 of grauwacke is, however, of a different character from 
 lamination in clay-slate; in the former it is the result of 
 deposition, in the latter it is the effect of a subsequent 
 change which the rock has undergone, called cleavage. 
 
 15K Cltavage differs from ordinary lamination in this 
 respect, that it causes clay-slate to split up into thin plates 
 at right angles, or nearly so, to fhe bed of stratification. 
 while lamination simply implies that any stratum can be 
 split up into a number of thinner layers or laminae. Cleav- 
 age occurs in several varieties of rock, but it is most regular 
 and distinct in clay-slate ; and it is owing to this structure 
 that the rock has the property of being split up into thin 
 divisions for roofing and other purposes. The appearance 
 which cleavage presents in the mass is represented beneath, 
 by the nearly perpendicular lines cutting those of stratifica- 
 
 Section eihibiting lines of Cleavage. 
 
 tion at a high angle. How cleavage has been produced, is 
 still an undecided problem among geologists; though it 
 may be stated generally, that it seems to have taken place 
 long after the deposition of the strata in which it occurs, and, 
 like crystallization, to owe its origin to the influence either 
 of heat or of electricity, or perhaps to both. (See note.) 
 
 441. What of the sedimentary structure 7 
 
 442. What of lamination and cleavage? 
 
 443. Explain the diagram. 
 
GEOLOGY 
 
 159. The succession of strata in the clay-slate, gran- 
 wacke, and silurian systems, has not yet been very clearly 
 ascertained. In general terms, it may be stated that the 
 lower slates partake of a micaceous or hornblendic charac- 
 ter ; that they become less crystalline as we ascend in the 
 series, and are succeeded by finely-laminated grauwacke, 
 with interstratified limestones. In the grauwacke there is 
 no apparent order of succession, although, in most locali- 
 ties, limestones and argillaceous beds prevail in the lower, 
 and grits and conglomerates in the upper portion of the 
 system. In the silurian, order is still less obvious; but, on 
 closer study, it is found that grits and grauwacke-looking 
 rocks prevail in the lower portion of the system, dark- 
 coloured shales and limestones in the middle, and slaty mi- 
 caceous sandstones in the upper. The following detailed 
 section will convey to the student a more correct idea of 
 the order and succession among these systems : 
 
 1. Slightly micaceous thin-bedded sandstones. 
 
 2. Gray and blue argillaceous limestones. 
 
 3. Liver-coloured shale, with concretions of earthy 
 
 limestone. 
 
 4. Highly concretionary subcrystalline blue and gray 
 
 limestone. 
 
 5. Dark-gray argillaceous shale, with nodules of 
 
 earthy limestone. 
 
 6. Thin-bedded impure limestone, containing shells, 
 
 alternating with finely-laminated micaceous 
 sandstone of a greenish colour. 
 
 7. Sandstones, grits, and limestones ; arenaceous 
 
 beds prevailing. 
 
 8. Dark-coloured flags, chiefly calcareous ; sand- 
 
 stones and sandy schists. 
 
 9. Grauwacke slates and sandstones, coarse lime- 
 
 stones, and thick-bedded grauwacke rocks. 
 
 10. Dark argillaceous limestone, with shells and 
 
 corals. 
 
 11. Peculiar slaty and flaggy beds: mottled in colour ; 
 
 sometimes coarse and conglomerate, generally 
 of moderate fineness, alternating with coloured 
 clayey beds. 
 
 12. An immense thickness of clay-slate of various 
 
 colours blue, black, greenish, purple, or mot- 
 tled ; of fine grain, sometimes compact, some- 
 times soft and useless. 
 
 SILURIAN. < 
 
 GRAU- 
 WACKE. 
 
 CLAY-SLATE 
 
 1 
 
 444. What of the succession of strata in these systems T 
 
 445. Explain the tabular arrangement. 
 
CLAY-SLATE, GRAUWACKF, AND 9U t'RIAN SYSTEMS. 113 
 
 160. The organic remains of these systems are possessed 
 of more than ordinary interest, from the fact of their being 
 the earliest forms of life with which we are acquainted. In 
 the preceding systems we have no traces either of vegetable 
 or of animal existence : life begins to dawn only with the 
 development of the clay-slate group, and to become more 
 abundant as the deposition of the grauwacke and silurian 
 proceeds. The earliest forms of vitality are not plants, 
 but animals animals undoubtedly low in the scale of 
 organized being, but still perfect animals, as perfectly 
 adapted to the condition of things under which they had to 
 live as those now existing. They are wholly marine; and 
 here it may be observed, that no remains of terrestrial ani- 
 mals have yet been discovered by geologists earlier than 
 towards the close of the Secondary Formations. In the clay- 
 slate and grauwacke, no traces of vegetable organism have 
 been found, and only about thirty species of corals and 
 shell-fish ; in the silurian, animal remains become much 
 more abundant; but doubt is entertained respecting some 
 fragments of sea-weeds and ferns said to belong to this for- 
 mation. Whether the remains of plants and animals were 
 entombed in these earlier formations, and have since been 
 obliterated by the agency of heat, geological science has 
 not been able to determine; but at present, we are war- 
 ranted in stating, that only a few rare corals and shells 
 occur in the clay-slate system ; a greater number of corals, 
 shells, and Crustacea in the grauwacke; and a variety of 
 corals, shells, Crustacea, fish bones, and teeth, in the silu- 
 rian. So far as they have been examined, all these remains 
 belong to species long since extinct ; indeed, are distinct 
 from those which occur in the Secondary Strata, and bear 
 only a generic resemblance (often a faint one) to existing 
 races. 
 
 161. From the scantiness and peculiarity of organic life, 
 it is difficult to arrive at any conclusion as to the condition 
 
 446 What of the organic remains found here ? 
 
 447. What kind of animals exclusively? 
 
 44S. Where are terrestrial animals to be sought for t 
 
 449. Are the animals found of any existing species T 
 
 4oO. What is argued from their scantiness and peculiarities t 
 
114 
 
 GEOLOGY. 
 
 of the world at this early period. The existence of shell- 
 fish would seem to indicate the co-existence of marine plants 
 upon which they fed; and though we are aware that mol- 
 luscous animals might prey upon each other, still, the pro- 
 bability is, that marine vegetation was to some extent spread 
 over the bottom of the transition seas. The preponderance 
 of coral-like animals points to a warm and favourable con- 
 dition of the waters for their development ; and it may be 
 that this highly heated condition entirely prevented the 
 growth of terrestrial plants, and rendered even those of 
 marine growth of so rare occurrence. Be this as it may, 
 we are only certain of several species of Zoophytes, Mol- 
 lusca, and Crustacea in the clay-slate and'grauwacke rocks 
 among which the most characteristic are those exhibited 
 in the following group: 
 
 1. Cyathophyllum Cyathus ; 2. Heliopora Porosa ; 3. Catenipora La- 
 byrinthica ; 4. Producta ; 5. Spy-ifera ; 6. Terebratula. 
 
 162. The fossils of the Silurian system are much more 
 abundant ; there are a greater number of species belonging 
 to each genus; annulosa, Crustacea, and fishes, are decided; 
 and, according to many geologists, plants allied to the algae 
 
 451. What inferences seem authorized ? 
 
 452. Explain the diagrams. 
 
 453. What of the fossils of the silurian system T 
 
 454. What classes o*" animals are found here, and what varieties I 
 
CLAY-SLATE, GRAUWACKE, AND SILURIAN SYSTEMS. 115 
 
 (sea-weeds), the equisetaceae (horse-tails), filices (ferns), and 
 others, make their appearance. Passing over the remains 
 of plants and true vertebrated fishes, about the existence of 
 which at this period there is still great obscurity, we shall 
 notice some of the ascertained peculiarities of the radiata, 
 mollusca, and articulata belonging to the Transition era. 
 
 163. The waters of the Silurian period seem to have 
 been crowded in some localities with zoophytes and corals, 
 for certain limestones are as much composed of their re- 
 mains as a coral reef is of recent corals. Among the radi- 
 ata, the crinoid or encrinitc family occur for the first time, 
 these differing from other corals (see par. 309) in the self- 
 dependent nature of their structure, their fixed articulated 
 stalk, and floating stomach furnished with movable rays for 
 the seizure and retention of their food. The shell-fish also 
 become more numerous and distinct in form ; spirifcrce, 
 terebratida, and products, are every, where abundant : and 
 chambered shells, like the existing nautilus, begin to people 
 the waters. It must be remarked, however, that the encri- 
 nites and chambered shells of this early period are not so 
 numerous, so gigantic, or so perfect in their forms, as those 
 of the Secondary Strata ; it is in the mountain limestone 
 group that the crinoidea attain their meridian, and in the 
 lias and oolite that the ammonites and nautili are most fully 
 developed. Of the Crustacea of this era, the most interest- 
 ing and abundant type is the trilobite (three-lobed), of 
 which several genera and many species have been de- 
 scribed, and to which scarcely any existing creature bears 
 an analogy. The trilobite (see 7, H, 9 in the following 
 engraving) was a true crustacean, covered with shelly 
 piates, terminating variously behind in a flexible extremity, 
 and furnished with a head-piece composed of larger plates, 
 and fitted with eyes of a very complicated structure. It is 
 supposed by some to have made its way through the water 
 by means of soft paddles, which have not been preserved; 
 and by others merely to have sculled itself forward by the 
 aid of its flexible extremity. Of its various organs, the 
 most interesting is the eye, of which several specimens have 
 
 455. What wonderful structure .is found in the trilobite ? 
 
116 
 
 GEOLOGY. 
 
 been obtained in a very perfect state. This organ, accord- 
 ing to fossil anatomists, is formed of 4JO spherical lenses 
 in separate compartments, on the surface of a cornea pro- 
 jecting conicaJly upwards, so that the animal, in its usual 
 place at the bottom of waters, could see everything around. 
 As there are two eyes, one of the sides of each would have 
 been useless, as it could only look across to meet the vision 
 of the other; but on the inner sides there are no lenses, 
 that nothing may, in accordance with a principle observable 
 throughout nature, be thrown away. It is found that in 
 the strolls, a surviving kindred genus, the eyes are con- 
 
 l.Astrea; 2. Turbinolia Fungites ; 3. Terebratula Risca; 4. Lep- 
 ta>.na Lata ; 5. Actinocrinites ; 6. Euomphalus Rugosus ; 7. Asaphus de 
 liuchii ; 8. Asaphus Tuberculatus ; 9. Calymene Biumenbachii ; 9a. Side 
 view of Calymene while rolled up. 
 
 456. What of the serolis ? 
 
CLAY-SLATE, GRAUWACKE, AND SILURIAN SYSTKMa. 11? 
 
 structed on exactly tlie same principle, except that they are 
 not so high a necessary difference, as the back of the 
 seroJis is lower, and presents less obstruction to the crea- 
 ture's vision. This little organ of a trivial little animal 
 carries to living man the certain knowledge that, many ages 
 ago, the air he breathes, and the light by which he sees, 
 were the same as at this hour, and that the sea must have 
 been in general as pure as it is now. If the water had been 
 constantly turbid or chaotic, a creature destined to live at 
 the bottom of the sea would have had no use for such deli- 
 cate visual organs. " With. regard to the atmosphere," says 
 Dr. Buckland, " we infer that, had it differed materially 
 from its actual condition, it might have so far affected the 
 rays of light, that a corresponding difference from the eyes 
 of existing crustaceans would have been found in the organs 
 on which the impressions of such rays were then received. 
 Regarding light itself also, we learn, from the resemblance 
 of these most ancient organizations to existing eyes, that 
 the mutual relations of light to the eye, and of the eye to 
 light, were the same at the time when crustaceans endowed 
 with the faculty of vision were placed at the bottom of the 
 primeval seas, as at the present moment." 
 
 1()4. The animals of this early period, like those now ex- 
 isting, were partly herbivorous (living on plants), and partly 
 carnivorous (living on the jitsh of others). The polypes 
 and crinoidea, it is true, merely secreted limy matter from 
 the waters of the ocean wherewith to build their calcaredus 
 structures; but while certain tribes of shell-fish were living 
 on the sea-weeds which flourished along the shores, other 
 races were preying upon these, or upon each other. Among 
 the vegetable eaters were the products, terebratulae, &c.; 
 the ammonites and trilobites were those which lived upon 
 others. 
 
 16j>. That the. transition strata hnve been derived partly 
 from the disintegrated materials of the gneiss and mica 
 
 457. What does this structure demonstrate in relation to the ancient 
 
 earth ? 
 
 458. How IB this argued by Dr. Buckland 1 
 
 4-59. What of those herbivorous and carnivorous J 
 460. Whence were the transition strata derived f 
 (5 
 
 .* 
 
1 18 GEOLOGY, 
 
 schists, and partly from the granite, is abundantly obvious 
 In the gneiss and mica schists, the primitive crystals of the 
 granite in many instances had undergone little attrition, 
 and in most cases only sufficient to make them arrange 
 themselves in a flat or laminated position. In the transi- 
 tion systems, the material has suffered sometimes both a 
 mechanical and chemical change. The felspar of the gra- 
 nite and primary strata presents itself in the clay-slate as a 
 soft argillaceous sediment, destitute of the potash and soda 
 which entered into its crystallized condition. The quartz 
 presents itself in sandy grains, without any particular form, 
 sometimes finely pulverized, at other times coarse and 
 gritty. The mica is variously disseminated, scarcely ap- 
 pearing in some strata of the grauwacke; but occurring in 
 others of the silurian, so as to give them a micaceous and 
 laminated aspect. All this implies the combined agency 
 of air and water the atmosphere to assist in the chemical 
 decomposition of the felspar, water to transport it to the 
 sea of deposit. The fineness and thickness of the clay-slate 
 deposit indicates an im.'nense depth of still water; the 
 sandy and conglomerate beds of the grauwacke not only 
 the action of rivers, but the action of the sea upon its shores ; 
 while the calcareous beds of the silurian implies the agency 
 of the coral animal, precisely similar to that now going for- 
 ward in the Pacific. Here, then, we have a condition of 
 the world with hills and valleys, rivers and seas the atmos- 
 pheric agents acting upon the cliffs and precipices; the 
 aqueous also degrading the rocks, transporting the material, 
 and depositing it along the shores of seas, whose waters 
 gave birth to corals, shell-fish, and fishes. Fine clayey silt 
 formed clay-slate; sand and other mud slaty sandstones; 
 gravel grauwacke conglomerate; and coral polypes beds 
 and reefs of limestone. We have no evidence of terrestrial 
 life ; and the necessary inference is, that the conditions of 
 the world did not then permit of its being called into ex- 
 istence. 
 
 461. How is the agency of both air and water shown? 
 
 462. What other indications are furnished by these systems ? 
 
 463. What peculiarities of the ancient earth are here considered as 
 
 proved 1 
 
CLAY-SLATE, GRAUWArKE, AN l> SILURIAN SYSTEMS. 1 19 
 
 106. The igneous rocks associated with the transition 
 scries are granite, serpentine, porphyry, greenstone, varieties 
 of trap, and mineral veins. Indeed there is scarcely a de- 
 velopment of the clay-slate or grauwacke systems without 
 associated granitic rocks ; and the greater portion of the 
 silurian strata are thrown into inclined and contorted posi- 
 tions by the same agency, while effusions of trap make their 
 appearance among the latter strata. Perhaps the most ex- 
 tensive and gigantic efforts of volcanic power were exhib- 
 ited at the close of this period; and there is abundant 
 proof that all the principal mountain chains in the world 
 were then upheaved The Grampian and Welch ranges, 
 the Pyrenees, Hartz mountains, Dofrafelds, Uralian, Him- 
 inaleh, Atlas range, Mountains of the Moon, and other 
 African ridges, the Andes, and Alleghanies, all seem to 
 have received their present elevation at the close of the 
 transition period. From this fact, the student will more 
 readily perceive how the primary and transition strata 
 should be thrown into highly inclined and contorted posi- 
 tions ; how they should be traversed by so many dykes and 
 mineral veins; and how slaty cleavage, and other alterations 
 by heat, should have taken place. 
 
 167. The extent of country over which the day-slate, 
 grauwackf, and silurian systems fir" spread, must be suffi- 
 ciently indicated by the mention oi .he principal mountain 
 ranges in the world, from whose sui s and flanks their 
 strata slope away for many leagues on either side. 
 
 168. The geographical features of transition districts 
 are bold and mountainous, and are well illustrated by the 
 characteristic scenery of Wales, the Cumberland Lakes, 
 and the Scottish Highlands. " Supported by granite," 
 says Professor Phillips, " and mixed with igneous masses, 
 the slaty rocks of the English lakes rise to more than 3000 
 feet in height, and present a variety of outline, and intri- 
 cacy of combination, which, in connexion with clear lakes 
 and considerable waterfalls, leave to Switzerland little supe- 
 
 464. What igneous rocks are found in the transition series ? 
 
 465. What characterized the transition period of the earth's history 1 
 
 466. What of their localities and physical geography 7 
 
2 GfcOLOGY. 
 
 riority." This grandeur, intricacy, and variety of aspect 
 can be readily accounted for, when we consider tiie height 
 to which these strata have been elevated, the vertical posi- 
 tions into which they are thrown, and the irregularity of 
 their composition, which allows them to be scooped out 
 and worn down to a thousand forms here craggy and 
 splintery, there sinking, or rather cleft into fearful gorges 
 and ravines. 
 
 lf>9. The economic uses to which the minerals of these 
 systems are applied are numerous and important. From 
 the clay-slate are derived roofing-slate, writing-slate, and a 
 variety of slates for ornamental and other purposes. Flag- 
 stones and pavement are obtained from the grauwacke and 
 silurian beds, and several ornamental marbles from the 
 limestone of the same systems. But the mere rock min- 
 erals ate of little value in comparison with the metfillic 
 veins found in these strata. Tin, lead, copper, silver, gold, 
 and other metals, are found abundantly in the veins which 
 traverse the clay-slate; indeed they form in Britain, as well 
 as in other countries, the principal metalliferous rocks, 
 with the exception of the lead and ironstone, of the carbon- 
 iferous system. 
 
 EXPLANATORY NOTE. 
 
 GRAUWACKE a German miner's term, signifying gray rock ; adopted 
 in geology to designate the grayish slates and siliceous conglomerates 
 of the transition strata. English-geologists have conferred upon this 
 group the name of Cambrian, from its forming a large portion of the 
 surface of Cambria or Wales ; the term grauwacke is more general and 
 descriptive. 
 
 SILURIAN a term invented by Mr. Murchison to designate those 
 calcareous and argillaceous beds which lie between the grauwacke and 
 old red sandstone. The word is derived from Silures, the name of an 
 ancient tribe who inhabited that district of country between England 
 and Wales where these rocks are very clearly developed. 
 
 PYRITES a mineral composed of sulphur and iron sulphuret of iron. 
 If is usually of a brass-yellow colour, brilliant, and crystallized. Those 
 little shining crystals so abundant in some kinds of roofing-slate are 
 cubic pyrites. The name is derived from the Greek, pyr, fire ; because 
 the mineral occasionally produces spontaneous combustion. 
 
 LAMINATION (Lat., lamina, a leaf or blad) applied to thin layers 
 or leaf-like divisions of rocks. 
 
 ARENACEOUS (Lat., arena, sand) sandy. Rocks chiefly composed 
 
 467. What are the economical uses of these minerals T 
 
 468. Define the terms found in the note. 
 
OLD RED SANDSTONE SYSTEM. 121 
 
 of sand are described as arenaceous. The principal constituent of sand 
 is quartz or silex ; and the terms siliceous, quartzose, and arenaceous, 
 are applied to rocks according to the appearance which their textures 
 
 resent. Thus, highly indurated and close-grained sandstone is said to 
 e siliceous ; if the particles of quartz be large and distinct, quartzose ; 
 and if moderately fine, and rather loose in texture, arenaceous. 
 
 GRITS hard sandstone, in which the grains of quartz are sharp and 
 angular, are technically called grits, as millstone-grit, grindstone- 
 grit, &c. 
 
 CLEAVAGE. The peculiarities of this structure have given rise to 
 many speculations and experiments. Mr. R. W. Fox submitted a mass 
 of moist clay, worked up with acidulated water, to a weak electric 
 action for several months ; and it was found at the end of that time to 
 present traces of cleavage, the laminae being at right angles to the elec- 
 tric forces. Others .ire of opinion that cleavage is superinduced when 
 considerable chemical action takes place in any finely pulverized sub- 
 stance as clay cleavage being thus regarded as a species of rude 
 crystallization. Another class of theorists, from observing that slaty 
 cleavage occurs among the shales of the coal measures, when these are 
 in the neighbourhood of igneous rocks, attribute the structure to heat. 
 It is not unlikely that all these causes may have been concerned in 
 producing cleavage ; for, when better understood, it is more than pro- 
 bable that heat, electricity, and chemical action, are ouly modifications 
 of one universal agency. 
 
 OLD RED SANDSTONE SYSTEM. 
 
 170. Until a comparatively recent period, geologists were 
 accustomed to consider gneiss, mica schist, clay-slate, and 
 old red sandstone, as sufficiently distinctive of all the strati- 
 fied systems which lay underneath the coal measures. We 
 have seen, however, that, in point of mineral composition, 
 as well as in organic remains, the clay-slate differs essen- 
 tially from the grauwacke; and that grauwacke, as we 
 ascend, begins to lose its arenaceous character, and to be 
 succeeded by a series of argillaceous and calcareous beds 
 more prolific in fossils, and in the mass perceptibly differ- 
 ent. To this series of strata Mr. Murchison applied the 
 term Silurian system a system which may be said to par- 
 take of the character of the grauwacke beds beneath, as it 
 insensibly passes into the gray micaceous flagstones of the 
 o!d red sandstone above. The student must not, however, 
 suppose that all these systems are to be met with fully de- 
 
 469. What of grits and cleavage 7 
 
 170. What theory is broached of the identity of heat, electricity and 
 c!; p micai agency? 
 
 47 1 . What of the old red sandstone system f 
 
122 GEOLOGY. 
 
 veloped in every country; all that the science of geology 
 affirms is, that, when they are present, the above is their 
 order of occurrence, and the general aspect and character 
 they assume. Sometimes, indeed, the clay-slate is repre- 
 sented by a few indistinct argillaceous beds; and in many 
 places it is difficult to discover anything like a well-defined 
 series of strata corresponding to the silurian rocks of Mr. 
 Murchison; but, generally speaking, there is always some 
 shade of distinction, either in mineral or fossil character, 
 which enables us to trace the gradation of these successive 
 systems. VV hatever difficulty may be experienced in ascer- 
 taining (he presence and limits of the grauwacke and silu- 
 rian systems, there is seldom any doubt as to the old red 
 sandstone, which, in the British islands, is one of the most 
 clearly developed of rock formations. 
 
 171. T/ie composition of the old red sandstone, as indi- 
 cated by the name, is chiefly arenaceous, presenting a suc- 
 cession of sandstones alternating with subordinate layers of 
 sandy shale. The sandstones pass, in fineness, from close- 
 grained fissile flags to thick beds of conglomerate, the latter 
 being composed of pebbles from the size of a hazel-nut to 
 ihat of a man's head. The whole system is tinged with 
 the peroxide of iron, the colours ranging from a dark rusty 
 gray to brick-red, and from a mottled purple and fawn shade 
 to axiream-yellow. The mottled aspect is principally found 
 in the shales which, from their sandy character, may be 
 regarded as imperiled sandstones. There are also some 
 Cdlcareous beds in the system, but these ure not regularly 
 developed, and are all siliceous and concretionary in their 
 composition and texture. From their impure and concre- 
 tionary aspect, they are generally known by the name of 
 cornstones, and are of little or no use as limestones. Taken 
 iii the mass, the composition of this system is sufficiently 
 indicated by the term old rtd sandstone the epithet " old" 
 bv ing applied to distinguish it from another series of red 
 sandstones which occurs above the coal measures, and is 
 usually designated the new red sandstone. 
 
 472. What is said of the order of its succession? 
 
 473. What is the composition and variety of this sandstone,? 
 
 474. To what is its colour ascribed ? 
 
OLD RED SANDSTONE SYSTEM. .123 
 
 [When sand is found cemented together by iron or car- 
 bonate of lime which has been infiltrated through the mass 
 in a state of solution, thus forming compact stones, it has 
 been called alluvial sandstone. When rounded pebbles are 
 thus cemented, they form conglomerate or puddingstone; 
 and if the mass be composed of angular fragments, it is 
 called breccia. Of this variety, the beautiful pillars in the 
 interior of the Capitol of the United States, at Washington 
 are built.] 
 
 1 72. 77ie order of succession among the old red sandstone 
 strata varies considerably in different localities. It has 
 been stated that the prevailing mineral characters are fine- 
 grained red sandstones, including detached pebbles; beds 
 of coarse conglomerate ; fine-grained fissile micaceous beds 
 of a gray colour, locally called tilestones and flagstones; 
 layers of mottled shales; arid strata of yellow sandstone. 
 Now, although in some districts the conglomerate may be 
 undermost, and in others the tilestones, yet, making allow- 
 ance for these local deviations, the following may be taken 
 as the most frequent order of occurrence: 
 
 COAL MEASURES : - 
 
 1. Yellow sandstones, fine-grained, including detached peb- 
 bles, and alternating with layers of mottled shale. Remains 
 of fishes, but no traces of vegetables. 
 
 2. Red conglomerate, or Puddingstone, of vast thickness, either 
 in one mass, or interrupted by occasional beds of red sand- 
 
 g 
 
 < K 
 
 a ^ 
 
 D > 
 
 ^ 
 
 stone. No organic remains 
 
 3. The 
 red 
 
 red sandstone proper, generally in thick beds of a brick- 
 colour, enclosing detached pebbles of quartz and other 
 primary rocks. Conglomerate beds and concretionary lime- 
 stones are occasionally interstratified. Organic remains rare, 
 and not very distinct. 
 
 4. Gray micaceous beds, sometimes dark and bituminous. These 
 vary in thickness, from one inch to several feet. Remains of 
 fishes abundant; some vegetable impressions. 
 
 GRAUWACKE. 
 
 The preceding synopsis represents the usual order of the 
 system as it occurs in Scotland. All of these groups are 
 well marked in the field ; and when treated not as distinct 
 systems, but as portions of one great system, materially aid 
 the investigations of the geologist. 
 
 47o. What of the order of succession T 
 476. Explain the tabular arrangement. 
 
124 GEOLOGY. 
 
 173. The organic remains of the system, if not so numer- 
 ous as those of the grauwacke beneath, or the carboniferous 
 measures above, are at least equally interesting, on account 
 of their peculiarities and adaptation to the conditions under 
 which they were destined to exist. The remains of plants 
 are few and indistinct ; but are apparently allied to those 
 found in the true silurian rooks. In the tilestone group 
 have been found impressions of ferns, equisetaceaB, leaves 
 resembling those of the flag and flowering rush, and circu- 
 lar markings like the floral envelopes or berries of some 
 shrubby plant. Most of these are highly carbonized and 
 broken, as if drifted from a distance by water, and deposited 
 among the sandy material in which they are now imbedded. 
 A few carbonaceous layers occur among the schistose beds; 
 but vegetable matter nowhere abounds in sufficient quantity 
 to form bituminous layers or thin seams of coal. Taken 
 as a whole, the old red sandstone system is particularly 
 barren of vegetable remains, and seems to evince a condi- 
 tion of the earth which did not permit of the growth of 
 plants unless in detached and limited areas; these plants 
 being by no means high in the scale of vegetable organiza- 
 tion. Its animal remains are more abundant and distinct; 
 but present little variety the prevailing types being marine 
 fishes of simple but curious structure. 
 
 174. The fossil Jishes, or ichthyolite$,ofthe old red sand- 
 stone, present the first distinct trace of the existence of the 
 highest division of the animal kingdom; namely, vertebrata. 
 It must be remarked, however, that the earliest genera are 
 not of the most perfect structure; but form, as it were, a 
 link between the humbler Crustacea and fully-developed 
 fishes. The cephalaspis, coccosteus, and ptericthys, repre- 
 sented in the following engraving, are the most prominent 
 types of these crustacean-like families. The cephalaspis, 
 in general figure, resembles the asapkus of the silurian 
 rocks, is covered with bony plates, and takes its name from 
 the buckler-shape of its head (Gr., Icrphale., the head, and 
 aspis, a buckler). The coccosteus is also enveloped in a 
 
 477. What variety of organic remains are found ? 
 
 478. What of its fossil fishes ? 
 
 479. Describe their peculiarities and uaiaes. 
 
OLD RED SANDSTONE SYSTEM. 
 
 120 
 
 bony covering, is furnished jvith a tail for locomotion, and 
 takes its name from the berry-like tubercles which dot its 
 plates (Gr., kokkos, a berry, and osteon, a bone). The 
 ptericthys has the same kind of covering or external skele- 
 ton : but its distinguishing feature is a pair of wing-like 
 appendages, which seem not only to have aided in locomo- 
 tion, but to have reared defensively when attacked. It 
 takes its name from these appendages (Gr.,p/mw, a wing, 
 and ichthys, a fish), and is one of the most abundant fossils 
 in this formation being as characteristic of the old red 
 
 1. Cephalaspis. 2. Coccosteus. 3. Ptericthys. 
 
 sandstone as the trilobite was of the silurian rocks. In the 
 holitpfychius (figure on next page), and some others, this 
 bony covering prevails; but it is formed of a greater number 
 of plates finely enameled and curiously engraven, while the 
 general outline of the figure more closely approximates to 
 that <f existing fishes, with a tail arid fins as organs of loco- 
 n oti ->n. In other genera, the plates pa<s by gradations into 
 bony scales, regularly arranged, so as to join or overlap 
 
 480. Explain the dii?ram on this page. 
 
GEOLOGY. 
 
 Holoptychius Nobilissimus. 
 
 each other. This structure is well illustrated by the osteole- 
 pis (Gr., osteon, a bone, and lepis, a scale), which presents 
 the form of a perfect fish furnished with pectoral, abdomi- 
 nal, and caudal fins. In the osteolepis (see figure) the 
 bony scales are placed alongside each other like the bricks 
 in a building ; calculated at once to afford a strong protec- 
 tion to the internal parts, and to yield to the bendings of 
 the body while in motion. In the previous forms of animal 
 life, the organs of motion are but imperfectly developed; 
 
 Osteolepis. 
 
 but in the osteolepis a great advance is exhibited, its fins, 
 tail, and elongated form of body being such as to combine 
 strength with agility. Some families of these early fishes 
 are furnished with spiny fins, or are otherwise armed with 
 detached spines from two to five inches in length, and 
 which are known to geologists by the name of ichthy odont- 
 lites (Gr., ichthy f, a fish, doru, a spear, and litlios, a stone). 
 In all of them the tail is unequally lobod, like that of the 
 shark a character which distinguishes cartilaginous from 
 
 481 Whnt do these diagrams exhibit/ 
 
OLD RED SANDSTONE SYSTEM. 127 
 
 osseous fishes ; the shark, dog-fish, sturgeon, &c. belong- 
 ing to the former, the cod, herring, salmon, &c. to the lat- 
 ter division. (Par. 181.) 
 
 175. From what we have seen of the fossil flora and fauna 
 of this system, they seem to indicate a condition of life 
 higher in point of development than that which existed 
 during the deposition of the grauwacke and silurian rocks. 
 The cephalaspis, coccosteus, and ptericthys, are successive 
 advances upon the simply organized asaphus; and the 
 lioloptychius, osteolepis, and glyptolepis, belong to orders 
 still more fully developed than the ptericthys. But while 
 this advance in the scale of organization took place, some 
 peculiarity in the waters of the ocean, or other condition, 
 seems to have prevented the increase of previously existing 
 orders ; for in none of the beds of the old red sandstone do 
 we find the corals, shell-fish, and Crustacea of the silurian 
 system. It is true that in the lower, or flagstone series, 
 remains of crustaceans have been discovered; but in such 
 an imperfect state, that it is impossible to decide what ana- 
 logy they bear to those of the silurian limestones. Again, 
 the vegetation which existed during the formation of the 
 grauwacke rocks seems to have vanished almost entirely 
 while the deposition of the old red sandstone was going 
 forward ; for, unless at a few detached points, do we find 
 anything like a vegetable organism throughout the whole 
 mass of the formation. 
 
 1 76. The conditions of the world during the deposition of 
 the old red sandstone are but imperfectly indicated by the 
 fossil organisms to which we have adverted. Flanking the 
 primary and transition hills, the old red sandstone is emi- 
 nently a littoral deposit, the lower or gray micaceous series 
 evincing sediment in calm water, the sandstone and con- 
 glomerate beds the action of currents and other aqueous 
 agitation, and the yellow beds a recurrence of calm depo- 
 sition. Many of the strata present the ripple mark of the 
 tide as perfect as that now to be traced on the sands of the 
 existing shore; and the conglomerate throughout its entire 
 
 482. What is the geological reasoning touching this period, based 
 Hoon its fossils ? 
 
 4SJ3. What of the conditions of the globa at this period T 
 
128 
 
 composition points to causes analogous to those by which 
 the gravel-beaches of the present day are collected. The 
 colouring matter (peroxide of iron) of the formation shows 
 that the waters must have been impregnated with mineral 
 solution, so as to be deleterious to animal life; and it is a 
 curious corroboration of this fact, that the fossil fishes are 
 most abundantly found in the flagstone and yellow sand- 
 stone series the strata least coloured by the metallic im- 
 pregnation. Whence the metallic oxide was obtained by 
 which the formation is more or less tinged throughout, is a 
 matter of hypothesis among geologists; but that opinion 
 which ascribes it to volcanic origin is the most commonly 
 entertained, and indeed the only one which seems adequate 
 to account for the phenomenon. If, then, the old red sand- 
 stone period was one of extraordinary volcanic disturbance, 
 rendering the earth and atmosphere less capable of nourish- 
 ing an abundant vegetation, and poisoning the waters against 
 the development and propagation of animal life, the student 
 may readily perceive why organic remains should be so 
 scantily disseminated through its material, even while an 
 advance was being made in the kind and character both 
 of vegetable and animal existence. 
 
 177 The igneous rock* associated with the system, and 
 by which it has been upheaved into its present position, 
 are greenstone, claystone, porphyry, felspar, amygdaloid, 
 and many other varieties of trap. Occasionally, the trap is 
 cut through by dykes of more recent greenstone, felspar, 
 and serpentine; but true granitic rock is seldom or ever 
 in intimate connexion with any portion of the series. By 
 the termination of the old red sandstone deposit, the gra- 
 nitic igneous era may be said to have passed away, and to 
 have been succeeded by that of the trap an era which 
 produced more complicated displacements and contortions 
 of the stratified rocks, though less extensive and gignntic 
 elevations. In Scotland, the Grampians belong to the 
 former era, the Ochils to the latter ; two ranges which, 
 even to the untutored eye, present so many points of dis- 
 
 484. How is the iron accounted for ? 
 
 485. What igneous rocks are found here 1 
 4S6. What of the trap era of the globe ? 
 
OLD RED SANDSTONE SYSTTM. 129 
 
 similarity both in their external contour and internal com- 
 position, as at once to be ascribed to different eras. The 
 volcanic forces which were smouldering throughout the 
 whole formation of the old sandstone, seem, at the conclu- 
 sion of the deposit, to have spent themselves in one gigantic 
 paroxysm, and to have upheaved the newly-consoiidated 
 strata into mountain ridges of extreme irregularity, along 
 whose flanks, as they extended seaward, were deposited 
 unconformably the strata of the succeeding formation. 
 
 178. The extent of country occupied by the old red sand- 
 stone is very great, owing, in many instances, to the flat 
 position of the strata, which thus cover a larger amount of 
 surface than they would have done had they been highly 
 inclined like the primary formations. All the members of 
 the series are widely developed in Scotland ; the lower 
 portions occur between England and Wales, in Ireland, 
 and in Germany; the middle portions occupy extensive 
 areas in Russia and the flats of Central Europe, in Siberia 
 and Tartary, and flank also the southern Himmalehs; and 
 different members of the system occur in various districts 
 of North and South America, as well as in Central Africa. 
 
 1 79. The geographical features of red sandstone districts 
 are in general varied and irregular; the hills being less 
 bold and precipitous than those of primary formations, and 
 more lofty and undulating than those of any subsequent 
 period. Where the strata lie flat, and comparatively un- 
 broken, the scenery is rather uninteresting; but the soil is 
 light and fertile, being based on sand, gravel, or reddish 
 clay, composed of the debris of the formation. On the 
 other hand, the mountains of the old red sandstone exhibit 
 great diversity of scenery: rising in easy undulations, sink- 
 ing and swelling in every direction, yet preserving a com- 
 mon continuity of range, they present in the chain a suc- 
 cession of rounded heights and cones; but in the mass, an 
 irregular surface of hills and valleys, glens and recesses, of 
 great beauty and amenity. The Ochils and Sidlaws, in 
 Scotland, with their intervening valleys, belong exclusively 
 
 487. What of the localities and extent of this system T 
 4^8. What of itt physical geography ? 
 
130 
 
 GEOLOGY. 
 
 to this formation, and may be taken as the type of its phy- 
 sical features. 
 
 ISO. The minerals of commerce derived from the old red 
 sandstone are comparatively few. From the lower group 
 of beds are obtained those thin schists of gray micaceous 
 sandstone so generally employed in foot-pavements, in 
 roofing and in flooring; hence the terms tilestone &n<\ flag- 
 stone. From the superior red and yellow groups, building- 
 stones of various qualities are obtained ; but none of these 
 are of great beauty or durability. The claystone, porphy- 
 ries, and felspars, are exceedingly durable ; but are seldom 
 used by the builder, owing to the difficulty of hewing them 
 into form. From the trap, some of the best material for 
 macadamizing is obtained in the lowlands of Scotland ; 
 while among the debris of the same rocks, the lapidary 
 finds many geodes of the finest chalcedonies, agates, jas- 
 pers, and carnelians. 
 
 CLASSIFICATION OF FOSSIL FISHES. 
 
 181. Before proceeding with our description of the suc- 
 ceeding formations, it will be necessary to advert to the 
 system of classification which has been adopted in reference 
 to fossil fishes, inasmuch as it differs from that which Cuvier 
 applied to existing races. This celebrated naturalist col- 
 lected the whole number of species into two groups, ac- 
 cording to the nature of the skeleton and the hard parts 
 one group embracing the OSSEOUS, or bony, and the other 
 the CARTILAGINOUS fishes. The former group he further 
 separated into two orders the Acanthopttrygian, or thorny- 
 finned, and the Malacopterygian, or soft-firmed. This me- 
 thod, however, does not meet the wants of the geologist, 
 because the skeleton is seldom or ever found in such a 
 state as to answer the purposes of classification Fossil 
 scales, teeth, spines, and fragments of fishes, are found in 
 abundance, but these afford too imperfect data for arrange- 
 ment; and when an eirtire specimen occurs, it is merely 
 
 489. What ofits economical uses 1 
 
 490. What was Cuvier's groups of fishes? 
 
 491. Why will this system fail to arrange fossil fishes ? 
 
CLASSIFICATION OF FOSSILS. 131 
 
 the genera] shape and character of its scaly covering upon 
 which the ichthyologist can decide with certainty. Pro- 
 ceeding upon this principle, M. Agassiz takes the dermal 
 covering as the foundation of his system the skin being 
 that organ which indicates not only important structural 
 and functional difference?, but also shows the relation of 
 every animal to the element in which it moves. (Appen.) 
 182. Instead of the divisions Osseous and Cartilaginous, 
 he disHngitifkes Jmtr great orders ofjishes according to the 
 nature of their scales, and finds that other important dis- 
 tinctions of structure, &/c. harmonize with these differences 
 of scales. This discovery is invaluable; for, of all parts of 
 fishes, the scales are those most abundantly found in a fos- 
 sil state; and if by a single scale the geologist can detect 
 the order to which any fish belonged, he has also a clue to 
 its habits and mode of life, and to the conditions under 
 which it flourished. The following is a sketch of the prin- 
 cipal divisions and subdivisions proposed by M. Agassiz: 
 
 I. SCALES ENAMELED. 
 
 1. GANOIDIANS (Gr., ganos, splendour, from the bright surface of their 
 
 enamel). The fishes of this order are covered with angular scales, 
 composed internally of bone, and coated with enamel. The scales 
 are regularly arranged, and entirely cover the skin. The sauroid 
 fish, or those which, from the structure of their teeth and other 
 peculiarities, approximate to reptiles, are amongst the most inte- 
 resting of this order. Nearly all the species referred to it are 
 extinct; the sturgeons, and bony-pike of the North American lakes, 
 are living examples. 
 
 2. PLACOIDIANS (Gr.,p/ax, a broad plate). Fishes of this order have 
 
 their skin covered irregularly with plates of enamel, often of con- 
 siderable dimensions, but sometimes reduced to small points, like 
 the shagreen on the skin of the shark, and the prickly tubercles 
 of the ray. It comprehends all the cartilaginous fishes (sharks and 
 rays), with the exception of the sturgeon. 
 
 II. SCALES NOT ENAMELED. 
 
 3. CTENODIANS (Gr., kteis, genitive ktenos, a comb) Ctenoid fishes 
 
 have their scales of a horny or bony substance without enamel, 
 jagged like the teeth of a comb on the outer edge. The perch, 
 ana many other existing genera, are of this order, which contains 
 but few fossil forms. 
 
 492. What is Agassiz's method, and how many orders of scales? 
 
 493. Explain his divisions and subdivisions 
 
132 
 
 GEOLOGY. 
 
 4. CYCLOIDIANS (Gr., cyclos, a circle). The fishes of this order have 
 smooth, horny, or bony unehameled scales, entire at the margin, 
 with concentric or other lines on the upper surface. The herring, 
 salmon, &c. belong to this order, which, along with the former, 
 includes almost the whole number of existing species. 
 
 Such are the divisions proposed by M. Agassiz, and now 
 universally adopted by geologists, although it is not unlikely 
 that a more perfect system may soon be propounded, which 
 will embrace in one category both fossil and existing species. 
 M he subjoined engraving more summarily represents the 
 i'our orders of scales above al'uded to: 
 
 1. Ganoid; 2. Placoid ; 3. Ctenoid; and, 4. Cycloid, Scales. 
 183. Each of these ordrrs contains both bony and cartila- 
 ginous fishes. The representatives of each prevailed in 
 different proportions during different epochs; the two first 
 (enameled scales) existed be'ore the commencement of the 
 chalk system ; the third and fourth orders, which contain 
 nearly five-sixths of living species, appear for the first time 
 in the chalk strata, when all the preceding fossil genera of 
 the two first orders had become extinct. Another remark- 
 able circumstance observed by M. Agassiz is, that all, rr 
 nearly all, the fossil fishes found in strata beneath the mag- 
 
 l. Heterocercal, or Unequally bilobate; 2. Equally bilobate ; and, 
 3. Single and rounded, forms of tail. 
 
 494. What of the diagrams here given ? 
 
 495. What different epochs are represented ? 
 
 496. Define the terms and explain the diagrams. 
 
EXPLANATORY NOTE. 133 
 
 nesian limestone are heterpctrcal, that is, have their tails 
 unequally bilobate (see fig.), like the shark, sturgeon, lepi- 
 dosteus, &c.; while this form of tail is rarely found in the 
 oolite and superior strata. Among existing fishes, the tail, 
 or caudal fin, is generally equally bilobate, as in the trout ; 
 or single and rounded, as in the wrasse ; but seldom hete- 
 rocercal. This latter form is produced by a remarkable 
 prolongation of the vertebra, which bears a striking ana- 
 logy to the prolongation of the same parts in reptiles; thus 
 connecting the cartilaginous fishes with the reptilia, not 
 only by internal structure, but also by the evidences of ex- 
 ternal form. 
 
 EXPLANATORY NOTE. 
 
 OLD RED SANDSTONE. To this system English geologists sometimes 
 apply the term " Devonian," because it happens to be very exten- 
 sively developed in Devonshire. Distinctions of this kind are always 
 objectionable, and particularly in the present instance, where the 
 general term, Old Red Sandstone, is so eminently descriptive. 
 
 PEROXIDE OF IRON. When the oxygen of common air unites with 
 the atoms of iron, an oxide, or rust, of iron is the result ; and when 
 this rust has absorbed as much oxygen as it is capable of, it is then 
 termed a peroxide, or thorough oxide, of iron. 
 
 ICHTHYOLITE (Gr., ichthys, a fish, and lithos, a stone). A fish, or any 
 part of a fish, found in a fossil state, is termed an ichthyolite. 
 
 PUDDINGSTONE any conglomerate of rounded pebbles cemented 
 together by a silicious or sandy paste. When select specimens are 
 cut and polished, they resemble a section of plum-pudding; hence the 
 term puddingstone. 
 
 PORPHYBY (Gr., porphyra, purple). This term was originally applied 
 to a reddish unstratified rock found in Egypt, and used by the ancients 
 for statuary purposes. It is now employed by geologists to denote a 
 reddish igneous rock containing imbedded crystals of felspar ; and all 
 rocks (whatever their colour) which contain imbedded crystals distinct 
 from their mass, are said to be porphyritic. We have thus felspar, 
 porphyry, porphyritic granite, and porphyritic greenstone. 
 
 AMYGDALOID (Gr.,amygdalon, an almond, and eidos, a form) almond- 
 shaped. The term is applied to certain trap rocks in which other 
 minerals are occasionally imbedded like almonds in a cake. Some 
 varieties of amygdaloid are locally termed toad-stones, from the resem- 
 blance which their colour and makings bear to that of a toad's skin. 
 
 GEODES (Gr., geodcs, earthy) a term applied to rounded pebbles 
 having an internal cavity lined with crystals; also to rounded or 
 nodular pebbles themselves ; and to nodules of ironstone hollow in the 
 centre. 
 
 497. Explain the the terms of the note. / 
 
 498 Define the terms of the note. 
 
134 GEOLOGY. 
 
 CARBONIFEROUS SYSTEM. 
 
 184. At the close of the Old Red Sandstone period the 
 earth seems to have undergone an almost total change in 
 its geological conditions. The red sandstones and gravelly 
 conglomerates which had been formed along the shores and 
 bottom of the sea, were upheaved into dry land; thus add- 
 ing to the extent of land previously existing, and gradually 
 circumscribing the limits of the ocean in which subse- 
 quent deposits were to take place. As disintegrated gra- 
 nite furnished the felspar, quartz, and mica of the gneiss 
 and mica schist, and as from these, again, were obtained 
 the materials of the clay-slate, grauwacke, and silurian 
 rocks, so from all these, together with the newly upheaved 
 red sandstone, were derived the material of the succeeding 
 formation. These successive attritions would reduce quartz 
 to sand of various fineness, felspar to loose impalpable clay, 
 mica from large plates to minute scales, and crystalline 
 limestone to a dully powdery consistence. The rocks 
 formed of these ingredients would necessarily present a less 
 compact texture; arid thus it is in the Carboniferous System 
 that the sandstones are more arenaceous, the shales soft and 
 earthy, and the limestones non-crystalline and often impure. 
 Besides the sandstone, clay, and limestone, two new rock 
 substances make their appearance among the strata of this 
 system, namely, coal and ironstone the former being the 
 result of compressed and altered vegetation, and the latter 
 a chemical aggregation of the metallic particles around 
 some earthy basis. The iron of the old red sandstone was 
 disseminated through the mass as mere colouring matter ; 
 in the carboniferous formation it is principally collected in 
 layers, or in nodules. The vegetation of previous periods 
 was so scanty as to leave only a few dubious impressions 
 among the strata. During the era about to be considered, 
 it was so abundant, as to form numerous beds of coal, rang- 
 ing in thickness from a few inches to twenty or even thirty 
 feet. 
 
 185. The term "Carboniferous" has been applied to this 
 
 499. To what system do coal and ironstone belong 1 
 i)00. What is the source aiH nature of each ? 
 
MOUNTAIN, OR CARBONIFEROUS LIMESTONE. 1JV> 
 
 system from the fact, that vegetable deposits of which the 
 main solid element is carbon constitute its most distin- 
 guishing feature. It is regarded by many as marking the 
 commencement of the SECONDARY PERIOD; and holds a 
 position in the earth's crust intermediate between the old 
 and new red sandstones. Having been deposited after the 
 upheaval of the old red sandstone, it rests in many places 
 unconformably upon that system, and occupies smaller and 
 more detached areas, which often assume a basin or trough 
 lorm, as shown in par. 201. It is composed of two very 
 distinct groups, the mountain limestone and the coal mea- 
 sures, which in some respects require separate descriptions. 
 
 MOUNTAIN, OR CARBONIFEROUS LIMESTONE. 
 
 186. The distinguishing feature in the mineral composi- 
 tion of this group is sufficiently indicated by the name 
 Mountain Limestone. It must not be supposed, however, 
 that it is entirely composed of calcareous beds ; but merely 
 that the limestones are the most characteristic members; 
 for many of the inferior strata are pure quartzose sand- 
 stones, containing scarcely a trace of lime, and alternating 
 with thin seams of coal and bituminous shales. As deve- 
 loped in the British islands, the group may be said to con- 
 sist of thick-bedded gray or bluisli sub-crystalline lime- 
 stones, divided by partitions of grits and shales, and of 
 whitish quartzose sandstones of various fineness, separated 
 by subordinate layers of shale, thin seams of coal, and bands 
 oi ironstone. It is generally found flanking or crowning 
 the trap-hills which intervene between the old red sandstone 
 and coal measures, presenting bold escarpments; hence 
 the term mountain limestone. The epithet carboniferous 
 is also applied to it, because it invariably underlies the true 
 coal measures wherever these occur, and is generally asso- 
 ciated with thin seams of coal and bituminous shales. Like 
 all stratified rocks, this is broken up by fissures and dislo- 
 cations caused by subterranean movements; but, indepen- 
 
 501. What difference in the metal and vegetation of this system! 
 
 502. Of what two groups is it composed T 
 
 503. What is the nature of mountain limestone I 
 604. What relation has it to the seams of coal? 
 
I '10 OKOLOGY. 
 
 dently of these, it is numerously intersected by what are 
 termed joints and divisional planes the former being rents 
 (or backs, as they are called by quarrymen) perpendicular 
 to, and the latter partings parallel with, the plane of strati- 
 fication. 
 
 187. The order of succession among the strata of this 
 group is by no means determinate. In some districts, only 
 a few beds of calcareous shales and grits occur between 
 the limestone and old red sandstone; in others, a vast suc- 
 cession of white quartzose sandstones alternating with 
 bituminous shales, thin seams < f coal, and bands of iron- 
 stone ; while in Fife and Mid-Lothian, these sandstones 
 are associated with strata of shell and fresh-water (?) lime- 
 stone. Whatever may be the character or thickness of 
 the rocks beneath, the true mountain limestone of itself 
 constitutes a well-marked suite of strata, easily distin- 
 guishable from any other. Sometimes it consists of two, 
 four, or six beds, divide'! by partings of argillaceous mat- 
 ter; at other times the beds are separated by layers of 
 calcareous sandstone and shale; while riot unirequently it 
 occurs in one mass of vast thickness, flanking some trap- 
 hill precisely aiter the manner in w r hich a coral reef skirts 
 the island around which it is forming. In general, there 
 occur above the limestone calcareous shales, sandstones, 
 and thin seams of coal, which pass into the true coal mea- 
 sures ; but in the north of England, there intervenes a 
 series of very pebbly or quartzose sandstones, known by 
 the name of Millstone Grit. Notwithstanding these vari- 
 ations, the calcareous members gradually disappear, and 
 the carboniferous become more frequent as we ascend, so 
 that there is no great difficulty in fixing the line of demar- 
 cation between the two groups. 
 
 188. The organic remains of the mountain limestone are 
 eminently marine. It is true that the occurrence of thin 
 seams of coal attest the presence of terrestrial plants which 
 must have been drifted into the sea of deposit ; and there is 
 some doubt among geologists as to the origin of certain 
 
 505. What variety of strata occurs in this group ? 
 
 506. Where occurs the millstone grit 1 
 
MOUNTAIN, OK CARBONIFEROUS LIMESTONE. I :}7 
 
 limestones among the lower strata; but laying these aside, 
 the whole character of the group is as decidedly oceanic as 
 the living coral reefs of the Pacific. The most remarkable 
 advance upon the marine life of former periods, as < vi- 
 denced by the Ibssils of the mountain limestone, is that 
 which appears among the Radiata. In the silurian rcks f 
 the corals were chiefly of a sessile kind ; in 
 this group many of them are free and inde- 
 pendent animals, bearing little or no analogy 
 either to previous or existing forms. The 
 most prevalent of these was the Crinoid or 
 Encrinitf family, of whose exuviae many bed* 
 of limestone are almost wholly composed. 
 Of the encrinite (Gr., krine, a lily), or lily- 
 shaped corals, are found many genera and 
 sub-genera the distinctions being made 
 from the external figure of the stalk and 
 head. That exhibited in fig. A may be taken 
 as the type of the class ; it is the encrinitcs 
 nionilifurmis, so called from the necklace- 
 shape of its stalk. Besides the encrinites 
 moniliformis, which is by far the most pre- 
 valent of the crinoideans, there were the 
 pentairinus, five-sided instead of round, the 
 actinocrinus, or spiny encrinite, the ajrincri- 
 nite, so called from the pear-like form of its 
 head, and many others deriving their names 
 from similar distinguishing features. By 
 examining fig. A, the student will perceive 
 that the encrinite consisted of a stalk com- 
 posed of numerous joints, rendered flexible 
 by means of cartilage, and perforated for the 
 passage of an internal canal ; that it was 
 fixed at its base, and supported at its free 
 extremity, a cup-like body(s) containing the 
 mouth and stomach; that this cup-like body was composed 
 
 607. What of the fossils found in this group ? 
 
 50^. Of what families are the remains of animals here ? 
 
 509. What is represented in the diagram T 
 
 510. Describe this singular animal. 
 
138 GEOLOGY. 
 
 of many pieces, which branched out into numerous tenta- 
 cula (<?) for the purpose of seizing its prey. The whole 
 animal is supposed to have been invested with a gelatinous 
 covering, by which its structure was held together. In the 
 skeleton of some specimens, not less than 2(i,000 bones, 
 or pieces of calcareous matter, have been counted, all beau- 
 tifully marked, and ingeniously adapted to each other; and 
 in a framework so liable to be broken, we find traces of a 
 power to reproduce mutilated parts, such as we find in the 
 crabs and star-fishes of the present day. Little more is 
 known of the structure of these crinoidea, or of the habits 
 and peculiarities of the different genera. The seas at this 
 period seem to have swarmed with them ; their remains 
 are found in every stratum of a calcareous character, and 
 masses of limestone from 40 to 120 feet in thickness are 
 almost wholly composed of them, just as existing coral-reefs 
 are formed of various corals. In consequence of the com- 
 plex constitution of the skeleton, and the perishable nature 
 of the enveloping membrane, entire specimens are seldom 
 or ever found; the separate pieces having been drifted and 
 scattered about after the surrounding cartilage was decom- 
 posed. Fig. B. represents a fragment of mountain or en- 
 
 Fig. B Fragment of Encrinital Limestone. 
 
 61 1. What is most remarkable in their structure 1 
 
 512. Wherein do they resemble crabs and star-fish ? 
 
 513. In what state are they usually found ? 
 614.' Describe and explain the ievera. diagrams. 
 
MOUNTAIN, OR CARBONIFEROUS LIMESTONE. 133 
 
 crinital limestone, which, when sufficiently hard, furnished 
 a curious and highly ornamental marble. 
 
 I8D. Bt sides crinoidea, ihe mountain limestone contains 
 many othrr species of radiuria branched, fungous-shaped, 
 fan-shaped, star-shaped, and tubular. These differ in many 
 instances from the corals of the silurian, as they differ from 
 those of the present day; and are confusedly mingled with 
 corallines, shells, teeth, spines, and scales of fishes. The 
 following engraving represents some of the more prevalent 
 forms among the corals and corallines of this era : 
 
 1. Syringipora. 2. Retepora. 3. Cyathophyllum basaltiforme. 
 190. The shell-Jish of this group are also exceedingly 
 numerous, and of curious and gigantic forms. They belong 
 to all orders equal and unequal bivalves, single and many- 
 chambered univalves; many of them are not to be f und 
 in any other strata than those of the carboniferous era. 
 Several families seem (like the- oyster and cockle of the 
 present d iv) to hnve been gregnrious, covering large spaces 
 of the ocean's bed; for shells are found composing beds of 
 limestone from one to six feet in thickness; others to have 
 been solitary, changing their places as necessity required ; 
 while the chambered shells, like the argonaut and nautilus, 
 possessed the power of sinking or floating at pleasure. 
 (See par. 222.) Like existing shell-fish, they appear to 
 have inhabited the seas at moderate depths from the shores, 
 and to have preyed partly on each other, and partly on 
 marine vegetables. Their numbers and size indicate a 
 
 515. What variety of shell-fish? 
 
 516. What proof of their being gr garious ? 
 
 517. What geological reasoning ia hence derived ? 
 
 518. Explain the diagrims. 
 

 14;) GBOLOGY. 
 
 genial condition of the ocean both as regards temperature 
 and calcareous matter the former fostering their growth 
 with rapidity, and the latter yielding material for the struc- 
 ture of their shelly coverings. Some of the more typical 
 shells belonging to this formation are the Producta, Tere- 
 bratula, Spinfera, and Inoceramus among the bivalves; 
 and the Euomphalus, Ammonite, Bellerophon, Orthocera- 
 tite, and Goniatite among the univalves, which are chiefly 
 many-chambered. 
 
 1. Producta scabriculus ; 2. Inoceramus vetustus ; 3. Bellerophon 
 tangentialis ; 4. Orthoceras cinctum. 
 
 191. Crustacea nnd Jishes have been found in all the 
 nembers of the carboniferous system, from the lowest beds 
 of the mountain limestone to the highest of the coal mea- 
 sures. The crusfacea are chiefly trilobites, though broken 
 plates of other genera are not uncommon; and some of 
 the calcareous shales yield species bearing a faint analogy 
 to the chiton of modern seas. The trilobites of the moun- 
 tain limestone, however, are less numerous and varied than 
 those of the silurian era, of whose Fauna it will be remem- 
 bered they formed the most distinguishing feature. Irh- 
 thyolites are exceedingly numerous, either as entire fishes, 
 detached scales, spines, teeth, or coprolites. The fishes 
 belong for the most part to the Ganoid order, though Pla- 
 coidians are not unfrequent. Many of these are of gigantic 
 size, such as the megalichthys (large fish), holoptychius, 
 &c. and bear so much analogy to reptiles in the bones of 
 their head and external coverings, as to induce M. Agassiz 
 to term them " sauroid fishes." Their pnlatal bones, spines, 
 
 519. What of the Crustacea ? 
 
 520. What varietv of ichthyoiites 7 
 
COAL MEA^t'RF*. 141 
 
 and teeth are found in abundance, seme of the latier being 
 more than four inches in length thereby denoting ihe 
 gigantic size of these predatory animals. Their coprolites 
 (Gr., kopros, dung, and lithos, a sione), or fossil excre- 
 ments, are scattered throughout the shales and calcareous 
 strata, and attest, by the fish-scales, bones, &c. which they 
 contain, the nature of the food on which they subsisted. 
 
 COAL MEASURES. 
 
 192. The term "Coal Measures" is applied to that series 
 of rocks which immediately overlies the mountain limestone, 
 and from which the well-known mineral, coal, is obtained. 
 The group is composed of alternations of coals, sandstones, 
 shales, bands of ironstone, fire-clay, and layers of impure 
 limestone. The coals present every degree of fineness and 
 purity, and are generally distinguished as follows: An- 
 thracite, a hard, shining variety, destitute of bitumen, often 
 called mineral charcoal ; caking, a highly bituminous sort, 
 like that of Newcastle, which cakes or runs together during 
 combustion; cubic,\ess bituminous, breaking up into cubi- 
 cal masses ; cannd, a compact lustrous variety, which breaks 
 with a conchoidal fracture; jet, still more compact and 
 lustrous; and lignite, or brown coal, in which the woody 
 structure of the vegetables is still perceptible. The sand- 
 stones are in general quartzose, of a dull-white or brown 
 colour, and thick-bedded ; sometimes they are flaggy, or 
 schistose, and in this instance are either of a calcareous or 
 argillaceous character. The shales are all dark-coloured, 
 and bituminous; the fire-clays grayish-white, and more or 
 less sandy ; the ironstone occurs either in bands or nodules; 
 and the limestones are all earthy and impure. The iron- 
 stone of earlier formations occurs either in veins, or is dis- 
 seminated as colouring matter through the mass ; in this 
 system it appears as an argillaceous carbonate, either in 
 thin layers from one to twelve inches thick, in irreguhu 
 
 521. What of their sire, and means of subsistence 7 
 
 522. Define and explain coal measures. 
 
 523. Into what varieties are the coals distinguished ? 
 
 524. With what other minerals are they associated f 
 535. How.- doe* ironstone occur heret 
 
 ,7 
 
142 GEOLOGY. 
 
 noddles, or in bands of regular nodules, called sf.ptaria, 
 from the nodule being often internally divided into numer- 
 ous septa, or partitions, as shown in 4 of the following 
 engraving. These nodules seern to have been formed by 
 some process of attraction round a central nucleus, as in 
 nine cases out of ten they contain nuclei of leaves, teeth, 
 scales, or spines of fishes, coprolites, or some other organic 
 matter. Beneath is represented as central nuclei 1, a 
 fragment of a plant; 2, a fish-tooth; 3, fossil excrement, 
 or coprolite; and, 4, true septaria, with their curious parti- 
 tions of white cirbonate of lime, giving the section the 
 appearance of a beetle; from which circumstance such 
 nodules are known in some places as beetle-stones. 
 
 Ironstone nolules, showing varieties of central nuclei. 
 li)3. There is no regular suc.r.f.ssion among the beds of 
 this group; though it rnav be remarked, that the thickest 
 and best seams of coal abound about the middle of the 
 series. Immediately above the mountain limestone the 
 coal beds are thin, the shales thick-bedded, and more or 
 less calcareous ; and the sandstones often calcareous and 
 argillaceous. As we ascend, the argillaceous and calcare- 
 ous members become less prevalent, the coals thicker and 
 mor? frequent, and the shales more bituminous. Further 
 up in the series, the coals gradually disappear, fire-olqys 
 and light-coloured shales abound, the sandstones become 
 more purely arenacous, assume various shades of colour, 
 and insensibly pass into the superincumbent new red sand- 
 stone. In general, all the members alternate indiscrimi- 
 
 526. What of the nuclei of these nodules ? 
 
 527. Explain the diagrams, and their common name ? 
 
 528. What of the succession in the beds of this strata ? 
 
 529. What is the relation of the new red sandstone 1 
 
COAL MEASURE*. M3 
 
 natrly with each other, present various degrees of fineness, 
 colour, and mineral composition, and are persistent over 
 extensive areas. Occasionally, a stratum will thin out and 
 disappear ; at other times it will part, as it were, into two, 
 with a layer of different material between; yet, notwith- 
 standing such anomalies, there is no series of strata so 
 regularly deposited as the coal formation. 
 
 11)4. In the organic remains of the coal mfatures, the 
 abundance of terrestrial vegetation is by far the most dis- 
 tinguishing feature : though, as might be expected from the 
 nature of the deposit, marine shells, fishes, and other aquatic 
 exuviae are not unfrequent. It has been already stated that 
 coal is of vegetable origin ; in other words, that its mass is 
 composed of plants altered by compression and that process 
 of bituminization described in par. 115. On account of 
 this change, it is often impossible, at first sight, to detect 
 any trace of vegetable structure; but on closer inspection, 
 the woody fibre may be seen in many specimens; while it 
 is possible in almost all to make visible the cells and fibre 
 by exposing thin slices to the transmission of a powerful 
 light. In this way Mr. Witham observed the various vege- 
 table tissues in coal, thereby adding another testimony to 
 the numerous evidences of its organic origin. In most of 
 the bituminous beds, however, the external form is oblite- 
 rated, and it is to detached fosstib in the sandstones and 
 lighter shales that the geologist is i,.tiobted for his know- 
 ledge respecting the Flora of the carboniferous era. About 
 four hundred species have been already determined, chiefly 
 gigantic equisetums, ferns, club-mosses, cactuses, pines, and 
 plants allied to the bulrush, cane, and bamboo. Most of 
 these resemble existing plants merely in their generic dis- 
 tinctions, having belonged to species which flourished 
 during the coal-forming period, and became extinct with 
 the peculiar conditions of the globe which gave them birth. 
 Some of the most characteristic of the vegetable fossils be- 
 
 530. What fossil remains are abundant in coal, and what are less 
 
 frequent? 
 
 531. What of the origin of coal, and how formed? 
 
 532. How is its organic origin made visible ? 
 
 533. What of the species of plants already determined ? 
 
144 
 
 GEOLOGY. 
 
 longing to this formation are represented beneath ; namely 
 1. Sigillaria, so called from the graven appearance of 
 its stern; 2. Calamitcs, from the leed-like jointings of its 
 stalk; 3, Stigmaria, from its stigmata, or punctures; 4. 
 Lepidodendron (Gr., lepis, a scale, and dtndron, a tree), 
 from the scaly appearance of its bark. These fossils occur 
 
 1. Sigillaria pachyderma ; 2. Calamites cannaeformis ; 3. Stigmaria 
 ficoides ; 4. Lepidodendron Sternbergii. 
 
 in all the members, from the lowest white sandstone be- 
 neath the mountain limestone, up to the commencement 
 of the new red sandstone, at which stage they disappear, 
 and do not seem to have flourished during the deposition 
 of any subsequent formation. The best preserved speci- 
 mens are found in the shales and sandstones; the interior 
 structure of the plant being converted into soft quartzose 
 sandstone, and the bark, or cuticle, into a glistening bitu- 
 minous coal. In the coal, the vegetable structure is always 
 more or less obliterated, though sometimes a solitary trunk 
 occurs of the same quartzose material as those imbedded 
 in the shales and sandstones. Of these fossil trees, many 
 have been found of gigantic dimensions; as, for example, 
 a lepidodendron in the Jarrow coal-field 13| feet wide at the 
 base, arid 39 feet high^ exclusive of the branches at the top, 
 which were also entire; and a conifera of the genus atira- 
 caria in Craigleith quarry, 3 feet in diameter, and 20 feet 
 long. Besides the sigillaria,&c. above described, there are 
 
 53-4. Explain the diagrams. 
 
 535. Name the variety in locality and appearance. 
 
 536. Have any large trees been found in the coal formation 1 
 
COM, MF AS runs. 
 
 145 
 
 numerous species of tree-ferns, club-mosses, equisetums, 
 and other cryptogamic plants preserved in the shales: their 
 dark carbonaceous leaves and branches being often beau- 
 tifully displayed upon the light-coloured ground of the ma- 
 terial in which they are imbedded. Of these the following 
 engraving exhibits some of the most characteristic ; namely, 
 Aster ophyllites (Gr., aster, a star, and phyllo/1, a leaf); 
 Sphenopteris (sphen, a wedge, and pttron, a wing) ; Pecop- 
 tt-.ris (pekos, a comb, and pferon, a wing); all so named 
 from the shape of their respective leaves. 
 
 Stem an'd leaves of Asterophyllites; 2. Spheaopteris Arcaris ; 3. Pe- 
 copteris Mautelli ; 4. Sphenopteris affinis. 
 
 195. Of the conditions of the world during the deposition 
 of the carboniferous system, we have more obvious evidence 
 than those under which any of the earlier systems were 
 formed. The extent of the seas in which the deposit took 
 place is very clearly indicated by the course of the moun- 
 tain limestone, which must have been formed at no great 
 depths from the shore, as its corallines, corals, shells, and 
 other exuviae, prove it to be of littoral origin. All the 
 members of the system, with the exception perhaps of the 
 limestones, are eminently sedimentary ; and the numerous 
 alternations of these strata evince frequent changes in the 
 depositing agents. At one time the rivers seem to have 
 
 537. Explain the diagrams. 
 
 538 What of the geological indicitions here ? 
 
 539. What of the sedimentary deposits from rivers I 
 
14(5 GEOLOGY. 
 
 carried down sand to form sandstones, at another clay and 
 mud lo form shale, arid at a third period vegetable drift to 
 form coal ; for strata of these materials often directly over- 
 lie each other. It must be borne in mind, however, that 
 sand, clay, and plants, might be carried down at the same 
 time, and that they would arrange themselves according to 
 their gravity the sand depositing itself along the shores, 
 the mud farther seaward, and the vegetables in any still bay 
 where currents of wind or water might drift them. Such 
 an arrangement would take pface under the ordinary opera- 
 tions of water ; but during violent inundations, there would 
 be a confused intermingling of sand, mud, and plants, and 
 this we often discover; so that, taking all things inlo account, 
 we learn that the same agencies of rivers, waves, and tides, 
 existed during the deposition of the carboniferous rocks as 
 exist at the present day, only on a more gigantic and uni- 
 form scale. Looking at the abundance of marine life which 
 must have thronged the waters during the formation of the 
 mountain limestone, and at the vast amount of vegetation 
 which the earth must have sustained while the deposition 
 of the coal measures took place, we are led to infer that the 
 earth then enjoyed a much higher and more uniform tem- 
 perature than it has ever since experienced. At present, 
 we find a faint analogy in the Fauna of the tropical seas, 
 and in the Flora of the tropical jungles, to those of the 
 carboniferous era ; but so faint, that we can scarcely insti- 
 tute a comparison between the results produced. The 
 coral-reefs of the Pacific are insignificant compared with 
 the thickness and extent of the mountain limestone; and 
 the vegetable drift of the Mississippi and Ganges combined, 
 would scarcely produce carbonaceous matter sufficient to 
 colour one stratum of shale. Notwithstanding this, there 
 is a resemblance between the coral productions of the 
 Pacific and those of the mountain limestone; and between 
 the palms, tree-ferns, canes, and cactacea3 of the tropics, 
 and the fossil plants of the coal measures. The heat of the 
 tropics is directly derived from (he sun, and the torrid zone 
 
 540. What inference is drawn touching the ancient earth ? 
 
 541. How is a higher and more uniform temperature inferred ? 
 
COAL MEASURES. 147 
 
 occupies but a narrow belt of the earth's surface ; whereas 
 the coal measures are to be found almost in every region 
 of the globe. The sun could not, therefore, have yielded 
 that temperature which nourished the plants and animals 
 of this period ; for though the sun's heat had been greater 
 than at present, it could not have been universally diffused. 
 The conclusion, therefore, to which most geologists have 
 come, is, that the earth, originally an incandescent mass, 
 was gradually cooled down hot enough to render gneiss 
 and mica schist crystalline; cool enough during the grau- 
 wacke and silurian eras to permit of marine corals, shell- 
 fish, and Crustacea ; cooler still during the life of the plated 
 fishes of the old red sandstone ; and only sufficiently genial 
 throughout the deposition of the carboniferous period to 
 foster a growth of terrestrial vegetation all over its surface, 
 to which the existing jungles of the tropics are mere bar- 
 renness in comparison. This hi'gh and uniform tempera- 
 ture, combined (as suggested by Brogniart) with a greater 
 proportion of carbonic acid gas in the atmosphere, would 
 not only sustain a gigantic and prolific Flora, but would 
 also create denser vapours, showers, and rains; and these, 
 again, gigantic rivers, periodical inundations, and deltas. 
 Thus all the conditions for extensive estuary deposits would 
 arise from this high temperature; and every circumstance 
 connected with the coal measures points to such conditions. 
 IU6. With regard to the formation of coal, geologists 
 are not yet fully agreed. On examining sandstone or shale, 
 it is easy to perceive from their structure, texture, and com- 
 position, that they must at one time have been respectively 
 loose sand and mud, borne down and deposited by water ; 
 but the case is somewhat different with beds of coal. This 
 mineral, being chiefly composed of carbon, hydrogen, and 
 oxygen the same elements which enter into the composi- 
 tion of plants and revealing in its mass evidence of vege- 
 table structure, no doubt is entertained of its organic origin. 
 But whether the plants of which it is composed were 
 
 642 Wny is it argued that the sun could not furnish heat enough 1 
 643. Whence is it supposed that the necessary heat was derived T 
 
 544. What geological leasoning is here adopted ? 
 
 545. Of what chemical elements is coal chiefly composed? 
 
148 GEOLOOY. 
 
 drifted down by rivers and deposited along with layers of 
 rnud and sand in estuaries, or whether dense forests and 
 peat-mosses were submerged, and then overlaid by deposits 
 of sand and mud, are the questions at issue. According to 
 the latter hypothesis, the vegetable matter must have grown 
 in dense jungles for many years; then the land must have 
 sunk, and become the basin of a lake or estuary, in which 
 situation rivers would wash into it rnud and sand, and these 
 would cover the vegetable mass, and form beds of shale and 
 sandstone. This being done, it is supposed that the area 
 of deposit was again elevated, so as to become the scene of 
 luxuriant vegetation ; again submerged, and overlaid by 
 new deposits of sandstone and shale ; once more elevated, 
 and covered with plants, and then submerged ; and this 
 alternating process of submergence and elevation is con- 
 tended to have taken place as often as there are beds of 
 coal in any particular coal-field. The other theory is, that 
 while partial elevations and submersions might take place 
 as at the present day, the great mass of the coal measures 
 was deposited in lakes arid estuaries; that the vegetable 
 matter of which coal is formed was drifted into these estu- 
 aries by rivers and inundations; and that various rivers 
 might discharge themselves into one estuary, some chiefly 
 carrying down sand, while others transported plants, mud, 
 and heterogeneous debris. This theory also supposes that 
 the transporting rivers were subject to periodical inunda- 
 tions, and that, during the intervals of overflow, the deltas 
 were choked with a rank vegetation, which, in conjunction 
 with the vegetable drift from inland, went to the formation 
 of beds of coal. 
 
 ] 97. Both theories are at present beset with many diffi- 
 culties; but the latter is the more generally received, as 
 accounting for most of the phenomena connected with 
 our coal-fields. According to the former theory, a sub- 
 mergence and elevation must have taken place for every 
 seam of coal ; and as in some districts from thirty to forty 
 
 546. What are the questions in dispute among geologists 1 
 
 547. Name the two theories and their differences. 
 
 548. Name some of the objections to the first theory. 
 
COAL MEASURES. 149 
 
 seams occur, varying in thickness from a few inches to 
 many feet, it is impossible to conceive how the earth, in 
 this unstable condition, could have nourished such a prolific 
 Flora as the coal measures clearly demonstrate. It is also 
 justly objected against this theory, that some thick beds of 
 coal are subdivided by thin layers of sandstone, or fer- 
 ruginous shale, a fact which would imply that many eleva- 
 tions and submergences took place even during the forma- 
 tion of a single coal bed ; whereas by the latter theory, 
 those layers of sandstone, &c. present no difficulty, as the 
 river, while it bore down vegetable drift, would carry at the 
 same time sand and other debris. Further, shells and fishes 
 are sometimes found imbedded in coal ; and it is difficult 
 to conceive how these could have got there, unless in the 
 ordinary way of deposit and sediment. Forests of coniferae, 
 palms, and tree-ferns, could not have been submerged and 
 covered up with sand and mud, without the trunks being 
 abundantly found in an upright position; now, this upright 
 position of fossil trees is rarely or ever met with. Again, 
 had coal resulted from submerged peat-mosses, instead of 
 from growing forests, there is no means by which we can 
 account for the occurrence of shells, fishes, and thin layers 
 of sandstone in its mass. By the latter theory, all these 
 can be readily accounted for. Over vast deltas, such as 
 those in which it supposes the coal measures to have been 
 deposited, there would not only occur growing stems of 
 palms, f rns, reeds, and the like, to be silted up perpen- 
 dicularly, but there would also occur morasses choked 
 up with a rank growth of grasses, while in the creeks and 
 Ingoons, shell-fish, fishes, and other aquatic life would 
 abound. In the deltas of existing rivers, the latter theory 
 meets with a perfect analogy; and when the student is told 
 of the rafts of the Mississippi, the mangrove jungles of the 
 Niger, and the sand and mud-banks of the Ganges (par. 
 27 V J, ^O, &/c), he can have little difficulty in forming a 
 conception of the estuaries in which the sandstones, shales, 
 shell limestones, and coal of the carboniferous era were 
 deposited. 
 
 649. Why is the latter theory rendered probable T 
 
150 GEOLOGY. 
 
 198. The i ff neons rocks assuciatfd. with tlic. carboniferous 
 system are all of the trap family greenstones, clinkstones, 
 basalts, trap-mils, &c. They are principally composed of 
 felspar and hornblende, with admixtures of clay, augite, 
 and occasionally hypersthene. The greenstones (vulgarly, 
 whinstones) occur in large indeterminate or tabular masses, 
 arid are often hypersthenic; the clinkstones differ little from 
 the greenstones in mineral composition, but are more com- 
 pact, split up into thin schistose-like fragments, and yield a 
 metallic sound when struck by the hammer; the basalts 
 are easily known by the columnar structure, their dark and 
 compact aspect, and from their containing little spherical 
 crystals of a greenish mineral called olivine; and the trap' 
 tuffs are of all varieties, from a soft scoriaceous-looking 
 mass to a confused conglomerate of fragments of basalt, 
 greenstone, sedimentary rocks, &c. [Some of the most 
 interesting scenery in this country is formed by greenstone 
 columns, standing upright, or leaning only a few degrees. 
 The Palisadoes, on the Hudson river, a few miles above 
 New York, are an example. But in Oregon, where the 
 Columbia river passes through mountains of trap, and pro- 
 bably basalt, from 400 to 1000 feet in height, a vastly more 
 extensive formation of this kind exists.] The trap rocks 
 of the carboniferous era are easily distinguishable from those 
 of any other, partly by their darker colour, and from the 
 fact of their yielding more or less bitumen by distillation ; 
 and partly from the prevalence of basalts, and of trap-tufts 
 containing fragments of limestone, sandstone, and shale. 
 Among the traps of the old red sandstone, felspar, por- 
 phyries, and amygdaloids prevail, but are rarely to-be met 
 with among those of the coal measures; while, on the 
 other hand, the traps associated with the tertiary strata 
 assume a lighter cotour, and a decidedly scoriaceous and 
 lava-like aspect. 
 
 199. The positions of the carboniferous trap rocks are 
 
 550. Of what family are the igneous rocks of this system 1 
 
 551. Of what minerals are they chiefly composed ? 
 562. Define and explain the italicised terms. 
 
 553. How are the trap rocks of this system distinguished ? 
 
 554. What of their positions T ' 
 
COAL MEASURES. 151 
 
 either disrupting, overlying, or interstratified. They disrupt 
 and elevate, as in the mountain limestone hills, and in the 
 rounded heights and isolated irregular cones of the coal 
 measures. Basalt, or greenstone, sometimes overlie, as if 
 poured in a state of liquid lava over the subjacent strata ; 
 and trap-tuffs also overlie, from their evidently having been 
 strown abroad in the form of volcanic dust and ashes. The 
 trap rocks of this era more frequently assume the in terst ra- 
 tified form than those of any other formation; apparently 
 irom the fiict, that volcanic discharges took place in the seas 
 and estuaries in which the coal measures were being depo- 
 sited these discharges, whether in the form of lava or ashes, 
 being overlaid by subsequent deposits of sedimentary matter. 
 2'JO. The structure and texture of these igneous rocks 
 differ as widely from the granitic series beneath as from the 
 volcanic above. They are generally close-grained, and less 
 distinctly crystalline tharr the former, and more compact 
 and less vesicular than the latter. The structure of the 
 tuffs and porphyries is massive and indeterminate; of the 
 greenstones sometimes massive, but generally tabular or 
 cuboidal; and of the basalts always columnar. This differ- 
 ence in the structure and texture of these rocks seems to 
 have arisen not so much from any difference in their min- 
 eral composition, as from the circumstances attending 
 their cooling. This has been satisfactorily proved by the 
 experiments of Sir James Hall and Mr. Gregory Watt, who, 
 by fusing various kinds of trap, produced, by different 
 modes of cooling, not only columnar basalt, but spherical 
 greenstone and vesicular tufa. The same substance which, 
 when suddenly cooled, forms a black glass or obsidian, will, 
 by a slower process of re r rigeration, ibrm basalt, or by a 
 still slower, pass into earthy tufi. By gradually cooling 
 the fused mass, columnar basalt may be formed; but if at 
 a certain stage of the process, it be rapidly cooled, spheri- 
 cal masses will be produced, which, when exposed to the 
 weather, exfoliate, or decompose coating after coating. 
 l$y these experiments, it was also proved that the primary 
 
 555 How are volcanic dischaiges proven to have taken place 7 
 
 556 What of their structure and texture T 
 
 557. Ho.v is this shown to have been dependent AH cooling? 
 
152 
 
 GEOLOGY. 
 
 form or crystal into which volcanic rock arranges itself 
 when cooled, is spherical; and by these spheres pressing 
 
 StafFa Fingal's Cave. 
 
 upon each other, are produced tabular, cuboidal, and colum- 
 nar forms. This fact can be readily illustrated by putting 
 a number of spherical pellets (of putty or any other yielding 
 material) into a vessel, and then gently pressing upon them, 
 when they will be seen to arrange themselves in five and 
 six-sided columns, precisely similar to the five and six- 
 sided columns of Staffa, or the Giant's Causeway. 
 
 20 1 . The fffcct of igneous forces upon the coal measures 
 has been to throw them into troughs and basins, to elevate 
 and depress them in a very extraordinary manner. The 
 
 e g 
 
 c c 
 
 Trough or Basin Form of Coal-fields. 
 
 558. What of the primary form or crystal of volcanic rock T 
 
 559. What varieties result from this spherical form ? 
 
 560. How may we illustrate this by experiment ? 
 
 561. Whnt obvious effect of igneous forces is named? 
 
 562. Expl-rn the firnt diagram. 
 
COAL MEASURFS. 
 
 153 
 
 foregoing engraving represents a section of the South Glou- 
 cestershire coal-field (omitting faults), and may be taken as 
 the type of the trough or basin. Here a is the elevatory 
 axis of the Mendip hills, overlaid by the old red sandstone 
 d; b b are strata of carboniferous limestone resting at a 
 high inclination upon the slopes of the hills, and reappear- 
 ing at/; c c and the other darkened layers are beds of coal; 
 tee denote the new red sandstone lying unconformably 
 upon the coal measures; gg detached outliers of lias; and 
 h is a detached outlier of inferior oolite, which are respec- 
 tively continued in i and k; I is the upper oolite, and m m 
 are beds of Oxford clay situated to the north of the town of 
 Malmesbury. The upthrows and downthrows of the coal 
 strata which have taken place in consequence of irregular 
 upheavings and sinkings among the masses on which they 
 rest, are repre- 
 sented in the 
 subjoined figure. 
 Here the faults 
 or slips d d d, 
 and the dyke e, 
 are respectively 
 accompanied not 
 only by an up- 
 throw or down- 
 throw, but also by a different inclination of the strata. This 
 mode of fracture is of frequent occurrence in every known 
 coal-field, showing in a striking manner the nature of the 
 agitations which have taken place below. In the vale of 
 the Esk, in Mid-Lothian, which does not measure more 
 than ten miles each way, the coal-field shows 120 ascer- 
 tained dislocations, one of which, at Sheriffhall, throws 
 down the strata five hundred feet. In the Newcastle coal- 
 field, there is a famous slip called the ninety-fathom hitch, 
 the deviation from the line of stratification being no less 
 than 450 feet. The coal-fields of Fife and Clackmannan 
 abound in such dislocations, several of them throwing the 
 
 563. What of the next diagram ? 
 
 564. What is the geological reasoning here ? 
 
 565. Name instances of remarkable dislocations of strata. 
 
 Dislocations of Coal Strata. 
 
154 GEOLOGY. 
 
 strata from 400 to 1200 feet up or down, as the case may 
 be, from the general position. 
 
 202. The extent of country occupied by the carboniferous 
 system is not great, the deposit being found only in limited 
 and detached areas. It occurs largely in the British islands, 
 and to this circumstance is mainly owing our greatness as 
 a nation the formation being rich in co*al, iron, and lime 
 three of the most essential minerals to civilized existence. 
 It presents itself in the Lowlands of Scotland, in the nor- 
 thern and middle districts of England, in Wales, and in 
 Ireland ; it occurs also in some districts of Spain, in central 
 France, Germany, and in Middle Europe; in Hindostan, in 
 Australia, and New Zealand; in the island of Batavia, and 
 on the eastern coast of China; in Melville island; in Nova 
 Scotia, and in the States of North America, especially in 
 Pennsylvania. 
 
 203. The physical aspect of carboniferous districts is 
 rather tame and unprepossessing. The hills connected 
 with tbe mountain limestones sometimes present considera 
 ble variety of scenery, owing to the bold escarpments of 
 that rock, its extensive fissures and caverns, and the irregu 
 lar undulations of the trap. These features are also aided 
 by the general verdure and fertility of limestone districts, 
 which present a freshness and luxuriance peculiar to them- 
 selves. The coal districts are almost always tame and 
 unattractive, relieved by few elevations or depressions of 
 picturesque beauty, and being, in general, bleak and unfer- 
 tile from the cold and retentive nature of the soil. Occa 
 sionally, a basaltic crag or isolated trap-hill relieves the 
 monotony; but this is the exception to the general rule. 
 
 204. The economical value of the carboniferous system 
 fully compensates for any deficiency in the fertility of its 
 soil, or in the picturesque beauty of its geographical fea- 
 tures. Building-stone of the finest quality (of which that 
 of Craigleith, near Edinburgh, and of Calelo in Fife, are 
 good examples) are obtained from the sandstones beneath 
 the mountain limestone; while the millstone grit and flaggy 
 
 566. What of the extent of the carboniferous system ? 
 
 567. What of the physical geography? 
 
 568. What of tf t economical value of this system ? 
 
COAL MEASURES. 155 
 
 beds of the coal measures yield other valuable freestones. 
 Of all the limestones in the crust of the earth, the Mountain 
 is that which is most valuable and abundant; and from it 
 sre principally derived those stores of lime so indispensable 
 10 the purposes of the builder, agriculturist, iron-founder, 
 &c. Where the encrinal beds are sufficiently hard and 
 crystalline, they furnish a very prettily-marked marble; the 
 joints, stalks, plates, and star-like tubes of the corals shin- 
 ing out from the darker matrix in which they are imbedded. 
 Many ornamental spars (Derbyshire spar) are found in the 
 veins of the mountain limestone, which are also the princi- 
 pal sources of lead ore in the British islands ; Derbyshire, 
 Alston Moor in Cumberland, and Lead Hills in Lanark- 
 shire, being well-known lead-mining districts. Silver and 
 gold are both more or less associated with the ores of 
 lead, especially the former; but they are seldom sought, 
 after, unless in connexion with lead. Fire-clay is dug up 
 from the coal measures for the making of fire-bricks, fur- 
 nace linings, &c.; ochre (hydrated oxide of iron), which 
 occurs in several coal-fields, is extensively used as a pig- 
 ment : and alum (sulphate of alumina) is obtained from 
 many of the pyritous shales of Germany. Ironstone, which 
 is found in the coal-shales either in bands, nodules, or 
 septaria,ls one of the most valuable products of the carbon- 
 iferous system. It is obtained in great abundance, and 
 being easily reduced to a metallic iorm by the application 
 of coal and lime, in which the system abounds, it may be 
 said to form one of the prime elements of any country's 
 mechanical and commercial greatness. About two millions 
 of tons are annually manufactured in Britain for the fabri- 
 cation of the innumerable machines, utensils, and imple- 
 ments to which cast-iron, malleable-iron, and steel, are 
 respectively applied. But notwithstanding the great value 
 of these rocks and metals, they do not equal in importance 
 those strata of coal, which form the main distinguishing 
 feature of the system. The varieties principally used in 
 
 569. What metals have been found in this system T 
 670. What earths are obtained thence ? 
 
 571. What of the value of the ironstone ? 
 
 572. N'tne the varieties of coal. 
 
156 GEOLOGY. 
 
 Britain are caking, splint, cubic, and cannel coal ; anthra- 
 cite is that mainly employed in the United States; lignite 
 and brown coal in Germany; and jet wherever it can be 
 obtained, for the manufacture of ornaments. Coal, of which 
 we have historical notice so early as the beginning of the 
 twelfth century, is justly regarded as the main support of 
 the whole system of British production ; it fuses the metals, 
 produces steam which sets machinery in motion, yields gas 
 for light, heats our apartments, prepares our ibod, and, in 
 short, renders all the resources of nature fit for civilized 
 use. The annual consumption of coal in the British em- 
 pire is estimated at about thirty millions of tons; and the 
 export at from three to four millions. At this rate of con- 
 sumption, fears have been entertained that our coal-fields 
 would speedily be exhausted ; and these fears, considering 
 that the deposit is limited, are not altogether without foun- 
 dation. However, calculating the amount of unwrought 
 coal in South Wales, in the middle and northern districts 
 of England, and in the Lowlands of Scotland, and making 
 allowance for more perfect systems of mining, and more 
 economical modes of burning, it is estimated that, at the 
 present rate of consumption, there is coal sufficient to meet 
 the demand for 2000 years. 
 
 EXPLANATORY NOTE. 
 
 CARBONIFEROUS (Lat., carbo, coal, and fero, I bear) coal-bearing or 
 coal-yielding ; applied to that system of strata from which the chief 
 supplies of coal are obtained. 
 
 SUB-CRYSTALLINE less than crystalline, or not distinctly crystallized. 
 In geology, the prefix sub is often used in this sense ; thus we say 
 columnar basalt, when the columns are distinct and regular in shape, 
 and sub- columnar , when the mass presents traces of an irregular 
 columnar structure. 
 
 ENCRINITES In many instances, the calcareous matter of the en- 
 crinite has been dissolved, so as to leave a screw-like cast of the imper- 
 foration and jointings. These casts are known by the vernacular 
 names of screw-stones and pulley-stones; just as turbinoliae (fig. 2, p. 
 116) are called by quarrymen pipe-heads, and the smaller stalks of en- 
 crinites pipe-shanks or tubes. Separate pieces of the stalks are known 
 
 673. To what important uses is coal adapted ? 
 
 574. What of the consumption of coal? 
 
 575 What of the extent of supply ? 
 
 576. Define and explain the several terms in the note. 
 
COAL MEASURES. 157 
 
 in the north of England as St. CvthberPs beads, from a legend alluded 
 to by Sir Walter Scott in the following lines : 
 
 On a rock, by Lindisfarne, 
 
 St. Cuthbert sits, and toils to frame 
 
 The sea-born beads which bear his name. 
 
 From the wheel-like shape of the pieces which compose the stem of 
 the encrinite, they are sometimes technically termed entrochi (trochus, 
 a wheel), and the limestone through which they are scattered entrochal 
 limestone. This term, however, is principally applied to the pieces of 
 the minutest stems. 
 
 LIMESTONE CAVERNS. Caves and fissures present themselves in all 
 rocks which have been subjected to the influence of subterranean 
 movements, or to the eroding power of water ; and may thus occur 
 either in igneous rock, as Fingal's Cave in Staifa, or in sandstone, as 
 the caverns of Arbroath. It is, however, in limestone that the most 
 celebrated caves and grottos are to be found ; indiscriminately in the 
 mountain, magnesian, or oolitic beds, but on a scale of far greater 
 splendour and magnificence in the former. Those of Derbyshire, 
 Mitchelston in Ireland, Paros and Antiparos in the Archipelago, Aus- 
 tralia, &c. are examples of this class, and have been formed partly 
 from fissures caused by igneous movements, and partly by the eroding 
 influence of springs and subterranean streams. The joints and divi- 
 sional planes which so numerously intersect the mountain limestone, 
 no doubt greatly facilitate these excavating operations. 
 
 ANTHRACITE (Gr., anthrax, coal) a variety of coal almost wholly 
 deprived of its bitumen. It may be regarded as a natural charcoal 
 formed by subterranean or by chemical heat. Common bituminous 
 coal is often found converted into anthracite by effusions of igneous 
 rock ; and this fact suggests the idea that all deposits of the kind have 
 been similarly produced. The most extensive fields of anthracite are 
 in Pennsylvania and the bordering states of North America. 
 
 BITUMENS or THE CARBONIFEROUS SYSTEM. Besides the many varie- 
 ties of coal, which are bitumens mingled more or less with earthy 
 impurities, there are other bituminous substances derived from the 
 system. Naphtha, petroleum, mineral pitch, and asphalte, ooze out by 
 rents ; mineral caoutchouc (elaterite, or elastic mineral pitch) is found 
 in crevices of the limestone ; and a number of mineral resins and fats 
 such as common mineral resin, sphero-resinite (globular drops of 
 mineral resin), mellite (crystallized resin or honeystone), Hatchetine, 
 (mineral tallow), &c. are obtained in small quantities. Carburetted 
 hydrogen (fire-damp) and carbonic acid gas (choke-damp), both so fatal 
 to miners, seem to be evolved from the coal beds after the same man- 
 ner as several of the above-named products. 
 
 COPROLITES (petrified excrements) are found in all the systems of 
 the secondary and tertiary epochs. They are chiefly the voidings of 
 fishes and sauroid animals, and yield unequivocal evidences of their 
 origin in containing scales, bones, and other fragments of the creatures 
 on which these voracious animals preyed. Many specimens of copro- 
 lite retain on their external surfaces the convolutions and corrugations 
 
 577. Define the terms used in the note. 
 
158 GEOLOGY. 
 
 of the intestines; and masses of it have been found in situ within the 
 ribs of ichthyosauri. 
 
 NEW RED SANDSTONE SYSTEM. 
 
 205. After the deposition and upheaval of the carbonifer- 
 ous system, a new era occurs in the history of the globe. 
 Overlying the coal measures in some places conformably, 
 and in others not, there appears a set of red sandstones, 
 variegated (yellow, purple, and greenish) shales, thick- 
 bedded magnesian limestones of a cream colour all of 
 which present an aspect not to be mistaken for any previ- 
 ous system of strata. As to their organic remains: there 
 are a few species of marine zoophytes, shells, and fishes, 
 but scarcely a trace of vegetation, showing that the condi- 
 tions which gave birth to the exuberance of terrestrial plants 
 during the coal era had undergone an extensive and pecu- 
 liar change. To these red sandstones, magnesian lime- 
 stones, arid mottled shales, the term New Red Sandstone 
 System has been applied, in contradistinction to the Old 
 Red which underlie the carboniferous strata ; and this 
 term we adopt in preference to those of Puikilitic (Gr., 
 poikilos, variegated) and Safiferous (salt-yielding), which are 
 in use by some geologists. 
 
 206. The composition of the New Red Sandstone may 
 be said to be arenaceous, argillaceous, calcareous, mag- 
 nesian, and saline. The arenaceous members are chiefly 
 reddish sandstones of various fineness, from a hard quartz- 
 ose grit to a brecciated conglomerate. Few of them are 
 laminated or micaceous, and the thicker beds often present 
 curious spherical concretions of a harder texture, containing 
 some foreign substance as a nucleus. The grains of the 
 sandstones are of a clear quartz, merely coloured externally 
 by a coating of the red oxide of iron, as if the debris of the 
 rocks from which they were derived had been deposited in 
 ferruginous waters. The argillaceous members are usually 
 
 578. What new system is next considered 1 
 
 579. What does this system overlie ? 
 
 580. What of the organic remains found here ? 
 
 681. What of the composition of the new red sandstone T 
 582. What of the arenaceous ? 
 
NEW RED SANDSTONE SYSTEM. 159 
 
 called " marls," from the fact of their often containing a 
 little calcareous matter, and being less laminated in struc- 
 ture than the coal shales. They are generally red ; but are 
 sometimes mottled purple, yellow, and green (called varie- 
 gated marls), and contain irregular beds and plates of gyp- 
 sum (sulphate of lime). The calcareous members vary 
 from an almost pure carbonate t)f lime to an admixture of 
 eirbonate of lime and carbonate of magnesia ihence called 
 Alagnesian Limestone. They vary in colour from an ash- 
 gray to a cream-yellow; are sometimes finely laminated; 
 at other times granular and crystalline, and in this state 
 called dolomite, after M. Dolomieu. Frequently, a layer 
 exhibits a cellular or vesicular texture, the walls of the cells 
 being sparry, and the cells themselves filled with loose 
 powdery limestone. This cellular structure is abundant in 
 the magnesian limestone of Durham, and has received 
 various terms from the shape of the cells; as honeycombed; 
 botryoidal, composed of little spherical concretions like a 
 bunch of grapes; and mammil/ary, when the concretions 
 assume an elongated or pap-like shape. These concre- 
 tionary and cellular forms are said to be coralloidal that 
 is, like to corals in shape; but they have nothing to do 
 with organic structure, being merely the result of chemical 
 or mechanical aggregation. The talinr members are chiefly 
 rock-salt, which occurs in white crystallized masses, or 
 reddened by the argillaceous sediment among which it 
 occurs. Salt springs abound in the new red sandstone, 
 partly from the shales being all more or less impregnated 
 with salt, atid partly from the decomposition of the rock-salt 
 itself Gypsum occurs among the marls either in films or 
 foliated fragments, the latter variety being the sclenite of 
 mineralogists , and oxide of copper is the green colouring 
 matter of the shales. 
 
 583. Which are called marls ? 
 
 584. Which are magnesian limestone T 
 
 585. What are the names given to the varieties of cellular structure f 
 
 586. How are they formed ? 
 
 587. What of rock salt, and saline springs ? 
 
 588. Which variety of marls is the gypsum and the selenite ? 
 
H)J GEOLOGY. 
 
 207. The order of succession among tJif nimbcrs of the 
 new red sandstone is not very regular or persistent. In 
 England, the lower part of the series consists chieflv o, 1 ' red 
 sandstones and grits, the middle of magnesiau limestones 
 and gypseous marls, and the upper portion of variegated 
 sandstones and marls, enclosing local deposits of gypsum 
 arid rock-salt. On account of this triple succession, Pro- 
 fessor Sedgvvick has divided the system into the following 
 groups: 
 
 Description. 
 
 "1. VARIEGATED MARLS red, with bluish, greenish, and 
 whitish laminated clays, or marls holding gypsum gen- 
 erally, and rock-salt partially (as in Cheshire). In- 
 cluded in these marls are certain beds of gray and 
 whitish sandstones. 
 
 6. VARIEGATED SANDSTONES red sandstones with white 
 and mottled portions, the lower parts in some districta 
 pebbly. 
 "5. LAMINATED LIMESTONES of Knottingley, Doncaster, 
 
 &c. with layers of coloured marls. 
 4. GYPSEOUS MARLS red, bluish, and mottled. 
 3. MAGNESIAN LIMESTONE yellow and white; of various 
 texture and structure ; some parts full of fragmentary 
 
 Groups. 
 
 UPPER. 
 
 MIDDLE. 
 
 2. MARL SLATES laminated ; impure calcareous rocks 
 of a soft argillaceous or sandy nature. 
 
 1. RED SANDSTONE with red and purple marls, and a few 
 micaceous beds. The grits are sometimes white, or 
 yellow ; and pebbly. When conformable, this sand- 
 stone occasionally passes into the coal measures on 
 which it rests. 
 
 It must not be supposed, however, that the system always 
 forms so complete a section-; for in some places the gypse- 
 ous marls predominate, in others the magnesian limestone, 
 while in several a mass of redstones, with subordinate layers 
 of coloured shales, represent the whole system. The fol- 
 lowing table shows how the deposit occurs in Germany, 
 England and France; from which the student may also learn 
 the important fact, that it is by general types, and not by 
 
 LOWER. 
 
 589. What of the order of succession in England ? 
 
 590. Describe the tabular arrangement of groups. 
 
 591. What variations from this 1 
 
 692. What is shown by the three tables ? 
 
NFW RED SANDSTONE SYSTEM. 
 
 161 
 
 any conventional series of strata, that systems are to be 
 identified in different countries: 
 
 GERMANY. 
 
 Keuper Marls and 
 Grits. 
 Muschelkalk. 
 Hunter Sandstein. 
 Stinkstein ; Rauwacke. 
 Gypseous Marls. 
 Zechstein. 
 Kupfer Schiefer. 
 Rothe-todte-liegende. 
 
 ENGLAND. 
 
 Variegated Marls and 
 Grits. 
 
 FRANCE. 
 
 Marnes Irisees. 
 
 Muschelkalk. 
 Gres Bigarre. 
 
 Variegated Sandstone. 
 Upper Limestone. 
 Gypseous Marls. 
 Magnesian Limestone. 
 Marl Slate. 
 Lower Red Sandstone. 
 
 
 
 Gres Rouge. 
 
 208. " The organic remains of this system," says Pro- 
 fessor Phillips, " though few in number, are exceedingly 
 interesting to Che naturalist and geologist, from the strong 
 testimony they offer of the successive changes of the living 
 creation, according to the new circumstances of the land 
 and sea. The fossil plants, shells, fishes, and reptiles of 
 this system appear to partake both of the character of those 
 in the older carboniferous, and the newer oolite deposits. 
 Calamites, like those of the coal formation, are mingled 
 with cycadeae, resembling closely those of the oolites. Pro- 
 ducts, so common in mountain limestone, occur in the 
 zechstein with terebratulse, like those of the lias and oolites. 
 Fishes of the genus palaBoniscus here occur for the last 
 time, in ascending the series of strata ; and here, perhaps, 
 for the first time we have remains of oviparous quadrupeds 
 the protosaurus and phytosaurus." Exhibiting this tran- 
 sition from one system of life to that of another, the new 
 red sandstone has been regarded as the boundary between 
 the LOWER and UPPER SECONDARY STRATA the old red 
 sandstone, mountain limestone, coal measures, and new red 
 sandstone, belong to the lower or older secondary forma- 
 tion ; and the lias, oolite, and chalk, to iheupper or younger 
 secondary. 
 
 209. The number of fossil species hitherto detected in the 
 new red sandstone of England amounts to fifty or thereby, 
 while fully thrice that number has been found in France 
 
 593. What of the organic remains ? 
 
 594. What variety of fossils is found here 1 
 
 595. Describe the two series of secondary strata 1 
 
 596. What number of fossil species are found ? 
 
162 GEOLOGY. 
 
 and Germany. These consist of traces of marine plants, a 
 few terrestrial plants, several zoophytes, one species of cri- 
 noidea, about two dozen species of bivalves, one chambered 
 shell, several fishes, the mutilated skeletons of two sauroid 
 animals, and the traces of footsteps, called ichnites, from 
 the Greek ichnon, a footmark. Like the vegetation of the 
 coal era, the plants of the new red sandstone are chiefly 
 vascular cryptogamia; the corals, bivalves, and fishes, are 
 apparently the same ; and it is only in the chambered shells, 
 and in the sauroids, that new types are presented. Alto- 
 gether, the system seems to have been deposited under 
 circumstances peculiarly unfavourable to animal and vege- 
 table life; at least few organic exuviae are to be met with 
 in its strata. 
 
 210. The igneous rocks associated with the system are 
 chiefly dykes of greenstone, which pass indiscriminately 
 through the magnesian limestone, coal measures, and old 
 red sandstone. These dykes belong to no definite volcanic 
 era, but seem to have been formed by minor forces acting 
 over limited extents. The granitic rocks of the primary 
 period, as well as the traps of the old red sandstone and 
 carboniferous measures, establish themselves in well-marked 
 and characteristic ranges; while the igneous rocks of the 
 new red sandstone, lias, and oolite, are mere local effusions 
 limited to dykes and partial upheaves. In their mineral 
 character, these rocks differ little from the traps of the coal 
 measures consisting chiefly of greenstone, pitchstone, and 
 clay-stone porphyry. 
 
 211. The extent of country over which this system is 
 spread is not well ascertained. Slight traces of it occur on 
 the western coast and islands of Scotland, and on the Fife 
 shores of the Forth; it occupies a wider area in the basin 
 of the Solway and its tributaries; spreads largely over the 
 central districts of England from the Tyne southwards ; 
 and is found in the north of Ireland. Extensive areas are 
 covered by it in the continent of Europe in France, Ger- 
 
 597. What are the footmarks called ? 
 
 598. Of what do the igneous rocks here consist? 
 
 599. What of the extent of country where this system occurs? 
 
NEW RED SANDSTONE SYSTEM. 163 
 
 many, Poland, along the flanks of the Alps, in Austria, and 
 between the Volga and the Ural mountains; and, accord- 
 ing to Professor Hitchcock, it is spread over considerable 
 spaces in some of the river valleys of the United Slates. 
 
 212. The physical aspect of new red sandstone districts, 
 as may be conjectured from the limited force of the igneous 
 rocks, is rather flat and gentle. There are no picturesque 
 crags, mountain ranges, or deep ravines to diversify the 
 scenery; which consists of rounded terraces of magnesian 
 limestone, and level expanses of red sandstone and shales, 
 here and there dotted with a gentle eminence of limestone 
 or gravel. Over the limestone the sward is thick and ver- 
 dant, and the soil above the red sandstone is of average fer- 
 tility; but where the retentive shales spread out in flat 
 hollows, they ibrm the basis of extensive morasses as, for 
 example, those of south Lancashire, in England. 
 
 213. The minerals of commerce derived from the forma- 
 tion are not numerous the most important being magnesia 
 and rock-salt. The magnesian limestone, when reduced 
 to quick-lime, is employed with effect on certain soils; it 
 furnishes the builder with mortar; and yields, under chemi- 
 cal treatment, the magnesia of the apothecary. In some 
 localities it furnishes a beautiful and durable building-stone; 
 that of Bolsover moor, in Derbyshire, being the material 
 employed in the construction of the new houses of Parlia- 
 ment. Some of the limestone schists are also suitable for 
 lithographic purposes, the admired German blocks being 
 chiefly derived from this source. Gypsum is obtained from 
 the marls of the series, which also yield the main supply of 
 rock-salt in various parts of the world- such as Cheshire 
 and Worcester in England, in Spain, Poland, Germany, and 
 Austria. This salt occurs in beds or irregular masses, from 
 JO, 20, or 30 feet, to 120 feet in thickness; is of various 
 degrees of purity and colour. Sometimes it contains 
 scarcely two parts in the hundred of foreign matter, at 
 others it is of a red colour, and mixed to the extent of half 
 
 600. What of its physical geography.? 
 
 601. Of what uses are the magnesian limestone ? 
 
 602. What of t: e rock-salt 1 
 
1(54 GF.OLORY. 
 
 its bulk with earthy impurities. Urine, or salt-springs, 
 which often issue 1'rom this deposit, contain from 20 to 30 
 per cent, of salt, and are doubtlessly derived from the solu- 
 tion of the solid masses by subterranean waters. The 
 kupfer-schieftr of Germany is worked to some extent as 
 an ore of copper; but no other metal is derived from the 
 system. 
 
 214. The formation of rock-salt is a subject, in connexion 
 with this system, which has much engaged the attention of 
 speculative geologists. The sandstone and marls with 
 which it is associated are evidently derived from deposition 
 in water; but the irregularity of the salt beds, the fact of 
 their occurring in masses of vast thickness, and the soluble 
 nature of the compound, all point to a somewhat different 
 origin. At present, salt lakes and superficial accumula- 
 tions of salt occur in various parts of the world, and these 
 have furnished data for reasoning as to the saliferous depo- 
 sits of earlier eras. Salt lakes are chiefly derived from salt 
 springs, and being subjected to the vaporizing influence of 
 the sun, which carries off only fresh vapour, their waters 
 become in time saturated w r ith saline matter. But water 
 can hold only a fixed amount of salt in solution ; and so 
 soon as this amount is attained, the salt begins to fall to the 
 bottom by its own gravity. In the course of ages, these 
 layers will form a thick bed. interstratified, it may be, with 
 mud, or other earthy sediment; and if the lake should be 
 ultimately dried up, the salt will constitute a deposit some- 
 thing analogous to the rock-salt of the new red sandstone. 
 Such is the process which some geologists have advanced 
 to account for the formation of rock-salt supposing mat 
 portions of the seas of deposit were occasionally cut off 
 from connexion with the main ocean, and subjected to a 
 rapid evaporating power, without receiving fresh accessions 
 of vvater. The limited extent of rock-salt basins seems to 
 favour such a theory; but when we consider the frequency 
 of disturbance by volcanic forces in earlier ages, and the 
 fact of many of these deposits occurring near to, or in cen- 
 
 603. Whence are brine springs derived ? 
 
 604. How is the formation of rock-salt accounted for f 
 
NEW RED SANDSTONE SYSTEM. 165 
 
 nexion with, mountain elevations, it is more than probable 
 that igneous action, as well as a high atmospheric tempera- 
 ture, had to do with their formation. If such were the 
 origin of rock-salt, it must have been formed during the 
 deposition of other systems than the new red sandstone; 
 and this geological research has confirmed ; lor although 
 the most extensive accumulations do occur amid the sand- 
 stones and shales of the system under review, still, deposits 
 of considerable thickness are found in connexion with 
 oolite, green-sand, and tertiary rocks, while numerous salt 
 springs issue from the carboniferous strata. 
 
 215. The formation of magnesian limestone has also 
 given rise to several theories. Minute quantities of mag- 
 nesia occur variously combined in the crust of the earth ; but 
 only in the limestones of this system is it sufficiently de- 
 veloped to constitute a peculiar and distinguishing feature. 
 The most prevalent hypotheses advanced to account for 
 this peculiarity are first, that the carbonate of magnesia 
 was deposited at the same time as the carbonate of lime; 
 and, second, that it was subsequently injected in the form 
 of gaseous vapour. Neither hypothesis seems to account 
 for all the phenomena presented ; although the former is 
 that which admits of most extensive application. 
 
 EXPLANATORY NOTE. 
 
 NEW RED SANDSTONE SYSTEM.- 1 In some recent works, it has been 
 attempted to arrange the rocks of this system, as developed in Eng- 
 land, under two grand divisions; the first including the lower new red 
 sandstone and magnesian limestone, and the second the variegated 
 sandstones and gypseous marls. This arrangement has been made in 
 order to facilitate comparison with the contemporaneous systems of 
 continental and eastern Europe. In Germany and the neighbouring 
 countries the former division corresponds with the Rothe-todte-lifgende, 
 and the latter with what is now generally known as the Triassic 
 system (so called from its being readily divisible into three groups 
 the Bunter Sandstein,Muschelkalk, and Keuper Marls). To the rocks 
 of eastern Europe, which seem contemporaneous with the new red 
 sandstone, Mr. Murchison has applied the term Permian system, from 
 
 605. What renders it probable that igneous as well as aqueous agency 
 
 his bnen employed T 
 
 606. What is the probable theory of the formation of magnesian 
 
 limestone T 
 
 6^7. Explain the terms of th* note. 
 8 
 
166 GEOLOGY. 
 
 their being widely developed in the ancient kingdom of Permia, which 
 extends for several hundred miles along the western flanks of the Ura- 
 lian chain, and thence westward to the river Volga. 
 
 ZECHSTEIN (mine-stone) so called from its containing a deposit 
 (Kupfer-schiefer, or copper-slate) which is worked as an ore of copper, 
 and the underlying sandstone has received the name Rothe-todte-liegende 
 (red dead-lier), because it is of a red colour, is dead or worthless as far 
 as any metallic ore is concerned, and underlies the real metallic de- 
 posit. The other terms, Stinkstein, Muschelkalk, Ores Rouge, &c. re- 
 quire no translation. 
 
 ICHNITES, or fossil footsteps, present a curious example of the means 
 by which geologists are enabled to decipher the history of the earth. 
 Most people must have observed how distinct the impressions of the 
 feet of birds and other animals are often left on the mud or sand of 
 ebbing rivers. If this mud should remain exposed to the sun and air 
 till sufficiently dried, and then be overlaid by some new sediment, the 
 impression of the foot will l brm a mould into which the new matter 
 will be deposited. Should the two layers ever be consolidated into 
 stone, on being separated, the one would present a mould, and the 
 other a cast of the footsteps ; and this is precisely what takes place 
 among the strata of the earth's crust. FossJ footsteps have been dis- 
 covered in the new red sandstone of Cocklemuir in Dumfriesshire, and 
 in that of Hildburghausen in Saxony, supposed to be those of reptiles 5 
 hence termed sauroidichnites. Others have been detected in the sand- 
 stones of Connecticut, United States, and ascribed to gigantic birds 
 allied to the Ostrich family ; consequently called Ornithictmites, from 
 the Greek words ornis, a bird, and ichnon, a trace or footprint. To 
 these Professor Hitchcock adds a third class, tetrapodichnites, or the 
 footsteps of some unknown four-footed animal. 
 
 OOLITIC SYSTEM. 
 LIAS, OOLITE, AND WEALDEN GROUPS. 
 
 216. After the deposition of .the new red sandstone, a fur- 
 ther change was effected upon the general conditions of the 
 globe, so as to produce not only an entirely different set of 
 strata, but alsi different races of plants and animals. In 
 most districts, the red sandstones and magriesian limestone 
 were upheaved, to form new land, while poriions of the 
 former dry land were submerged beneath the ocean. By 
 this process of elevation and depression the courses of pre- 
 vious rivers would be altered, former seas circumscribed 
 and rendered more shallow, plants and animals subjected 
 
 608. How are fossil footsteps explained, and where found ? 
 
 609. What system is here considered, and what groups compose it ' 
 
 610. What geological reasoning is presented 7 
 

 OOLI nc >YSTKM. 167 
 
 to a new distribution, and thus a different set of deposits 
 would necessarily ensue. Instead oi mngnesian rocks, we 
 have dark argillaceous and oolitic limestones; for varie- 
 gated saliferous marls, we have bine pyritous clays; and 
 instead of red and mottled sandstones, yellow calcareous 
 grits. All this points to a new epoch in the terrestrial con- 
 ditions of the world ; and to the system of strata thus depo- 
 sited geologists apply the term oolitic (Gr.,wn, an egg, and 
 lif/ios, a stone), from the rese'rnblance which the texture of 
 many of the beds bear to the roe or eggs of a fish. Oolite, 
 or roesfone, is an aggregate of rounded calcareous particles, 
 varying from the size of a millet-seed to that of a marble 
 the smaller being almost perfectly spherical, the larger irre- 
 gular, and having their interstices filled with calcareous 
 matter or broken shells. The system in England com- 
 prises three well-defined groups; namely, the Lias, the 
 Oolite proper, and the Wealden clays. 
 
 217. T/ie Lias, the lowest group in the system, is com- 
 posed of dark argillaceous limestones, bluish clays, and 
 shales. The clays in general predominate, and occur with 
 interstratified limestones; they contain occasional layers of 
 jet or other coal: ironstone in septsria is not unfrequent; 
 and many of the shales abound in bitumen and iron pyrites. 
 As indicated by the name (lias, c rruption of layers"), the 
 limestones are finely stratified, and i we evidently been de- 
 posited in tranquil waters. Most of th shales, in addition 
 to their bituminous and pyritous qualities, are impregnated 
 with muriate of soda (common salt), and with the sulphates 
 of magnesia and soda: and Mr. Bakewell states that it is 
 not uncommon, after wet weather, for the Yorkshire sea- 
 cliffs, which are composed of these shales, to ignite spon- 
 taneously, and burn for several months. The Oolite is 
 more varied in its composition, consisting of oolite lime- 
 stones, calcareous grits, or conglomerates, yellowish sands, 
 and clays all more or less calcareous. The peculiar rounded 
 grains which constitute the oolitic texture, consist either 
 
 611. Define oolite. 
 
 612. What of the lowest group? 
 
 613. What of their various composition, and of the shale* 1 
 
 614. What of the oolite composition ? 
 
168 OEOLOT/Y. 
 
 entirely of lirne, or of an external coating of lime, collected 
 round minute particles of sand, coral, shells, &,c. ; the grits 
 are composed of sand, lime, fragments of shells and corals; 
 arid many of the clays present the same brecciated texture. 
 The Wealden group (from \\\e wealds or wolds of Kent and 
 Sussex, where the deposit prevails) consists of beds of 
 bluish clay, argillaceous limestones, impure oolites, and 
 ferruginous sandstones. Nodular ironstone occurs in the 
 clays, and beds of pisiform (Lat., pisum, a pea) iron-sand 
 are occasionally met with, while oxide of iron is more or 
 less diffused through the whole group. Fossil plants are 
 abundant ; and, as may be expected from this circumstance, 
 local traces of coal are not unfrequent. 
 
 218. Taking the whole systtm into account, it is apparent 
 that calcareous and argillaceous compounds prevail; indeed 
 it may be said to be an argillo-calcareous deposit, including 
 subordinate layers of sandstone, bands of ironstone, and 
 traces of coal. Among the lias strata, dark hues prevail; 
 among the oolite, cream-yellow and ochraceous colours; 
 the clays of the wealden are dark blue, while its other beds 
 partake of a ferruginous tint. 
 
 219. With regard to the succession among the strata, no 
 very regular order is observed ; though no fact in gf ology is 
 better established than the supra position of the lias, oolite, 
 and wealden, as above-described. The lias is the most 
 extensive and persistent of the three groups, and seems to 
 have been deposited over wider areas ; the oolite is less 
 persistent, being often interrupted by changes from sand- 
 stones to brecciated grits, and from grits to oolitic lime- 
 stones; and the wealden is the least extensive, being justly 
 regarded as a half estuary half marine deposit, peculiar to 
 certain districts. Taking the system as developed in Eng- 
 land, the following is the ascertained order among the 
 strata, between which and the contemporaneous rocks of 
 the continent there is no essential mineral or fossil dis- 
 tinction : 
 
 615. How is the wealden group distinguished? 
 
 616. What variety is in the whole system T 
 
 617. What of the order of succession ? 
 
OOLITIC SYSTEM. 
 
 
 WEALDEX 
 
 OOLITE. 
 
 LIAS 
 
 i 
 
 TJlue laminated clays, containing concretional iron- 
 stone and thin layers of argillaceous limestone. 
 (The weald clay.) 
 
 Sands and sandstones, frequently ferruginous ; beds 
 of clay and sandy shale, all more or less calcare- 
 ous. (Hastings sands.) 
 
 Various estuary limestones, alternating with sands 
 and clays. (Purbeck beds.) 
 
 Portland oolite ; calcareous irony sand and concre- 
 tions; and a calcareous clay, locally called " Kim- 
 meridge clay." 
 
 Coralline oolite (coral rag); calcareous sands and 
 grits; Oxford clay, including, layers of impure 
 clayey limestone. 
 
 Oolitic and shelly strata (Cornbrash) ; forest mar- 
 ble ; Bath oolite ; yellow sandstones, divided 
 by clays and calcareous sands ; marls and fuller's 
 earth. 
 
 TThick beds of dark-coloured bituminous shale; beds 
 of pyritous clay ; and indurated lias marls. 
 
 Lias limestones and clays ; bands of ironstone ; 
 layers of jet and lignite ; sandstones more or less 
 calcareous. 
 
 229. The organic rrmains of the oolitic system are very 
 numerous, and have long attracted the attention of geolo- 
 gists. They show a decided advance upon pre-existing 
 races, inasmuch as insects, amphibious reptiles, and mam- 
 malia, majte their appearance in the. animal kingdom ; 
 while new tribes of vegetables, such as the cycadere, lilaceas, 
 &c. are added to the Ibrmer Flora. The organisms of the 
 lias, the oolite, and the lower members of the wealden, 
 indicate the marine origin of these deposits; those of the 
 upper weald an estuary character, from the comminglement 
 of fresh water with marine species. With this distinction, 
 the Fauna and Flora of this epoch may be thus summarily 
 detailed: Plants seaweeds; a few equisetums; many 
 ferns allied to the sphenopteris, pecopteris, &c. of the coal 
 measures; cycadeae, allied to the existing cycas revoluta 
 and pine-apple; coni ferae, resembling the yew and pine; 
 besides lilacese and other undescribed genera. Animals 
 ^oophytes, more like existing species than those of the 
 
 618. Explain the order of the wealden group. 
 
 619. How is it with the two other groups ? 
 
 620. What of the organic remains of this system? 
 
 621. Describe the fauna and flora of this epoch. 
 
170 GEOLOGY. 
 
 mountain limestone and silurian rocks; crinoidea, chiefly 
 the apiocrinite and pentacrinite ; star-fishes, resembling the 
 common ophiura and asterias ; echinida (sea-urchins), of 
 which the cidaris is one of the most beautiful and abun- 
 dant; shell-fish, both vivalves, univalves, and chambered; 
 annulosa, like the common serpula and land-worm ; crus- 
 tacea, resembling the lobster-tribe ; insects like the beetle 
 and dragon-fly; fishes belonging chiefly to the ganoidia; 
 reptiles allied to the tortoise, to the crocodile, and gavial of 
 existing rivers, but differing widely in their external forms 
 and modes of existence; mammalia, two or three speci- 
 mens of small marsupial animals allied to the opossums. 
 In the upper or fresh-water wealden, there are no zoophytes 
 or marine rnollusca ; but there are, according to Phillips, 
 various land plants, fresh-water bivalves and univalves, 
 some fishes, sauroid animals, and remains of turtles, both 
 fresh-water and marine. 
 
 221. The fossils most characteristic of the system are the 
 cycadeaB, of which the stems, fruit, and leaves are found in 
 abundance, the sea-urchins, the ammonites of various ge- 
 nera and gigantic size, the sauroid reptiles, the ptero-dac- 
 tyles or flying-lizards, the fresh-water and marine turtles, 
 and the marsupial mammalia. The cycadese occur princi- 
 pally in the upper or fresh-water portion of the weald, 
 intermingled with the stumps and prostrate trunks of trees. 
 They are found most plentifully in what is locally desig- 
 nated the " dirt-bed" of Portland a stratum of dark argil- 
 laceous mud, which must at one time have been the soil in 
 which they and other vegetables flourished, but which, by 
 a submergence of the land, was converted into the bottom 
 of an estuary, over which other strata of clay, limestone, and 
 s;md were deposited. " At the distance of two feet," says 
 Bakewell, " we find an entire change from marine strata to 
 strata once supporting terrestrial plants; and should any 
 doubt arise respecting the original place and position of 
 these plants, there is, over the lower dirt-bed, a stratum of 
 fresh-water limestone, and upon this a thicker ditt-bed, 
 
 622. What fossils are characteristic ? 
 
 623. What geological argument is thence derived T 
 
OOLITIC SYSTEM. 
 
 171 
 
 containing not only the cycadeae, but stumps of trees from 
 three to seven feet in height, in an erect position, with 
 their roots extending beneath them. Stems of trees are 
 found prostrate upon the same stratum; some of them are 
 from twenty to twenty-five feet in length, and fiom one to 
 two feet in diameter. The following section of a cliff in 
 Dorset exhibits very clearly proofs of the alternation from 
 
 i 
 
 a a a, Portland Stone (marine formation) ; 6, Dirt-bed, consisting of 
 black mould and pebbles (temporary dry land) ; c, Burrstone, and d, 
 Calcareous Slate (both of fresh- water formation). 
 
 marine strata to dry land covered with a forest, and of a 
 subsequent submergence of the dry land under a river or 
 lake which deposited fresh-water limestone." 
 
 222.*O/"fAe radiata, mollusca, and crustacea of this era, 
 it may be observed, that while they differ essentially from 
 those of the older secondary strata, they approximate in 
 form to existing races. The gigantic and prolific crinoidea 
 of the mountain limestone had disappeared, and been suc- 
 ceeded by a few dwarfish specimens of apiocrinite and penta- 
 crinite ; while the cidaris (see fig. p. 172), clypeus, and other 
 echinida (sea-urchins), attest a higher degree of orgnniza- 
 
 * (See Appendix.) . 
 
 524 Describe the diagram. 
 
 525. What difference is. observed from those of the older secondary 
 strata ? 
 
173 
 
 GKOLOaV. 
 
 lion among radiated animals. Among the shell-fish, the 
 grypli(Ba t trigonia, ottrca, and ammonite, are the most cha- 
 2 ^ 3 
 
 1. Cidaris intermedia; 2. Gryphaea incurva ; 3. Trigonia costata ; 
 4. Ostrea deltoidea. 
 
 racteristic hundreds of species of the latter having left 
 their remains in the most perfect state of preservation in 
 the shales and limestones of the lias. The ammonite (of 
 which two species, and a section of the interior, is figured 
 below) receives its name from its resemblance to the curved 
 horn on the head of the statue of Jupiter Ammon. It was 
 
 1. Ammonites obtusus ; 2. Section of Ammonites obtusus, showing the 
 interior chambers and siphuncle ; 3. Ammonites nodosus. 
 
 a chambered shell belonging to the cephalopodous division 
 of mollusca that is, having its organs of motion arranged 
 round the head; and had many congeners in the euompha- 
 lus, nautilus, orthoceratite, hamite (hook-shaped), scaphite 
 (boat-shaped), baculite (staff-shaped), and other many-cham- 
 bered shells. It is one of the most widely-distributed mol- 
 luscs in the secondary strata, and is found of all sizes, from 
 that of a pin's head to three or four feet in diameter. The 
 economy of the ammonite destined it in general to live at 
 
 626. Describe the first diagrams. 
 
 627. What of the other diagrams ? - 
 
 628. Describe the wonderful structure of the ammonite. 
 
OOLITIC SYSTEM. 173 
 
 the bottom of deep waters, but to be able to rise at pleasure 
 to the surface. For this purpose the outer chamber (o o) 
 of the wreathed shell was fitted for the reception oi the 
 animal, while the interior chambers (i i) were hollow, so as 
 to make the whole structure nearly of the same weight as 
 the element in which it moved. Through all of these 
 chambers an elastic tube passed by means of a pipe or 
 siphuncle (s s), the tube being in connexion with the cavity 
 of the heart, which, under ordinary circumstances, was 
 filled with a dense fluid. When alarmed, or wishing to 
 descend, the animal withdrew itself within the outer cham- 
 ber, and the pressure upon the cavity of the heart forced 
 the fluid into the siphuncle, so as to increase the gravity of 
 the shell, by which means it readily sunk to the bottom. 
 On the other hand, when wishing to ascend, it had only to 
 project its arms, and the fluid, being freed from the pressure, 
 returned from the siphuncle to the cavity of the heart, thus 
 restoring the whole structure to its ordinary floating gravity 
 As the pressure of water at the bottom ot the sea would 
 break the plates of any ordinary shell, as it does a bottle 
 when it is lowered to a great depth, the shell of the am- 
 monite has been strengthened by a curious kind of internal 
 arch-v.ork, so as to be able to resist the weight of the in- 
 cumbent fluid. This arch-work so completely meets all 
 human ideas of ingenious contrivance for the purpose which 
 it was destined to serve, as to form one of the most striking 
 examples of that adaptation of means to ends which prevails 
 throughout the works of nature, and which is so well fitted 
 to impress the conviction of a great designing First Cause. 
 223. T7te insects, Jt*ke* t and rrptiles of the oolitic system 
 have greatly attracted the attention of naturalists and geolo- 
 gists; and, as might be expected from remains so obscure, 
 have given rise to much diversity of opinion. The insects 
 discovered in the slaty limestones of the true oolite at St>- 
 lenliafen in Germany, and Stonesfield in England, some- 
 \vhat resemble the dragon-fly and serricorn beeiles of the 
 present day. The fishes present the enameled scale and 
 
 629. What reflections are suggested 1 
 
 630. What or' the inserts, fishes and reptiles of this system 1 
 
174 GF.OLOfJY. 
 
 unequally-lobed tail of the cartilaginous order, and find a 
 distant analogue in the existing rc.ttracioii of the Austral- 
 asian seas. It WHS slated, that the hones and teeth of rep- 
 tiles had been found in the marls of the new red sandstone; 
 but in the lias and the strata above it, the exuviae of these 
 animals are so abundant, and of such vast size, that the 
 epoch in which these strata were deposited has not unaptly 
 been termed " the age of reptiles." Of these there are ter- 
 restrial and marine chelonida (tortoises and turtles); lizards, 
 whose arms and legs were fitted with a filmy membrane, 
 like bats, to enable them to fly (pterodactyles) ; amphibious 
 saurians, like the gavial and crocodile; and water saurians, 
 to which there is now no existing analogy. Of these sau- 
 roid or lizard-shaped reptiles, the ichthyosaurus and plesio- 
 saurus are most abundantly disseminated through the upper 
 secondary formations. The general form of the ichthyo- 
 saurus (Gr., ichthy?, a fish, and saurus, a lizard) appears 
 from its skeleton (see fig.) to have been not unlike that of 
 a crocodile, with the substitution of paddles for feet. The 
 head is lengthened into a narrow pointed muzzle, and the 
 
 Skeleton of Ichthyosaurus communis. 
 
 jaws armed with sharp and formidable teeth. The skele- 
 ton of the I. tenuirostris (slender-muzzle) usually measures 
 about four feet in length ; but detachrd remains of other 
 species have been found, indicating a length of twenty or 
 even thirty feet. The plesiosaurus (so called from its 
 greater affinity to the lizard tribe than to fishes) was dis- 
 tinguished by the extraordinary length of its neck, which, 
 in the commonest species (P. doKchofleirus, or long-necked), 
 
 63.1. Whnt of their variety? 
 631;. Describe the diagram. 
 
OOLITIC SYSTEM. 175 
 
 occupies nearly half the entire length of the animal. The 
 head is very small in proportion, and the tail is short, stout, 
 and pointed. The vertebras of the neck exceed in number 
 those of any other animal known. It is conjectured by 
 Mr. Conybeare, by whom the first scientific investigation of 
 this saurian was made, that, as it breathed air, and had fre- 
 quent need of respiration, it generally swam upon or near 
 the surface of the water, arching back its long neck like 
 the swan, and plunging it downwards at the fishes that 
 passed within its reach. Its length seems to have been 
 from ten to fifteen feet. From the nature of their extremi- 
 ties, both the ichthyosaurus and plesiosaurus must have 
 moved with great difficulty upon land, and seem princi- 
 pally to have inhabited the waters. Besides these, geolo- 
 gists enumerate many other species of saurians aquatic, 
 amphibious, and terrestrial ; such as the megalosaurus (great 
 saurian), geosaurus (land saurian), hylae.osaurus (forest sau- 
 rian), tdeosaurus (perfect saurian), &c. 
 
 2*24. Respecting the mammalia of this era, no very satis- 
 factory data have yet been procured, the only evidence 
 being two or three lower jaw-bones from the slaty limestone 
 of Stonesfield. Though some French geologists have at- 
 tempted to ascribe a sauroid character to these remains, it 
 is the opinion of Cuvier, Dr. Buckland, and Professor Owen, 
 that they belong to true didelphys (dis, two, delphys, wombs) 
 animals; that is, double-wombed, or marsupial creatures, 
 like opossum and kangaroo. Should this be the case 
 and comparative anatomy is too unerring in its deductions 
 to admit of any doubt then in the upper oolite are we for 
 the first time made acquainted with mammalia in the his- 
 tory of creation. " The close approximation of these fossil 
 animals," says Profess >r Owen, " to marsuphl genera, now 
 confined to New South Wales and Van Dieman's Land, 
 leads us to reflect upon the interesting correspondence be- 
 tween other organic remains of the British oolite, and other 
 existing forms now confined to the Australian continent 
 
 633. What conjecture has been indulged as to the plesiosaurus T 
 
 634. What other species are found ? 
 
 635. What proof of the mammalia of this era T 
 
 636. To what genus of animals are they supposed to belong f 
 
I7<5 GEOLOGY. 
 
 and adjoining seas. Here, for example, swims the cestra- 
 cion, which has given the key to the nature of the palates 
 from our oolite, now recognized as the tenth of congeneric 
 gigantic forms of cartilaginous fishes. Not only trigonia, 
 but living terebratulcB exist, and the latter abundantly in 
 the Australian seas, yielding food to the cestracion, as their 
 extinct analogues doubtless did to the allied cartilaginous 
 fishes called acrodi and psammodi, &c. Auracariae and 
 cycadeous plants likewise flourish on the Australian conti- 
 nent, where marsupial quadrupeds abound, and thus appear 
 to complete a picture of an ancient condition of the earth's 
 surface, which has been superseded in our hemisphere by 
 other strata, and a higher type of mammalian organization." 
 Professor Phillips remarks to the same effect " It is inte- 
 resting to know that the earliest mammalia of which we 
 have yet any trace were of the marsupial division, now 
 almost characteristic of Australia, the country where yet 
 remain the trigonia, cerithium, isocardia, zamia, tree-fern, 
 and other forms of life so analogous to those of the oolitic 
 periods." 
 
 225. "During- the oolitic period" continues the latter 
 authority, " the arctic land was covered by plants like those 
 of hot regions, whose vegetable remains have locally gene- 
 rated coal-beds, adorned by coleopterus, neuropterus, and 
 other insects, among which the flying lizafd (pterodactyl us) 
 spread his filmy wings. The rivers and shores were watched 
 by saurians more or less amphibious (rnegalosaurus, iguano- 
 don), or tenanted by reptiles which by imaginative men 
 have been thought to be the originals of our gavials and 
 crocodiles, while the sea was full of forms of zoophyta, 
 mollusca, articulosa, and fishes. Undoubtedly the general 
 impression, gathered from a survey of all those monuments 
 of earlier creations, is, that they lived in a warm climate; 
 and we might wonder that the result of all inquiry has 
 shown no trace of man or his works, did we not clearly 
 perceive the oolitic fossils to be all very distinct from exist- 
 ing types, and combined in such different proportions, as 
 
 637. What of Australia ? 
 
 638. What geological reasoning is hazarded ? 
 
OOUTIC 5.VSIT.M. 177 
 
 to prove that circumstances then prevailed on the globe 
 materially different from what we now see, and probably 
 incompatible with the existence of those plants and animals 
 which belong to the creation whereof man is the appointed 
 head." 
 
 22(3. The igneous rocks associated with the system in 
 England belong chiefly to the trappean order. In no case 
 have they caused much displacement or great disturbance 
 among the strata, being gentle outbursts of trap-tuff, or in- 
 tersecting dykes of greenstone. These dykes are always 
 connected with some volcanic axis of the carboniferous 
 period, and seem to have been among the last upheaving 
 efforts of the trappean era. In Caithness, granitic rocks 
 pass through the oolitic strata, but with this exception 
 the igneous rocks, which have upheaved or altered the sys- 
 tem, belong either to the latest trap, or the earliest volcanic 
 epochs. 
 
 227. The extent of country occupied by the oolite is by 
 no means extensive, though partial deposits are very gene- 
 rally disseminated over the globe. It is most fully de- 
 veloped in England, occupying the eastern sea-board from 
 Yorkshire to Dorset ; it occurs in a small patch at Brora in 
 Sutherland, in Syke, and other of the Hebrides, and par- 
 tially in Ireland and Wales. Portions of the system are also 
 found in France and Germany; skirting the Alps; in 
 Spain and the Balearic islands; flanking the Apennines 
 and Atlas range; on the southern slope of the Himmalehs; 
 but no true equivalents to the European oolite have hitherto 
 been detected in America. 
 
 228. Unless in England, the oolitic system is not so ex- 
 tensively developed as to impart any distinctive geographi- 
 cal ftature; and there, though pleasing, the aspect is tame 
 compared with that imparted by the older strata. The lime- 
 stones in general form rounded escarpments over the sub- 
 jacent clays, " so that several longitudinal hollows and 
 ridges undulate the area occupied by the system." None 
 
 639. What of the igneous rocks found here 7 
 
 640. In what localities does this system occur I 
 U 11 What of its physical geography f 
 
178 GKOLORY. 
 
 of these ridges are of great height (400 to 600 feet), but 
 they are dry and fertile; and thus present an agreeable con- 
 trast with the level river valleys occupied by the lias and 
 wealden clays. 
 
 229. In an economical point of view, the rocks of this 
 system are by no means unimportant. The lias limestones 
 generally consist of from 80 to 90 per cent, of carbonate 
 of lime, combined with bitumen, alumine, and iron ; and 
 when the latter mineral enters largely into their composition, 
 they form, when burned, a lime which has the properly of 
 setting under water. The finer kinds of lias receive a 
 polish, and are used for lithographic purposes. The lias 
 clays are often much impregnated with bitumen and iron 
 pyrites, and will burn slowly when laid in heaps with fagots 
 and kindled. By this process the sulphur of the pyrites is 
 decomposed, and combining with the oxygen of the atmo- 
 sphere, and with a portion of the alumina in the shale, 
 forms sulphate of alumina, or the alum of commerce. 
 During the sulphur monopoly, several patents were ob- 
 tained for the extraction of sulphur from iron pyrites 
 (sulphuret of iron) most of which would have been profit- 
 ably adopted, had the native produce of Sicily continued 
 at the then exorbitant rate. Iron has also been extracted 
 from the ironstone and pisiform iron-sands of the wealden 
 group; and jet (which is simply altered coniferous wood) 
 occurs in the same measures. Fuller's earth, at one time 
 so valuable in the useful arts, is found in the upper oolite in 
 beds of great thickness. It is essentially composed of 
 silica, alumina, and 24 per cent, of water, and, like other 
 soft aluminous marls, possesses in a high degree the power 
 of absorbing grease; hence its value in cleansing and 
 scouring woollen stuffs. Some of the oolite sandstones 
 form excellent building material, such as those of Bathtind 
 Portland; several ornamental marbles are obtained from 
 the same group ; while the Purbeck beds of the wealden 
 furnish the most prevalent paving-stones in London. 
 
 642. What of the economical uses of these groups? 
 64 1. Name some of the minerals and earths yielded. 
 
. OOLITIC SYSTKM. 179 
 
 EXPLANATORY NOTE. 
 
 LIAS. The term Liassic is commonly applied to this group by recent 
 authors. 
 
 COR.VBRASH is said to derive its name from the facility with which it 
 disintegrates and yields to the plough, being, according to the provin- 
 cial term, brashy or breaky ^enough to enable the plough to prepare the 
 surface, where it prevails, for the growth of grain or corn. 
 
 SAUROID ANIMALS are generally classed, according to their organs 
 of locomotion ; namely, swimmers, or those fitted with paddles, as the 
 ichthyosaurus, plesiosaurus, mososaurus, phytosaurus, steneosaurus, 
 teleosaurus, saurodon, &c. ; with limbs like mammalia, and fitted for a 
 terrestrial life, the megalosaurus and iguanodon ; analogous to living 
 amphibia, the protosaurus, geosaurus, pleurosaurus, hylaeos lurus, &c. 
 
 THE CHAMBERED SHELLS of this system include many genera, all of 
 which are fitted with interior hollow chambers and siphunrles. The 
 most common are the ammonite, nautilus, euomphalns, bellerophon, 
 goniatite, hamite (hamus, a hook), scaphite (sr.apha, a boat), orthocera- 
 tite (orthos, straight, keras, a horn), bacuhte (bactUum, a staff), lituite, 
 (lituus. an augur's rod or crosier), &c. &c. Sometimes the shelly mat- 
 ter of the ammonite has been entirely destroyed, leaving only a cast of 
 the interior, each chamber in this case playing upon auother by the 
 intricate jointings of the septa, or divisional lines ; such casts are 
 known by the name of ammonites catena, or ammonite chains. 
 
 CRETACEOUS, OR CHALK SYSTEM. 
 
 230. Immediately overlying the. wealden, and forming 
 the upper portion of the secondary formation, occurs a set 
 of calcareous, argillaceous, and arenaceous strata, dis- 
 tinguished in Europe as the Cretaceous System, from its 
 containing the well-known mineral, chalk (Lat., crtta). In 
 this system, as stated in par. 140, the arenaceous members 
 are no longer staridstones, but loose unsolidified sands; the 
 argillaceous beds are generally so r t and marly clays; and 
 the calcareous, instead of compact or crys'alline limestones, 
 present that soft earthy texture which prevails in chalk. 
 All this attests a comparative recentness of formation, apart 
 from great pressure, long-continued chemical action, or the 
 indurating effects of heat. The strata occupy very limited 
 spac 's, and being decidedly of marine origin, point more 
 to detached and inland seas as the areas of their deposit, 
 
 644. Define the terms of the note. 
 
 645. What variety of chambered shells ? 
 
 646. Define the cretaceous system and its strata. 
 
 647. What inferences are drawn by geologists from the nature of 
 
 chalk ? 
 
180 ftEOLOc;v. 
 
 than to the shores or bays of the ocean. Being thus, as it 
 were, a local deposit, and of a thickness not exceeding 803 
 or 900 feet, the chalk has been more thoroughly explore d 
 than any of the older systems, and its fossils more rigidly 
 compared with existing species. Upon investigation it has 
 been fjurid that it embraces three well-marked groups; 
 namely, the Grem-sand, the Gault, and Chalk. 
 
 23 1 . The composition of these groups is a 1 most sufficient- 
 ly indicated by their respective terms. The Green-sand, 
 which forms the lower division, is so named from its green 
 colour, which it owes to a chloritous silicate of iron. 
 These sands, however, are not uniformly green, but partake 
 of ochraceous and yellow tints; they present various de- 
 grees of fineness; and not unfrequently contain cherty 
 bauds, irregular deposits of Fuller's clay, and ochre. In 
 England, they are usually divided into the Lower and 
 Upper green-sands, because of a bed of soft bluish marly 
 clay which occurs about the middle of the group. Re- 
 garding this bed as subordinate, the green-sand is easily- 
 distinguished from the rest of the system by its arenaceous 
 composition and greenish hues. The Gault, or golt (a 
 local term), overlies the green-sand, and is not of great 
 thickness, nor very regular in its occurrence. It is a bluish 
 chalky clay, which effervesces strongly on the application of 
 acids; it is interstratified with layers of green-sand, and 
 holds irregular balls of argillaceous ironstone and iron 
 pyrites. In some districts the gault assumes a reddish tint, 
 from the iron it contains ; but in other respects its compo- 
 sition is very persistent. The Chalk, which forms the 
 upper group of this system, is too well known to require 
 description. It consists chiefly of carbonate of lime, has 
 an earthy texture, and is so soft as to yield to the nail. 
 Though generally white, it sometimes passes into a dusky 
 gray, or even red colour, as in the north of England ; and 
 where it has come in contact with igneous rocks, it is in- 
 
 648. What groups are marked ? 
 
 649. To what does green-sand owe its colour t 
 
 650. What is gault and its varieties 1 
 
 651. Of what does chalk consist? 
 
 652. How is it found in England T 
 
CRETACEOUS, OR rHAl.K SYSTEM. . 181 
 
 durated, and of a crystalline texture, like that of statuary 
 marble. In England, the chalk strata average from 600 to 
 803 feet in thickness, and are usually divided into the lower 
 and upper beds ; the former being more compact, of a 
 dusky white varied with green grains, and containing few 
 flints the latter being a soft white calcareous mass, with 
 chert nodules and regular layers of flints. Traces of 
 stratification are scarcely distinguishable in the mass of the 
 chalk, but are clearly evinced by the lines of flints and 
 other nodular concretions. In some of the continental 
 chalks, carbonate of magnesia prevails to the extent of 8 
 or It) per cent., giving to such beds a still more earthy 
 texture. 
 
 232 The order of succession among the strata is such 
 as has been shown above ; but, to render it more distinct, 
 we may transcribe the following sectional detail of the 
 system as it occurs in the south of England : 
 
 ("UPPER CHALK usually a white soft calcareous 
 
 Jmass, with chert nodules at regular intervals, and 
 layers of flints. 
 LOWER CHALK harder and less white than the 
 ! upper ; sometimes varied by green grains ; gene- 
 
 i rally with fewer flints. (Red in the north of 
 England.) 
 GAULT, OR CHALK MARL beds of bluish laminated 
 clays, h ghly calcareous, with layers of green- 
 sand, and ferruginous nodules. 
 
 ("UPPER GREEN-SAND a mass of sands, occasionally 
 indurated to chalky or cherty sandstone, of green 
 
 !or grayish-white colour, with nodules of chert. 
 Soft bluish clay, with green grains. 
 
 GREEN-SAND. ^ LOWER GREEN-SAND a considerable mass of green, 
 
 or ferruginous sands, with layers of chert; local 
 
 beds of blue clay ; rocks of chalky or cherty 
 
 limestone ; and deposits of ochre and fuller's 
 
 (_ earth. 
 
 All the members detailed above do not occur in other cre- 
 taceous districts; for example, there is no green-sand in the 
 north of England; no chalk along the Carpathians; no 
 gaultin America; while in South America the system is 
 represented by impure chalky beds of no great thickness. 
 
 653. Explain'the tabular arrangement. 
 
 654. How is it in different districts ? 
 
182 
 
 GEOLOGY. 
 
 233. The organic remains found in the system are emi- 
 nently marine. There are very few plants, and these 
 chiefly of marine types, such as algae, confervae, and other 
 sea-weeds. Rare fragments of ferns, cones of coniferous 
 trees, cycadites, and dicotyledonous wood, have been de- 
 tected in the green-sand ; and a patch of lignite is said to 
 occur in the lower chalk, near Rochelle in France. Re- 
 specting this deposit, M. Brogniart thinks it may have been 
 formed by the local submergence of a peat rnoss; but gene- 
 rally speaking, there is no formation so destitute of terres- 
 trial organisms as the chalk. Among the animal remains, 
 sponges, corals, star-fishes, annulosa, univalve, bivalve, and 
 chambered mollusca, Crustacea, fishes and reptiles, are 
 found in abundance; but, with one exception, mammalia 
 are not known in the cretaceous rocks. The same races 
 which appeared in the oolite appear also in the chalk, but 
 of very different genera; so much so, that it has been ob- 
 served thtit the cretaceous system contains genera never 
 found in any rocks more ancient or more modern. "There 
 
 1. Pecton quinque-costatus ; 2. Flagiostoma spmosum ; 3. Hamitea 
 intermedius ; 4. Spatangus cor-anguinum ; 5. Galerites albogalerus ; 
 6. Scaphites striatus ; 7. Belemnites mucronatus. 
 
 appears no sufficient evidence," says Professor Phillips, " in 
 the fossils of this system to justify any positive inference as 
 to the character of the climate then prevailing in the north- 
 
 655. What of its organic remains ? 
 
 656. Describe the figures of the animal 
 
 fossils in the diagrams. 
 
CRETACEOUS, OR CHALK SYSTEM. 183 
 
 ern zones : but we may be sure that the sea was very little 
 disturbed by inundations from the land, otherwise ferns and 
 other plants, and not fuci, would have been found in the 
 sandy strata." It is true that the evidence respecting the 
 climate, and other conditions of the cretaceous era, is still 
 imperfect; but the recently discovered remains of the 
 highest order of mammalia (quadrumana, or monkey tribe) 
 point to a tropical climate; and this fact, taken in conjunc- 
 tion with the occurrence of cycadites, seems to establish 
 a temperature little different from that which prevailed 
 during the wealden epoch. The foregoing engraving re- 
 presents a few of the more characteristic fossils belonging 
 to the system. 
 
 234. Igneous rocks are no where associated with the 
 chalk in England; but basalt and other traps break through 
 and overlie the strata in the north of Ireland the Giant's 
 Causeway presenting one of the finest examples of this 
 connexion. In the Pyrenees, cretaceous strata are said to 
 be in contact with granitic rocks; but generally speaking, 
 the system has escaped with fewer displacements by igfne- 
 ous agency than any of the earlier formations. As has been 
 stated, where chalk comes in contact with igneous dis- 
 charges, the heat has rendered it hard and crystalline like 
 primary marble. The same effects have been produced by 
 enclosing pounded chalk in an iron tube, and subjecting it 
 to the heat of a furnace. 
 
 23.5. The geographical extent of the system is limited, 
 when compared with earlier formations. It is pretty ex- 
 tensively developed in the south arid south-east of England, 
 filling up the hollows and basins left by the oolite and lias. 
 It appears in the north of Ireland overlaid by basalt and 
 other trap rocks; but is unknown in Wales or in Scotland. 
 It is spread over wide areas in France and Germany; and 
 is found about Dresden, in the Alps, Carpathians, and Py- 
 renees. According to Professor Rogers, it occupies a vast 
 
 657. Which of the mammalia have been found here ? 
 
 658. Where are igneous rocks found in connection with this system, 
 
 and how explained ? 
 
 659. What of the extent of the system, and the physical aspect of 
 
 the cretaceous districts T 
 
184 GEOLOGY. 
 
 area in the North American states; and, by recent ac- 
 counts, has been detected in the western river-plains of 
 South America. 
 
 236. The physical aspect of chalk districts is easily 
 distinguished by the smooth flowing outline of the hills and 
 valleys. Here there are no rugged arid lofty peaks, as in 
 the earlier formations; no tabular-looking escarpments, as 
 in the lias and oolite; but easy undulations, forming in 
 their extent the well-known " wolds" or " downs" of south- 
 ern England. These downs are characterized " as covered 
 with a sweet short herbage, forming excellent sheep pasture, 
 generally bare of trees, and singularly dry even in the 
 valleys, which for miles wind and receive complicated 
 branches, all descending in a regular slope, yet are fre- 
 quently left entirely dry; and, what is more singular, con- 
 tain no channel, and but little other circumstantial proof 
 of the action of water, by which they were certainly exca- 
 vated." Chalk districts thus possess great amenity and 
 rural beauty, and are as yet but little broken up by the 
 enterprise of modern agriculture. 
 
 237. The minerals of commerce derived r rom the sys- 
 tem are by no means numerous. Chalk is used for many 
 purposes in the arts and in agriculture: it furnishes polishing 
 paste, and the well-known whitening of the painter. Beds 
 of fuller's earlh occur in the lower green-sand, and in some 
 districts the more indurated strata of the group produce a 
 rou2h building-stone. Flint is one of the most valuable 
 products of the system ; furnishing material or the manu- 
 facture of china and porcelain, flint glass, and gun-flints 
 the latter having been in universal use before the invention 
 of the percussion cap. 
 
 238. TliR formation of flint, within a mass so different 
 in composition as chalk, is still in some respects an un- 
 solved problem in geology. It occurs in nodular masses 
 of very irregular forms and variable magnitude; some of 
 these not exceeding an inch, others more than a yard in 
 circumference. Although thickly distributed in horizontal 
 
 660. What of its economical uses ? 
 
 661. How is the formation of flint explained T 
 
CRETACEOUa, OR CITALK SYSTEM. lo 
 
 layers, they are never in contact with each other, each 
 nodule being completely enveloped by the chalk. Exter- 
 nally, they are composed of a white cherty crust; internally, 
 they are of gray or black silex, and often contain cavities 
 lined with calcedony and crystallized quartz. When taken 
 from the quarry they are brittle and full of moisture, but 
 soon dry, and assume their well-known hard and refractory 
 qualities. Flints, almost without exception, enclose re- 
 mains of sponges, alcyonia^ echinida, and other marine 
 organisms, the structures of which are often preserved in 
 the most delicate and beautiful manner. In some speci- 
 mens the organism has undergone decomposition, and the 
 space it occupied either left hollow, or partially filled with 
 some sparry incrustation. From these facts, it would seem 
 that flints are as much an aggregation of silex around some 
 organized nucleus, as septaria (par. 192) are aggregations 
 of clay and carbonate of iron. This is now the generally 
 received opinion: and when it is remembered that the or- 
 ganisms must have been deposited when the chalk was in 
 a pulpy state, there can be little difficulty in conceiving 
 how the silex dissolved through the mass would, by chemi- 
 cal affinity, attach itself to the decaying organism. Chalk 
 is composed of carbonate of lime, with traces of clay, silex, 
 and oxide of iron ; flint, on the other hand, consists of 98 
 per cent, of pure silex, with a trace of aiumine, oxide of 
 iron, and lime. Silex is quite capable of solution: it 
 occurs in the hot springs of Iceland and most thermal 
 waters ; has been found in a pulpy state within basalt ; 
 forms the tabasheer found in the cavities of the bamboo, 
 and the thin pellicle or outer covering of canes, reeds, 
 grasses, &c. ; and siliceous concretions are common in the 
 fruits and trees of the tropics. All these facts point to a 
 very general diffusion of silex in a state of solution; and 
 whatever may have caused its abundance in the waters 
 during the deposition of the upper chalk, there can be little 
 
 662. What of the nuclei of flint T 
 
 663. What of the relative composition of chalk and flint ? . 
 . 664. How is silex known to be capable of solution I 
 
 665. Where is it found 7 
 
186 GEOLOGY. 
 
 doubt respecting the mode in which it has been collected 
 around the organic remains of these early seas. 
 
 EXPLANATORY NOTE. 
 
 THE ORIGIN OF CHALK, so different in its texture and appearance 
 from all other limestones, has given rise to many hypotheses. tf There 
 appears no evidence," says Mr. Brande, " of its having been deposited 
 from chemical solution ; but, on the other hand, it bears marks of a 
 mechanical deposit, as if from water loaded with it in fine division. 
 And upon this principle, some gleam of light may perhaps be thrown 
 upon the enigmatical appearance of the flints ; for it is found, that if 
 finely-powdered silica be mixed with other earthy bodies, and the 
 whole diffused through water, the grains of silica have, under certain 
 circumstances, a tendency to aggregate into small nodules ; and in 
 chalk, some grains of quartz are discoverable." There can be little 
 doubt that such has been the original state of chalk, from whatever 
 source derived ; for, without the supposition that the calcareous par- 
 ticles were diffused through the waters in which it was deposited, it 
 were impossible to account for almost any of the phenomena connected 
 with it as a formation. But while such has evidently been the origin 
 of the great mass of the chalk rocks, it does not preclude the chemi- 
 cal agency of springs, or the organic efforts of secreting animalcules. 
 All other limestones in the crust of the earth point to a complex for- 
 mation, in which mechanical, .chemical, and organic agencies have 
 been concerned ; and it is but reasonable to suppose that chalk is the 
 result of similar forces. 
 
 BELEMNTTES (Gr., belemnon, a dart) a genus of fossil-chambered 
 shells, perforated by a siphuncle, and so called from their straight dart- 
 like form. Unlike other chambered shells, they were internal; that 
 is, enclosed within the animal like the pen of the squid and cuttle-fish. 
 Many of these belemnites are of great size, showing the gigantic 
 nature of the cephalapods to which they belonged. Being long, straight, 
 and conical, they are commonly known by the vernacular names of 
 * thunder stones" and " thunder bolts." 
 
 TERTIARY STRATA. 
 
 239. THE TF.RTIARY SYSTEM comprises all the regular 
 strata of limestone, marl, clay, sand, and gravel which 
 occur above the chalk. Before the labours of the celebrated 
 Cuvier and M. Brogniart, these beds were regarded as mere 
 superficial accumulations, not referable to any definite 
 period. Now, however, they are recognized as constituting 
 
 666. What of the origin of chalk ? 
 
 667. What geological reasoning is here authorized 1 
 
 668. What are belemnites, and their vernacular names t 
 
 669. What strata does the tertiary system comprise ? 
 
 670. How is it distinguished from alluvial or superficial accumu- 
 
 lations 1 
 
TERTIARY STRATA. 137 
 
 a distinct formation differing from the cretaceous not only 
 in its mineral composition, but in the higher order of or- 
 ganisms which it contains, and from the superficial sands 
 and clays, in being regularly stratified, and in imbedding 
 the remains of animals distinct from existing races. In 
 general the strata are loosely aggregated, are of no great 
 thickness, and present appearances which indicate frequent 
 alternations of marine a.nd fresh-water agencies. Thus, 
 marine remains are found in some beds, while others con- 
 tain exclusively land animals and plants, and fresh-water 
 shells. The whole suit being less consolidated than any 
 of the secondary systems, and containing plants and ani- 
 mals approaching to existing forms, it presents a freshness 
 of aspect which serves to distinguish it from older deposits; 
 at the same time the regularity of its deposition prevents it 
 from being mistaken for any mere alluvial accumulation. 
 In general it occupies very limited and detached areas, as 
 if it had been formed in shallow inland seas and estuaries, 
 to which the waters of the ocean at times had access, and 
 where at other periods fresh-water inundations prevailed. 
 Another essential difference between the tertiary and the 
 more ancient formations consists in the fact, that the latter 
 maintain a wonderful uniformity in their composition and 
 character all over the globe; whereas the former present 
 almost as many distinctions in composition as there are 
 areas of deposit. For this reason it is impossible to give a 
 description applicable to all tertiary strata ; those of Eng- 
 land and France, however, may be taken as types suffi- 
 ciently characteristic. 
 
 240. Respecting the composition of the system, arenaceous 
 and argillaceous beds may be said to prevail, with inter- 
 stratified limestones, calcareous grits, and marls. The are- 
 naceous members are either pebbly conglomerates of a rusty 
 yellow, or sands little indurated and variously tinted by the 
 oxide and silicate of iron. The sands are seldom suffi- 
 ciently consolidated to form sandstones; and the conglo- 
 
 671. What of its composition f 
 
 672. What of the arenaceous variety 1 
 
 673. What variety in the argillaceous bdi 1 
 
I* 5 ? OfcoLOttY. 
 
 merates are often mere layers of rolled pebbles, without 
 any cementing matrix. The argillaceous beds also present 
 many varieties; some being almost pure laminated clay of 
 a dull blue colour, others of a brownish tint, with a slight 
 admixture of sand, while many pass into marls more or less 
 calcareous. None of these clays are so compact as to form 
 shales; indeed lamination is more frequently absent than 
 otherwise, there being nothing except their fossils and asso- 
 ciated beds to distinguish them from the clays of subsequent 
 alluvial valleys. The calcareous layers are still more varied 
 in their composition and aspect, and bear no resemblance 
 to the indurated half-crystalline limestones of older forma- 
 tions. The marine limestone of the Paris basin is of a 
 coarse sandy texture; that of Austria a rough coralline 
 rock : the fresh-water beds near Weimar are hard and corn- 
 pact ; those of other districts are soft, marly, and full of 
 shells. In some localities marls are so calcareous as to be 
 used as limestones, while in others they pass into soft fria- 
 ble clays. From this extreme diversity of composition, it 
 is evident that many agencies have been concerned in the 
 deposition of the tertiary system, and that most of them 
 have been of a local character, producing results not differ- 
 ing widely from those of the present day. 
 
 241. The succession of strata is no less varied than their 
 mineral composition. As at the present day distant rivers 
 are depositing different sorts of material at one and the 
 same time, so in distant tertiary basins different strata vari- 
 ously succeed each other. Luckily, none of the deposits 
 are of great thickness, and as they have been closely exam- 
 ined for the sake of their fossils, the alternations of the 
 beds have been pretty accurately ascertained. The follow- 
 ing is a descending section of the Paris basin, according to 
 Cuvier and Brogniart: 
 
 6. UPPER FRESH-WATER GROUP marl s, marly sands, shelly limestone, 
 and siliceous or burr limestone. 
 
 4 UPPER MARINE GROUP marls, sands and sandstones of a white or 
 ochraceous colour, and loosely aggregated ; thin layers of lime- 
 stone. 
 
 674. What of the calcareous layers? 
 
 675. Explain the table 7 
 
TERTTARY STRATA. 
 
 189 
 
 3 LOWER FRESH-WATER marls, gypsum (sulphate of lime), with bonea 
 of animals, and siliceous limestones. 
 
 I. LOWER MARINE consisting principally of a coarse sandy limestone 
 (calcaire grassier), with calcareous marls 
 
 sand. 
 
 and layers of greenish 
 
 1. PLASTIC CLAY GROUP consisting of bluish plastic clays, with layers 
 
 of sand, beds of lignite, and rolled pebbles. Supposed to be of 
 estuary origin. 
 
 Although a very different succession takes place among the 
 teriiaries of the south of England, yet there is sufficient 
 resemWance in the position and. aggregation of their strata, 
 as well as in their organic remains, to establish the fact, 
 that they belong to the same epoch as the rocks of the Paris 
 basin. The annexed section shows the order of their oc- 
 currence to the south of London : 
 
 4. BAGSHOT SANDS. 
 
 3. LONDON CLAY of a dull gray, or blue, or ochraceous colour; often 
 
 full of green grains. Septaria and other ferruginous nodules occur 
 
 in some parts. Numerous fossils. 
 
 2. PLASTIC CLAY AND SANDS sands of various colours, with occasional 
 
 beds of lignite ; also layers of sandy clay, with or without sheila. 
 1. SANDS green and ferruginous, accompanied by flint pebbles, oyster 
 shells, &c. 
 
 In other parts of England the order of occurrence is some- 
 what different. It may be stated, however, in general 
 terms, that the sands are most extensively developed; the 
 clays chiefly in the southern basins; while at Oxford, 
 Ramsholt, &c. the upper beds consist of a coarse conglo- 
 merate of corals, sand, pebbles, shells, &c. locally known 
 as the "Crag," and s > calcareous in some places as to be 
 
 I. Hirer Thames: 2. Marine sands: 3. London clay; 4. Plastic clay 
 and sands ; 5. Chalk with flints; 6. Green-sand and Gault-clay. 
 
 676. What of the tabular arrangement 1 
 677 Expla n the diagram. 
 9 
 
190 GEOLOGY. 
 
 used as a limestone. As with the Paris and English depo- 
 sits, so with other tertiary basins in Europe: those of 
 southern France, Spain, Italy, Austria, Hungary, &c. all 
 showing an irregular succession of clays, sands, marls, lig- 
 nites, and gypsum, which, when examined in relation to 
 their positions, modes of aggregation, and fossils, are clearly 
 referable to the same period of formation. Tne foregoing 
 engraving illustrates the tertiary deposits of the Thames 
 basin, with the subjacent chalk and green-sand. 
 
 242. -As to the extent of country occupied by tertmry de- 
 posits, there is yet no very accurate knowledge, inasmuch 
 as many sands and clays, now regarded as the alluvium of 
 existing valleys, may hereafter be referred to this system ; 
 and several areas of gravel, now looked upon as tertiary, be 
 classed with more recent accumulations. As developed in 
 Europe, the system spreads over wide areas, all remarkable 
 for their conformation and connexion with the outline of 
 existing seas. Indeed, were the islands and continent of 
 Europe to be submerged to the depth of 600 or 600 feet, 
 the waters of the German, Baltic, English Channel, and 
 Mediterranean seas, would cover most of the tertiary strata, 
 showing that, with the exception of the general elevation 
 which raised them into dry land, there has been compara- 
 tively little subterranean disturbance since the time they 
 were deposited. In Britain the formation is exhibited in 
 Hampshire, Isle of Wight, in the basin of London, and 
 from the Thames northwards along the coast to the mouth 
 of the Yare ; but has not been detected either in Ireland or 
 Scotland, though several gravel and clay deposits in the 
 latter country may yet be discovered to belong to the same 
 era. It occurs interestingly developed near Paris; trends 
 along the north coast of France, Belgium, Westphalia, 
 Holstein, and Jutland, in apparent connexion with the 
 German Ocean; spreads over the level tract lying between 
 the Baltic and Northern Ocean in Russia ; and occupies 
 the greater portion of the central flats which lie between 
 the Baltic and Black seas. Besides these expanses, there 
 
 678. Why are the localities of this system still unsettled ? 
 
 679. What geological reasoning is here ? 
 
TFKFIAKY STRATA. 101 
 
 are many secluded patches along the valleys of the Rhone 
 and Danube, the Swiss hikes, and the Italian shores of the 
 Mediterranean. The system has also been detected along 
 the southern basis of the Himmalehs, and in several of the 
 North American valleys; and when geological research has 
 been farther extended, there is little doubt of its being dis- 
 covered in other quarters of the world. In speaking of the 
 extent of country occupied by deposits of incoherent sands, 
 marls, and clays, like those of the tertiary epoch, it must be 
 borne in mind how much more waste they would suffer by 
 denudation than the older and more consolidated strata. 
 No doubt every rock system, on its being elevated into dry 
 land, must have suffered diminution by denuding causes; 
 but most of all those whose materials are loosely aggregated 
 like the strata now under icview. 
 
 243. Igneous rocks are not found in connexion with the 
 tertiaries of England, though subterranean movements have 
 thrown them into anticlinal ridges and basin-shaped hol- 
 lows. In the south of Europe the case is otherwise, and 
 the geologist finds in the igneous discharges of Auvergne, 
 Switzerland, the Rhine, Hungary, and Italy, a link which 
 connects the traps of the secondary period with the pro- 
 ducts of recent and active volcanoes. According to JV1. de 
 Beaumont the western Alps (fi -n the Mediterranean to 
 Mont Blanc) were upheaved dur. g this era ; and the 
 eastern range i supposed to be of suli more recent origin, 
 or at all events not to have been upraised till after the de- 
 position of all the tertiary strata. Along the Rhine, in 
 Hungary, and in central France, the igneous elevations 
 assume a more diminutive aspect those of Auvergne never 
 arranging themselves in a continuous axis, but presenting 
 a congeries of conical crateriform hills of no great altitude. 
 In their composition, these igneous rocks are chiefly tra- 
 chytic passing from a pretty compact grayish felspathic 
 mass to scoriaceous tufa ; but in no case presenting the 
 dark bituminous aspect of the coal-measure traps, nor the 
 
 6^0. What of igneous rocks and volcanic discharges? 
 681. What is the nature of these igneous rocks ? 
 
19*2 GEOLOGY. 
 
 amygdaloidal and porphyritic texture of those associated 
 with the old red sandstone. 
 
 244. Respecting the geographical aspect of tertiary dis- 
 tricts, the general absence of igneous rocks would indicate 
 a level and somewhat unvaried scenery; and this is the 
 feature which prevails in the wide tertiary plains of northern 
 and middle Europe. In England the strata partake of the 
 undulations of- the subjacent chalk, principally developed, 
 however, in the flatish basins of London and Hampshire. 
 From the open and porous character of the sands arid 
 gravels, tertiary soils are in general light and dry, capable 
 of profitable cultivation, but by no means naturally fertile. 
 The hills and vine-growing slopes of Auvergne can scarcely 
 be considered as reposing on a tertiary basis any more than 
 the snow-clad crags and peaks of the Alpine range, both of 
 which form decided exceptions to the general rule. 
 
 245. The organic remains of the system constitute its 
 most important and interesting feature. The ibssils of 
 earlier periods presented little analogy, often no resem- 
 blance, to existing plants and animals; here, however, the 
 similitude is frequently so complete, that the naturalist can 
 scarcely point out a distinction between them and living 
 races. Geology thus unfolds a beautiful gradation of being 
 from the corals, molluscs, and simple Crustacea of the grau- 
 wacke the enamelled fishes, crinoidea, and cryptogamic 
 plants of the lower secondary the chambered shells, sau- 
 roid reptiles, and marsupial mammalia of the upper second- 
 ary up to the true dicotyledonous trees, birds, and gigantic 
 quadrupeds of the tertiary epoch. The student must riot, 
 however, suppose that the fossils of this era bring him up 
 to the present point of organic nature, for thousands of 
 species which then lived and flourished became in their 
 turn extinct, and were succeeded by others long before 
 man was placed on the earth as the head of animated exist- 
 ence. Of Plants, few marine species have been detected ; 
 
 682. Flow is its physical geography ? 
 
 683. What of the organic remains ? 
 
 684. What geological reasoning is hazarded here 1 
 
TERTIARY STRATA. 193 
 
 but the fresh-water beds have yielded cycadese, conifers, 
 palms, wiliows, elms, and other species, exhibiting the (rue 
 dicotyledonous structure. Nuts allied to those of the cocoa 
 and other palms have been discovered in the London clay; 
 and seeds of the fresh-water characea, or stoneworts, known 
 by the name of gyrgonifes (Gr., gyros, curved, and gonos, 
 seed), are common in the same deposit. Of the Radiata, 
 Articuluta, and Mollusca, so many belong to existing genera, 
 that the circumstance has suggested a classification of ter- 
 tiary rocks according to the number of recent species which 
 they contain. Thus, if out of 100 fossil shells 5$0 should 
 belong to recent species, the deposit in which they are im- 
 bedded is presumed to be of later origin than one from 
 which only 10 per cent, of recent shells can be obtained. 
 Proceeding upon this plan, M. Deshayes and Mr. Lyell 
 arrange the entire system into ihe following groups, as fur- 
 ther explained in note, page 96-7 : 
 
 PLEISTOCENE Sicilian deposits, with 9o per cent, of recent species. 
 PLEIOCENE Italian and Crag deposits, with 41 per cent, of recent 
 
 species. 
 MEIOCENE Vienna, Bordeaux, Turin, &c. 18 per cent, of recent 
 
 species. 
 EOCENE Paris, London, Belgium, 3 per cent of recent species. 
 
 From the above per centage the student will perceive, with 
 respect to the marine mollusca of the tertiary era, that they 
 approach existing forms too nearly to require any particu- 
 lar description. 
 
 246. The vertebrate animals make a similar approach to, 
 ^r recession from, existing races as we ascend or descend 
 among the tertiary strata. " The Fishes" says M. Agassiz, 
 "are so v nearly related to existing forms, that it is often 
 difficult, considering the enormous number (above 8000) 
 of living species, and the imperfect state of preservation of 
 the fossils, to determine exactly their specific relations. In 
 general, I may say that I have not yet found a single species 
 which was perfectly identical with any nmrine existing fish, 
 except the little species which is found in nodules of clay, 
 of unkmwn geological age, in Greenland. The species 
 
 6S5 What of the groups of fossil shells ? 
 6b6. What of tishes, reptiles, and birds 1 
 
194 GEOLOGY. 
 
 of the Norfolk crag, of the upper subapennine formation, 
 and of the molasse, are mostly referable to genera common 
 in tropical regions. In the lower tertiaries of Condon, the 
 basin of Paris, and Monte Bolca, at least a third of the 
 species belong to genera which are now extinct." As with 
 the fishes, so with the Reptilia, among which we find, for 
 the first time in the history of the globe, the remains of 
 genuine crocodiles, snakes, and representatives of the frog 
 tribe; besides several existing genera of fresh-water and 
 marine turtles. The *iurians of the saliferous and oolitic 
 eras had by this time passed away, to be succeeded by the 
 above-named reptiles, whose forms and habits seem to have 
 been more in accordance with the altered conditions of 
 external nature. Of Birds, eight or ten species have been 
 discovered in the Paris basin, referable to the genera 
 buzzard, owl, quail, woodcock, sea-lark, curlew, and peli- 
 can. (tSee Appendix.) 
 
 247. The mammalia of the tertiary strata are those fos- 
 sils which have most attracted the attention of palaeontolo- 
 gists ; and this deservedly so, from their being the proto- 
 types of many existing species, and as marking the dawn 
 of conditions suited to the Fauna of the present day. Of 
 these ancient forms, between fifty and sixty species have 
 been determined, a majority of which belong to a division 
 of the order Pachydcrmata, now only represented by four 
 
 living species; namely, three 
 tapirs, and the daman of the 
 Cape. This division com- 
 prehends most of the tht- 
 roid animals, now so fre- 
 quently alluded to in works 
 on geology, of which the 
 
 pa/fBotherium (see fig.) was 
 Form of Palaeotherium. r c , v & ' , 
 
 one of the most prevalent 
 
 and characteristic. A detailed enumeration of the mam- 
 malia of this era would be inconsistent with the rudimentary 
 
 687. What of the mammalia ? 
 
 688. How many species have been determined 7 
 
 689. Name some of these. 
 
 690. Explain the diagrams. 
 
TERFIARY STRATA 195 
 
 nature of this treatise ; we shall therefore merely advert to 
 the leading orders now determined by the most eminent 
 f >ssil anatomists. Quadrumana (four-handed, or monkey 
 tribe), one or two species from the eocene beds of the Eng- 
 lish basins; Marsvpialia (pouch-nursing), three or four 
 species of a diminutive size; Cheiroptera (hand-winged), 
 two or three species of bat, chiefly from the gypsum beds 
 of Montmartre ; Insectivora (insect-eaters), partial remains 
 of a species of mole ; Carnivora (flesh-devourers), several 
 species have been determined allied to the bear, hyaena, 
 fox, dog, seal, cat, weasel, &c.; Rodentia (gnawers), ten 
 or twelve species allied to the beaver, rat, hare, lagomys, 
 
 Restored Form of Deinotherium. 
 
 squirrel, &c.; Pachydtrmata (thick-skinned), many genera 
 and species, such as the rnatstodon, the deinotherium (see 
 fig.), elephant, hippopotamus, rhinoceros, horse, boar, tapir, 
 and a host of animals allied to the tapir; Ruminantia (cud- 
 chewers), a few species, as the stag, deer, elk, antelope, 
 ox (?), &c.; Cetacea (whales), one or two species; and 
 gigantic Edentata (toothless animals), now faintly repre- 
 sented by the sloth, the ant-eater, and the diminutive arma- 
 dillo. (See Appendix.) 
 
 248. Of the conditions of the world during the deposition 
 of the tertiary strata, we are enabled to form some esti- 
 mate from the nature of their fossils, and from the peculiar 
 composition and aggregation of their rocky materials. So 
 far as Europe is concerned, part of the existing land must 
 have been then elevated above the waters, forming a series 
 of insular ranges, with flat valleys and shallow seas between. 
 
 691. What geological reasoning is found here 1 
 
196 
 
 From these islands, and from continents now submerged, 
 rivers of considerable extent seem to have borne sand, clay, 
 and vegetable debris, and to have deposited them in ihe 
 seas and estuaries, while gravel, flint pebbles, broken corals, 
 and shells, were strewn along the shore by ordinary littoral 
 influences. Such materials would give rise to beds of sand, 
 clay, gravel, lignite, and calcareous conglomerate, enclosing 
 marine remains, with others of fresh-water and terrestrial 
 origin brought down by the rivers. But several tertiary 
 basins exhibit strata of decided fresh water origin, alter- 
 nating with others as decidedly marine; and to account 
 for this phenomenon, we must have recourse to another set 
 of agents. In the deltas of many modern rivers, like that 
 of the Niger, lagoons of fresh water are frequently cut off 
 from connexion either with the branches of the river or 
 with the ocean, and in these myriads of shell-fish, aquatic 
 plants, crocodiles, hippopotami, and other fresh-water and 
 amphibious races abound. At some subsequent period the 
 connexion with the ocean is renewed there being in gene- 
 ral only a slight eminence of mud or sand to separate them 
 and thus the succeeding deposits assume a character 
 decidedly marine. By these means it is easy to conceive 
 how alternations of marine and fresh-water strata would 
 occur: and particularly when we know that the south of 
 Europe (central France and the Alps) was, during the ter- 
 tiary era, subjected to extensive volcanic disturbances, 
 which would give rise to frequent submergences and ele- 
 vations. We are thus enabled to account for the composi- 
 tion and aggregation of the tertiary strata ; and when we 
 reflect on their comparatively recent origin, and the fact 
 that they are in many places not overlaid by other material, 
 there is no difficulty in perceiving how they should be so 
 loose and incoherent in their texture. Again, when we 
 look at the nature of their fossils, we are led to associate 
 with them ideas of a warm arid genial climate. The lands 
 which furnished the cycadea?, palms, cocoa nuts, and 
 monkeys of the English tertiaries, and the mastodons, ele- 
 phants, rhinoceroses, hippopotami, crocodiles, and turtles 
 of the Paris basin, must have enjoyed a temperature similar 
 to i hat of the present tropics. The beds of lignite bear 
 
TI.RTIAHV STRATA. 
 
 107 
 
 evidence of a luxuriant vegetation for the support of so 
 many huge graminivora ; while the presence of birds, in- 
 sects, and the higher orders of mammalia, point to atmo- 
 spheric and other vital conditions little different from those 
 now existing. In fact, we find in the deltas of the Ganges 
 and Niger in their jungles, lagoons, and swamps in 
 their elephants, hippopotami, and crocodiles almost perfect 
 analogies to those estuaries and shallow seas in which the 
 tertiary strata of Europe were deposited. 
 
 249. In an economical point of view, the tertiary strata 
 are of considerable local importance. The celebrated burr 
 millstones of France, are obtained from the upper fresh- 
 water siliceous limestones of the Paris basin; some of the 
 strata of which also furnish marble capable of receiving a 
 high polish. Marked by the numerous shells which are im- 
 bedded in it, this marble is by no means unnrnamental, and 
 has been used in the construction of the jets deau in the 
 galleries of the Tuilleries. Many of the fresh-water lime- 
 stones rapidly disintegrate on exposure to air and moisture, 
 and, falling down to the state of marl, are used as manure; 
 while the " crag" is occasionally so calcareous, as to serve 
 the ordinary purposes <;f limestone. Pipe and potters' 
 clay are extensively obtained both from the London and 
 Paris basins ; the term plastic, applied to the lower beds, 
 being derived from the circumstance of the clay readily 
 receiving the mould or form of the potter (Gr. plasso, 
 I form). Gypsum (sulphate of lime) is perhaps the most 
 valuable member of the deposit ; it is found abundantly in 
 the Paris basin, and when calcined, reduced to powder and 
 kneaded with water, forms the well known plaster of Paris 
 so extensively used by image-makers, plasterers, stereotype- 
 founders, and others. Gypsurn has also been recently ap- 
 plied as a topdressing to crops, and as a fixer of the vola- 
 tile principles of organic manures. Lignite (Lat., lignum, 
 wood), or wood-coal, is found in some tertiary districts, the 
 o.ily deposit of importance in England being that of Bovey 
 Hayfield, near Exeter. Amber frequently occurs with 
 
 692. Whit are the economical uses of the system T 
 
 693. Wh.ch is the mosf valuable product ? 
 
 9* 
 
133 GEOLOGY. 
 
 these lignitip beds, and appears to have been a gum or gum- 
 resin exuded by the trees with which it is associated, 
 
 EXPLANATORY NOTE. 
 
 THEROID ANIMALS. The termination therium (Gr. therion, a wild 
 beast) is adopted in geology to designate certain classes of fossil mam- 
 malia, whose structure and habits have not yet been fully established 
 by anatomists. The individual animals are characterized by a prefix 
 which applies to some peculiarity of form, the place where found, or 
 the name of the discoverer. Thus we have the (temotherium (terrible 
 wild beast) ; the palteotherium (ancient) ; the anop/otherium (unarmed, 
 having no weapons of defence) ; the Wtfg'atherium (great) ; the elasmo- 
 therium (from the laminated structure of its teeth) ; the anthraco- 
 therium (found in the lignitic beds) ; the ceu'notherium (recent) ; the 
 s/t?atherium (found in the Sivalic range of the Himmalehs) ; &c. 
 Though most of these animals are found in tertiary deposits, it would 
 appear that some, such as the megatherium, outlived that era, and 
 continued inhabitants of the globe long after the commencement of 
 the current epoch. 
 
 SUPERFICIAL ACCUMULATIONS. 
 
 250. After the deposition of the Tertiary Strata, a 
 great change took place in the relative distribution of land 
 and ocean. Most parts of Europe, America, and the other 
 continents were elevated above the waters ; other regions 
 seem to have been submerged, and an arrangement of 
 physical conditions established not differing widely from 
 those now existing. But these new conditions did not for 
 an instant arrest the degrading and transporting power of 
 water, the wasting effects of the atmosphere, the disturbing 
 efforts of volcanoes, or the progressive development of 
 organic life : the same agents which had exerted them- 
 selves from the beginning of time, in modifying the physical 
 features of the world, continued their career, only differing 
 in, power and degree according to this new arrangement. 
 Thus, accumulations of sand, gravel, clay, vegetable and 
 animal matter took place above the previously deposited 
 strata every river, lake, sea shore, shell-bed, coral-reef, 
 and peat-moss, contributing its peculiar quota. It is to 
 
 694. Define theroid. 
 
 695. Define the terms in the note. 
 
 696. What system is here considered? 
 
 697. How are these recent and progressive formations explained? 
 

 SUPERFICIAL ACCUMULATIONS. l!)9 
 
 such recent and progressive formations, now occupying the 
 surface of the earth's crust, that the attention of the student 
 is here directed. 
 
 251. The term "Superficial A ccunudations" is applied 
 to these loosely-aggregated masses of matter whatever be 
 tfieir composition or mode of formation to distinguish 
 them from the tertiary sands and clays, in all of which 
 stratification is distinct and undeniable. Other designa- 
 tions have been proposed, such as post-tertiary (atler- 
 trrtiary), quaternary (fourth system), &c. : but that which 
 we have chosen merely indicates their position, leaving 
 further subdivisions to be made in the* course of description. 
 The most natural division is that which attempts to arrange 
 these accumulations according to the respective dates of 
 their formation. Thus: 
 
 1 Deposits now in progress, and depending upon ordinary causes. 
 
 2. Those whose origin depended upon ordinary causes now dormant. 
 
 3. Those which owe their origin to extraordinary causes now dormant. 
 
 A classification of this kind, however, is attended with so 
 many difficulties, that it is next to impossible to adopt it 
 with any degree of accuracy. For instance, it is often 
 very difficult to distinguish the gravel of some ancient lake, 
 containing bones of the stag, elk, and elephant, from true 
 tertiary strata; and who shall decide whether certain inland 
 ranges of sand and gravel arose from extraordinary or 
 ordinary causes? Again, in many valleys alluvial matter 
 has been accumulating from the time that they received their 
 existing configuration up to the present day, thus making 
 the most ancient and most recent of such deposits depend 
 upon one long-continued and progressive agency. Further, 
 an iceberg laden with rock debris and boulders, strewing 
 its burden, as it melts away, along the bed of the ocean, is 
 an ordinary operation; yet were the bottom of the sea, 
 with its mud, gravel, and immense boulders, to be elevated 
 into dry land, appearances would present themselves which 
 geologists would be very apt to ascribe to violent and 
 
 698. Define their peculiarities. 
 
 699. Which is the most natural division T 
 
 700. What objections to this are stated T 
 
200 
 
 GEOLOGY, 
 
 unusual operations of water. Under these circumstances, 
 the more philosophical mode of treating the Superficial 
 Accumulations will be to adopt no classification which in- 
 volves either the time, the ordinary or extraordinary cause 
 of their formation ; but simply to treat them in succession 
 according to their composition, or the agents obviously 
 employed in their deposition. Following out this view, the 
 principal agencies and their results may be arranged as 
 under: 
 
 Agencies. 
 DETRITAL. 
 
 MARINE. 
 
 FLUVTATILE. 
 
 * 
 LACUSTRINE. 
 
 MINERAL 
 
 AND 
 CHEMICAL. 
 
 ORGANIC. 
 
 VOLCANIC. 
 
 Nature of Accumulations. 
 
 ( Erratic blocks or boulders ; dark tenacious clays. 
 <Ossiferous gravels, sands, and pebbly clays. 
 (Ossiferous caves, fissures, and breccia. 
 ( Raised or ancient beaches ; submarine forests. 
 < Marine silt, sand-drift, shingle beaches, &c. 
 ( Submarine deposits and accumulations. 
 Terraces on valley sides, marking successive water- 
 levels. 
 Valley deposits, consisting of river sand, gravel, 
 
 silt, &c. 
 
 Deltoid or estuary deposits, ancient and progressive. 
 Sites of ancient lakes now silted up with various 
 
 debris. 
 
 Marls, such as shell, clay, and calcareous marls. 
 Lacustrine silt, and accumulations now in progress. 
 Calcareous calc-tuff, sinter, travertine, stalactites, 
 
 and stalagmites. 
 Siliceous and aluminous deposits from springs, &c. 
 Saline and sulphurous deposits from springs, from 
 
 the sea, volcanoes, &c. 
 Bituminous exudations, pitch lakes, &c. 
 Vegetable peat-mosses, jungles, vegetable drift. 
 Animal shell-beds, coral-reefs, &c. 
 S Soils primitive earths, with admixtures of organ- 
 l ized matter. 
 
 (Earthquakes elevations and depressions, &c., 
 j caused by 
 
 J Volcanoes elevations, disruptions, and other 
 "A changes caused by 
 
 I Discharges and accumulations of lava, scoriae, dust, 
 I &c. 
 
 The above synopsis comprises all masses of matter which 
 produce any sensible modification of the earth's surface 
 
 701. Explain the tabular arrangement. 
 
 702. What of the organic and volcanic agencies T 
 

 ERRATIC BLOCK, OR HOCLDER, GROUP. 201 
 
 other accumulations than these must be of a very local and 
 limited description. 
 
 ERRATIC BLOCK, OR BOULDER, GROUP. 
 
 252. The terms " erratic block group" " boulder forma- 
 tion" "diluvium" and " diluvial drift" are indiscrimi- 
 nately given by geologists to a thick mass of dark tenacious 
 clay which overlies extensive districts, intermingled with 
 numerous boulders having a rounded and water-worn ap- 
 pearance. There is nothing like regularity of deposit in 
 this formation, unless it may be said that it attains the 
 greatest thickness and uniformity of composition on exten- 
 sive plateaus like those of the coal measures, at the. eastern 
 extremity of certain valleys, and on the south-eastern flank 
 of hills belonging to the secondary period. The clay is 
 generally of a dark blue colour, though in some localities 
 it assumes a reddish hue. There are no lines of lamina- 
 tion in the mass, and no appearances of stratification, unless 
 in some districts where there is a sort of natural division 
 into " upper and lower clays" the lower being dark and 
 more compact, the upper lighter in the hue, and separated 
 from the other by a thin reddish streak. Waiving these 
 minutiae, the whole may be described as a covering of com- 
 pact dark clay, from 10 to 120 feet in thickness, full of 
 boulders and rolled stones from the size of an egg to many 
 tons in weight; these blocks occupying the bottom, middle, 
 or surface of the mass, without regard to gravity or any 
 other law of arrangement. The boulders are of granite, 
 syenite, primitive greenstone, gneiss, mica schist, and other 
 crystalline rocks of a hard and durable texture. Limestone 
 blocks are of very rare occurrence, and the more friable 
 rocks of the upper formations are seldom or ever to be 
 met with. This clay, with its intermingled boulders, gene- 
 rally rests upon the denuded outcrops or edges of the rock 
 formations; is sometimes underlaid by masses of gravel; 
 and not unfrequeritly contains " nests," or irregular patches 
 of rounded pebbles. 
 
 703. By what names is the next group called T 
 
 704. Of what materials do the boulders consist T 
 
 705. What are the peculiarities of this clay. 
 
202 GEOLOGY. 
 
 253. Besides these patches which are interwoven with the 
 clay, there are independent accumulations of gravel, anu 
 rubbly masses of rock-fragments, which seem to have been 
 formed contemporaneously with the boulder-clay, and by 
 the same agency. In Britain such accumulations generally 
 occupy the eastern extremity of longitudinal valleys, where 
 they form curious ranges of flat-topped hillocks; abut against 
 the base of some mountain ; or gather, without regard to 
 any order of arrangement, along the eastern flank of those 
 trap hills which present a bold front or " crag" to the west- 
 ward. They are found for the most part in more open 
 situations than the clay, as if they had been arrested in their 
 progress eastward by prominences and shallows, while the 
 clays were borne to deeper and rr.ore sheltered recesses. 
 Like the dark clays, they are destitute of organic remains, 
 their larger pebbles are derived from primitive rocks, inter- 
 spersed with fragments of sandstone, shale, and coal from 
 the secondary formations. 
 
 254. To account for the origin of the group thus described, 
 many theories have from time to time been advanced, of 
 which only two deserve notice, as being at all adequate to 
 the purpose intended. The first is that which supposes 
 a set of powerful currents to have passed over Britain and 
 the adjoining continent; these currents taking a course 
 from the north arid north-west towards the south and south- 
 east, and sweeping before them clay, sand, gravel, and loose 
 blocks, which were deposited, as the force of the waters 
 abated, without any order or arrangement. How long the 
 currents continued, theorists do not aver; but from the 
 water-worn aspect of the boulders and gravel, an indefinite 
 period is allowed. With respect to the direction of the 
 drifting force, little doubt is entertained, for many reasons: 
 1. Blocks of granite, gneiss, &/c. which must have been 
 derived from the Grampians, are found scattered along the 
 eastern lowlands of Scotland; primitive rocks from the 
 Lammermuir and Cheviot ranges are detected in the vale 
 
 706. What vaiiety of accumulations are found here? 
 
 707. What is the first theory broached ? 
 
 708. What proofs of aqueous agency are manifest? 
 
 709. Whence did the currants flow ? 
 
ERRATIC BLOCK, OR BOULDER, GROUP. 203 
 
 of the Tweed and in Northumberland ; others from the 
 Cumberland mountains are widely dispersed over^Durhaui 
 and the east of Yorkshire ; boulders from the Welsh range 
 are found in the midland counties of England ; while the 
 erratic blocks of Friesland and Germany point to the Scan- 
 dinavian ridge as the source from which they were derived. 
 2. Those hills which range east and west have, without ex- 
 ception, their western brows swept bare, while their eastern 
 flanks are thickly strewed with gravel and boulders. 3. 
 Many accumulations of gravel bear evidence of their having 
 been piled up by a force from the north-west. 4. Blocks evi- 
 dently derived from the outcrops of certain strata are often 
 fouud among the debris a few yards to the south-east, show- 
 ing clearly that the transporting power passed over them 
 from the north-west. 5. The supposed currents have been 
 modified in their direction by ranges of hills, so as to set 
 the volume of water with greater rapidity down the valleys 
 which lie between them, as the greatest accumulations of 
 drill and b >ulders are found at the eastern extremities of 
 such gorges and valleys. But while no doubt is entertained 
 either as to the agency of water in the formation of these 
 accumulations, or as to the direction in which the waters 
 flowed, great difficulty is felt in conceiving any current 
 sufficiently powerful to sweep be fore it blocks of several 
 tons weight, and that over heights and hollows for many 
 hundred-; of miles. Indeed it seems impossible to recon- 
 cile the theory of violent currents with the phenomena pre- 
 sented; for, granting the occurrence of some extraordinary 
 cataclysm, during which the waters of the ocean were 
 thrown over the land, the currents must have abated in 
 velocity as they drew to a close, leaving the detritus to 
 arrange itself more in accordance with the laws of gravity 
 than what is exhibited in a mass of clay and boulders. 
 
 2-55. Tke second theory supposes that those portions of 
 Europe now covered with erratic blocks were submerged 
 after the deposition of the stratified formations ; thai tins 
 submergence was caused by some extraordinary revolution 
 
 710. What difficulties are sUted ? 
 
 711. What other theory is stated T 
 
204 GEOLOGY. 
 
 in the planetary relations of our earth ; that it was accom- 
 panied by a change of climate, and other terrestrial condi- 
 tions; ttfat while in this state, icebergs and avalanches 
 formed around the earlier mountains which were still left 
 above water ; and that these icebergs, as they were loosened 
 from the shore by the heat of summer, and floated south- 
 ward by the currents of the ocean, dropped their burden of 
 boulders and gravel precisely as Captain Scoresby (page 34) 
 found modern icebergs dropping their debris in the northern 
 seas, and as the officers of the recent Antarctic expedition 
 observed similar phenomena in the Southern Polar Ocean. 
 It is further supposed, .that while icebergs distributed the 
 erratic blocks and other debris in d.ep waters, avalanches 
 and glaciers were forming moraines of gravel in the valleys 
 of the then existing land analogous to what is observed in 
 the alpine glens of Switzerland. Again, one cannot read 
 Mr. Simpson's account of the shores of the Polar seas, and 
 learn that the ice formed during winter over whole leagues 
 of gravel, breaks up during summer, and i blown on the 
 beach by winds, or piled up by the tides, where, melting, it 
 leaves long flat-topped ridges, without perceiving a won- 
 derful resemblance between these effects and the long 
 singularly-shaped ridges of " diluvial" gravel. According 
 to this theory, it is easy to account for the south-eastward 
 direction of the drift, for the Polar Ocean still maintains its 
 great southward current to the equatorial seas, modified, 
 undoubtedly, in its course, by the inequalities of the bot- 
 tom over which it passes. The chief difficulty to be obvi- 
 ated is the temporary diminution of temperature which the 
 north of Europe must have then experienced ; and this can 
 only be accounted for by some derangement in the plane- 
 tary relations of our globe. 
 
 256. Both theories art beset with many difficulties, and 
 though the latter accounts more satisfactorily for most of 
 the phenomena of the erratic block group, still there are 
 many points respecting the distribution and extent of the 
 deposit to be investigated before either can be finally 
 
 712. What of icebergs ? 
 
 "13. How is the only difficulty obviated t 
 
OSSIFEUOUS SANDS AND (i RAVEL. 205 
 
 adopted. All that can be affirmed in the present state of 
 the science is the composition arid nature of the clay, gravel, 
 and boulders, as above-described the course of the cur- 
 rents concerned in their deposition the fact of the land 
 having a configuration of hill and valley not differing much 
 from what now exists and the peculiar scantiness, if not 
 total absence, of organic remains. If the latter theory be 
 adopted, it is easy to perceive how the soft bottom of the 
 ocean, as it was elevated into dry land, would be furrowed 
 and channeled by the receding waters here being swept 
 bnre of its mud, but retaining the boulders; there being 
 covered by accumulations of transportable clay and gravel ; 
 while the deeper hollows being left undrained, would form 
 lakes and morasses, which were in turn to be silted up by 
 subsequent material. 
 
 OSSIFEROUS SANDS AND GRAVEL. 
 
 257. Next in point of antiquity to, if not contemporaneous 
 with, the clays and boulders of the preceding' group, may be 
 ranked those ossiferous sands and gravels found scattered 
 at intervals over the valleys of Britain, the continent of 
 Europe, and the river plains of North America. They are 
 termed ossif trout (Lat., os, a bone, and fero, 1 bear), from 
 their containing bones of elephants, hippopotami, horses, 
 bears, deer, and other animals, which belong to existing 
 species, but do not now inhabit the regions where these 
 remains occur. For instance, large portions of England, 
 Wales, Scotland, and Ireland are covered by irregular accu- 
 mulations of rounded pebbles and gravelly sands, in which 
 are found bones of the elephant, hippopotamus, &c., none of 
 which have been known in this country within the historic 
 period. In similar deposits the skeletons of elephants and 
 mammoths have been discovered in Siberia and the north 
 of Europe; the bones of the mammoth, mastodon, and 
 megatherium in America ; and even among the Esquimaux 
 
 714. What is supposed to be ascertained? 
 
 715. What of ossiferous sands and gravel I 
 
 716. Why so named ? 
 
 717. Where are they found ? 
 
 
 TY 
 
 Y 
 
 m. 
 
20(5 
 
 GFOLOOV. 
 
 of the Polar seas Captain Ross and Mr. Simpson observed 
 platters fashioned from the fossil grinders of these gigantic 
 mammalia. Neither at present, nor throughout the whole 
 historic period of four thousand years, have any of those 
 countries been in conditions of climate to support such 
 huge graminivora, .and therefore geologists are compelled 
 to assign a very remote and ancient origin to the gravels in 
 which their relics are entombed. 
 
 Scale of 
 
 Skeleton of Megatherium. 
 
 258. The composition and aggregation of these sands <& 
 gravels point to the long-continued action of water bt 
 
 7 IS. Whv have ^eolopists assigned remote antiquity to these ? 
 7)9 What proof of aqueous agency here ? 
 
OSS1FEROUS SAVDS AND C7RAVFL. 2!)7 
 
 which their pebbles were rounded and smoothed like those 
 of the rivers, lakes, and sea-shores of the present day. The 
 mineral character of the pebbles enables the geologist often 
 to decide with certainty as to the quarter from whence 
 they were drifted ; and in Britain this generally corresponds 
 \vith that from which the erratic blocks were derived. Like 
 the boulders, the great mass of the pebbles are from primi- 
 tive rocks, interspersed with secondary sands, rolled flints, 
 and calcareous cement. The imbedded bones are more 
 or less impregnated with iron and lime, are harder and 
 heavier than recent bone, but never so much petrified as to 
 obliterate the bony structure. The gravels have all a light 
 ferruginous tint, and can only be distinguished in certain 
 localities from true tertiary gravel by the recentn^ss of their 
 fossils, or by some circumstance of position or mode of 
 aggregation. 
 
 259. Ah/eh lihcertainty prevails with respect to the origin 
 and aggregation of these ossiferous sands and gravels. 
 Many of them are no doubt local, and have been formed 
 by the action of rivers, the silting up of lakes and other 
 extensive shallows; and could such be separated from those 
 which appear to have been accumulated by some very 
 powerful and extensive agency, the task were greatly sim- 
 plified. Unluckily, however, this seems to remain an 
 insuperable difficulty, so that geologists are compelled to 
 class together all deposits of ancient ossiferous gravel into 
 one group, without much regard to the agencies concerned 
 in their accumulation. This grouping is rendered still 
 more indefinite by the assertion of some eminent geolo- 
 gists, that ossiferous gravels'have been found underneath 
 the erratic boulder clay, containing the same kind of bones 
 with those above it. Should this be the case, it would 
 tend to establish the theory, that the ossiferous gravels and 
 erratic blocks look their origin from the same set of un- 
 usual causes; that they belonged to an era which was 
 posterior to the tertiary, and prior to the existing arrange- 
 ments of nature; and that before this epoch, which was 
 
 720. What peculiarities are named ? 
 
 721. What theories of their origin and aggregation 7 
 
208 GEOLOGY. 
 
 of considerable duration, many of the tertiary races had 
 died away, and been succeeded by others, most of which 
 still exist, though now extinct in the regions where they 
 then flourished. 
 
 OSSIFEROUS CAVES, FISSURES, AND BRECCIA. 
 
 260. Belonging to the same era with the ossiferous gravels, 
 and only here separated for the sake of perspicuity, occur 
 numerous caverns and fissures filled with the bones of ele- 
 phants, rhinoceroses, hyaenas, bears, deers, and other ani- 
 mals. These caverns are found in England, France, 
 Belgium, Germany, along the coasts of the Mediterranean, 
 in North America, and in Australia. They are situated 
 almost exclusively in thick strata of limestone, a rock pecu- 
 liarly liable to be fissured and worn out by the action of 
 springs and subterranean waters. Among the mud of these 
 ancient caverns, or covered over with calcareous incrusta- 
 tions, lie the bones of land quadrupeds perfectly preserved, 
 and capable of being compared with existing races. " The 
 result," says Professor Phillips, " is extremely remarkable: 
 instead of a large proportion of the existing species of ani- 
 mals, which, during the early periods of history, if not in 
 later times, might have been expected to fall into fissures, 
 retire into caves, or be dragged by wolves to their dens, we 
 find the greater number of bones to belong to elephants, 
 large feline animals, the rhinoceros, hippopotamus, elk, 
 hyaena, indiscriminately entombed with oxen, deer, and 
 many smaller animals." Masses of bones 'are also found 
 filling fissures and other openings in rocks, mingled with 
 pebbles, rnud, fragments of shells, &c. To such accumu- 
 lations the term osseous breccia is applied, from the frag- 
 mentary nature of the compound. 
 
 261. Tke number of ossiferous caverns is very great, but 
 we can only allude to those which occur in England. In 
 general they are situated on the limestone escarpments of 
 the secondary hills, or on the terraced side of some valley. 
 In the latter case, they are considerably above the existing 
 
 722. Where are these caverns found ? 
 
 723. What peculiarities characterize these ? 
 
 724. How are they situated in England? 
 
OSSIFEROUS CAVES, FJSSURES, AND BRECCIA. 213 
 
 bed of the valley, though at one time they must have been 
 on a level with the waters which occupied its expanse. 
 The most celebrated are Banwell Cave and Hutton Hole 
 in the Mendip hills, Dream Cavern near Wirksworth, Peak 
 Cavern in Nidderdale, Rents Hole at Torquay, and Kirk- 
 dale Cave in Yorkshire. The latter has been thus de- 
 scribed: " Kirkdale Cave is situated about twenty-five 
 miles north-east of Xprk, above the northern edge of the 
 great vale of Pickering, and thirty feet above its waters. 
 Its floor is upon the great scale, level for the whole length 
 yet explored (250 feet), and nearly conformable to the plane 
 of stratification of the coralline oolite in which it occurs. 
 In some parts the cave is three or four feet high, and roofed, 
 as well as floored, by the level beds of this rock ; in other 
 parts its height is augmented by open fissures, which com- 
 municate through the roof, and allow a man to stand erect. 
 The breadth varies from four to five feet to a mere passage; 
 at the outlet or mouth against the valley was a wide expan- 
 sion or antechamber, in which a large proportion of the 
 greater bones, ox, rhinoceros, &c. were found. This 
 mouth was choked with stones, bones, and earth, so that 
 the cave was discovered by opening upon its side in a stone 
 quarry. On entering the cave, the roof and sides were 
 found incrusted with stalactites, and a general sheet of 
 stalagmite, rising irregularly into bosses, lay beneath the 
 feet. This being broken through, yellowish mud was 
 found about a foot in thickness, fine and loamy toward the 
 opening, coarser and more sandy in the interior. In this 
 loam chiefly, at all depths, from the surface down to the 
 rock, in the midst of the stalagmitic upper crust, and, as 
 Dr. Buckland expresses it, ' sticking through it like the 
 legs of pigeons through a pie-crust,' lay multitudes of bones 
 of the following animals; 
 
 CARNIVORA hyaena, tiger, bear, wolf, fox, weasel. 
 PACHYDERMATA elephant, rhinoceros, hippopotamus, horse. 
 RUMINANTIA ox, three species of stag. 
 RoDEimA hare, rabbit, water-rat, mouse. 
 BIRDS raven, pigeon, lark, duck, snipe. 
 
 725. Describe Kirkrfale Cave 
 
 726. What animals are found in thin cave t 
 
 18* 
 
210 GEOLOGY. 
 
 The hyaena's bones and teeth were very numerous pro- 
 bably two or three hundred individuals had left their bodies 
 in this cave; remains of the ox were very abundant; the 
 elephants' teeth were mostly of very young animals ; teeth 
 of hippopotamus and rhinoceros were scarce; those of 
 water-rats very abundant. The bones were almost all 
 broken by simple fracture, but in such a manner as to 
 indicate the action of hyaenas' teeth, and to resemble the 
 appearance of recent bones broken and gnawed by the liv- 
 ing Cape hyaena. They were distributed ' as in a dog-ken- 
 nel,' having clearly been much distuibed, so that elephants, 
 oxen, deer, water-rats, &c. were indiscriminately mixed ; 
 and large bones were found in the narrowest parts of the 
 cavern. The peculiar excrement (album graecum) of 
 hyaenas was not rare; the teeth of hyaenas were found in 
 the jaws of every age, from the milk-tooth of the young 
 animal to the old grinders worn to the stump : some of the 
 bones were polished in a peculiar manner, as if by the 
 trampling of animals." 
 
 26*2. The conclusions to be drawn respecting these ossifcr- 
 ous caverns are 1. that some of them formed the dens of 
 ravenous animals, like the wolf and hyaena, which dragged 
 in the carcases of other animals, and feasted upon them in 
 quiet, leaving the bones to be covered in process of time by 
 incrustations of calcareous matter; 2. that others were par- 
 tially filled by these means, and partly by the drifting in of 
 bones and dead animals by some extraordinary inundation; 
 3. that many (fissures especially) were filled by the same 
 drifting process, or by the accidental fulling in of the ani- 
 mals; 4. that several appear to have been used during suc- 
 cessive ages as retreats for animals of all kinds, and even 
 for man himself, as remains of savage life are found in 
 caverns, the floors of which are formed of calcareous incrus- 
 tations, mud, and the bones of animals extinct long before 
 man made his appearance. 
 
 727. What is remarkable in these bones ? 
 
 728. What conclusions are drawn concerning these ossiferous caverns! 
 
RAISED BEACHES StBMAKINE FORF.STS. 211 
 
 EXPLANATORY NOTE. 
 
 BOULDERS, on BOWLDERS a term generally applied to rounded 
 masses of stone lying on the surface, or loosely imbedded in the sub- 
 soil. Boulders are found of all sizes, those of granite, syenite, and 
 primitive greenstone being the largest, and often weighing from ten to 
 thirty tons. 
 
 DILUVIUM. The terms diluvium, alluvium, and collnvium, are to be 
 found in all geological works, but the distinctions made between them 
 are often not very obvious. Colluvium (Lat., con, together, and /wo, I 
 wash) is meant to apply to masses of detrital matter washed together, 
 without hinting at the nature of the force by which they were accu- 
 mulated. Alluvium (Lat., ad, to) is generally applied to matter brought 
 together by the ordinary operations of water, such as river-silt; while 
 diluvium (Lat., dis, asunder), on the other hand, is regarded as implying 
 the extraordinary action of water. In this sense diluvium was at one 
 time restricted to those accumulations of gravel, &c. supposed to have 
 been the consequence of the Deluge; but it has now a wider significa- 
 tion in geology, being applied to all masses apparently the result of 
 powerful aqueous agency. 
 
 MORAINES the name given in Switzerland to the longitudinal depo- 
 sits of stony detritus which are found at the bases and along the edges 
 of all the great glaciers. The formation of these accumulations is thus 
 explained by Professor Agassiz : The glaciers, it is well known, are 
 continually moving downwards, in consequence, probably, of the in- 
 troduction of water into their fissures, which, in freezing, expands the 
 mass ; and the ice being thus loosened or detached from the rocks be- 
 low, is gradually pressed forward by its own weight. In consequence 
 of this motion, the gravel and fragments of rocks which fall upon the 
 glaciers from the sides of the adjacent mountains are accumulated in 
 longitudinal ridges, or moraines. . 
 
 OSSEOUS BRECCIA. Any rock composed of an agglutination of angu- 
 lar fragments is designated by the Italian word breccia ; and when 
 fractured bones are abundantly mingled with the mass, it is termed an 
 osseous breccia. A breccia, or brecciated rock, differs from conglome- 
 rate or puddingstone, in .having its component pebbles angular and 
 fragmented, whereas those of the latter are rounded and water-worn. 
 
 SUPERFICIAL ACCUMULATIONS CONTINUED. 
 RAISED BEACHES SUBMARINE FORESTS. 
 
 263. Where the sea and land join, the former, by the 
 action of its waves and currents, soon forms a level beach 
 or shore, along which is strewn sand, gravel, shells, and 
 other marine exuviae. In tidal seas, this beach is succes- 
 sively inundated and exposed by the flowing and ebbing 
 
 729. Explain the terms o^the note. 
 
 730. What of raised beaches 
 
of the waters ; and in seas where there is no perceptible 
 tide, the winds and waves gradually form a fringe of drifted 
 matter, so that in either case there is impressed upon the 
 land a water-mark which it is impossible to mistake for any 
 other appearance. Where an elevation of the land takes 
 place, th|s beach will form a terrace composed of sand, gra- 
 vel, and other marine debris, ranging more or less parallel 
 with the new line of coast: such terraces are known by the 
 name of raised or ancient beaches. But the earth's crust is 
 as liable to depression as elevation ; and though depressions 
 are not so obvious, in consequence of the overflow of the 
 ocean, still, in certain localities, the ebbing tide exposes 
 the stumps of trees and other terrestrial evidences of these 
 districts having at one time formed dry land. Phenomena, 
 of this kind are known as submarine forests, and are classed 
 with ancient beaches, as showing the depressing and ele- 
 vating forces to which the terrestrial crust is still subjected. 
 264. Raised beaches have been discovered in many parts 
 of the world ; in some, evinced by a single terrace, in 
 others, by a succession of terraces. Several of these beaches 
 are comparatively recent as the Chili upheave of 1822, 
 and the Ullah Bund at the mouth of the Indus in 1819 (par. 
 74) and are obviously the results of local earthquakes and 
 volcanic eruptions. Others are of more ancient date, though 
 still coming within the historic period ; while most of the 
 higher terraces evidently belong to the dawn of the present 
 geological era. Examples of such phenomena occur in the 
 valleys of the Forth and Clyde, and along many parts of the 
 coast of Scotland. One terrace, ranging from 40 to 60 
 feet above the present sea-level, is very continuous, and 
 contains the shells of the limpet, whelk, cockle, common 
 buccirium, and other existing species. It forms the plateau 
 on which many of our modern sea-ports are situated, arid 
 preserves an outline generally parallel with the existing 
 shore. Traces of a lower terrace, ranging from 6 to 15 
 feet above the present high-water mark, occur at several 
 
 731. What of submarine forests 1 
 
 732. What oi'the agency of volcanoes and earthquakes ? 
 
 733. Describe the variety of these beaches. 
 
RAISED BEAPHES SI BMARINE FORESTS. 213 
 
 points on the eastern coast; but doubts are entertained 
 whether it might not be the result of other causes than ter- 
 restrial elevation. As in Scotland, so in England evidences 
 of a former sea-beach have been detected along the coasts 
 of Lancashire, Yorkshire, and Durham, in the valley of the 
 Mersey, and in the Bristol Channel, The same terraced 
 appearances, with the remains of existing sea-shells, are 
 found on the coasts of France, Portugal, Sicily, Greece, 
 Norway, Sweden, and other parts of the European sea-board. 
 In the Mediterranean, one terrace, nearly 50 feet above 
 the sea, and full of shells, is discernible at many distant 
 parts of the shore; on the coast of Norway, accumulations 
 of marine shells are found nearly 200 feet above the exist- 
 ing beach ; and along the borders of the Baltic, well-de- 
 fined plateaus of marine detritus occur at elevations varying 
 from 50 to 100 feet. All these examples, with many others 
 which might be adduced from the coasts of South and 
 North America, point to successive elevations of the land, 
 analogous to those by which the stratified formations were 
 raised from their seas of deposit into open day. The re- 
 mains found in the gravel and sand of these beaches are 
 chiefly shells belonging to species now inhabiting the ocean, 
 though a careful examination detects varietits apparently 
 extinct. The more elevated terraces, like those of Scot- 
 land and Scandinavia, are evidently of great antiquity, and 
 where they occupy wide expanses in ancient firths and 
 bays, are apt to be mistaken by the superficial observer for 
 true diluvial or even tertiary gravels. 
 
 265. With regard to the origin of submarine forests, 
 geologists are somewhat at variance one clasl of theorists 
 advancing such phenomena as evidences of submergence, 
 another contending that they merely occupy low flat dis- 
 tricts, which have been successively lost and won by the 
 sea. Without advocating either hypothesis, it may be stated 
 that the sites of these so-called forests are generally flattish 
 districts, a few feet under the ordinary sea-level, and when 
 exposed after a storm, or during ebb tides, present a series 
 
 734. What is tho geological reasoning here 7 
 
 735. Name the theories of the origin of these forests t 
 
 10 
 
214 oroLOGr. 
 
 of half-fossilized stamps, with their roots imbedded in a 
 stratum of dark-blue clay, evidently the soil in which they 
 grew. The stumps have undergone various degrees of pe- 
 trifaction, and many of them are also incrusted with iron 
 pyrites. Phenomena of this kind have been detected in 
 the estuary of the Tay, in the Firth of Forth, on the coast 
 of Hampshire, and other places proving, to all appearance, 
 that the land in which they grew had been submerged be- 
 neath the ocean. Those who oppose this view, suppose 
 the trees to have grown in low alluvial tracts, which were 
 sheltered from the inroads of the sea by sand-hills and other 
 barriers, and that on these barriers being broken down, the 
 forests were overthrown, and their trunks and roots covered 
 by the inundating waters of the ocean. This latter hypo- 
 thesis, however, has few adherents, the submergence of land 
 being as common a phenomena as its elevation. Submer- 
 gences, like those of the Japanese towns in 1596, of Port 
 Royal in 1692, of parts of the Portuguese and African coasts 
 during the Lisbon earthquake of 1775, are occurrences to 
 which all districts have been and are still liable; and there 
 is nothing more unusual in detecting the stumps and roots 
 of trees on the bed of the ocean, than in perceiving the 
 houses of Port Royal, which were visible for nearly a cen- 
 tury after their submergence. 
 
 266. The conclusion to be drawn from the occurrence of 
 raised beaches and submarine forests is, that the crust of the 
 earth is still subjected to the same elevating and depressing 
 forces which were instrumental in modifying its surface 
 during the deposition of the earlier formations. The results 
 of existing forces may be insignificant when compared with 
 those of former periods, but they are precisely analogous. 
 An elevation of 100 feet may produce a very narrow terrace 
 of gravel, where the land shelves rapidly beneath the water; 
 but where the sea is shallow, as in most bays and estuaries, 
 it will lay bare thousands of acres composed of mud, clay, 
 sand, gravel, and marine exuviae. A new formation would 
 thus be constituted as peculiar and as characteristic of its 
 era arid origin as the tertitiary or any other system of strata. 
 
 736. What conclusions are drawn 1 
 
MARINE SILT, SAND-DRIFT, SHINGLE BEACHES, &C. 
 
 MARINE SILT, SAND'DRIFT, SHINLE BEACHES, &C. 
 
 267. Under the term " Marine Silt" is comprehended 
 all those masses of sand, mud, clay, gravel, &c., which are 
 still in progress of accumulation along the existing shores 
 of the ocean. Waves, tides, and other oceanic currents, 
 are the forces by which they are collected and arranged, 
 although a great, perhaps the greater, proportion of the 
 material is derived from the land by the ceaseless transport 
 of streams and rivers. It is necessary, however, to form 
 geological distinctions between marine, estuary, river and 
 lake deposits, as far as practicable, according to the agency 
 more immediately concerned in their aggregation ; for it 
 is only by so doing that we are enabled to account for the 
 peculiarity of their organic remains, and therefrom to form 
 correct ideas respecting the character of the earlier for- 
 mations. Along the entire shore of the ocean, drifted 
 matter is always more or less accumulating ; scantily around 
 headlands and exposed places, where the sweep of the tidal 
 current is powerful ; abundantly in .sheltered bays and re- 
 cesses. Of the extent of such deposits it is impossible to 
 form any thing like a correct estimate, travellers and 
 voyagers having hitherto directed little or no attention to 
 the geological features of the t nntries which they visit. 
 Instances of marine silt are afforded Sv the sands of Tents- 
 moor and Pilmoor between the Tay and St. Andrews in 
 Scotland, by the " warp" yearly reclaimed near the mouth 
 of the Humber, the fens of Lincoln and adjoining counties, 
 the extensive sands and marshes near Yarmouth, the Chesil 
 bank at Portland, and the flats of Somerset and Gloucester 
 on the estuary of the Severn. Some of these tracts are of 
 considerable extent ; but they are insignificant compared 
 with what has taken place in other regions. The isthmus 
 of Sue/, for example, uhich is now 27 miles broad, is said 
 to have doubled its width since the time of Herodotus 
 (4090 years ago) ; Tehama, a country on the Red Sea, has 
 increased from three to six miles seaward since the Chris- 
 
 737. Define marine silt. 
 
 738. What instances are -named f 
 
216 GF.OLOGV. 
 
 tian era; Tyre and Sidon, sea ports mentioned in Scripture, 
 are now several miles inland ; hundreds of square miles of 
 Holland, and the other Low Countries of the continent, 
 are the direct formation of the existing seas. 
 
 268. Sand~drift is so intimately connected with marine 
 silt, that both may, without much impropriety, be con- 
 sidered as one deposit. When the latter is chiefly com- 
 posed of sand and comminuted shells, its surface, on being 
 exposed by the ebbing tide, becomes so dry and light as to 
 be easily borne about by the wind. Blown into slight emi- 
 nences and irregular ridges, a portion of it is placed beyond 
 the reach of the returning tide, and this process, repeated 
 year after year, gives rise to extensive flats of sand curiously 
 blown into dunes or little hillocks, and scooped out into 
 hollows or bunkers. The seeds of the arundo arenaria 
 (bent), elymus, and other maritime plants, soon spring up 
 from this newly-acquired land, and bind it together by their 
 long interweaving roots ; other species succeed ; and thus, 
 in process of time, a vegetable sward gathers over it, and 
 protects it from farther removal. Such accumulations arc 
 known by the name of sand-drift, and are of all ages, from 
 that covered by many inches of vegetable soil, and brought 
 under the plough of the farmer, to the loose sand which 
 was drifted up during the ebb of the latest tide. Consider- 
 able tracts of this sandy formation are to be found skirting 
 the coasts of every country at some places in long narrow 
 fringes, at others in wide expanses of many thousands of 
 acres. It is always at the head of bays, in creeks, and 
 other recesses, sheltered by some headland from the sweep 
 of the tidal current, that such deposits occur ; indeed, by 
 the erection of artificial jetties or projections, fringes of 
 sand may be collected along the coast of any tidal sea. 
 The difficulty of preventing tracts of this nature from 
 shifting and drifting about, and the damage which follows 
 to cultivated soil by sand being blown over it, has given 
 rise to many schemes for their retention. The common 
 bent (arundo arenaria) is regularly planted on the sandy 
 
 739. What of Tyre and Sidon ? 
 
 740. Define sand-drift, and its dunes and bunkers. 
 
 741. How is drifting prevented ? 
 
MARINE SILT, SAND-OiUF I, SHINGLE BEACHES, &C. 217 
 
 plains of Poland, and Lord Palmerston has followed the 
 same process with complete success on a large tract of 
 sand-drift between Ballyshannon and Sligo in Ireland. The 
 French government plants and protects forests of sea-pine, 
 to prevent the sands of the Bay of Biscay near the Garonnne 
 from being drifted inland ; and at one time it was held 
 penal to pull the bent which grew upon the links or downs 
 of Scotland. 
 
 269. Shingle beaches are those accumulations of rounded 
 and water-worn stones which are piled up on certain parts 
 of the coast by the conjoint action of the waves and tides. 
 They occur only along exposed districts, from which the 
 sand and finer debris is swept onwards to the more shel- 
 tered recesses. The battering force of the waves during 
 high storms is so powerful, that masses of shingle are often 
 found from '4 to 12 feet above ordinary tide-mark leaving 
 appearances very perplexing to the geologist who is unac- 
 quainted with the force of waves, the weight which stones 
 lose when immersed in water, and the curious wedge-like 
 arrangement which takes place among the individual peb- 
 bles. In addition to the forward motion imparted to these 
 beaches by the waves, they are also subjected to the lateral 
 current of the tides; arid thus riome of them move onward 
 along the coast with so perceptible a motion, that they have 
 been designated travelling beaches. Where shingle is 
 found at considerable altitudes, or in places now removed 
 from the sea, it is apt to be confounded with diluvial matter ; 
 but an attentive examination of the manner in which it is 
 piled up, and the remains which it contains, will prevent 
 such a mistake. 
 
 270. The fossils imbedded in marine silt, sand-drift, and 
 shingle, all belong to existing races, though some of these 
 races are now extinct in the countries where their remains 
 are found. Marine silt, in many places, must be as ancient 
 as the time when the land and sea received their present 
 configuration ; and from the peculiar nature of its formation, 
 must contain both land and marine relics the latter, how- 
 
 742. Define shingle beaches. 
 
 743. Define travelling beacheg. 
 
 744. What of the fossils here 1 
 
213 CROLCK3Y. 
 
 ever, greatly prevailing. Scarcel} any of the fossils 
 petrified ; most of them retain their usual structure ; and 
 unless where the sands are highly calcareous or ferrugi- 
 nous, there is no such thing as induration among the ma- 
 terials which compose these deposits. 
 
 SUBMARINE DEPOSITS AND ACCUMULATIONS. 
 
 271. Submarine deposits are those which take place 
 tinder the waters of the ocean, and are not subjected in 
 any measure to littoral influences. Of such deposits geolo- 
 gists know scarcely any thing with certainty, as few seas 
 have been sounded with a view to detect the nature of the 
 material accumulating beneath. This only we know, that 
 where soundings have taken place, mud, sand, shells, bro- 
 ken corals, &c., have been found, evidently deposited there 
 by submarine currents, which are modified in their velocity 
 according to the inequalities of the bottom. Many of these 
 currents are ascertained, and according to the regions 
 whence they come, and over which they pass, so will the 
 material be which they are depositing along the bed of the 
 ocean. Thus the two polar currents, as they direct their 
 course to the equator, carry with them icebergs and floes 
 laden with the rocks and gravel of the artic and antarctic 
 islands ; the gulf stream transports the sea-weeds, animal 
 remains, and other debris of equatorial countries; while 
 the outward current of the Mediterranean deposits in the 
 Atlantic the products of its temperate regions. All these 
 agents are unceasingly at work ; and thus strata are now in 
 formation along the bottom of the sea which, if elevated 
 into dry land, would vie in extent with many of the second- 
 ary systems* 
 
 272. Submarine accumulations have been detected in the 
 Yellow Sea, which is rapidly shoaling, in the Gulf of 
 Mexico, in the Caribbean Sea, the German Sea, and in 
 other divisions of the great ocean. The latter, according 
 to Mr. Stevenson, is deepest on the Norwegian side, where 
 the soundings give 190 fathoms; but the mean depth of 
 
 745. What of submarine deposits? 
 
 746. What agencies are described ? 
 
 747. What of submarine accumulations ? 
 
TER RACES IN VALLEYS. 219 
 
 the whole basin may be stated at no more than 31 fathoms. 
 The bed of this sea is traversed by several enormous banks, 
 one of which, occupying a central position, trends from the 
 Firth of Forth in a north-easterly direction to a distance of 
 110 miles; others run from Denmark and Jutland upwards 
 of 105 miles to the north-west ; while the greatest of all 
 the Dogger bank extends for upwards of 354 miles from 
 north to south. The superficies of these enormous shoals 
 is equal to one-fifth of the whole area of the German 
 Ocean, or about one-third of the extent of England and 
 Scotland. The average height of the banks measures 
 about 78 feet, the upper portion of them consisting of fine 
 and coarse siliceous sand, mixed with comminuted corals 
 and shells. As in the German Ocean, so in all other seas 
 agents are at work depositing, however slowly, materials 
 which are destined to form part of the stratified formations 
 of future continents and islands. 
 
 TERRACES IN VALLEYS. 
 
 273. Terraces on the sides of valleys, like those along 
 the sea-coast, indicate levels formerly occupied by -water. 
 The latter are ancient sea-beaches, supposed to be the re- 
 sult of elevations of the land; the former may arise partly 
 from elevations of the same nature, and partly from their 
 rivers having cut for themselves a deeper channel. Thus, 
 a terrace in an estuary or river opening towards the sea 
 may be considered as indicating a raised beach ; but ter- 
 races inland, and above the level of this beach, undoubtedly 
 owe their origin either to the drainage of lakes, or the 
 deepening of river channels. River-terraces are in gene- 
 ral of no great breadth, but sweep along the sides of the 
 valley, looking at a distance like a road embankment ; 
 hence the term, " parallel roads" has been applied to those 
 observed in Glen Roy. Their surfaces are covered to a 
 considerable thickness- with sand and pebbles showing 
 the long-continued action of water at that elevation. In 
 some valleys there are two or three successive terraces (see 
 
 748. What geological reasoning here ? 
 
 749. How aro terraces formed, and where? 
 
 750. What varistv of teiraces 1 
 
t;::o!.oov. 
 
 fig.), marking the gradual declension of the rivers to their 
 present level ; and not unfrequently isolated mounds of 
 gravel (d) stand out in the plain, of the same height with 
 some of the terraces, as if these knolls had been shoals and 
 sandbanks when the water occupied a higher level. 
 
 a, Upper terrace ; 6, Lower terrace ; c, Existing river ; d, Isolated 
 mound of gravel, of the same height with the lower terrace. 
 
 274. Such terraces are found indiscriminately in all 
 parts of valleys at their heads, in their broad expanses, 
 and in their estuaries. They are frequent where rivers de- 
 scend from mountainous districts, but not very distinct and 
 definite even should the water have formed glens and 
 valleys of erosion many hundred feet in depth. The rea- 
 son of this is, that the sides are so steep, so liable to land- 
 slips and other waste, that the terraces gradually become 
 obliterated, leaving the bank as one continuous inclination. 
 On the sides of valleys, properly so called, the case is other- 
 wise, the terraces being left level and distinct as on the 
 day they were deserted by the waters. These appearances 
 would seem to indicate the existence of ancient lakes and 
 other accumulations of water at a high level, which were 
 either suddenly or gradually drained as the river cut 
 through the barriers which produced them. Indeed, most 
 of the valleys in our own^island appear to have been at one 
 time mere chains of lakes and morasses, now drained in 
 consequence of the waters which flowed from them having 
 gradually deepened their channels. This natural process 
 of drainage is still going forward amid the swamps and 
 lakes of other countries ; and it is therefore easy to con- 
 ceive how terraces, beaches, or ancient water-marks are 
 formed, and will continue to be formed, until rivers have 
 
 751. Explain the diagram. 
 
 752. What geological reasoning here 1 
 
DEPOSITS IX VALLEYS. 221 
 
 worn down their channels to the lowest depth which the 
 relative level of sea and land will permit. Instances occur 
 in Glen Roy, in the valleys of the Tay, Eden, Tyne, Wear, 
 Tees, Ouse, and other British rivers, all of which present 
 the same level shore-like appearance. Similar terraces or 
 beaches are found extending along large tracts in the 
 vicinity of the great American lakes showing that these 
 " fresh-water seas," as they are not inappropriately termed, 
 at one time occupied a higher level, and spread over much 
 wider areas. 
 
 DEPOSITS IN VALLEYS. 
 
 275. Deposits in valley?, as distinguished from those in 
 lakes and estuaries, are of a very complex description. In 
 general, they consist of clay, marsh-silt, sand, gravel, and 
 shingle according to the nature of the country through 
 which the river flows. Rapid streams leave along their 
 banks only the heavier stones and gravel, and carry all 
 light and impalpable matter to their embouchures. Slug- 
 gish rivers, on the other hand, deposit a great portion of 
 their suspended impuri les in the valleys through which 
 they flow, thus forming inland tracts of alluvial soil. All 
 rivers, however, are liable to sudden freshets, and as they 
 wind and bend their way seaward, they tear up formerly- 
 deposited matter here piling up masses of shingle and 
 boulders, there mounds of sand, and again overlaying the 
 whole with a covering of mud. It is therefore impossible 
 to say what was accumulated by the ordinary and what by 
 the extraordinary operations of rivers, or to separate the 
 ancient from the modern. Again, mrst of our valleys 
 (locally termed dales, haughs, carses, &c.) have been the 
 sites of lakes and morasses in which heterogeneous silt was 
 deposited, and there is thus an insuperable difficulty in 
 distinguishing between what is really fluviatile and what 
 lacrustine. 
 
 276. Without making too nice distinctions, river depo- 
 
 753 What of the lakes? 
 
 754. Define and describe deposits in valleys. 
 
 755. What geological reasoning is here T 
 
 756. What of river and lake deposits f 
 
 10* 
 
222 GEOLOGY. 
 
 sits may be described as more heterogeneous in theii 
 material, and more irregularly laid down, than those of 
 lacrustine origin. In lakes, the gravel, sand, and mud are 
 distributed in layers according to their respective gravities, 
 whereas the shingle, gravel, and mud collected by river- 
 torrents are piled up without respect to any law of sedi- 
 mentary arrangement. Notwithstanding this, there are 
 valley-deposits which it is impossible to ascribe either to the 
 one agency or to the other; and all that the geologist can 
 do, is merely to describe the composition and the nature of 
 the organic remains which may be imbedded therein. Of 
 these accumulations, many are of great antiquity, and con- 
 tain bones of the mammoth, elk, deer, horse, ox, bear, wild 
 boar, wolf, and other animals now extinct in the regions 
 where their relics are found ; others are still in progress, 
 connecting the present with the past; while some are now 
 far removed from the agencies by which they were formed 
 the rivers having shifted their channels to give birth to 
 newer formations. 
 
 DELTAS AND ESTUARY DEPOSITS. 
 
 277. Of modern deposits, those formed in estuaries are 
 the most perplexing to the geologist, on account of the 
 numerous and often opposite agencies concerned in their 
 production. The prevailing agent is the river at whose 
 mouth they are accumulated ; and this brings down mud, 
 sand, gravel, vegetable debris, and the remains of terrestrial 
 animals during quiet periods the most impalpable silt, 
 during inundations the most heterogeneous mixture. Fur- 
 .her, the deltas of rivers subjected to periodical inundations 
 constitute, during the dry season, low flat tracts full of 
 swamps, lagoons, and mud islands, which nourish the 
 rankest jungfe growth, gigantic reptiles and amphibia, beds 
 of shells, and shoals of fishes. During the wet season many 
 of these plants and animals are swept seaward, or buried 
 in situ, by the debris brought down by the current. Again, 
 the sea acts in most of these estuaries, running inland from 
 
 757. What of deltas and estuary deposits ? 
 
 7o>. What of tlv> variety of agencies concerned ? 
 
DELTAS AND ESTUARY DEPOSITS. 223 
 
 ten to a hundred miles, and consequently depositing marine 
 detritus and marine organisms amid those of a terrestrial 
 and iresh-water character. The student cannot therefore 
 fail to perceive how very complex the nature of such depo- 
 sits must be, and how necessary it is to exercise caution in 
 pronouncing what agent or agents were concerned in the 
 formation of any individual layer. As in modern estuaries, 
 so in those which existed in former times, and thus the 
 difficulty arises with respect to the alternation of marine 
 a;id fresh-water strata in tertiary basins, the mingling of 
 fresh-water with marine organisms in the wealden, and the 
 complication of terrestrial, fresh-water, and marine products 
 among the rocks of the coal-measures. Bearing these facts 
 in mind, and carefully studying the formation of modern 
 estuary deposits, the geologist is prepared to account for 
 appearances in the older systems of strata, which would 
 otherwise remain unsolved. 
 
 278. Estuary deposits may be said to consist of irregular 
 layers of mud, clay, sand, gravel, and vegetable debris, 
 intermingled with organisms of terrestrial; fresh-water, and 
 marine origin. When accumulated to such an extent as 
 to constitute dry land, they form rich alluvial tracts of a level 
 and uniform appearance, decidedly prejudicial to health, 
 but favourable to the growth of the cultivated vegetables. 
 In inland and non-tidal seas, as the Mediterranean, Gulf of 
 Venice, and Baltic, the agency of the rivers prevails, form- 
 ing deltas and shoals which gradually encroach upon the 
 limits of the seas; but in tidal waters oceanic agencies are 
 also at work, either assisting in the accumulation of estuary 
 silt, or distributing the debris brought down by rivers over 
 areas far removed from their embouchures. The accumu- 
 lations of this kind now forming are almost as numerous as 
 the streams which enter the sea; but the notice of some of 
 the more extensive is all that the limits of this treatise will 
 allow. And here the student should bear in mind one 
 essential difference between the older formations and those 
 of existing estuaries ; namely, that among the former a 
 great uniformity prevails, not only in mineral composition, 
 
 759. Of what do estuary deposits consist ? 
 
2'24 EOLOGT. 
 
 but in the kind of organic remains which they contain, thus 
 evincing a uniformity of climate and other terrestrial condi- 
 tions; while among the latter scarcely two deposits present 
 one feature in common. The Ganges, for example, bears 
 down to its delta the spoils of the tropics palms, canes, 
 tree-ferns, bones of elephants, lions, and tigers; the Nile 
 the scanty aquatic plants of Egypt and bones of the croco- 
 dile, the camel, and other domestic animals; the Niger the 
 hippopotamus, rhinoceros, and camelopard of Central Afri- 
 ca ; and the Mississippi the pines, buffaloes, elks, and deer 
 of North America. In subsequent ages, should these de- 
 posits be elevated into dry land, nothing could be more 
 dissimilar than their organic remains, and yet we know that 
 they belong to one common period of formation. 
 
 279. The most extensive deposits of this class are those 
 of the Mississippi and Amazon in America, the Po and 
 Rhone in Europe, the Niger and Nile in Africa, and the 
 Ganges and rivers of the Yellow Sea in Asia. The delta 
 of the Mississippi is partly of oceanic and partly of fluviatile 
 origin, and coilsists of alternations of blue and reddish 
 clays with vast rafts of buried wood, and remains of the 
 buffalo, elk, deer, jaguar, wolf, fox, and other animals pecu- 
 liar to northern regions. [This delta at the mouth of the 
 Mississippi has advanced several leagues since New Orleans 
 was built. Some idea may hence be formed of the force 
 with which the agency of rivers acts in effecting geological 
 changes.] The plain of the river is from thirty to fifty 
 miles broad, but near the sea it widens to treble that 
 breadth. The whole of this valley, extending for hundreds 
 of miles inland, consists of recent alluvium, which the river 
 is perpetually shifting and re-depositing. The most cha- 
 racteristic feature in the deposit is the rafts of drift-trees 
 brought down every spring, and which, according to 
 Captain Hall, are matted together into a net-work many 
 yards in thickness, and stretching over hundreds of square 
 leagues. Respecting the material deposited near the mouth 
 
 760. What variety is indicated ? 
 
 761. What geological illustrations are named I 
 
 762. Where are they most extensive ? 
 
 763. What of the Mississippi T 
 
DELTAS AND F.STLARV DEPOSITS. 225 
 
 of the Amazon, we have less particular information , but it 
 is stated by Captain Sabine, that its sediment discolours 
 the waters of the ocean three hundred miles .off shore. 
 This sediment is constantly carried to the north-west as far 
 as the mouth of the Orinoco, and thus an immense tract of 
 swamp is formed along the coast of Guiana, with a long 
 range of muddy shoals bordering the marshes the whole 
 being gradually converted into dry land. Although on a 
 less gigantic scale, the deltoid deposits of Europe have, even 
 within a very recent period, made considerable accessions 
 to the land. During the last thousand years, that of the 
 Rhone has gained upon the Mediterranean from four to 
 six miles. " Notre Dame des Ports," says Mr. Lyell, 
 " was a harbour in 898, but is now a league from the 
 shore; Psalmodi was an island in 815, and is now two 
 leagues from the sea ; and the Tower of Tignaux, erected 
 on the shore so late as 1737, is already a French mile 
 from it." At the head of the Adriatic, the Po and other 
 streams have borne down so much sediment, that " from the 
 northernmost point of the Gulf of Trieste down to the south 
 of Ravenna, there is an uninterrupted series of recent ac- 
 cessions of land more than one hundred miles in length, 
 which, within the last two thousand years, have increased 
 from ten to twenty milts in breadth" 
 
 280. Turning to Africa: lower Egypt is the gift of the 
 Nile; and Herodotus estimates the sediments borne down 
 by ihis river to be so abundant, that if diverted into the 
 Red Sea, they would fill it up in ten thousand years. The 
 Nile still transports its annual burden of debris, but the 
 seaward growth of the delta is prevented by littoral currents, 
 which sweep it onward to other parts of the Mediterranean. 
 The Niger presents one of the best examples of modern 
 deltoid deposits, and affords the geologist much insight as 
 to the manner in which terrestrial, fresh-water, and marine 
 remains become imbedded in the same formation. This 
 delta, as yet so imperfectly examined, ranges along the 
 
 764. What remarkable instances are named 7 
 
 765. What.of the Nile and Lower Egypt? 
 
 766. What do the deltas of th Niger show t 
 
. GEOLOGY. 
 
 coast for more than two hundred miles, having a beach of 
 sea-sand slightly elevated above its general level. Behind 
 this beach, stretching inland for more than one hundred 
 and fifty miles, there extend vast expanses of swamp, man- 
 grove-jungle, and mud islands, intersected by creeks, la- 
 goons, and branches of the river. Over this expanse 
 (annually inundated for several months) deposits of sand, 
 clay, silt, and mud are constantly taking place, burying 
 within them the remains of rhinoceroses, hippopotami, 
 crocodiles, &c. which inhabit the jungle, terrestrial ani- 
 mals which the current transports from the high country, 
 arid myriads of shell-fish arid other aquatic races which 
 abound in the lagoons. Here, then, we have salt-water 
 agencies prevailing for many leagues inland during the dry 
 season; gigantic amphibia at all seasons; shell-beds and 
 formations of marl in the lagoons; terrestrial animals from 
 inland; jungles and morasses to form lignite; and sand, 
 mud, and gravel to form sandstone and shale. Should a 
 period, therefore, ever arrive when the delta of the Niger 
 shall become habitable dry land, appearances will present 
 themselves perfectly analogous to the tertiary formation, 
 and one by which a flood of light is thrown upon the for- 
 mation of the coal measures. 
 
 281. The delta of the Ganges, according to Major Ren- 
 nel, is considerably more than double that of the Nile, 
 occupying not less than an area of 44,000 square miles. 
 That portion of it which borders on the sea is composed of 
 a labyrinth of rivers and creeks, all filled with salt-water, 
 except those immediately communicating with the princi- 
 pal branch of the river. This tract alone, known by the 
 name of the Sunderbunds, is equal to the whole princi- 
 pality of VV'ales; but from its recent alluvial character, is 
 subject to numerous shiftings, though ultimately settling 
 down and shoaling up the Bay of Bengal. The quantity 
 of sand and mud brought down by the Ganges is so great, 
 that the sea only recovers its transparency at the distance 
 of sixty miles from the coast ; thus not only adding new 
 
 767. What agencies are named ? 
 
 768. What is peculiar in the deltas of the Ganges 1 
 
DELTAS AND ESTUARY DEPOSITS. 2*27 
 
 material to the shoals and islands of the Sunderbunds, but 
 forming immense tracts of submarine strata at various 
 depths from four to seventy fathoms. As Egypt is said to 
 be " the gift of the Nile," so may the great plain of China 
 be considered as the gift of the Hoang-Ho, the Kiang-Koo, 
 and their tributaries. The same agencies which formed 
 the habitable plain are still at work, gradually shoaling up 
 the Yellow Sea, and converting its basin into solid land. 
 Navigators speak of their keels ploughing up the fine im- 
 palpable sediment at a distance of six and eight leagues off 
 shore, along which a perceptible increase is taking place 
 every year. Sir George Staunton infers, from certain ex- 
 periments, that the Hoang-Ho contains one part of sediment 
 in every two hundred ; and estimating the average depth of 
 the Yellow Sea to be one hundred and twenty feet, calcu- 
 lates that this river by itself is capable of converting an 
 English square mile into solid land in the course of seventy 
 days. 
 
 282. From the examples given, the student will perceive 
 that estuary deposits that is, deltas or deposits taking place 
 at the mouths of rivers are among the most important in 
 modifying the present configuration of land and sea ; that 
 they constitute the connecting link between formations 
 now in progress and those of distant eras; and present 
 appearances which enable the geologist to infer as to the 
 manner in which the greater portion of the stratified sys- 
 tems were deposited. Their organic remains are numerous; 
 are partially fossilized, or differ little from recent wood, 
 bones, and shells; and all belong to vegetables and animals 
 which have been placed upon the earth since the com- 
 mencement of the present geological era. Where tidal 
 influences prevail, these remains are chiefly marine; where 
 river inundations predominate, they are fresh-water and 
 terrestrial ; while others, as beds of oysters, &c. are of true 
 estuary origin. 
 
 769. What of the Chinese rivers, and the reasoning thereon 
 
 770. What do we learn by these examples 1 
 
 771. What geological facts and deductions are hereT 
 
228 GEOLOGY. 
 
 LACUSTRINE, OR LAKE, DEPOSITS. 
 
 283. By lacustrine deposits are meant those accumula- 
 tions which have been collected in fresh-water lakes since 
 the present order of things was established. Looking 
 back to certain coal-fields, and to the fresh-water beds of 
 the wealden and tertiary strata, we have almost evidence 
 sufficient to justify the conclusion, that these beds must 
 have been formed in lakes, or at least in estuaries where 
 quiet fresh-water influences greatly predominated. Indeed 
 it is impossible to conceive of a condition of the world 
 without inland lakes, morasses, and swamps, in which 
 aquatic races flourished, shell rnarl was formed, and peat- 
 moss accumulated. But the boundaries of those ancient 
 lacustrine deposits are now obliterated ; and all that the 
 geologist can do is, to judge of the manner of their accu- 
 mulation, and the nature of their contents, by comparing 
 them with similar deposits now occupying the surface of" 
 the earth, or still in progress of formation. 
 
 284. Modern lake deposits consist of clay-silt, sand, 
 gravel, rolled pebbles, beds of marl, and accumulations of 
 peat-moss. Generally situated in plains or hollows, sur- 
 rounded by hills, a lake receives the waters and debris of 
 several streams, and its quiet expanse performing the office 
 of a great settling pool, the debris falls down as sediment, 
 and the waters pass off by one outlet purged of all their 
 impurities. This sediment, collecting at the mouths of the 
 streams, forms little deltas, which gradually push them- 
 selves forward into the lake; aquatic plants soon spring up 
 on their surface, whose annual growth and decay constitute 
 beds of peat ; fresh-water shell-fish and the calcareous de- 
 bris of the springs and streams collect in certain localities 
 as marl ; and these various formations repeated and con- 
 tinued, in process of time shoal up the lake, which forms 
 a flat alluvial tract, swampy at first, but soon acquiring 
 
 772. What of lacustrine deposits ? 
 
 773. Of what do they now consist ? 
 
 774. What results from the sediment ? 
 
LACUSTRINE, OR L\KE, DEPOSITS. 225 
 
 firmness and dryness for the purposes of cultivation. Silted- 
 up lakes are rife in this country as well as in other parts of 
 the world ; they occupy the central and wider parts of our 
 dales and valleys ; and though all superficial evidences of 
 the lake be obliterated, the regular manner in which the 
 materials are distributed serve readily to distinguish lacus- 
 trine from fluviatile silt. Respecting the extent of surface 
 occupied by lake deposits, it is impossible as yet to form an 
 accurate estimate, though it is evident that the soil of 
 most inland valleys, both in this and in other countries, is 
 composed of it. The prairies of North America, the 
 pampas of South America, and the steppes of Europe and 
 Asia, are regarded by many as the sites of lakes now 
 drained or silted up ; and, considering their relation to ex- 
 isting rivers and valleys of drainage, there is ample foun- 
 dation for the opinion. Considerable tracts of alluvial land 
 are still in progress of formation along the borders of most 
 modern lakes, whose sites under the double process of silt- 
 ing up and drainage, are evidently destined to become 
 alluvial plains like those to which we have adverted. By 
 drainage is meant that tendency which rivers issuing from 
 lakes have to deepen their channels, and thereby not only 
 to lower the level of their parent waters, but also to render 
 them, from their shallowness, more liable to be choked up 
 by aquatic vegetation. 
 
 285. Of the various substances composing lake deposits, 
 marl is the only one whose formation deserves particular 
 notice. This substance may be looked upon as the lime- 
 stone of the superficial accumulations just as the chalk, 
 oolite, lias, zechstein, mountain limestone, and cornstone, 
 were the calcareous beds of their respective formations. It 
 occurs in various states of purity, from a marly clay, which 
 \vilJ scarcely effervesce with acids, to a shell-marl containing 
 from 80 to 90 per cent, of lime. Marl-clay, for instance, 
 occurs as a whitish friable clay with an admixture of lime, 
 
 775. How are silted up lakes known T 
 
 776. What examples of such alluvia are named f 
 
 777. Define drainage. 
 
 778. What of marl and its varieties I 
 
2-.0 GEOLOGY. 
 
 and sometimes also of magriesian earth ; the term clay- 
 marl is applied when the calcareous matter prevails over 
 the clay ; shell-marl is almost wholly composed of lime 
 and fresh-water shells, with a trace of clay or other earthy 
 matter, and, where solidified by chemical aggregation, is 
 known as rock-marl. With respect to the origin of these 
 marls there are various opinions, though it is generally 
 admitted that they are derived partly from calcareous springs 
 which enter the lakes, and partly from the shells and secre- 
 tions of the fresh-water molluscs which inhabit them. What 
 tends to confirm this opinion is the fact, that marl-clay and 
 clay-marl are found chiefly among the deposits of ancient 
 or modern lakes situated in limestone districts where cal- 
 careous springs abound; and that shell-marl is often almost 
 wholly composed of the exuviae of molluscs, many genera 
 of which are still inhabiting the same lakes and marshes in 
 which the deposit is found. Marl occurs irregularly inter- 
 stratified with clay-silt, peat-rnoss, or gravel, and is dug for 
 agricultural purposes in many of the ancient lake-sites and 
 alluvial valleys of Britain 
 
 286. The organic remains found in lacustrine deposits 
 are chieflly fresh-water shells, such as limnaea, planorbis, 
 paludina, cyclas, mya, cypris, ancylus, &c. ; bones, horns, 
 and other portions of mammalia, as the stag, elk, deer, ox, 
 horse, bear, fox, beaver ; detached skeletons of birds ; and 
 drift or submerged plants, of which oaks, pines, birches, 
 hazels, reeds, rushes, and other vegetation commonly found 
 in peat-mosses, are the most abundant. Human skeletons 
 are occasionally met with ; and canoes, stone battle-axes, 
 &c., of great antiquity have been dug up from the silt of 
 Loch Doon in Ayr, as well as from the shell-marl of Kin- 
 nordy Loch in Forfarshire. All of these remains, whether 
 plants or animals, belong to races now existing upon the 
 globe, although some genera (as the elk, wild-boar, and 
 beaver in Britain) may have become extinct in the regions 
 where their exuviae are found. 
 
 779. What of the organic remains ? 
 
CHEMICAL AND MINERAL DEPOSITS. 231 
 
 EXPLANATORY NOTE. 
 
 EMBOUCHURE a term adopted from the French, signifying the mouth 
 of a river, or rather that area over which its current spreads as it enters 
 auy sea or lake. 
 
 FRESHETS, OR LAND-FLOODS, are sudden risings of rivers, by which 
 they inundate their banks, and carry destruction before them. The 
 term debacle (from the French debacler, to unbar) is often used instead ; 
 but more properly means a rush of water, breaking down all opposing 
 barriers, and carrying away and dispersing fiagments of rocks and 
 other debris. 
 
 VALLEYS OF EROSION are those which have been formed by the 
 abrading power of water. Rivers having a rapid descent gradually 
 deepen their channels; year after year their banks are undermined, 
 and fall into the current, until they have acquired a slope sufficiently 
 gentle to render them stable ; but this stability is only temporary, for 
 the deepening of the channel goes forward, causing the bank to assume 
 a still more gentle slope, till in time a valley of considerable width is 
 formed. Such are termed valleys of erosion, in contradistinction to 
 those produced by the silting up of chains of lakes, called flat valleys, 
 to those caused by subterranean sinkings, called valleys of depression, 
 or to those originally formed by rents and fissures resulting from earth- 
 quakes. 
 
 LAGOON (Lat., lacuna, a morass) a term originally applied to those 
 creeks and pools which abound along the coast of the upper Adriatic ; 
 but now employed to designate all similar collections of water, in 
 whatever region they occur. Lagoons are sometimes of considerable 
 depth (those enclosed by circular coral islands) ; but generally they 
 are so shallow (those of deltas) as to emit noxious exhalations. 
 
 STEPPES the Russian name given to the vast system of plains pecu- 
 liar to Northern Asia. It is synonymous with the prairies or savannahs 
 of North America ; and the pampas or ilhanos of South America. These 
 plains are variously classified, according to the level, undulating, or 
 swampy character of the surface, the kind of vegetation they produce, 
 and other obvious appearances. 
 
 SUPERFICIAL ACCUMULATIONS CONTINUED. 
 CHEMICAL AND MINERAL DEPOSITS. 
 
 287. Under this head are comprehended all those superfi- 
 cial accumulations of mineral, saline, or bituminous matter 
 arising from the action of springs, evaporization, subli- 
 mation, or other natural chemical processes. Such pro- 
 ducts are extremely numerous; but only a few of them 
 exert a perceptible influence in modifying the crust of the 
 globe. Calc-tujf and calc-sinter are deposited by calcareous 
 
 780. Define and explain the terms of the Note. 
 
 781. Define steppes, and give its synonymes. 
 
 782. What and where are chemical and mineral deposits? 
 
UROLOGY. 
 
 springs after the manner described in par. 53. The far- 
 mer, as the name tujfortufo, implies, is a porous vesicular 
 mass, soft when first deposited, but becoming hard on ex- 
 posure to the air, so as to resemble marble or alabaster. 
 It is generally of a yellowish-white, and encloses moss, 
 twigs, shells, fragments of bones, and other debris that may 
 be brought within reach of the spring by which it is de- 
 posited. The latter, from the German word sintern, to 
 drop, or from sinter, a scale, is more compact and crystal- 
 line, and has a concretionary structure, owing to the suc- 
 cessive films which are daily added to the mass. Both are 
 found around the sources and edges of calcareous springs, 
 sometimes spreading to a considerable extent, and not un- 
 frequently investing high cliffs with a crust of unrivalled 
 splendour. Stalactite and stalagmite are kindred produc- 
 tions, both being produced in calcareous caverns by the 
 dropping or oozing of water. The former (Gr., stalaktis, 
 anything which drops) are those pendents of carbonate of 
 lime which hang from the roofs of caverns like icicles; 
 they are formed by the slow dropping of calcareous water. 
 The latter (Gr., stalagma, a drop), on the other hand, are 
 the crusts and protuberances produced on the floors of such 
 caverns. Sometimes the stalactites and stalagmites meet, 
 forming pillars and arches which seem to support the roof. 
 Caverns adorned in this manner occur in Derbyshire, in 
 the islands of Paros and Antipar ;s, and in other parts of 
 the world, and have been described by travellers in the 
 most fascinating terms. Tavertine (a corruption of the 
 word Tiburtinus) is another calcareous incrustation, depo- 
 sited by water holding carbonate of lime in solution. It is 
 abundantly formed by the river Anio at Tibur, near Rome, 
 at San Vignone in Tuscany, and in other parts of Italy. 
 It collects with great rapidity, and becomes sufficiently 
 compact in a few years to form an excellent building stone. 
 " A hard stratum," says Mr. Lyell, " about a foot in thick- 
 ness, is obtained from the waters of San Filippo in four 
 months; and as the springs are powerful, and almost uni- 
 form in the quantity given out, we are at no loss to com- 
 
 783. Define the italicised terms of this page. 
 
CHEMICAL AND MINERAL DEPOSITS. 233 
 
 prehend the magnitude of the mass which descends the 
 hill, which is a mile and a quarter in length, and the third 
 of a mile in breadth, in some places attaining a thickness 
 of 2-50 feet. To what length it might have reached it is 
 impossible to conjecture, as it is cut off by a stream which 
 carries the remainder of the calcareous matter to the sea." 
 Tavertine is a light, porous, or concretionary rock, well 
 adapted for arches and other structures where weight is 
 objectionable; it is for this reason that it has been used in 
 the construction of the cupola of St. Peters. 
 
 288. Silicious and aluminous deposits derived from 
 springs are of very limited extent those produced by the 
 Iceland geysers, and the thermal waters of the Azores, 
 being the only examples deserving of notice. According 
 to Dr. Webster, the hot springs of the Valle das Furnas, in 
 the island of St. Michael, rises through volcanic rocks, 
 and precipitates considerable quantities of silicious sinter. 
 Around the circular basin of the largest spring there are 
 seen alternate layers of coarse sinter mixed with clay, in- 
 cluding grasses, fern, reeds, &c., in different states of petri- 
 faction. Wherever the water has flowed, sinter is found 
 rising eight or ten inches above the ordinary level of the 
 stream. The herbage and leaves are more or less incrusted 
 with silex, and exhibit all the successive stages of petrifac- 
 tion, from the soft state to a complete conversion into 
 stone; but in some instances alumina is the mineralising 
 material. Fragments of wood, and one entire bed, from 
 three to five feet in depth, composed of reeds common to 
 the island, have become wholly silicified ; and a breccia is 
 also an act of ibrmation, composed of obsidian, scori*, and 
 pumice, cemented by silicious sinter. The same kind of 
 appearances are produced by the geysers of Iceland and 
 several other thermal waters. Where alumina and silica are 
 held in solution by the same spring, the deposit produces an 
 admixture called lripoli,so named from Tripoli in Barbary, 
 where a. similar compound of silica, alumina, and oxide of 
 iron is abundantly obtained for polishing purposes. All the 
 
 784. What of silicious and aluminous deposits ? 
 
 785. Where are they found 1 
 
234 GEOLOGY. 
 
 varieties of tripoli do not seem, however, to be derived frotr. 
 the same source ; - f or Ehreriberg has found the flinty por- 
 tion of several varieties to be composed of the silicioua 
 coverings of animalcules. The fact of hot springs holding 
 silica in solution, its converting organic matter into flint, 
 and forming layers of tripoli and sinter, is of high import- 
 ance to the geologist, as it furnishes him with data to reason 
 respecting the origin of the chalk-flints, the occurrence of 
 layers and nodules of chert in limestone, and other appear- 
 ances among the older stratified systems. 
 
 289. Bituminous exudations that is, springs of naphtha, 
 petroleum, &c. are very abundant in some countries, 
 forming pools of fluid pitch and consolidated masses of 
 asphalte, and impregnating layers of sand, clay, &c., so as 
 to render them inflammable. Naphtha, the most limpid of 
 the bitumens, is found exuding from the earth upon the 
 shores of the Caspian and some other Eastern countries. 
 Near the village of Atniano, in the state of Parma, there 
 exists a spring which yields this substance in sufficient 
 quantity to illuminate the city of Genoa, for which purpose 
 it is employed. It is generally of a yellow colour, and is 
 readily distinguished Irom other bitumens by its peculiar 
 odour. Springs of petroleum, or rock oil, are found in 
 Modena, Parma, Sicily, and other parts of Europe, in Syria 
 and Persia, in the Burmari empire, in Texas, and in Bar- 
 badoes, whence the appellation Barbadoes tar. It is a 
 brown thickish liquid, and in this state readily mingles 
 with loose rocky substances, so as to render their mass 
 bituminous. On exposure to the air it becomes viscous or 
 slaggy, and then constitutes mineral pitch, of which the 
 lake of Trinidad, and that of Jefferson county, Texas, are 
 well-known accumulations. Asphalte differs from mineral 
 pitch in being so much consolidated as to be rendered 
 brittle. It is found on the surface and banks of the Dead 
 Sea, in Trinidad, Barbadoes, and other localities. It is 
 supposed that these products are sublimed or distilled froin 
 
 786. What of bituminous exudations ? 
 
 7S7. Deline naphtha and its sources, and uses. 
 
 78S. What of petroleum, asphalte, &c. ? 
 
CHEMICAL AND MlNfRAL DEPOSITS. ;> 
 
 bituminous rocks in the solid crust by the power of subter- 
 ranean heat, and gradually make their way through chinks 
 and fissures to the suriace. Whatever be the source from 
 which they are produced, the manner in which they mingle 
 with the layers now forming in the bottoms of lakes and 
 seas, furnishes the geologist with analogies which may aid 
 him in accounting tor the occurrence of bituminous strata 
 in which no traces of vegetation can be detected. 
 
 290. The economical uses of the bitumens are too well 
 known to require much detail. Asphalte was extensively 
 used by the ancients as a cement ; hence the name, which 
 is derived from the Greek, a, not, and sphallo, I slip that 
 is, something to stick together with, or prevent from slip- 
 ping. It is now used extensively in the manufacture of 
 materials for roofs, linings for water-cisterns, foot-pavements, 
 &c. Distilled naphtha is extensively employed as a solvent 
 
 . for caoutchouc, and is also occasionally used as a substitute 
 for oil in lamps. 
 
 PEAT-MOSSES JUNGLE VEGETABLE DRIFT. 
 
 291. Modern vegetable formations are commonly distin- 
 guished as subterranean forests, peat-mosses, jungle, and 
 vegetable drift, though it must be evident that in many 
 cases no real distinction can be drawn between them. 
 Submarine forests have been already noticed (par. 265) as 
 evidences of terrestrial submergence; subterranean forests 
 are those accumulations of trunks, branches, and roots 
 which occur inland, apparently produced by the inunda- 
 tion and subsequent silting up of low-lying tracts, in which 
 trees flourished abundantly. But as the subsequent silt is 
 most abundantly composed of aquatic and other peat-form- 
 ing planis, subterranean forests and peat-mosses may be 
 regarded as depending upon the same agency for their pro- 
 duction. It must be remembered, however, that peat-bogs 
 and mosses of very great extent are to be found in northern 
 countries entirely destitute of trees, having been formed by 
 
 789. How is it produced, and to what uses aplied ? 
 
 790 What are subterranean forests, and how produced ? 
 
 791. Wh.it of peat-mosses, j-mgles, and vegetable drift 1 
 
236 GEOLOGY. 
 
 the annual growth and decay of the sphagnum palustre and 
 other marshy vegetation. With respect to the amount of 
 vegetable matter derived from tropical jungles, no accurate 
 information has yet been obtained, though analogy would 
 warrant the conclusion that the result is too important to be 
 overlooked by geologists. The same may be said of vege- 
 table drift, of which the rafts of the Mississippi, already 
 adverted to, afford a striking example. It is therefore to 
 subterranean forests and peat-mosses that the attention of 
 the student is chiefly directed, these being by far the most 
 extensive of modern vegetable formations. 
 
 292. Subterranean forests are found in estuaries now 
 silted up, in ancient lakes, and under ordinary peat-bogs. 
 When they occur in estuaries or in low alluvial lands ad- 
 joining the sea, they would seem to have been drilled from 
 inland by river inundations; for most of the trunks and 
 branches lie in such a position as to forbid the supposition 
 that they grew in these situations. " A very interesting 
 case of this kind," says Professor Phillips, " was exhibited 
 some years ago by the deep cutting of a canal connected 
 with the Aire and Calder navigation. At a depth of twelve 
 feet from the surface of the fine alluvial sediment, here 
 occupying the broad valley of the Aire, a quantity of hazel 
 bushes, roots, and nuts, with some mosses, fresh-water 
 shells, and bones of the stag, were met with. In some 
 parts of the superjacent sediments an English coin was 
 found, and oars of a boat were dug up. Where a little 
 water entered this peaty and shelly deposit from the adja- 
 cent upper magnesian limestone, it produced in the wood a 
 singular petrifaction ; for the external bark and wood were 
 converted into carbonate of lime, in which the vegetable 
 structure was perfectly preserved. In like manner some 
 of the nuts were altered; the shell and the membranes 
 lining it were unchanged; but the kernel was converted 
 into carbonate of lime, not crystallized, but retaining the 
 peculiar texture of the recent fruit. In this particular case 
 no reasonable doubt can exist that the peaty deposit, full 
 
 792. What example is related ? 
 
 793. What geological inferences are drawn f 
 
PEAT-MOSSES JUXULE VEOETARLE DRIFT. 237 
 
 of land mosses, hazel bushes, and fresh-water shells, was 
 water-moved, and covered up by fine sediments from the 
 river and the tide." As with the example now quoted, so 
 with numerous accumulations of trunks, roots, and branches 
 of trees found in silted-up estuaries and in heads of bays 
 both along our own coasts, the shores of the Baltic, and 
 other sea-boards. Most of them have evidently been drifted 
 thither by rivers and tidal influences, although forests in 
 some low tracts may have been overthrown and buried by 
 inundations of the sea. When subterranean forests occur 
 beneath lake deposits, or under ordinary peat-bogs, they 
 point to causes by which the drainage of low woody valleys 
 has been choked up, and their surfaces covered with water, 
 so as to destroy the trees, and bury them by subsequent 
 accumulations and peat-growth. 
 
 293. Peat or turf, as it is often called is a natural 
 accumulation of vegetable matter, varying in age from last 
 year's growth to that which was formed several thousand 
 years ago, and in appearance from a loose fibrous mass of a 
 brown colour to a dark and compact substance resembling 
 lignite or brown coal. It is forming in all marshes by the 
 annual decay of aquatic vegetation, and is encroaching 
 upon shallow lakes by a similar process. The plants which 
 enter most abundantly into its composition are the sphag- 
 num palustre, or " peat-plant," a number of mosses, rushes, 
 reeds, and other marsh-loving tribes, crowned in some situ- 
 ations by heather, to whose antiseptic properties De Luc 
 ascribes the conservation and accumulation of the other 
 vegetable substances. Formations of peat have been vari- 
 ously classified : thus, common peat, composed of the stem, 
 leaves, and roots of marsh plants; woody peat, derived from 
 the branches, leaves, trunks, and roots of trees ; peat-turf, 
 the heathy turf which covers moorland districts ; hill-peat, 
 when formed on the sides of declivities; and peat-bog, when 
 it accumulates in hollow places, or on flat marshy surfaces. 
 Whatever distinctions may be made, the main facts con- 
 nected with their formation are the same they are indi- 
 
 794. What oftnrf and its origin 7 
 7P/V What varieties of peat T 
 ] 1 
 
CEOLOOV. 
 
 vidually th, J result of decomposed vegetation accumulate*! 
 under certain conditions and in particular localities. They 
 are to be met with in almost all temperate and cold moist 
 countries, whether in the northern or southern hemisphere. 
 They occur abundantly in Scotland and England, and con- 
 stitute a large proportion of the surface of Ireland. They 
 occupy vast tracts in the Netherlands, Germany, qnd Russia, 
 as well as in North America and Canada, and are to be 
 found in insular regions, as Shetland, Iceland, and the 
 Falkland Islands. Oi the absolute surface occupied by peat, 
 we have no accurate estimate; but some idea of the geo- 
 logical importance of the formation may be formed from the 
 fact, that one of the mosses on the Shannon is fifty miles 
 long, and from two to three in breadth, while the great 
 marsh of Montoire, near the mouth of the Loire, is not less 
 than fifty leagues in circumference. Some of the Scottish 
 mosses have been dug for fuel to the depth of twenty feet, 
 and many in Ireland are reckoned at twice that thickness. 
 It must be borne in mind, however, that nearly one half 
 of the bulk is made up of water, and that the mass can be 
 reduced by compression to less than a fifth of its original 
 thickness. 
 
 294. The formation of peat, as has been stated, is con- 
 fined to moist situations, where the temperature is low, and 
 where vegetables may decompose without putrefying. It is 
 thus found in swamps, and on declivities where springs 
 abound, almost entirely composed of marsh plants; in the 
 sites of ancient lakes, covering layers of gravel, marl, silt, 
 &c. and mingled with earthy impurities ; or in low tracts 
 whose drainage has been choke'd, burying, and in part 
 formed of, the trunks and branches of trees which flou- 
 rished upon those spots previous to their inundation. It 
 increases with astonishing rapidity, instances having been 
 known where fifteen inches in thickness had been formed 
 in twenty years. Being light and spongy, full half its bulk 
 is composed of water, and tins retentive quality enables 
 new races of plants to flourish long after the surface of the 
 
 796. What peculiarities in relation to peat ? 
 
 797. What of the formation of peat T 
 
PF.A P-MOSSES JUNGI.F. VEGETABLE DRIFT. 
 
 moss has been raised above the drainage-level of the flat in 
 \vhich it occurs. When the mass has sufficiently accumu- 
 lated to change its character from that of a shaking morass 
 to a firm peal-bed, the marsh plants die out, and are suc- 
 ceeded by heatrfand other vegetation, which carry on the 
 process of accumulation at a less rapid but still perceptible 
 rate. Such is the ordinary mode of peat-growth, concern- 
 ing which there can be no difference of opinion, for many 
 of the accumulations are still in progress; but respecting 
 those collections of trees which are often found buried in 
 the mass, geologists are far from being agreed. From the 
 varied situations in which such collections occur, as well 
 as from the different positions in which the trunks are found 
 in the mass, it is evident that different agencies have been 
 at work in their aggregation. In river valleys, the trees 
 sometimes appear to have been drifted, and subsequently 
 silted up and covered by peat-growth ; in general, however, 
 they have evidently grown where they occur, and been 
 prostrated either by natural or artificial causes. If, for ex- 
 ample, the drainage of a wooded valley were obstructed, so 
 as to render the soil wet and "swampy, the further growth 
 of the forest would be checked ; the trees, deprived of their 
 firm anchorage in the ground, would be easily overturned 
 by winds; and as they were pro.-; rn ted, grasses, reeds, and 
 marsh plants would spring up through their branches, and 
 grow rank upon the nourishment ai.'orded by their decay. 
 This prostration of trunks and matting of vegetation would 
 further obstruct the drainage of the waters, so that in pro- 
 cess of time the whole of the trees would be overturned, 
 and the valley converted into a swampy morass. In such 
 a morass peat plants would luxuriate till, by their own 
 growth and decay, they reached a height beyond that of 
 the drainage-level, when their accumulation would cease, and 
 a peat-moss be completed perfectly analogous to many of 
 those in Ireland and Scotland. The same result would fol- 
 low whether the trees were prostrated by natural or artificial 
 causes; and there is eyidence afforded by the trunks in 
 many localities thit they were felled by man at no very 
 
 798. What geological reasoning is here 1 
 
240 GEOLOGY. 
 
 distant era. In the peat of Hatfield Chace, for instance 
 Roman coins and axes have been found, some of the latter 
 still fixed in the wood : a rnedal of Gordian was found 
 thirty feet deep in peat at Groningen ; and De Luc has 
 ascertained that the very site of the aboriginal forests of 
 Hercinia, Senaar, Ardennes, &c. are now occupied by 
 mosses- and fens a result chiefly brought about by the 
 Emperor Severus, who ordered all the wood in the con- 
 quered provinces to be destroyed. From these facts, the 
 student will perceive how necessary it is to examine the 
 mode in which the trunks occur, before the geologist can 
 venture to pronounce as to their collection. If the trees 
 are cut and hewn, man must have been concerned in their 
 prostration ; if they are merely broken over, or still attached 
 to their roots, natural causes alone have been at work. In 
 general, the smaller branches have decayed, leaving the 
 trunk and larger limbs, with fragments of the bark and the 
 root, in good preservation. The trees are principally oak, 
 fir, yew, hazel, birch, ash, and willow ; they lie prostrated 
 most abundantly towards the east and northeast ; and are 
 often of very gigantic dimensions. The greater number 
 seem to have undergone considerable decomposition be- 
 fore they were fully enveloped in peat-growth ; shewing 
 clearly that though the whole iace of a country were covered 
 by prostrated forests, it would only be in marshes and peat- 
 forming hollows that the trunks could be preserved from 
 utter decay. 
 
 295. Respecting the antiquity of peat-mosses, we can 
 form a tolerably correct idea from the nature of their im- 
 bedded fossils. The most ancient have been formed since 
 the sea and land received their present configuration, and 
 since the latter was peopled by those animals which now 
 inhabit it ; for from none have we well authenticated speci- 
 mens of greater antiquity than the existing elk, deer, wild 
 ox, buffalo, &c. Indeed the greater proportion of Euro- 
 pean morasses are of comparatively recent formation, yield- 
 ing the canoes and skeletons of the hair-clothed aborigines 
 
 799 Name some of the examples cited. 
 800. What of their antiquity ? 
 
PEAT-MOSSES JtNGLK VKGT. TABLE DRIFT. 241 
 
 the coins, axes, and other implements of their Roman 
 invaders tlie bones and horns of the elk, deer, ox, and 
 other animals with which we are still iamiliar. Many have 
 even been formed, as it were, but yesterday; for we learn 
 that the overthrow of a forest by a storm about the middle 
 of the seventeenth century gave rise to a peat-moss near 
 Lochbroom in Ross-shire, where, in less than half a cen- 
 tury after the fall of the trees, the inhabitants dug peat. 
 Whatever be their relative antiquity, they are all possessed 
 of great interest, from the evidence which they afford of the 
 rapid accumulation of vegetable growth, and from the per- 
 fect manner in which their tannin or antiseptic principles 
 have preserved the remains of man and the lower animals. 
 \Ve cannot look upon the vast collection of trees which 
 they contain, without being reminded of a period when 
 Britain was clothed with gigantic forests; on the rude stone 
 hatchets, canoes, and skeletons of men clad in skins, with- 
 out reverting to the condition of our earlier ancestors; or 
 on the coins, arms, and other implements of the Romans, 
 without associating therewith the means by which a rude 
 and barbarous country was reclaimed to culture and civili- 
 zation. 
 
 2=)6. The economical applications of peat constitute one 
 of its most important features. Cut in rectangular pieces, 
 and dried bv the heat of summer, it forms in many districts 
 the principal fuel, not only for domestic use, but for burn- 
 ing lime, heating corn and malt kilns, distilling alcohol, 
 &,c. To facilitate the process of drying, the water is some- 
 times pressed out of the square pieces by a compressing 
 machine, which also renders the material more compact 
 and durable in the fire. Peat is occasionally charred by 
 a smoihered combustion, which makes it a more suitable 
 substitute toi coal or coke in the smelting of iron and simi- 
 }-r purposes. Attempts have also been made to extract 
 tannin from its mass, to be used instead of oak and larch 
 bark in the preparation of leather. Decomposed peat forms 
 
 801. What geological and historical inferences here 7 
 
 802. What of its economical uses? 
 
GF.OLOOV. 
 
 an excellent mnmire for certain soils, and is now exten- 
 sively employed in modern agriculture. 
 
 SHFLL-BEDS, CORAL-REEFS, &C. 
 
 297. Th, animal accumulations of the present day, like 
 those of former era?, are chiefly discernible in the exuviae; 
 of shell-fish and coral animalcules. It is true that the re- 
 mains of fishes, insects, birds, and mammalia, are constantly 
 being entombed in the deposits now taking place; but, in 
 point of quantity, these are too insignificant to constitute 
 an independent stratum. Such remains must not, how- 
 ever, be overlooked, as their presence in any deposit will 
 indicate to future geologists the condition of the world 
 under which the animals flourished, just as the fossils of 
 older formations are the characters by which we can inter- 
 pret the conditions of the past. Besides the gradual en- 
 tombment of organisms which takes place in the ordinary 
 course of nature, there are extraordinary causes by which 
 hundreds and thousands of living beings are destroyed and 
 buried in common ruin. The desolation of populous cities 
 by earthquakes, the destruction of flocks and herds by simi- 
 lar catastrophes or by river inundations, the death of shoals 
 of fishes by submarine exhalations, the drowning of clouds 
 of locusts, and the like, will present curious appearances in 
 the accumulations in which they are imbedded; and it is 
 necessary thnt the student should bear such possibilities in 
 mind, otherwise he might be unable to account for peculiar 
 aggregations of fossils in older strata. 
 
 298. Shell-buds are accumulations of dead and living 
 shells found under the waters or along the shores of exist- 
 ing seas and lakes. Dead or drifted shells are strewn over 
 certain localities in considerable quantities by tidal and 
 other currents; fresh-water varieties are found in lakes con- 
 stituting beds of marl; and many gregarious species cover 
 large tracts of the bottom of the ocean. Dead shells are 
 
 803. What are the chief animal accumulations 1 
 
 804. To what agencies are the variety of fossils ascribed I 
 
 805. What of shell-beds, living and dead 1 
 
SHELL-BKDS, t'OKAL-HKKFS, &,C. 243 
 
 thus mingled indiscriminately genera inhabiting widely 
 different localities, and of the most opposite character, being 
 found in the same mass. A veiy different arrangement holds 
 with respect io living shells, particularly with those of a gre- 
 garious character; as the muscle, cockle, and oyster. These 
 live in beds or families, and seem to be governed in their 
 growth and accumulation by circumstances of depth, nature 
 of the bottom, and food, just as terrestrial animals are regu- 
 lated by climate and other vital conditions. Thus, cockles 
 and muscles delight in the muddy bottoms of tidal estuaries, 
 where the latter often form beds of two or three feet in 
 thickness, and several miles in extent; while the oyster, at 
 no great depth from the sea-shore, covers the bottom for 
 many leagues, to the exclusion of all other genera. Should 
 such estuaries ever be silted up and there is ample evi- 
 dence of like occurrences these shells would form strata 
 precisely analogous to those beds of shell-limestone which 
 are found among the inferior coal measures, the new red 
 sandstone, and other rock formations. Such, in fact, is the 
 case; and in many estuary and lacustrine deposits shell- 
 b^ds present themselves partially converted into .marl and 
 limestone; while in raised beaches they invariably consti- 
 tute the most interesting phenomena. 
 
 299. One distinction between the, position of ancient and 
 recent shell-beds requires, however, to be specially adverted 
 to. It has been ascertained that various genera of mollusca 
 live at different depths, constituting zones of marine life 
 analagous to zones of vegetable growth on the side of a 
 mountain. By this distribution certain families are littoral, 
 others live at depths varying from 100 to 600 feet, while 
 few or any are found in 1000 feet water. In general terms: 
 testaceous animals are regulated in their distribution by 
 depth, by the nature of the sea-bottom, and by the influ- 
 ence of submarine currents; the number of families is 
 greatest in shallow waters, gradually decreases as we de- 
 scend, and finally sinks to zero in the depths of the ocean. 
 Such an arrangement corresponds with all our ideas of 
 vitality : shell-fish can no more subsist under the pressure 
 
 806. Whit of tho variety ,n depths ? 
 
244 <;".oi,"f,r 
 
 of extreme depth, ;:bse;ice of ,Lght and f>od, than plants 
 can flourish in the thin cold atmosphere of highly elevated 
 regions. On examining the crust of the earlh, however, 
 strata wholly and partially composed of shells are found 
 covered by many thousand feet of rocks; but as the ani- 
 mals by which the shells were formed could not have ex- 
 isted at such depths, we are led to the conclusion that these 
 shelly beds were formed at moderate depths, that the bottom 
 of the sea was subsequently depressed, and received those 
 sediments of which the overlying strata are composed. 
 Strata destitute of organisms do not therefore prove the 
 non-existence of marine life at the time of their formation ; 
 they may have been formed at depths so enormous as ex- 
 cluded the mingling of testaceous remains with their com- 
 ponent materials. 
 
 309. Carol reefs, already adverted to in pars. 95 and 86, 
 are chiefly the production of the coral animalcule, and 
 evince, by their magnitude and extent, the powers of or- 
 ganic agency in modifying the form and structure of the 
 earth's crust As in the case of the sphagnum palustre 
 and other marsh plants, whose growth and decay went to 
 the formation of peat-moss, so among corals race after r;ice 
 departs, each leaving its stony skeleton as a foundation for 
 the operations of succeeding races, which are destined to 
 make way in turn for still newer generations. According 
 to Ehrenberg, the coral zoophyte miy be regarded as a 
 mere secreting membrane, having the power of separating 
 calcareous matter from the waters of the ocean, wherewith 
 to fashion for itself an internal solid skeleton of carbonate 
 of lime. Around and within the radiated pores of this 
 frame work the animalcule lives and propagates its kind, 
 expanding itself in the most brilliant colours during its 
 secreting operations, and contracting and withdrawing itself 
 within the pores when alarmed by danger. Although often 
 exhibiting the most beautiful hues crimson, blue, and 
 yellow in their native element, the soft parts, when taken 
 
 807. What geological reasoning upon this ? 
 
 808. What of coral reefs 1 
 
 809. What of the coral zoophyte ? 
 
 810. In what varieties are they found f 
 
SHELL-IHUM, 
 
 from he sea, become nothing m;>re to appearance th ; m a 
 brown slime spread over the stony framework. These zoo- 
 phytes swarm in incredible numbers, and are of many genera 
 aadsnb-genera each spe- 
 cies building for itself a 
 structure peculiarly fash- 
 ioned and decorated. Ac- 
 cording to their forms the 
 various genera are com- a: 
 inonly determined, and 
 thus we have such terms as 
 tree, fan, brain, star, and 
 organ-pipe coral, known to 
 the learned by their syno- 
 nymes caryophyllia, me- 
 andriua, astrsea (see fig.), 
 porites, madrepora, tubi- Mass of Astraeaviridis; a, a, expanded 
 
 pora, and the like. As with P ol yP e , s ! 6 > * Hypes withdrawn 
 .' , into their cells; c, c, stony mass 
 
 shell-hsh, so with coral am- uncovered by flesh, 
 rrials ; they do not inhabit 
 
 extreme depths, but generally carry on their operations along 
 the shores of rocky islands and on the tops o! submarine ridges 
 not more than one or two hundred feet under water. Indeed 
 the principal reef builders are rarely found beyond the depth 
 of f >rty or sixty feet, though solitary branching corals have 
 been dredged in fifty and even a hundred-fathom water. 
 Generally speaking, it would appear that the coral polype 
 has not the power of commencing its structure at great 
 depths, but attaches itself to comparatively shallow points 
 within the influence of those conditions favourable to its 
 development. 
 
 33 1. C<rral polypes in active operation are thus de- 
 scribed by Captain Basil Hnll : " When the tide has left 
 the rock tor some time dry, it appears to be a compact mass, 
 exceedingly hard and rugged; but as the tide rises, and the 
 waves begin to wash over it, the polypi protrude themselves 
 
 811. Describe the diagram. 
 812 What of deep and shallow water? 
 813. What description of their work is h"- f 
 11* 
 
246 GEOLOGY. 
 
 from holes which were before invisible. These animals are 
 of a great variety of shapes and sizes, and in such pro- 
 digious numbers, that in a short time the whole surface of 
 the rock appears to be alive and in motion. The most 
 common form is that of a star, with arms or tentacula, 
 which are moved about with a rapid motion in all direc- 
 tions, probably to catch food. Others are so sluggish that 
 they may be mistaken for pieces of the rock, and are gene- 
 rally of a dark colour. When the coral is broken about 
 high-water mark, it is solid hard stone; but if any part of it 
 be detached at a spot where the tide reaches every day, it is 
 found to be full of polypi of different lengths and colours ; 
 some being as fine as a thread, of a bright yellow, and 
 sometimes of a blue colour. The growth of coral appears 
 to cease when the worm is no longer exposed to the wash- 
 ing of the sea. Thus, a reef rises in the form of a cauli- 
 flower till the top has gained the level of the highest tides, 
 above which the animalcules have no power to advance, 
 and the reef of course no longer extends upwards." 
 
 302. The composition and construction of coral reefs, 
 though effected chiefly by lime-secreting zoophytes, are 
 still owing, in a great measure, to the pro:; iscuous aggre- 
 gation of marine debris. As produced by the zoophyte, 
 coral is almost a pure carbonate of lime, soft and porous 
 at first, but gradually becoming so hard and compact as to 
 he used in the South-Sea islands for building. During its 
 formation, however, it encloses shells, fragments of drift- 
 coral, sea-weeds, star-fishes, sea-urchins, drift-wood, and the 
 like; and these being cemented in one mass by the growth 
 of new coral, as well as by the infiltration of dissolved 
 carbonate of lime, the rock presents a brecciated appear- 
 ance extremely analogous to some older lime-stones. Where 
 reefs have been upheaved by subterranean agency, and are 
 now found on the sides of hills partially overlaid by vol- 
 canic tufa, the coral-stone has a sparry semi-crystalline 
 aspect, thus presenting the geologist with almost every 
 gradation of limestone, from the soil chalky mass of yester- 
 tiay's secretion to the compact texture of primary marble. 
 
 814. How do corals vary in composition ? 
 
SHELL-BED*, CORAL-REEFS, &.C. 247 
 
 303. The formation of enrol islands is effected in the 
 following manner: The polypes having attached them- 
 selves to the rocky bottom say on the summit of some 
 submarine ridge proceed to build upward and around, 
 till the reef remains almost dry at low-water level. Here 
 they leave off building in an upward direction, but still 
 proceed seaward, increasing the breadth of their structure, 
 and gradually bringing these additions up to the surface, 
 A continuous mass of calcareous matter is now seen, com- 
 posed principally of coral, but also abundantly of shells, 
 fragments of Crustacea, and other sea-drift. As the waves 
 break upon the new elevation, fragments are detached and 
 thrown up, shells and coral sand are washed upon the reef, 
 and these being cemented together by calcareous matter, 
 form a low ridge exposed to the influences of sun, winds, 
 and rains. In this state rents and fissures take place in the 
 mass, new fragments are detached by the waves, and piled 
 still higher: a perpetual rubbing and grinding of the frag- 
 ments produces calcareous sand, which is gradually drifted 
 upwards and inwards, filling inequalities, and forming in 
 sheltered recesses a narrow beach. Upon this new territory 
 sea-birds alight, nestle, and leave their droppings ; sea- 
 weeds and other marine drift are added ; a scanty soil is 
 formed ; seeds are drifted or borne by birds from the ad- 
 jacent continents ; plants spring up, and in course of years 
 clothe the infant island with vegetation. By this time 
 strayed land-birds have made it their home; insects and 
 reptiles are carried thither upon drifted trees, either alive 
 or in the larva or egg state ; and lastly, man appears, and 
 takes possession of the gradually increasing soil. Such a 
 mode of formation supposes no elevation or submergence 
 of sea-bottom by volcanic action. But in the Pacific, where 
 coral reefs are most extensively developed, subterranean 
 movements are frequent elevating in some regions, and 
 depressing in others. Thus, a gradual elevation would 
 cause not only a more rapid rise of reef, but would force 
 
 815 What of coral islands? 
 
 816. Whit of the agencies employed ? 
 
 817. What of subterranean or volcanic forces? 
 
243 
 
 the polype to opeiate continually further seaward, so that 
 the mass would assume a broad and stratiform appearance. 
 A gradual depression, on the other hand, would not only 
 lessen the supermarine extent of the reef, but would com- 
 pel the animalcules to build perpendicularly upwards, in- 
 stead of laterally, as in the case of elevation. From the 
 peculiar forms which coral reefs assume, it is more than 
 probable that both elevations and depressions are in pro- 
 gress over the bottom of the Pacific ; of the former, at least, 
 there is ample evidence in ancient reefs occurring inland 
 and at considerable elevations above the sea. Thus, on the 
 summit of the highest mountain of Tahiti, an island com- 
 posed almost entirely of volcanic rocks, there is a distinct 
 stratum of fossil coral ; and in the Isle of France, a bed 
 ten feet thick occurs between two lava currents. 
 
 304. The various forms which coral retfs present are 
 classed by Mr. Stutchbury in the following order: I. 
 Circular, consisting of a strip or belt encircling a lagoon, 
 wliioh comrnmunicates with the main ocean by one or more 
 channels ; 2. Flat, consisting of a tabular, oval, or irregu- 
 larly round mass, not intersected by channels or lagoons; 
 3. Long-narrow, consisting of long narrow ridges or islands, 
 with cross channels at irregular intervals; 4. Encircling 
 high land, but separated from it by a deep concentric chan- 
 nel with several openings into the main sea. To account 
 for these peculiar configurations, which are very persistent 
 over the whole of the Pacific, various hypotheses have been 
 advanced, all more or less involving the idea of subterra- 
 nean movements, to which that region is known to be 
 subjected. First, Circular reefs or atolls are supposed to 
 be founded upon submerged volcanoes the edges of the 
 crater forming a basis for the coral, and its interior depth 
 the lagoon. The coral islands of the dangerous Archipe- 
 lago are all of this kind, and consist of circular belts from 
 400 yards to one mile across the ring, which always en- 
 close a lagoon. They are seldom raised more than four 
 or six feet above the water; are abrupt towards the ocean, 
 
 818. What variety of form in coral reefs t ^ 
 
 819. How are these accounted for 7 
 
SHELL-BEDS, roK AL-UKEF>, &C- '249 
 
 which rapidly deepens to mure than 190 fathoms; vary from 
 two or three to 150 miles across; and are intersected by 
 deep channels, which allow a free communication between 
 the ocean and the lagoons. The bottoms of the latter are 
 often strewed with dead shells and fragments of coral ; 
 sometimes contain smaller reefs, and give birth to numer- 
 ous corallines, sponges, and shell-beds. The subjoined 
 engraving represents the atoll form, with its enclosed 
 lagoon : 
 
 Distant view of a coral island, with its enclosed lagoon. 
 
 Second, Flat or tabular reefs are founded upon some ele- 
 vated portion of the sea-bottom ; they have no lagoons or 
 channels, but form solid islands of coral, which in pro- 
 gress of time become covered with sand, soil, and other 
 debris. Reefs of this kind often exhibit lines of stratifica 
 lion in their mass, owing to the drifting of sand, shells 
 &-c., over their flat surface during the time ol formation. 
 Third, Long narrow reefs, which are of common occur- 
 rence, are evidently founded upon submarine ridges, inter- 
 rupted by irregularities" and depressions such depressions 
 causing the channels or gaps by which they are intersected. 
 Many of this class are of great length: Captain Flinders 
 describes one on the east coast of New Holland not less 
 than 350 miles, unbroken by any channel. Fourth, Reefs 
 encircling high land, but separated from it by a narrow 
 
 820. Explain the diagram 1 
 
 821. Explain the formation of each variety. 
 
250 GEOI.QPT. 
 
 channel, indicate a submergence of the islands which they 
 surround At their commencement they must have been 
 in connexion with the shore; a submergence, however, 
 would remove them from it, inasmuch as the waters would 
 cover them, and find a new shore farther inland. In their 
 new position, the zoophytes would build upwards, forming 
 perpendicular masses separated from the land by a greater 
 or less expanse of water, according to the amount of sub- 
 mergence, and the abrupt or gentle ascent of the land. 
 This class is beautifully illustrated by the reefs which 
 encircle the islands Raiatea and Tahaa : 
 
 Such are the general forms in which coral islands appear ; 
 though it must be observed that points of attachment are 
 afforded by many portions of sea-bottom upon which reefs 
 are reared after fashions the most grotesque and irregular. 
 395. The extent and magnitude of coral reefs are so 
 great, as to be put in comparison with those of the older 
 calcareous formations. They throng the Pacific over a 
 space comprehended between the 30th degree of latitude 
 on each side the equator ; the Arabian and Persian Gulfs 
 abound in the same formation ; so, also, the Indian Ocean 
 between Madagascar and the Malabar coast. Captain 
 Flinders describes the great reef which follows the line of 
 the north-east coast of New Holland as more than 1000 
 miles in lengih, in course of which there is one continued 
 
 822. What of the diagram ? 
 
 823. Where are they, and wnat of their extent 7 
 
 824. What example is named ? 
 
SOILS. 2.">1 
 
 portion exceeding 350 miles, without a break or passnge 
 through it. The thickness of the mass is variable in 
 some instances less than twenty feet, and in others more 
 than a hundred. Estimating the average at thirty or forty 
 feet, and taking into account the vast length to which coral 
 ridires extend, they constitute an amount of calcareous 
 matter equal to any of the older limestones, the carbo- 
 niferous alone excepted. 
 
 306. The growth of coral is by no means rapid; for ob- 
 jects long submerged have been dredged up merely covered 
 with a thin incrustation. It is stated in Captain Beechey's 
 Expedition to the Pacific, that no positive information could 
 he obtained of any channel having been filled up by coral 
 within a given period, and that several reefs had remained 
 for more than half a century at about the same depth from 
 the surface. By others, it has been estimated that the in- 
 crease of a reef is generally from four to six inches in one 
 hundred years; but this is little better than conjecture; for 
 although the growth of coral by itself be a comparatively 
 slow process, yet, by the accumulation of shells, broken 
 coral, and other dri r t, a reef may augment at a more rapid 
 rate. Whatever the rate of growth, the process of augmen- 
 tation is incessant ; and thus, in the course of centuries, 
 have the reefs and islands of the Pacific risen above its 
 waters. The student must not, however, confound eleva- 
 tion above the ocean wilh strict increase of coralline matter; 
 because there is every reason to conclude that vast areas of 
 the Pacific are undergoing a gradual upheave, by which 
 submarine reefs and ridges are continually being brought 
 to the surface, and existing islands further enlarged and 
 elevated. 
 
 SOILS. 
 
 307. The superficial coating of the earth on which plants 
 hare grown and decayed is properly denominated " soil." It 
 is chiefly composed of inorganic substances that is, of 
 clay, sand, lime, &c. with an admixture of decomposed 
 
 825. What of the growth of coral ? 
 
 R26. To what other agencies is increase ascribed T 
 
 827. What of soil and its composition T 
 
252 GKULOGY. 
 
 vegetable and animal matter. There is scarcely a portion 
 of the earth's crust entirely destitute of this covering, unless 
 it be the snow-clad peaks of the loftiest mountains, the 
 newly-deposited debris on the sea-shore, or the shifting 
 sands of the desert. However slight the admixture of or- 
 ganic matter may be, its presence constitutes soil, beneath 
 which is the subsoil, comparatively or altogether without 
 such admixture, and therefore justly classed as clay, sand, 
 gravel, lime, or mixed earth, as the case may be. Soil 
 subserves most important purposes in the economy of cre- 
 ation ; without it there could be no succession of vegeta- 
 tion ; without a succession of plants terrestrial animals could 
 have no subsistence. 
 
 308. The formation of soil is of easy comprehension. 
 Suppose a tract variously composed of clay, sand, lime, and 
 other primitive earths to be elevated above the waters, its 
 mass would soon become dry and compact, and being alter- 
 nately subjected to the sun and showers of summer, and to 
 the frosts of winter, its superficies would be rendered loose 
 and friable. Over this expanse birds would fly and animals 
 roam, mingling their droppings with the earth, and adding 
 their carcases and other exuviae ; the winds would carry the 
 seeds of plants from other regions, and these springing up, 
 would clothe patches of the waste with a scanty vegetation. 
 Mosses, lichens, and other lowly forms would spread over 
 the rocks and gravel, the arundo areriaria, elymus, &c. over 
 the sands, the sphagnum and other aquatic tribes in the 
 marshes, and grasses on the silts and richer portions. The 
 annual growth and decay of these plants would soon form 
 a covering of vegetable mould, enriched by the droppings 
 and exuviaa of animals which fed upon them; and thus in 
 process of time would the region present varieties of soil 
 capable of supporting the highest forms of vegetation. We 
 see such a formation every day taking place ar und us; 
 naturally, in those districts unreclaimed by agriculture, and 
 artificially, where manures are added to promote its fer 
 
 828. How is soil and subsoil distinguished ? 
 
 829. Describe the sources of the formation of soil. 
 
 830. What of natural and artificial soil? 
 
son?. 
 
 til it v. Independent of its utility to the vegetable and ani- 
 mal economies, soil is of great geological importance, inas- 
 much as it lessens the amount of degradation to which the 
 crust is exposed. Without the conservative influence of 
 the turf which protects the subsoils, every shower and 
 stream would wash away vast quantities of the loose ma- 
 terial, whereas the lightest sand is secure from abrasion 
 beneath the thinnest grassy covering. 
 
 309. Though the character and variety of soils is more 
 the study of agriculture than of geology, it may be useful 
 for the student to know the distinctions which have been 
 made by recent writers on the subject. The inorganic 
 portion of soils consists of what are called the primitive 
 earths namely, clay, silex or sand, lime, and magnesia 
 and of certain saline and metallic compounds, such as com- 
 mon salt, gypsum, soda, potash, and the oxides of iron and 
 manganese. The organic constituents are decomposed 
 vegetable and animal matters, the progressive decomposi- 
 tion of which, in conjunction with inorganic substances, 
 air, and water, furnish chemical compounds of humus, car- 
 bon, ammonia, &c. all of which are essential to the per- 
 fection of vegetable growth. Sand and clay being the 
 bulky components of soils, a soil is said to be sandy when 
 it contains no mote than 10 per cent, cf clay; a sandy 
 loam if from 13 to 40 per cent, of clay; and loam if from 
 40 to 70 per cent. On the other hand, should the clay 
 average from 70 to 85 per cent , it is denominated a clay 
 loam; from 85 to 95, a strong clay; and if no sand be pre- 
 sent, it is pure agricultural clay. The same sort of dis- 
 tinctions are made when lime is present in considerable 
 abundance 5 per cent, of carbonate of lime constituting a 
 marl, and 20 per cent, a calcareous soil. Where soils are 
 immediately derived from the rocks beneath, they partake 
 of the same chemical character ; and where separated by 
 layers of sand, clay, and gravel, they are still influenced in 
 their capacities for moisture by the porous or open texture 
 of the subjacent strata. There is thus an intimate con- 
 
 831. What of inorganic and organic portions! 
 
 832. What of varieties in soil 1 
 
254 GEOLOGY. 
 
 nexion between the deductions of geology and agriculture 
 a connexion which will be more fully pointed out in a 
 subsequent section. 
 
 EXPLANATORY NOTE. 
 
 ALABASTER a white semi-transparent variety of gypsum, or sul- 
 phate of lime. It is a mineral of common occurrence, and is manu- 
 factured into ornamental vases, and occasionally into small statues. 
 The ancients used it for ointment and perfume boxes. 
 
 MINERAL NAPHTHA is generally found of a yellowish colour, but may 
 be rendered, colourless by distillation. Its specific gravity is about 
 three-fourths that of water ; it boils at 160 degrees ; and appears to 
 be a pure hydro-carbon, consisting of 36 of carbon and 5 of hydrogen. 
 It is highly inflammable, and burns with a white smoky flame. A 
 liquid very similar to mineral naphtha is obtained by the distillation of 
 coal-tar. 
 
 PROSTRATION OF TREES It has been stated that the trunks found in 
 British peat-mosses are most abundantly prostrated towards the east 
 and nortli-east. This is just what might be expected where the trees 
 have bei n overthrown by natural forces ; for not only are our most 
 prevalent winds from the west and south-west, but our highest and 
 most destructive gales are also from the same quarters. 
 
 CORAL. Some varieties of this substance have long been in request 
 for ornamental purposes their value depending upon the size, solidity, 
 and colour of the specimen. Black and red varieties are the most 
 highly prized, portions of Sicilian coral having been known to bring 
 so much as eight or ten guineas per ounce. The price, however, is 
 extremely variable, other portions of the same mass selling for less 
 than a shilling a pound. Regular coral fisheries are established in the 
 Straits of Messina, on the shores of Majorca and Minorca, the coast of 
 Provence, and in other parts of the Mediterranean. Abundant sup- 
 plies are also obtained from the Red Sea,' the Persian Gulf, the coast 
 of Sumatra, &c. 
 
 SUPERFICIAL ACCUMULATIONS CONTINUED. 
 EARTHQUAKES AND VOLCANOES. 
 
 310. The effects produced by earthquakes, in as far as 
 elevations and depressions of the earth's crust are concerned, 
 have been already alluded to, but the various results by 
 which they are followed require further attention. An 
 earthquake may produce a momentary undulation of the 
 ground, followed by no perceptible result ; it may simply 
 elevate one region or depress another; it may be attended 
 by a vast destruction of animal life, and the submergence 
 
 833. Define and explain the terms of the note. 
 
 834. What various effects are ascribed to earthquakes ? 
 
FARTITQrAKFS AND VOU \\OF.S. l2.>.> 
 
 of f< rests; it may alter the course of rivers, and produce 
 new shores and beaches; it may create vast tidal waves, 
 which give rise to accumulations of debris; open new 
 springs and fissures, from which issue various products 
 differing from those hitherto known in the district. In- 
 nuir.erable instances of such changes could be cited ; a 
 feu, however, will suffice to convince the student of the 
 importance of this class of geological agencies: By the 
 gre?.t Chili earthquake of 1822, an immense tract of ground 
 not less than 100,000 square miles was permanently 
 elevated from two to six feet above its former level ; and 
 part of the bottom of the sea remained bare and dry at h.gh 
 wH-er, with beds of oysters, muscles, and other shells ad- 
 hering to the rocks on which they grew, the fish being all 
 de; d, and exhaling most offensive effluvia. By an earth- 
 quake in 1819, a tract the Ullah Bund in the delta of 
 the Indus, extending nearly fifty miles in length and sixteen 
 in breadth, was upheaved ten feet; while adjoining districts 
 were depressed, and the features of the delta completely 
 ai'ered. So also with the valley of the Mississippi in 1811, 
 which, from the village of New Madrid to the mouth of 
 the Ohio, was convulsed to such a degree as to create lakes 
 and islands. The earthquakes of Calabria, which lasted for 
 nearly four years from 1783 to the end of 1786 produced 
 numerous fissures, landslips, shifts or faults in the crust, 
 new lakes, ravines, currents of mud, falls of the sea-cliffs, 
 and other changes, which, taken in conjunction, afford the 
 geologist one of the finest examples of the complicated 
 alterations which may result from a single series of sub- 
 terranean movements, even though of no great violence. 
 In 1743 the town of Guatimala, in Mexico, with all its 
 riches and eight thousand families, was swallowed up, and 
 every vestige of its former existence obliterated ; the spot 
 being now indicated by a frightful desert four leagues dis- 
 tant from the present town. In 1692 a similar calamity 
 overtook the town of Port Royal, in Jamaica, when the 
 whole island was frightfully convulsed, and about 1000 
 acres in the vicinity of the town submerged to the depth of 
 
 835. What examples are cited 1 
 
250 
 
 fifty feet, burying the inhabitants, their houses, and the ship- 
 ping in the harbour. Such examples might be multiplied 
 indefinitely, even within the limits of the historic period; 
 but enough has been quoted to show the extensive nature 
 of the changes which may have been produced upon the 
 superficies of the globe since the commencement of the 
 current era. 
 
 311. Volcanic forces act in a similar manner, in as far as 
 they elevate, depress, and break asunder portions of the 
 earth's crust; indeed earthquakes and volcanic throes, con- 
 sidered as subterranean movements merely, produce pre- 
 cisely the same results. But volcanoes, properly so called, 
 act in another and equally important manner in producing 
 geological changes. They elevate the crust into long con- 
 tinuous ridges or mountain chains, form isolated cones, and 
 discharge accumulations of lava, scoriae, ashes, loose stones, 
 and other igneous debris. The same effects have been 
 produced by igneous forces in all ages, as are amply evi- 
 denced by the granitic rocks of the primary, and by the 
 trapptan eruptions of the secondary and tertiary epochs. 
 Volcanic rocks represent the igneous products of the pre- 
 sent era, and are associated with the superficial accumula- 
 tions, just as the older traps are with the coal measures, 
 oolite, and chalk strata. The granitic and trap locks occur 
 either as disrupting, interstratified, cr overlying masses; 
 so do the volcanic: the former cover extensive districts, and 
 form vast mountain ranges; so do also the latter, as will be 
 seen by an enumeration of some of the more celebrated 
 volcanoes. In Europe there appears to be three centres of 
 volcanic action namely, that of the Levant, to which ^Etna 
 and Vesuvius belong; that of Iceland, represented by Hecla; 
 and that of the Azores. In Asia there is abundant evi- 
 dence of volcanic action on the borders of the Mediter- 
 ranean, the Black Sea, the Caspian, and the Persian Gul r ; 
 while along the eastern borders of that continent there is a 
 range not less than 5000 miles in length and 250 in breadth, 
 
 836. What analogy between these and volcanoes ? 
 
 837. How else do the latter act ? 
 
 838. Describe the volcanic range in different countries. 
 
EARTHQUAKES AND VOLCANOES. 257 
 
 including Sumatra, Java, the Eastern Moluccas, and the 
 Phillipiue Islands; the same range bearing farther north- 
 ward, though less distinctly, for several thousand miles, and 
 terminating in the volcanic cones of the Aleutian isles. The 
 whole extent of the two Americas is also tfa versed by a 
 volcanic range, manifesting itself by eruptions along the 
 whole line, from the Rocky Mountains through Mexico and 
 the Andes, onward to Patagonia and Terra del Fuego. 
 The islands of the Pacific iurther attest the presence of 
 similar forces; as do those namely, the Canaries, Cape de 
 Verd, Ascension, St. Helena, Madagascar, Bourbon, &c. 
 which surround the continent of Africa. In these centres 
 of igneous action many of the volcanoes are extinct, others 
 are merely dormant, while many are incessantly active. 
 
 312. Passing over the disruptions produced by volcanic 
 forces, some idea of their importance in adding to the rocky 
 material of the earth's crust may be gleaned from what is 
 stated in par. 73, and from the following quotations. In 
 the year 1759 the plain of Malpais, which forms part of the 
 volcanic district of Mexico, was disturbed from the month 
 of June till August by hollow sounds and a succession of 
 earthquakes; and in September flames burst from the 
 ground, and fragments of burning rocks were thrown to a 
 prodigious height. Six volcanic cones were formed, of 
 which Jorullo, the central one, was elevated 1600 feet 
 above the plain, and continued burning, sending forth 
 streams of basaltic lava till the month of February in the 
 succeeding year. None of the other cones were less than 
 3JO feet in height. Twenty years after the eruption, this 
 spot was visited by Humboldt, who found around the base 
 o/ the cones, and spreading from them as from a centre, a 
 m."ss of matter 550 feet in height, extending over a space 
 of four square miles, and sloping in all directions towards 
 the plain. A subsequent eruption of this volcano took 
 
 ce in 1819, on which occasion the ashes discharged 
 e so abundant, that they covered the streets of Gua- 
 
 xuato to the depth of six inches, although the distance 
 
 839. What three conditions of volcanoes are cited 1 
 
 840. What historical incident? are named 7 
 
 me 
 
 n;ix 
 
2/W GEOLOGY. 
 
 of that city from the volcano is not less than one hundred 
 arid forty miles. During the eruptions of Surnbawa in 1815, 
 ashes were carried 300 miles in the direction of Java, and 
 more than 200 miles northwards towards the Celebes, in 
 sufficient quantity to darken the air; they were also found 
 floating in the ocean to trre west of Sumatra, a distance of 
 more than one thousand miles, forming a mass two feet 
 thick, through which vessels with difficulty forced their 
 way. The last example which we shall here notice is that 
 of the Skaptaa Jokul, in Iceland, which took place in 
 17H3. This eruption continued with greater or less ac- 
 tivity during the space of ten weeks, and produced the 
 most disastrous effects, as well as the most extensive geo- 
 logical changes, on the face of the island. "The immedi- 
 ate source," says Mr. Ansted, " and the actual extent of 
 these torrents of rocks have never been actually determined; 
 but the stream that flowed down the channel of the Skaptaa 
 was about fifty miles in length by twelve or fifteen in its 
 greatest breadth. With regard to its thickness, it was very 
 variable, being as much as five or six hundred feet in the 
 narrow channels, but in the plains rarely more than a hun- 
 dred, and often not exceeding ten feet." If such be the 
 magnitude of isolated and temporary eruptions, the student 
 cannot fail to perceive how much of terrestrial change must 
 have been produced by volcanic action even during the 
 few thousand years of human history; and can have no 
 difficulty in reasoning from modern igneous forces to those 
 which exerted themselves during the trappean and granitic 
 eras. (See Appendix.) 
 
 313. The products of volcanoes are commonly recog- 
 nized as lava, obsidian, pumice, scoriae, ashes, mud, steam, 
 and various gases, of which muriatic acid, carbonic acid, 
 and sulphuretted hydrogen are the most abuudant. Lava 
 i:s the name given to the melted rock-matter which issues 
 from active craters, and which, when cooled down, foo^ 
 varieties of volcanic trap, as trachyte, basalt, greenstone, 
 
 841. What geological reasoning is suggested ? 
 
 842. What are a'linvdant products of volcanoes ? 
 
 843. Explain each of those. 
 
EARTHQUAKES AND VOLCAXpFS. 253 
 
 a:id <J lenu-, aec -rding to the arti-mni of felspar, hor i- 
 b.ende, and augite whicli UK se rooks respectively coritaiii. 
 Obsidian, or volcanic glass, is a glassy lava of a black 
 colour, nearly opaque, and scarcely distinguishable from 
 artificial glass slag. Pumice is a light, porous, or vesicular 
 rock, the vesicles having been formed by the disengagement 
 of gases while the mass was in a state of fusion. Scoria, 
 cinders, ashes, and the like, are of the same mineral com- 
 position as the solidified lava, and seem to be produoed by 
 the dissipation of the liquid mass by the explosive energy 
 of steam and other gaseous forces. The admixture of water 
 with volcanic ashes forms a fetid clayey mud, which some- 
 times bubbles out from fissures, or is ejected in currents 
 with considerable violence. Gaseous products are in con- 
 tinual exhalation from active craters, or from rents in ex- 
 tinct volcanoes. Steam is the most abundant of these; 
 and next in order are the sulphurous vapours, from which 
 are derived those deposits of sulphur so extensively em- 
 ployed in the useful arts. The manner in which the rock 
 products arrange themselves is highly instructive, inasmuch 
 as it supplies the geologist with data to reason respecting 
 the occurrence of igneous rocks in connexion with the older 
 stratified systems. Lava issuing from active craters descends 
 in currents from the mountain side, filling up valleys, dam- 
 ming rivers, covering plains, and if in the neighbourhood 
 of the sea, spreading along its bottom, there in turn to be 
 covered by newer sediments. Scoriae, ashes, and other 
 light material being showered abroad, and borne by winds 
 often to a great distance, are scattered indiscriminately 
 over land and sea, forming layers of considerable thickness, 
 which under the waters are also covered by other deposits. 
 Lava cools irregularly; in one place presenting trachyte of 
 a porphyritic texture, at another passing into granular green- 
 'stone, and not unfrequently assuming a true basaltic struc- 
 ture. In all this the student must see repeated the same 
 processes by which the granitic and trappean compounds 
 were formed, the same modes of arrangement and relation 
 to the stratified rocks; and so can reason with certainty, 
 
 Ml. Wint variety results from the lava cooling 1 
 
 
203 
 
 from what is recent and apparent, to that which is ancient 
 and obscure. 
 
 314. The cause of volcanoes, earthquakes, and other sub' 
 terra/teem movements has been the subject of several theories, 
 Lut is yet by no means very satisfactorily determined. The 
 most prevalent opinion is that which connects them with 
 < ne great source of central heat the residue of that incan- 
 descent state in which our globe originally appeared. By 
 this hypothesis it is assumed that the crust of the earth is 
 f various thickness, that it contains vast caverns, and 
 is extensively fissured primarily by unequal contraction 
 from cooling, and subsequently by subterranean agitations. 
 Through these fissures water finds its way to the heated 
 mass within ; this generates steam and other gases, and 
 these exploding, and struggling to expand, produce earth- 
 quakes and agitations, which are rendered more alarming 
 by the cavernous and broken structure oi'the crust, and the 
 yielding material upon which it rtsts. Occasionally, these 
 vapours make their way through fissures and other aper- 
 tures as gaseous exhalations, or as hot springs and jets of 
 steam and water, like the geysers of Iceland. Oti the other 
 hand, when the expansive forces within, become so power- 
 lul as to break through the earth's crust, discharges of lava, 
 red-hot stones, ashes, dns', steam, and other vapours follow; 
 and repeated discharges of solid material gradually form 
 volcmic cones and mountain ranges. It does not follow, 
 however, that volcanic discharges must always take place at 
 the point where the greatest internal pressure is exerted, 
 for volumes of expansive vapour press equally upon the 
 crust and upon the fluid mass within, so that the latter wi!l 
 be propelled towards whatever craters or fissures do already 
 exist. This theory of central heat is further supported by 
 the occurrence of igneous phenomena in all regions of the 
 globe, and by the fact that most volcanic centres are iif 
 intimate connexion with each other a commotion in one 
 district being usually accompanied by similar disturbances 
 
 815 What of the cause of subterranean movements? 
 
 846. How are earthquakes explained ? 
 
 847. How are volcanoes accounted for ? 
 
 84S. What, igneous phen'^ienn prove central heat? 
 
rARTHQt-AKF.S AVT> VOLCANOES. 261 
 
 in another. The only other hypothesis which has met with 
 countenance from geologists, is that which supposes the 
 internal heat to be the result of chemical action among the 
 materials composing the earth's crust. Some of the metal- 
 lic bases of the alkalies and earths, as potassium, the mo- 
 ment they touch water explode, burn, melt, and become 
 converted into red-hot matter not unlike certain lavas. This 
 fact has given rise to the supposition that such bases may 
 exist within the globe, where, water finding its way to them, 
 they explode and burn, fusing the rocks among which they 
 occur, creating various gases, and producing caverns, fis- 
 sures, eruptions, and other phenomena attendant upon 
 earthquakes and volcanoes. As yet, our knowledge of the 
 earth's crust at great depths is excessively limited; we know 
 little of the chemical and magnetic operations which may 
 be going forward among its strata, and we are equally igno- 
 rant of the transpositions which may take place among its 
 metallic and earthy materials; but judging from what we 
 do know, this theory, however ingenious, seems by no 
 means adequate to the results produced. It is true that 
 there occurs nothing among the products of volcanoes at 
 variance with its assumptions; but the magnitude, the uni- 
 versality, and the perpetuity of volcanic action point to a 
 more stable and uniform source that source being the 
 internal heat or residue of that igneous condition in which 
 our planet originally appeared. 
 
 EXPLANATORY NOTE. 
 
 OBSIDIAN so named, according to Pliny, from Obsidius, who first 
 found it in Ethiopia. It is a true volcanic glass, of various colours, but 
 usually black, and nearly opaque. In Mexico and Peru it is occasion- 
 ally manufactured into adzes, hatchets, and other cutting instruments, 
 or fashioned into ring-stones. So closely does it resemble the black 
 slag of our glass furnaces, that in hand specimens it is almost impos- 
 sible to distinguish the artificial from the natural product. Obsidian 
 consists chemically of silica and alumina, with a little potash and oxide 
 of iron. 
 
 SULPHUR, also known as brimstone, is a yellow brittle mineral product 
 found in various parts of the world, but most abundantly in volcanic 
 
 849. What of the chemical theory? 
 
 850. Why is it objected to as improbable I 
 
 851. What of obsidian ? 
 
 12 
 
262 GEOLOGY. 
 
 regions. For economical uses, it is chiefly 'obtained from Sicily, the 
 south of Italy, and the West Indies, though many other districts could 
 yield a profitable supply. It commonly occurs massive, and intermin- 
 gled with earthy impurities ; but is sometimes found crystallized, or as 
 an efflorescence on the sides of fissures, around hot springs, and other 
 subterranean openings. The properties of sulphur are well known : 
 it is a simple combustible, solid, non-metallic; melts at the tempera- 
 ture of 226 degrees ; emits a peculiar odour when rubbed ; and takes 
 fire at 560 degrees, burning with a dull blue flame of a suffocating 
 odour. It is extensively used in medicine, and for numerous purposes 
 in the arts, as in the manufacture of gunpowder, matches, vermilion, 
 sulphuric acid, &c. Chemically speaking, sulphur is a very abundant 
 product in nature, being found in conjunction with iron, copper, lead, 
 and most of the metallic ores, being also widely diffused among the 
 earths and rocks, as well as entering into the composition of many 
 organized bodies. Though our commercial supplies of the -mineral be 
 principally obtained from volcanic districts, yet it is in the power of 
 the chemist to extract it from iron pyrites (sulphuret of iron), as stated 
 in par. 229. 
 
 VOLCANOES which give unremitting or periodical evidence of their 
 being the seats of subterranean fire, are said to be active; such as have 
 been in a state of commotion within the historic period, but now afford 
 no symptoms of igneous action, are termed dormant ; while those con- 
 cerning whose activity there is no historical or traditionary mention 
 are regarded as extinct. 
 
 RECAPITULATION. 
 
 315. Having described, as fully as the rudimentary na- 
 ture of this treatise will allow, the various stratified forma- 
 tions, together with their associated igneous rocks, it may 
 be of value now to take a general review of the facts estab- 
 lished by geologists in their endeavours towards a comple- 
 tion of the history of our planet. 
 
 316. Whatever may have been the constitution of the, 
 globe previous to the origin of granite, we are warranted in 
 concluding that rocks of this class form a floor or basis 
 upon which all the stratified formations recline. Among 
 the granitic rocks there is no evidence of a sedimentary 
 origin, no lines of stratification, no fossils; all of them are 
 massive, and highly crystalline. They upheave, disrupt, 
 and break through the overlying strata in a manner which 
 leaves no doubt of their having been produced by igneous 
 
 852. What is the source, nature and uses of sulphur 1 
 
 853. How many varieties of volcanoes are named ? 
 
 854. What is predicated of granitic rocks? 
 
2f>3 
 
 fusion ; and such an origin is now assigned to them by 
 almost all geologists. Had granite been a meie meta- 
 morphic rock that is, a product derived from the fusion 
 rf sedimentary strata some evidence of the fact must have 
 beeu furnished by enclosed fragments of the strata, by lo- 
 calities where the fusion had not been completed, or by 
 traces of sedimentary lines; for, in true metamorphic rocks 
 of the secondary period, some such proofs are always pre- 
 sent. But even supposing the fusion to have been complete 
 in every part, there is still the question Whence was this 
 heat derived? And this leads the geological theorist back 
 to the starting point, that our planet was at one time an in- 
 candescent igntou* mass. Whether the earth was originally 
 so formed, or was fused by external heat, the result would 
 be the same a globe of molten matter, gradually giving 
 oft* its heat to surrounding space, and cooling down so as 
 in process of time to be coated with a solid stony crust. 
 This crust contracting and expanding irregularly, accord- 
 ing as certain areas were good or bad conductors of heat, 
 would produce rents, fissures, elevations, and depressions 
 great in as far as our standard of judging is concerned, but 
 no more in comparison with the bulk of the globe, than 
 the scoria? on the surface of a glass-blower's furnace. As 
 this process of refrigeration went forward, the gases capa- 
 ble of constituting the atmosphere nnd water would con- 
 dense around and upon the earth the latter occupying the 
 hollows of the crust, and undergoing a rapid evaporization, 
 both by the internal heat of the mass and the external heat 
 of the sun and the former constituting a medium for the 
 elaboration of vapours, rains, and other meteoric pheno- 
 mena. Thus the various operations of Atmospheric, 
 Aqueous, and Igneous agency were set in motion to 
 modify the newly-formed crust, and to produce that long 
 series of changes which it is the province of geology to 
 consider. This constitutes the first era of our planet a 
 
 Son. What of the earth having been an incandescent igneous mass? 
 806 What geological reasoning is here T 
 ho7. What of the first era of our planet ? 
 
264 r.F.ot/vrv. . 
 
 period when it was void of those conditions necessary to 
 the support of vegetable and animal existence. 
 
 3 1 7. The products of the agencies now set in motion were 
 the gneiss and mica schist systems. The rains which fell 
 upon the granitic crust, the streams which descended from 
 its mountains, and the rivers which cut their way through 
 its gorges and valleys, would bear the abraded material to 
 the lakes and seas, there forming layers differing little in 
 mineral composition from the granite whence they were 
 derived. At this period the earth's surface must have been 
 extremely unstable, breaking down in some localities, and 
 being upheaved in others; so that floods of molten granite 
 would occasionally envelop the newly-deposited strata; and 
 thus it is often difficult to separate gneiss from rocks of true 
 granitic character. In process of time, however, the gra- 
 dual refrigeration of the globe would render the configura- 
 tion of its crust more stable, and so allow the sedimentary 
 matter to be deposited not only more regular! v, but also 
 less intermingled with igneous effusions. Such a state of 
 matters we discover in the mica schists, which are more 
 finely laminated, and more continuous in stratification, than 
 the subjacent gneiss. Of the sedimentary origin of gneiss 
 and mica schist, no one who has examined these rocks in 
 the field can have any doubt ; even in hand-specimens the 
 lines of lamination are generally well-marked ; the crys- 
 tals of which they are composed are fragmented and water- 
 worn, attesting the abrading agency to which 'they had 
 been subjected, while in granite every crystal is distinct 
 and entire. It is true that the rocks of these two systems 
 are of crystalline texture, and must have been subjected to 
 a very high degree of heat a temperature sufficient to 
 form garnet within mica schist, but not so powerful as to 
 obliterate the lines of deposit in the mass. Another and 
 unobjectionable evidence of their sedimentary origin is 
 afforded by the fact, that the litter system consists of alter- 
 
 858. How is the origin of the gneiss and mica systems explained ? 
 
 859. What proves that these rocks must have been subjected to very 
 
 high degrees of fu-at ? 
 
 860. What further proves their sedimentary origin? 
 
RECAPITULATION. 265 
 
 nations of various strata, as mica, talc, and chlorite schists, 
 crystalline li-uestone, and quartz. No vegetable or animal 
 remains have been found in either system ; hence the 
 inference, that the earth at this period was not sufficiently 
 cooled down to admit of organic development. This con- 
 stitutes the second geological era one during which the dry 
 land and waters were alike devoid of life and vegetation; 
 an epoch of incessant subterranean agitation, as is evi- 
 denced by the vast mountain ranges, dykes, veins, and other 
 effusions of granite by which the sedimentary strata are 
 elevated and contorted. 
 
 318. The tra of the clay-slate and gravwacke which suc- 
 ceeded was one during which important events took place 
 in the history of the earth. Mineralogically speaking, these 
 rocks present an immense difference from those of previous 
 systems. Among them the crystalline texture is faint; 
 clayey compounds are derived from the decomposed felspar 
 of the gneiss and granite, arenaceous rocks from the quartz, 
 and conglomerates from the pebbles collected along the 
 shores of the sea. Stratification is now abundantly obvious; 
 and frequent alternations of , sandstones, conglomerates, 
 shales, and limestones prevail. All this attests great diver- 
 sity of action rivers, currents, tides, and waves; deposition 
 in calm water, and accumulations by violent inundations. 
 These rocks imbed the remains of lowly-organized sea- 
 wtcds, of zoophytes, and of mollusca. Here the geologist 
 is, for the first time in the history of the earth, presented 
 with organized forms beings governed by the same laws 
 of vitality which now regulate plants and animate. These 
 organisms, it is true, are not of a high order; but they are 
 as complete in their structure and kind, as perfectly adapted 
 to the conditions under which they flourished, as the most 
 highly-organized orders of existing nature. In all their 
 parts we have abundant evidence of means to an end 
 proofs of that divine intelligence from whom nothing su- 
 perfluous or incomplete ever emanates. The presence of 
 
 861. What marked difference in the next system? 
 
 862. What of organized forms? 
 
 863. What geological reasoning is here ? 
 
200 GEOLOGY. 
 
 organized beings attests a great reduction of the former 
 temperature of the globe ; the existence of a shallow sea- 
 shore fit for the growth of marine plants; a sea-bottom 
 adapted to the support of corals and shell-fish ; and the 
 presence of lime and other salts in the waters of the ocean, 
 fitted for the production of such calcareous exuvise. The 
 deposition of the clay-slate and grauwacke forms the third 
 geological epoch one of comparative tranquillity and rest, 
 capable of sustaining sea-weeds, zoophytes, and mollusca, 
 but not yet suited to the creation of terrestrial life or vege- 
 tation. 
 
 319. The succeeding formations the Silurian and Old 
 Red Sandstone are more decidedly sedimentary than any 
 of the previous systems. They are composed of sandstones, 
 conglomerates, shales, clays, and limestones, alternating 
 with each other in such a manner as to prove the operation 
 of numerous agents during their deposition. At one season 
 the rivers seem to have carried down mud and clay, at 
 another sand of various fineness ; in one locality the waves 
 and currents produced pebbly conglomerates along the sea- 
 shore, at another laid down the most impalpable sand, on 
 which is often left impressed the ripple-mark of the receding 
 tide; along some regions of the sea-bottom certain lime- 
 stones were precipitated by chemical agency, in others it 
 was accumulated by the operations of coral zoophytes. 
 During the deposition of these rocks a change was effected 
 upon the climate and other atmospheric conditions of the 
 dry land, so as to enable it to sustain a scanty vegetation ; 
 and here, for the first time in the earth's history, have we 
 evidence of land-plants in the remains of equis^etums, ferns, 
 and other cryptogamia. The previous sea-weeds become 
 more prolific: other genera are added to the zoophytes and 
 mollusca; and Crustacea and Jishes constitute a new fea- 
 ture in the Fauna of the globe. Respecting the land- 
 plants, their remains are too imperfect to afford any just 
 idea of the climate, composition of the atmosphere, or ele- 
 
 864. What characterizes the next formations ? 
 
 865. What do we find here for the first time? 
 
 866. What geological inferences are here stated 7 
 
RECAPITULATION. 267 
 
 vntion of the land ; one thing only is evident, that they are 
 chiefly aquatic, and seem to have flourished in low situations 
 I v the sides of rivers, whose waters bore their detached 
 fragments to the seas of deposit. On the other hand, the 
 marine plants are much the same in kind with those of the 
 grauwacke, only flourishing more abundantly, to furnish 
 food to the new increase of herbivorous mollusca. The 
 silurian seas seem to have been crowded in some localities 
 with zoophytes and corals, for certain limestones are almost 
 wholly composed of their calcareous secretions; and among 
 these radiata, encrinites make their first appearance. New 
 and gigantic genera are added to the shell-fish ; Crustacea 
 are introduced in the form of the trilobite ; an intermediate 
 gradation between Crustacea and true fishes in the pterich- 
 thys, coccosteus, and ccphalaspis ; and perfect fishes in the 
 hokiptychius, osteolepis, and other ganoidia of the old red 
 sandstone. All this attests a great advance in the vital 
 conditions of the globe conditions, however, differing so 
 much from those which succeeded, that few of the races 
 created to live under them are to be found beyond the 
 limits of the strata then deposited. This constitutes the 
 fourth period of the world one of ordinary tranquillity 
 during the formation of the siiurian rocks and lower gray 
 sandstones ; but still occasionally interrupted by volcanic 
 action, as is evidenced by the interstratification of igneous 
 tufa aiinong sedimentary compounds. The colouring mat- 
 ter of the red sandstones and shales seems also to bear evi- 
 dence of igneous disturbance, but in centres considerably 
 removed from the seas of deposit. Whatever may have 
 been the amount of volcanic disturbance during the forma- 
 tion of these systems, there can be no doubt of its violence 
 and extent towards their close, when they were upheaved 
 into dry land, new mountain ranges formed, the previous 
 strata further fractured and displaced, and the seas of future 
 deposit circumscribed. And here the student rr.ust c-bsc-rve, 
 that the igneous products have undergone a change in their 
 composition and aspect as great as that which subsists be- 
 tween gneiss and sandstone. The products of previous 
 
 867. What of the volcanic agency here 1 
 
268 150 LOGY. 
 
 eras were granitic ; now they are chiefly greenstone, fel- 
 spar, porphyry, amygdaloid, and other trappea/t compounds. 
 No two sets of rocks could be more widely dissimilar, 
 could afford evidence of a more radical change in the in- 
 terior masses of the earth; and though the former are occa- 
 sionally detected piercing through secondary strata, it may 
 be received as a general truth, that by the close of the old 
 red sandstone the true granitic era had passed away. 
 
 320. The formation of the, carboniferous system con- 
 stitutes one of the most peculiar and interesting eras in the 
 history of our globe. Its limestones, fossil shell-beds, sand- 
 stones, shales, clays, coals, and ironstones, indicate a vast 
 variety and complexity in the causes concerned in their 
 production. Lakes, estuaries, and shallow seas, were the 
 theatres of deposit ; gigantic rivers, periodical inundations, 
 tidal currents, and waves, were the transporting agents; 
 broad river plains and deltas nourished vegetation; a wide 
 extent of newly-upheaved continents furnished the rock 
 debris ; and new races of plants and animals were called 
 into existence to people the scene. Sea-wer.ds, corallines, 
 and corals, were profusely scattered along the shores of the 
 ocean the latter in such abundance, as to constitute beds 
 of limestone lar more extensive than the coral reels of the 
 Pacific. Free radiated animals, like the star-fish, were 
 abundant; shell-Jink, both fresh-water and marine, swarmed 
 in myriads, leaving their exuviae to form beds many feet in 
 thickness; while new genera of Crustacea were added to 
 those which existed during the silurian era. Insecis, 
 verrnes, and other articulata, appear as a fresh i'eature in the 
 life of the globe ; andjishes, of the most gigantic and pre- 
 datory orders, abound in the seas and estuaries. The latter 
 are all of the ganoid and placoid orders ; and, judging from 
 their remains, several of them seem to mark a passage from 
 true cartilaginous fishes to sauroid reptiles. The most 
 characteristic organic development of this period, however, 
 consists in the almost inconceivable growth of terrestrial 
 vegetation, from which were derived those numerous beds 
 
 868. What renders the next formation important 7 
 
 869. What of the fossils of this period 1 
 
 S70. Whence are the immense beds of coal derived ? 
 
RECAPITULATION. 2G9 
 
 of coal peculiar to the system. Judging from existing 
 nature, this vegetation was chiefly of a tropical character 
 p'llms, pines, tree-ferns, cactaceae, canes, equisetums, reeds, 
 rushes, and allied orders ; but for many there is no ap- 
 proaching analogue among existing plants. Most of them 
 are of gigantic size, and indicate rapid growth. Every 
 plain, and swamp, and hill-side seems to have been choked 
 with their luxuriance, thus evincing conditions of tempera- 
 ture, moisture, soil, &c., more favourable to vegetable 
 growth than the world has ever since experienced. Still, 
 however, with all this verdure this diversity of hill and 
 plain, river, lake, and estuary this exuberance of marine 
 li e, the earth was a luxuriant desert, if we may so speak, 
 void of terrestrial vitality. This constituted another cycle in 
 the earth's history a period of excessive vegetation, but 
 only of ordinary tranquillity, as we find proofs of igneous 
 agency more or less displayed throughout the entire forma- 
 tion. The subterranean fires were, however, only smoulder- 
 ing to renew their activity, to upheave into dry land the 
 important products of the carboniferous strata. 
 
 32.1. The era of disturbance which succeeded icas that 
 during which the new red sandstone and magnesian lime- 
 stone were deposited. Before their commencement, and 
 just at the close of the coal-lbrming period, a magnificent 
 displa^ of subterranean agency took place. The hills upon 
 which the mountain limestone reclines, the conical and 
 isolated elevations of the coal measures, together with all 
 their fractures, dykes, and upheavals, were produced by 
 these forces. Every coal-field bears ample evidence of their 
 effects ; they seem to have continued in activity over a long 
 lapse of years, during which the previous luxuriance of 
 vegetation passed away, together with most of the zoophytes, 
 mollusca, and fishes which had peopled the waters. The 
 formation of new strata was not, however, suspended by 
 these disturbances; new rivers carried down to new seas of 
 deposit sand, clay, and mud ; but the sandstones and shales 
 formed b\ these materials are not like those of the coal 
 
 871. What charaet.-i-zed the next era T 
 h72. To what agency are these ascnbeil 
 
 !/* 
 
270 REOLOCY. 
 
 measures. They are all highly coloured, imbed few or no 
 remains of plants, contain deposits of gypsum and rock- 
 salt, and alternate with magnesian limestones. All these 
 facts point to the prevalence of volcanic influence the red 
 colouring matter, the local aggregations of rock-salt, the 
 peculiar composition and texture of the magnesian lime- 
 stone, are its immediate products. As these disturbing 
 influences passed away, creative energy began to be exerted 
 anew; and before the close of the new red sandstone epoch, 
 many new genera of fishes and true aquatic reptiles were 
 called into being. 
 
 322. The period of the. lias, oolite, and chalk was one of 
 restored tranquillity. The strata, with a few limited excep- 
 tions, are eminently marine and estuary, deposited in quiet 
 waters, and undisturbed by igneous agitation. Had we a 
 map of the globe at this epocn, it would present a number 
 of islands and low continents surrounded by comparatively 
 shallow seas ; the land supporting a tropical, but by no 
 means exuberant vegetation, and the waters swarming with 
 shell-fish, fishes and reptiles. An atmosphere such as we 
 now enjoy, a tropical temperature, and abundance of 
 moisture, were the conditions under which new tribes of 
 palms, ferns, cycadeae, conifera, and a few dicotyledonous 
 trees flourished; and under which chambered shells, naked 
 cephalopods, sea-urchins, star-fishes, new bivalves, Ctenoid 
 and cycloid fishes, numerous gigantic reptiles, marsupial 
 mammalia, and monkeys, were called into existence. In 
 all these forms we discover a nearer approach to existing 
 nature than was made by the Fauna and Flora of previous 
 eras ; and yet few, if any of the genera outlived the chalk 
 formation. The deposition of the oolitic and cretaceous 
 systems constitutes another epoch in the history of our 
 planet during which many of its inhabitants died out, and 
 were succeeded by other races better adapted to its pro- 
 gressive conditions. The period was eminently one of rest, 
 distinguished only at its termination by a few local disturb- 
 ances. 
 
 873. How did the next era contrast vvith the former 1 
 
 874. What were its peculiarities ? 
 
RECAPITULATION. 271 
 
 323. The tertiary strata were deposited under condi- 
 tions still more closely allied to those of the present day. 
 With the exception of gypsum and certain limestones, the 
 gravels, sands, marls, and clays are scarcely distinguishable 
 from those of recent times. They seem to have been 
 formed in estuaries and shallow seas, which at certain 
 seasons were cut off from the influence of salt water, or at 
 least were so situated that fresh water was then the pre- 
 dominating agent. None of the basins of deposit are of 
 great extent ; they generally occupy situations still flat, and 
 differing little in point of level or configuration from exist- 
 ing seas. The earth at this period appears to have spread 
 out in vast savannahs, abounding in verdure, and to have 
 been clothed with grasses, shrubs, and trees scarcely differ- 
 ent from living orders. Mammalia herbivora and car- 
 nivora of the most varied forms and sizes now peopled 
 the surface, in all of which we distinguish the prototypes 
 of existing genera. Birds are also added to the list of 
 terrestrial inhabitants, and such n^have been found are 
 identical in form with those now around us. The shell- 
 fish bear so close a resemblance to those of the present seas, 
 tint many of them are identical in species. The fishes are 
 chiefly of extinct genera, but otherwise closely allied in 
 their forms and mode of life to modern families. Whales, 
 walruses, seals, turtles, crocodiles, are now numerous and 
 indubitable; so that, all things considered, the tertiary era 
 brings us to the confines of existing conditions. This 
 epoch was terminated by a wide-spread and general dis- 
 turbance, by which the dry land and ocean received their 
 present configuration. This disturbance was accompanied 
 by an almost total destruction of the terrestrial Fauna and 
 Flora ; by a decided change of temperature in the regions 
 where the tertiary beds were deposited ; and by the produc- 
 tion of an accumulation (diluvium) over the greater part 
 of Europe at least, which forms a boundary between the 
 tertiary and current epochs not to be mistaken. With this 
 system the subterranean fires cease to discharge trappean 
 
 875. How is the era of the tertiary strata marked ? 
 
 876. Name iu peculiarities. 
 
272 GEOLOGY. 
 
 rocks, which had been the invariable products of every 
 igneous agitation from the dawn of the silurian period. It 
 is true that on a small scale there are many of the tertiary 
 traps undistinguishable from the products of modern vol- 
 canoes; but, judging them by their general relations and 
 composition, there is as wide a difference bettveen the 
 igneous rocks of the current epoch and the trap, as there 
 is between the trap and the older granite compounds. 
 
 3*24. The current era is that lithologically represented by 
 those superficial accumulations of gravel, sand, clay, marl, 
 peat-moss, shell-beds, coral-rees, &c., with which every one 
 who moves beyond his own dwelling must be to a certain 
 degree familiar. Many of these accumulations are of great 
 antiquity, and, both in their mineral and fossil characters, 
 blend with the tertiary strata. One tact to be observed 
 respecting the whole of them is, that they are loosely and 
 irregularly scattered over the surface, and have been evi- 
 dently deposited since the crust received its present con- 
 figuration. Still, it imist be borne in mind that there is no 
 such thing as geological rest the atmospheric, aqueous, 
 igneous, and organic agencies are incessant in their opera- 
 tions; so that what we denominate "an era," is, in fact, a 
 mere series of progressive movements, whose results pre- 
 sent as many points of similarity as will admit of their 
 being classed under one category. Even since the present 
 order of things was established, great changes have been 
 effected ; portions of dry land have been submerged, and 
 portions of sea-bottom raised above the waters; lakes have 
 been silted up, rivers changed from their courses, and 
 mountains formed; while organic agency has produced 
 peal-mosses and conl-reefsof astonishing magnitude. We 
 have seen that the Fauna and Flora of other epochs suc- 
 cessively died away with the change of conditions under 
 which they flourished ; and so the commencement of the 
 current era was marked by the creation of new orders suited 
 to its peculiar conditions. The^e nre the various races of 
 plants and animals now existing subjected to the same 
 
 877. What of the current era ? 
 
 878. Are geological changes still transpiring? 
 
 879. What geological reasoning is here ? 
 
RECAI'Il'ULATIO.V. 273 
 
 laws ol' vitality, but differing in habits, form, and kind from 
 those of other geological cycles. Formerly, the orders, 
 genera, and spe<yes W ere few, with an immense number of 
 individuals under each species; now, individuals are less 
 numerous, while the species, genera, and orders are in- 
 finitely more varied and complicated. As far as can be 
 inferred from the discovery of fossils, there has evidently 
 been a progressive development, of vegetable and animal 
 life; not progressive in point of perfectitude for the 
 zoophyte of the silurian seas is as complex and per.'ect in 
 its structure as those of the Pacific but progressive inas- 
 much as higher and more varied orders were successively 
 called into being. This view, borne out by all that has been 
 witnessed in the stratified systems, is confirmed by the cur- 
 rent era, which claims for itself still more highly-organized 
 orders of being these orders crowned, moreover, by the 
 creation and distribution of MAN. In none of the older 
 formations were found any remains of man or his works; 
 these are confined to the most recent and superficial accu- 
 mulations to masses of volcanic scoriae, peat-bogs, and 
 river-sands. 
 
 325. The history of the earth thus presents a long series 
 of mineral and vital gradations, as yet but imperfectly in- 
 terpreted by geology. The stratified formations, from the 
 gneiss to the existing surface, bear evidence of these grada- 
 tions, both in their composition and mode of aggregation ; 
 so also do the unstratified rocks the granitic, trappean, 
 and volcanic compounds by the order in which they suc- 
 ceed each other. On the other hand, plants and animals 
 rise, as it were, from the simple zoophyte to man himself, 
 appearing at successive eras, as new conditions permitted 
 their development. As system gradually merges into sys- 
 tem, so the Fauna and Flora of one period seem to live into 
 that of another, there being always certain races which 
 serve as links of connexion between succeeding eras. 
 This idea of gradation implies riot only an incessant on- 
 ward change among the rock materials of the earth, but 
 
 8SO. What of the relations of mail to this era ? 
 
 8dl. What geological theories are broached touching the progressive 
 history of .he earth 1 
 
274 GEOLOGY 
 
 also that certain races of plants and animals must be per- 
 petually dropping out, as links from the great chain of ani- 
 mated nature. And such is the fact even with respect to 
 the current era. The mammoth mastodon, megatherium, 
 and other huge pachydermata which passed from the tertiary 
 to the modern epoch, have long since become extinct, 
 leaving their bones in the clays and gravels of our valleys. 
 The elk, bear, wild boar, wolf, and beaver, are now extinct 
 in Britain; and what takes place in limited regions, must 
 also occur, though more slowly, in wider continents. The 
 dodo of the Mauritius, the dinornis and apteryx of New 
 Zealand, are now matters of history ; and the same causes 
 which led to their extinction seem hurrying onward to the 
 obliteration of the beaver, ostrich, kangaroo, and other 
 animals whose circumscribed range of existence is gradu- 
 ally being broken in upon by new conditions. Such facts 
 as these, taken in connexion with the numerous superficial 
 changes produced by rivers, lakes, seas, peat-beds, coral- 
 reefs, earthquakes, and volcanoes, have led to speculations 
 as to the conditions which yet await our planet. 
 
 326. Respecting the future history of the globe, it were 
 vain to offer any conjecture. Subjected as it is to the 
 numerous modifying causes previously described, we know 
 that vast changes are now in progress, and that the present 
 aspect of nature is not the same as that she must assume a 
 thousand years hence. But what may be the character and 
 amount of these changes, what the new conditions brought 
 about by them, or what the races of plants and animals 
 adapted to these conditions, we have nb means of deter- 
 mining. This only we are assured of, that whatever vicis- 
 situdes may affect the globe, they will be tempered in 
 perfect accordance with the happiness of organized exist- 
 ence : that Supreme Intelligence which has maintained the 
 past will continue to protect and superintend the future. 
 
 IMPORTANCE OF GEOLOGY. 
 
 327. The object of the science being to ascertain the 
 n-iinre of the materials composing the earth's crust, their 
 
 882. What speculations are indulged ? 
 8b3. Name the theoretical uses of geology. 
 
IMPORTANCE OF GEOLOGY. 27,> 
 
 mode of arrangement, and the causes producing that 
 arrangement, il has at once a theoretical and practical im- 
 portance. The former consists in thai impetus which it 
 giv, s to intellectual activity, the wholesome discipline which 
 it confers on the reasoning faculties, those exalted notions 
 of creation which it conveys, the sounder convictions of 
 man's relation to external nature which it imparts, and in 
 the thousand proofs which it establishes of a divine and 
 superintending intelligence. The latter, on the other hand, 
 arises from the economical benefits which it confers on 
 civilized life: from the aid which a knowledge of its de- 
 ductions affords to the arts of mining, engineering, archi- 
 tecture, and agriculture. 
 
 328. In its philosophical and speculative importance, 
 geology is second to none of the natural sciences. Depend- 
 ing for an accurate solution of its problems upon mechanics, 
 chemistry, botany, and zoology, it takes a wider range of 
 investigation than any other individual science; indeed, as 
 a history of the earth, it may be said to embrace the total 
 field of human research. Its study, therefore, calls into 
 activity not only the observing powers to note what actu- 
 ally occurs, but the reasoning faculties to account for the 
 source and mode of occurrence. It is thus liable to be 
 encumbered with the absurd and fanciful theories of im- 
 perfect knowledge theories, however, which gradually 
 disappear before the light of more accurate observation and 
 sounder reasoning. Though essentially aided by the other 
 sciences, it has not left the assistance altogether unrepaid; 
 but has afforded numerous suggestions to the chemist, and 
 thrown additional light on the study of plants and animals 
 by its peculiar fossil forms, which replace, as it were, the 
 lost links of vital gradation. But the discipline which it 
 confers on the reason ing powers is further enhanced by the 
 intellectual pleasure which its investigations afford. The 
 study of existing nature is confined to what is recent and 
 obvious : geology takes a bolder flight, and reveals the suc- 
 cessive conditions of the world to the remotest periods of 
 
 884. What of its practical value ? 
 
 8S5. What reflections are made upon speculative geology f 
 
276 GEOLOGY. 
 
 time; and as each era, with its peculiar forms of life and 
 vegetation, is unfolded, what research could be more fasci- 
 nating or instructive? As in existing nature everything is 
 impressed with proofs of divine wisdom, so in the revela- 
 tions of geology every fact teems with evidence of the 
 ceaseless agency of the same upholding power. 
 
 329. The practical or economical vahte of the science 
 refers more especially to the art of mining, to the construc- 
 tion of roads, tunnels, canals, harbours, buildings, &c. and 
 to the improvement of agriculture. In mining, a know- 
 ledge of geology is essential at every step. If the product 
 sought after be coal or ironstone, the geologist knows the 
 position which these strata occupy in the crust of the earth, 
 the nature of the rocks usually associated with them, the 
 kind of fossils imbedded, and can therefore direct the miner 
 with unerring certainty. For want of this aid, vast sums 
 of money have irorn time to time been expended in search 
 of these minerals the parties being misled by fragments 
 of black schorl among the primitive rocks, carbonaceous 
 shales amid the grauwacke, or by thin lignitic beds amid 
 the lias and oolite. Now, the practised geologist knows 
 that coal, as a distinct formation, does not exist previous to 
 the carboniferous era, and therefore would have warned 
 against the folly in sinking shafts in the clay-slate or old 
 red sandstone ; he knows, also, that after the commence- 
 ment of the new red sandstone, coal in workable beds 
 ceases to be found, and that lignite, jet, and brown coal 
 are mere local and insignificant deposits. Besides deter- 
 mining the position in which coal, ironstone, and other 
 useful strata occur, geology can direct the miner through 
 all those obstructions occasioned by faults, dykes, slips, and 
 the like ; for even these, irregular as they seem, bear cer- 
 tain evidence of their direction upthrow or downthrow 
 which the experienced eye can readily detect. As with 
 the minerals of commerce which occur in strata, so to a 
 certnin extent with the ores of lead, copper, tin, silver, and 
 gold which ;>re found in veins and lades. These veins 
 
 886. Illustrate its economical importance. 
 8y7. What further uses are subserved by it T 
 
MINING AND ENGINEERING. 277 
 
 follow certain courses in relation to the great axis of ele- 
 vation with which they are associated, are interrupted by 
 cross dykes and veins, are thrown up or down by disloca- 
 tions all of which an experienced geologist can determine 
 and map out, so as to save much fruitless waste of labour 
 and capital. 
 
 330. The importance of geology to the civil engineer and 
 architect is so obvious, that the fact requires little illustra- 
 tion. Possessed of a well-constructed lithological map, on 
 which are delineated the various kinds of strata, their dip, 
 direction, and other particulars, the engineer has a safer 
 and cheaper guide for his direction than the scattered data 
 of the boring rod. He sees at once the nature of the rocks 
 through which his work has to pass whether common 
 road, railway, or canal ; can estimate with certainty the 
 expense of construction, and avail himself of minerals 
 which he knows must lie in the vicinity; while'one igno- 
 rant of geological truths would blindly pass by such advan- 
 tages. In fixing a line of road or railway, the informed 
 engineer will avail himself not only of facilities for present 
 construction, but calculate, from his lithological knowledge 
 of the district, for the future benefit of those concerned in 
 the undertaking. In the case of canals, moreover, where 
 retention of water is indispensable, the geologist can effec- 
 tually aid in the selection of a route, by attending to the 
 nature and dip of the strata, and to the fractures and dislo- 
 cations to which they have been subjected. He is enabled, 
 from his knowledge of the rocks and their positions, not 
 only to prevent waste of water, but to select a route where 
 fresh supplies can be readily obtained from below. As 
 with roads and canals, so with tunnels, docks, Artesian 
 wells, and other undertakings commonly intrusted to the 
 civil engineer. It is true that such works may often be 
 satisfactorily enough completed without the aid of geology 
 but undoubtedly a knowledge of its deductions will materi- 
 ally Assist, by conferring a certainty and security on what 
 would otherwise be a mere system of trial and error. The 
 assistance which geology brings to the architect is not quite 
 
 88. How is the engineei profited by geology ? 
 
278 GF.OUMJY. 
 
 so obvious; as actual experiment is, after all, the host and 
 only test of a rock's durability. However, by observing the 
 effects of weather, water, and the like, on strata exposed in 
 natural sections, he can readily determine as to their fitness 
 for any particular structure* The amount of waste experi- 
 enced by ancient buildings is also another safe and valid 
 test ; and it is the travelled geologist, and not the mere build- 
 er, who can point to the locality, nay, to the very stratum, 
 whence the stones of these buildings were obtained. Thus, 
 both directly and indirectly, the science is brought to bear 
 upon architecture; a fact fully appreciated by the legislature 
 in its appointment of a commission, composed in part of 
 geologists, to determine the rock most suitable for the 
 structure of the new houses of parliament. 
 
 331. The assistance which geology is calculated to confer 
 on the science of agriculture, constitutes one of the most 
 apparent features in its economical importance. All fer- 
 tile soils consist of two classes of ingredients organic and 
 inorganic; the former derived from the decomposition of 
 animal and vegetable matter, the latter from the disintegra- 
 tion of the subsoil or rocks beneath. Without a certain 
 proportion of organic matter, no soil can be fertile; but it 
 is equally true, that without a due admixture of inorganic 
 compounds, all attempts to improve it will be fruitless. 
 These compounds are chiefly clay, lime, silicious earth, and 
 magnesia, with certain salts of iron, manganese, potash, and 
 s; da all of which are obtainable either from the igneous 
 or sedimentary rocks, or from the superficial accumulations 
 formed by their debris; and the farmer can at once effect 
 a permanent improvement on his land by supplying the 
 particular ingredient in which his soil may be deficient. 
 To do this, however, he requires to know not only the com- 
 position of the most prevalent rocks, but also the precise 
 spot which they occupy; in other words, he must be able 
 to comprehend the language and delineations of a geologi- 
 cal map of his own country. Besides this admixture of 
 inorganic substances, there are other conditions necessary 
 
 889. What light has it thrown upon agriculture 7 
 
 890. Illustrate this by examples. 
 
AGRICULTURE. 279 
 
 to fertility ; namely, facilities for drainage, capability of re- 
 taining moisture, the innocuous nature of the subsoil, and 
 power of absorbing and radiating caloric.- Soil overlying 
 trap and limestone requires less drainage than that covering 
 the coal measures, saliferous marls, or wealden, because the 
 former rocks are full of fissures and joints, while the latter 
 are cfcefly tenacious and unbroken clays. Again, land of 
 itself dry and friable may be rendered wet by springs which 
 arise along some line of dislocation. The farmer acquainted 
 with the deductions of geology would cheaply lead off these 
 springs at their source, while he who was ignorant would 
 laboriously furrow-drain his whole field, and find, alter all, 
 that his was the less effectual method of the two. Such 
 are mere indications of the assistance which geology is 
 calculated to confer on agriculture an assistance very apt 
 to be overrated, unless the farmer at the same time avail 
 himself of the discoveries of chemistry and vegetable phy- 
 siology. 
 
 332. It must not, however, be svpposed that the science is 
 of practical value only to the miner, engineer, architect, 
 and agriculturist; every individual is liable to be more or 
 less assisted by its deductions. The capitalist who specu- 
 lates in land, the agent who effects sales, the statistician, 
 traveller, and explorer, may all reap direct adva'ntage from 
 the same source. Take, for example,*a case of emigra- 
 tion : Two individuals, possessed of equal capital, set out, 
 say to New Zealand or to the Far West of North America. 
 The one ignorant of geology fixes upon a locality charac- 
 terized by the beauty of its scenery and the fertility of its 
 soil ; the other skilled in the science decides upon a long- 
 rejected lot, of bleak and barren aspect, but rich beneath 
 in coal, limestone, iron, copper, or lead, which his geologi- 
 cal knowledge at once enabled him to detect. The former 
 pays a high price for his land, and yearly toils over it to 
 reap therefrom a remunerating harvest ; the latter obtains 
 his despised territory for a mere trifle, nmkes his fortune in 
 the course of a few years, and when roads and canals are 
 
 891. What other sciences are auxiliary t 
 
 892. How is the practical value of geology to tne capitalist shown t 
 
280 UROLOGY. 
 
 constructed around liim, re-sells his property for fifty times 
 its original purchase-money. Such instances are by no 
 means of rare occurrence. Even our own country can fur- 
 nish examples where estates, sold under ignorance of their 
 mineral value, brought only ten or twenty thousand dollars, 
 for which, in less than a dozen years afterwards, an offer of 
 ten times that amount was rejected. 
 
 333. The advantages resulting to civilized life fnhn the 
 cultivation of geology must be rendered sufficiently obvious 
 even by the above hasty and imperfect outline; and yet it 
 is scarcely half a century since it was recognized as a legi'i- 
 rnate branch of natural science. Previous to that period it 
 was obscured by absurd theories, which drew down upon it 
 the imputation of being a visionary and dangerous pursuit; 
 now, by the cautious industry of its cultivators, it is estab- 
 lished as one of the most important of human acquirements. 
 It is taught in our schools and colleges, disseminated by 
 treatises and from lecture-rooms, and especially fostered by 
 every enlightened government. Like most other sciences, 
 it has still a wide field of research before it, many difficul- 
 ties to overcome, and prejudices to remove ; but, linked in 
 connexion with all that is valuable and interesting to man, 
 there is little apprehension for the successful attainment .f 
 its object a c mplere physical history of the planet we 
 inhabit. 
 
 S93 How recently has it come to be appreciated 7 
 894. What were the objections to it anciently t 
 
GEOGRAPHICAL GEOLOGY. 
 
 ASIA, 
 
 SIBERIA. The north-east parts of this immense region 
 present vast marshy plains, called steppes ; but its southern 
 districts are rich and fertile. The Ural and Altai Mountains 
 contain numerous mines, which furnish gold, silver, platina, 
 lead, copper, and iron, the latter appearing in great quan- 
 tities under the form of lode-stone ; also localities of the 
 diamond, topaz, beryl, lapis lazuli, emerald, onyx, quartz 
 crystals, aventurine, rubellite, chalcedony, cornelian, agates, 
 etc. At Ekaterineburgh, are extensive iron-works. The 
 general features of the Uralian range, resemble those of 
 the Altaian. The gold mines extend on the eastern flanks of 
 the former, in a zone running through six degrees of latitude, 
 north and south of Ekaterineburgh ; low ridges also run 
 north from the great Altai chain, in the governments of 
 Yeneseik and Tomsk, where, over an area of 203,000 
 square miles, great quantities of that noble metal are found 
 in the rocks and in the sand and gravel. The most pro- 
 ductive are the mines of Berezovsk, which is the only place 
 in the Russian territory, where the workings are subterra- 
 nean. Generally, the gangue is coarse gravel ; but aurifer- 
 ous veins also occur, inclosed in a bank of rock. 
 
 A ton of the soil yields thirty- six grains of gold, in 
 extraordinary cases, seventy. The auriferous rocks include 
 granites, metamorphised slates, and other igneous and 
 altered rocks. There are three localities of gold washings 
 in the eastern district: between the Tom and the Ob, 
 
 895. What are the chief minerals of Siberia ? 896 How far do 
 the gold mine- extend ? 897. How many localities of gold washings 
 in the eastern delict? 
 
2S2 GEOGRAPHICAL GEOLOGY. 
 
 between the Yenisei and Tom, and between the Lena and 
 the Yenisei. The metal is here found in ferruginous gravel 
 following diorite ; auriferous sands also cap the mountains. 
 In the auriferous alluvium, the quartzy fragments generally 
 yield the most. In the mines south of Miask, there was 
 found, in 1843, a lump of seventy-eight avoirdupois pounds 
 weight. 
 
 CIRCASSIA AND GEORGIA. This is a rough and rugged 
 region, much resembling the " Helvetic Republic." The 
 mountains tower to an immense height, and present sum- 
 mits covered with eternal snow ; while glens and gorges 
 wind into their very heart. In them are extensive groups 
 of basaltic columns. The country in the level parts is 
 exceedingly fertile, and, among the mountains, is highly 
 picturesque. It is very probable that rich and extensive 
 mines here exist. Near Tiflis are hot springs. 
 
 TURKEY. The most abundant rock in Syria and Pales- 
 tine, and which forms the greatest part of the mountains 
 of Libarius, Antilibanus, Carmel. Galilee, and the ridges 
 stretching south from Lake Asphaltites (Dead Sea), is upper 
 secondary limestone, in general, compact, yellowish white, 
 and resembling lithographic stone. On this Jerusalem is 
 built, and of it Solomon's Temple and other edifices were. 
 Mount Libanus is shaped like a horse-shoe, with its opening 
 towards the north, and is referable to the chalk formation. 
 The rocks often contain silicious nodules, as also nodular 
 masses of hornstone, passing into chalcedony, and fine 
 petrifactions. In the sandstones, which are highly ferru- 
 ginous, occur beds of asphaltum, particularly at Hermoii 
 and Carmel. On this mountain lignite is found, and, near 
 the summit, a brittle bituminous shale. On the east flank 
 of Antilibanus, the limestone is found with greenstone ; 
 and a vesiculous basalt with olivine. At Hawran the 
 same rock exists. In a dormant crater, five miles west of 
 Safad, basaltic vesiculous lava occurs, and a very porous 
 variety on the north shore of Lake Asphaltites, and the 
 
 898. What is said of Circassia and Georgia ? 899. What is the 
 most abundant rock in Syria? 900. Of what formation is Mount 
 Libanus? 
 
ARABIA. 283 
 
 ruins of Jericho On the borders of the lake, marly strata, 
 and a high ridge of rock salt, called Usdum, occur. 
 
 That portion of Syria adjacent to the Mediterranean, 
 is a fertile valley ; the part next hi order consists of a 
 double range of parallel mountains, running from south- 
 west to north-east, with innumerable cliffs, narrow valleys, 
 and ravines ; the eastern is an extensive level of rocks and 
 sands. The face of the country in Asia Minor is mount- 
 ainous. The Taurus presents to view a chain of snow-clad 
 mountains, stretching in a curve through the whole land. 
 To the east of Smyrna is a region called the " burnt coun- 
 try." Here are thirty volcanos with many streams and 
 beds of lava. The period of action in them must have 
 been very remote. The rivers of Lydia and other parts of 
 Asia Minor, have supplied large quantities of gold. The 
 country in the south-east part of Turkey is level, subjected 
 to constant inundations. The Dead Sea is placed between 
 two ranges of mountains, and is curved. It is 1337 feet 
 below the Mediterranean. 
 
 ARABIA. This peninsula is divided into, 1. Arabia 
 Petraea, or Hedjaz, the north part of which is mountainous, 
 and, in general, stony, sandy, and barren ; 2. Arabia 
 Deserta, or Nedsjed, which is, for the most part, desert ; 
 and, 3. Arabia Felix, or Yemen, containing many rich 
 provinces on the coast. Granitic rocks compose the high- 
 est peaks around the Red Sea ; as also the mountains on 
 each side of the Arabian Gulf. The same contain por- 
 phyry and greenstone. At Akaba, trap rocks occur ; and 
 ancient volcanic craters in the same region. " The valley 
 of the Jordan, from Mount Libanus to the Red Sea, is a 
 fissure, through which volcanic agency has been active, and 
 the character of the Dead Sea, as well as the thermal 
 springs on its margin, the extensive volcanic rocks in the 
 same region, the rock salt, and great amount of bitumen, 
 and the columnar and amygdaloidal rocks existing near 
 the Jordan, render it highly probable that this igneous 
 agency has been exerted at some former period." " The 
 
 901. What is the face of the country in Asia Minor? 902. Huw 
 is Arabia divided ? 903. What is the geology of the mountain.- \ 
 
4 GEOGRAPHICAL GEOLOGY. 
 
 compact limestone rocks, which bound the Nile in the 
 whole of Upper Egypt, and extend far into the Sahara, as 
 well as the West Ariatic compact limestones, in the north of 
 Arabia, are in the mass composed of the coral animalcules 
 of the European Chalk." Mount Hor and Wady Mousa, 
 are of the new red sandstone series, which extends through 
 ancient Petra to the south of Mount Sinai. 
 
 PERSIA, BALLOGISTAN, AND AFGHANISTAN. Persia on 
 the north part is mountainous ; in the middle and south- 
 east, sandy and desert ; in the south and west, level. Bal- 
 logistan consists of stupendous mountains, and plains, and a 
 iew fine valleys. Moraines occur on the plain north-west 
 of Ararat ; and in the mountains west of Ooroomiah, 
 granitic gneiss is the chief rock, having a dip from 10 d to 
 30 south-east. In the same region limestone, gray sand- 
 stone, and conglomerate with gypsum abound, and also 
 quartz rock, which likewise exists in some of the islands of 
 the lake, and other parts of Persia. Mountains of red sand- 
 stone and conglomerate exist back of Fabreez and other parts 
 of the country. Near the same town, also on the plain of 
 Khay, with gypsum and other places along the confines of 
 Georgia, beautiful rock salt is mined. The white or yellow 
 ish calcareous alabaster of Tabreez, deposited by thermal 
 waters, is found near Lake Ooroomiah. From the lake, the 
 saltest water in the world, are carried great quantities of salt. 
 This lake, which is 1400 yards above the sea, holds in solu- 
 tion one-fifth of its weight, and contains also much sulphu- 
 rated hydrogen. -These indicate volcanic agency in those 
 regions, as well as the sulphur in the soil, and the springs and 
 deposition of asphaltum in ancient Assyria. In Koordistan 
 is a hot sulphur spring. The water rushes out of a crevice 
 in a rock, and after passing some twenty feet, becomes a 
 branch of Khabour. It is as clear as crystal, and of a 
 temperature of 105 Fah. 
 
 In the Kourdish mountains is a crater ; and a boiling 
 spring on the Akhoor On the west side of the mountains, 
 near the Tigris, are some salt springs. An enormous 
 
 904. What rocks occur in the mountains west of Ooroomiah ? 
 905. What i said of the Lake ? 
 
TARTARY, INDIA AND THffET. 285 
 
 deposit of calc sinter occurs near the site of Tact-i-Solomon. 
 In Persian Armenia, stands the stupendous detached moun- 
 tain, Ararat, called by the Turks, Parmak-dahg, the finger 
 mountain. It consists entirely of ancient lava. Near it 
 exists a dormant volcanic crater. The marble in the ruins 
 of Persipolis resembles lias with casts of Turbo. Mines 
 of silver, copper, lead, iron, arsenic, and turkois, are found 
 in Persia. Copper, lead, and silver are mined, and fifty 
 furnaces in operation at or near Tokat. Thirty miles north- 
 east of Tabreez, there exists an extensive and rich ore of 
 copper, the native copper, and the blue and green carbo- 
 nates. Copper, iron, and silver, are also wrought near 
 Samsoun. In the Nestorian country, are mines of lead, 
 sulphur, and orpiment. The latter ore occurs in veins, 
 which run into the body of a high mountain. 
 
 TARTARY. Four grand systems of mountains intersect 
 or border on this vast domain: the Himala, Kuen-lun, 
 Thian-chan, and the Altai. The latter chain presents its 
 magnificent displays of the four great divisions of the strati- 
 fied rocks : primary, transition, secondary, and tertiary. In 
 these metallic deposits are numerous. Of gold 1 140 Ibs. 
 are annually derived ; and of silver 41,992 Ibs. (See Si- 
 beria.) The inland sea of Aral is salt, and has no outlet ; 
 in the vicinity are several small saline lakes. The central 
 part contains deserts of great extent. Volcanos, active and 
 extinct, here occur, filling a space of 7500 square miles. 
 The chief are : Pechan, Ouroumptsi, Kobok, Houtcheon, and 
 Aral-toube. 
 
 INDIA AND THIBET. On approaching the Himala range 
 on the south, we first come to sandstone of the newer 
 secondary series ; then, in succession, argillaceous schist, 
 mica and talcose slate, quartz rock, hornblendic slate, and 
 limestone. The summit is chiefly gneiss, traversed by 
 granite. Porphyry traverses the mica slate. At the 
 base occur tertiary strata, in which, in Birmah, have been 
 found the bones of the mastodon ; and between the Sut- 
 lej and Ganges, the bones of the elephant, mastodon, hip- 
 
 9*M>. What mines in Persia? 907. What mountains and v.Jcauos 
 in Tar inn t 
 
 T a 
 
286 GEOGRAPHICAL GEOLOGY, 
 
 popotamus, rhinoceros, elk, horse, deer, gavials, crocodiles, 
 sivatherium, and the monkey. Here also diluvium occurs. 
 In Middle India, the vast plains are composed mostly ' 
 of clays, sands, and gravel, with remains of animals and 
 fossil wood. Coal also exists, resting on granite. Indostan 
 is composed chiefly of unstratified rocks, though the strati- 
 fied primary exist also ; likewise extensive deposits of 
 secondary, tertiary diluvium, and alluvium. In con- 
 glomerate arid alluvium, diamonds are found in several 
 localities, principally at Golconda, of superior hardness and 
 brilliancy ; while Pegu produces beautiful ruby. Topaz, 
 cornelian, zircon, corundum., schorl, garnets, agates, jasper, 
 amethyst, cat's-eye, chrystolHe, &c., are common. Gold, 
 tin, iron, lead, zinc, and rock-salt occur. 
 
 Thibet is an extremely mountainous, rugged, and sterile 
 country, of very great altitude. From the bottoms or 
 margins of certain salt lakes borax is procured. Mines of 
 copper and mercury are said to be worked. From Slam 
 and Cochin- China large quantities of gold are procured. 
 Geologically, the Malaya peninsula may be considered, 
 when divested of its alluvial fringes, as one continuous belt 
 of hills and mountains, separated from the Indu-Chinese 
 region, in lat. 13 30' north. The zone of elevation con- 
 tinues uninterruptedly ; the western border being a broad 
 skirt of alluvium : beyond this another elevated, zone 
 occurs, succeeded by a second tract of alluvium, which 
 again is bounded by a third elevated belt. The rocks are 
 principally plutonic ; but considerable masses of sedi- 
 mentary matter occur. In Banca, the famous tin island, 
 the prevailing stratified rocks are clays and sandstones. 
 In Malacca are several thermal springs. Iron ores in 
 the south exist in vast profusion ; also, passim. In Singa- 
 pore much of the iron-masked rocks, containing nearly 60 
 per cent, of pure metal, is used to macadamize the roads. 
 It is very probable, also, that the whole length and breadth 
 of the land abounds in tin ore. In Junk- Ceylon and 
 
 908. What is the geology of Indostan ? 909. What- is the surface 
 of Thibet and geology of the Malaya peninsula \ 
 
CHINA, JAPAN, M \L\YSI A. 2^7 
 
 Phunga, about 13,000 piculs are annually dug out of the 
 goil. 
 
 At the two extremities of the peninsular zone of eleva- 
 tion, tin sand is diffused in great quantities, the production 
 being 60,000 piculs. Kedah, Perak, Linga, Sinkep, Salan- 
 gor, and the countries from Kalatan to Pahang, abound in 
 tin. In fine, the entire zone is incomparably the greatest 
 magazine of tin on the globe, whose existence was unknown 
 until 1709. Gold is found principally disseminated in small 
 particles and streaks in quartz. Like the tin ore, it has 
 been seen only in the disintegrated state. Copper, silver, 
 and arsenic have been detected in Banca. 
 
 Ceylon is chiefly stratified primary rock. The prevail- 
 ing rock, gneiss, is associated with dolomite, and subordinate 
 masses of quartz ro?k ; granite, sienite, and greenstone 
 exist. Iron is the most valuable mineral. Chiefly with 
 graphite in gneiss occur the gems : rose and yellow quartz, 
 cat's-eye, topaz, schorl, prase, garnet, pyrope, cinnamon- 
 stone, zircon, sapphire, spinelle, and corundum. 
 
 CHINA. The surface of this country is diversified with 
 mountains, valleys, and plains, whose known rocks are, 
 granite, sienite, porphry, sandstone, &c. The minerals 
 wrought are, gold, silver, copper, mercury, iron, lead, tin, 
 arsenic, coal, and marble. The other valuable minerals 
 are, porcelain clay, jasper, rubiefc, Corundum, lapis, lazuli, 
 topaz, jade, and agate. 
 
 JAPAN. But little more is known of the geology of this 
 empire than the fact that several volcanos exist. Gold, 
 silver, copper, and mercury are the chief metals, in the 
 working of which the Japanese excel. Sulphur, coral, 
 amber, porcelain clay, and amber abound. 
 
 MALAYSIA. Borneo is mountainous in the interior, but 
 low and marshy toward the coast. Primary formations 
 abound, forming the axes of the principal mountain chains ; 
 while the secondary, tertiary, arid alluvium occupy the 
 lower regions. Volcanos also exist. Diamonds and gold 
 
 910. What is the principal rock in Ceylon ? 911. What are the 
 chief minerals of Ceylon? 91 "2. What are the known rooks and 
 minerals in Ch na ? 
 
288 GEOGRAPHICAL GEOLOGY. 
 
 are the chief minerals. In the interior of Java, through 
 its whole length, is an uninterrupted range of mountains, 
 38 of which are large volcanos, and at their bases are ter- 
 tiary deposits of limestone, clay, and marl, with rock-salt. 
 Sulphur is here obtained in great abundance and purity. 
 Through the whole extent of Sumatra a chain of mountains 
 runs ; and between the ridges are extensive plains consider- 
 ably elevated above the surface of the maritime lands. 
 Here also are four volcanos ; while granite, trap, limestone, 
 and other primary rocks exist, as also tertiary clays. Gold, 
 tin, iron, copper, and lead abound. Coal has recently been 
 found, by a Siamese of Penang, on the south side of Junk- 
 Ceylon. ' The bed is three feet thick ; and the coal of a 
 blackish color, and very bituminous. Banca, which con- 
 sists of gneiss and mica slate with granite, abounds in tin 
 and copper. (See India.) The Philippine and Moluc- 
 cas are volcanic. Celebes, or Macassar, contains primitive 
 rocks ; gold is an export. 
 
 AUSTRALIA. This insular continent contains mountains, 
 extinct volcanos, and arid wastes. The coast for the most 
 part is bold, rocky, and mountainous ; the rocks which are 
 known being granite, mica and talcose slate, quartz, ancient 
 limestones and sandstones, coal formation, red marl, with 
 oolite and salt ; also porphyry, greenstone, amygdaloid, 
 clinkstone, and serpentine. Coal, iron of a pure quality, 
 copper, 'and lead abound. The Illawarra coal region is 100 
 miles south of Newcastle on the coast, and is referable to 
 the oolitic period.* The Burra Burra copper mine, in South 
 Australia, yielded in 18 months 9841 tons of the ore ; 
 value < 150,000. Gold has also been recently found here, 
 and topaz and agate. Fossil bones from limestone caverns 
 have been collected, and referred to 14 species of animals 
 similar to those living ; as the kangaroo, hypsiprimus, wom- 
 bat, dasyurus, and elephant. 
 
 * See M'Coy on the Fossil Botany and Geology of the rocks asso- 
 ciate ! with the coal of Australia. 
 
 on. What is the geology of Borneo :>nd Sumatra? 914. Whete 
 tlu- bin ra Lurra copper mine f^uatrd? 
 
mi.YNE^I . F.AHBA Y. 289 
 
 POLYNESIA. The predominant formations in this vast 
 archipelago are, the volcanic and the coral reefs. The coral 
 isle? are low and level, e. g., Whitsunday, Elizabeth, Queen 
 Charlotte, Egremont, Lagoon, and many other islets be- 
 tween the 30th parallels of lat., usually being scattered in 
 a linear manner over a great extent. The Dangerous 
 Archipelago is 1200 miles long; Maldivas, 480; and a 
 line of reefs between Papua and Australia is 700 miles 
 long. The volcanic isles rise to a great height ; as the 
 Sandwich, Friendly, Gallipagos, New Hebrides, Marque- 
 sas, and Gambler's. The shores of nearly all these are 
 lined with coral. The South Shetland and Orkney islands 
 consist of primitive rocks, along with those of more recent 
 igneous origin. Juan Fernandez is all basaltic greenstone. 
 The Society are of igneous rocks ; such as basalt. 
 
 AFRICA. 
 
 BARBARY. The southern part of this region is a sandy 
 plain. From the coast of the Atlantic to the borders of 
 Egypt extends the lofty chain of Mount Atlas, whose sum- 
 mit is of granite, gneiss, mica slate, and clay slate. Calca- 
 reous rocks chiefly make up" the north part of the range. 
 Secondary sandstones and tertiary strata occur, including 
 trap. In Algeria mineral springs and waters abound ; and 
 several mountains contain lead and copper. Bona is the 
 seat of the noted coral fishery. Salt of the best quality is 
 produced in abundance from rocks and various sources of 
 salt water. Salt lakes, or marshes and streams, appear 
 innumerable ; and banks and mountains are met with. 
 The mines near Biskra, and five leagues west of Milah, 
 are imbedded in the cretaceous fonnation, and inexhausti- 
 ble. Biled ul Gerid is sterile and sandy. Tunis abounds 
 with salt ; and mountains near the capital yield silver, cop- 
 per, and lead. The eastern part of Tripoli is desert ; gold 
 dust is exported. Barca is a barren desert. Gypsum is 
 also said to occur in Rarbajy. 
 
 915. What formations predominate in Polynesia? 916. What 
 rocks occur in the Atlas chain 1 
 
290 GEOGRAPHICAL GEOLOGY. 
 
 ZAHARA. This immense expanse is but a dreary waste, 
 interspersed with few oases. Some parts consist of soiJ 
 baked nearly as hard as marble by a torrid sun ; while 
 others are covered with a quartzose and calcareous sand, 
 which is whirled about by every wind, and often formed 
 into immense heaps. Occasionally rocks rise through the 
 sand, which, in the east part, are sandstone and limestone, 
 containing rock-salt and gypsum, and traversed by trap. 
 The rocks by the coast are basaltic. 
 
 THE REGION OF THE NILE. The south part of Egijpt 
 is primary ; the feldspar in the granite and sienite being 
 red. To the north of Syene (whence sienite) we met with 
 sandstone of the recent secondary rocks. Then succeeds the 
 limestone tract, which stretches from Thebes south. Allu- 
 vium occupies the portion between the Mediterranean and 
 the plain between Kous and Esne. Sands from the Lybian 
 desert, borne east by westerly winds, have formed on the 
 west side of the Nile remarkable downs or moving sand 
 hills. Since 1243, the delta has advanced a mile atDami- 
 etta ; and the same at Foah since the 1 5th century. Mines 
 of gold were once wrought in Nubia, and some is exported 
 at the present time. Excepting the banks of the river, the 
 country is sandy. Granite, sienite, porphry, sandstone, and 
 limestone are known to exist. Abyssinia is mountainous ; 
 gold occurs, arid salt abounds. Salt is the general medium 
 of commerce in Darfoor. On the east of the country of the 
 Shilluks gold abounds. Copper mines are said to exist in 
 Fertit. The Jibbel el Kumri are elevated 15,000 feet above 
 the sea. 
 
 WESTERN AFRICA. To the south of Zahara, from the 
 Senegal to the Cape of Palms, gold is found ; as also in the 
 sands of the Gambia, the Senegal, and the Niger. The 
 Gold Coast in the meridian of Greenwich has long yielded 
 large quantities of gold dust. Granitic mountains encom- 
 pass Sierra Leone. Copper, tin, lead, and iron occur in 
 Loango, The district in lat. 6 C south consists of granite, 
 sienite, gneiss, mica slate, clay slate, primary limestone, aud 
 
 917. What b said of Zahara ? 918. Give the geology of Eg ypt. 
 919. What metaLs ami rocks in Loango ? 
 
SOU THE UN AND EASTERN AFRICA. 291 
 
 queenstone. Salt, iron, and copper abound in Angola. 
 Cimbebas is desert on the coast. 
 
 SOUTHERN AFRICA. Three chains of mountains run 
 through this region parallel to the coast, the height increas- 
 ing toward the north. The rocks are sandstone, gneiss, 
 clay slate, grauwacke, and quartz rock. The first is the 
 chief rock in the extensive table lands extending to the 
 equator. Its strata, usually horizontal, give a tabular shape 
 to the tops of the mountains. Table Mountain is an exam- 
 ple. Masses of granite, basalt, pitchstone, and red iron ore 
 protrude through these rocks, whose relative situation is the 
 same as in Europe. The desert of Challahengah lies on the 
 tropic of Capricorn. Cape Town rises in the midst of a 
 desert, surrounded by black and dreary mountains. 
 
 EASTERN AFRICA. The Lupata Mountains extend 
 from the equator to those in South Africa. Hosambique, 
 especially between 25 and 22 south, is rich in gold, which 
 is washed down by the rivers in great quantities, and 
 makes a chief part of its commerce. Cazembe yields iron 
 and copper in abundance. In long. 33 10 east, lat 13 
 iO south, lies the extensive salt lake Maravi. Rich mines 
 of gold are worked in the kingdoms of Zanzebar. Azania 
 is sandy and hilly ; gold is an export. Mountains bound 
 its coast. The surface, soil, and productions of East 
 strongly resemble those of West Africa. 
 
 SOUDAN. The surface is much varied in elevation. 
 Gneiss, mica slate, clay slate, horn blendic rock, quartz 
 rock, and limestone, traversed by granite, greenstone, and 
 other trap rocks, constitute the parts of greater altitude. 
 Salt and natron lakes occur, and vast beds of rock-salt are 
 quarried. Sou-re, Bambarra, and other places abound in 
 gold. Basaltic columns occur at Goree. According to the 
 natives, Lake Tchad runs into the Nile by a subterranean 
 passage. 
 
 AFRICAN ISLANDS. Most of these are volcanic, con- 
 sisting of basalt or lava. Madagascar is traversed by 
 a chain of lofty mountains, mostly granitic, and rich in 
 
 920. What rocks in Southern Africa? 921. What metals are 
 found in Cazembe ? 922 What rocks in Soudan ? 
 
minerals. Bourbon, contains a volcano constantly in ac- 
 tion. The highest peak is 10,000 feet above the sea, 
 Mauritius is chiefly composed of lofty mountains; and 
 abounds in iron. St. Helena presents to the sea a per- 
 pendicular wall of rock, from 600 to 1200 feet high. 
 Diana's Peak, in the centre, rises 2700 feet above the sea. 
 The soil of the Cape Verde Ides is dry and arid ; and the 
 surface mountainous. Fogo, one of them, contains an 
 active volcano. Salt is a chief article of trade. The 
 Canaries contain numerous mountains, of which the most 
 noted is the volcanic Peak of Teneriffe, 12,072 feet high. 
 Madeira consists of a lofty mountain with many peaks. 
 In the Azores, are forty-two active and dormant volcanos* 
 and many submarine. 
 
 EUROPE. 
 
 ENGLAND Affords a variety of scenery : the north- 
 ern part is hilly ; the eastern coast, sandy and marshy 
 in many places ; and the great Alpine chain extends from 
 Cornwall to the extremity of Scotland. The last is com- 
 posed of primary and transition rocks, and probably con- 
 nected with all the granite ranges of the continent. A 
 range of calcareous hills extend, in a waving line, from 
 the western extremity of Dorsetshire, to the eastern side of 
 Durham. East of this line are no beds of mineral coal. 
 The unstratified rocks, and the Cambrian and Silurian 
 groups, are mostly confined to the western districts. The 
 part embraced between Orwell and Humber rivers and 
 east of the meridian of Greenwich, and the strip between 
 Liverpool and Lancaster bordering the sea, consist chiefly 
 of alluvial and diluvial soil. The vicinities of Southampton, 
 Cowes, and the Thames, are tertiary. 
 
 The southern coast, extending from Exmouth to Mar- 
 gate ; a line drawn from Exmouth to Birmingham ; thence 
 
 923. What is the geology of the African Islands ? 924. How ninny 
 vqlcanos in the Azores ? 925. Give the geology of England. 
 
ENGLAND. 293 
 
 one to Berwick ; the coast from Berwick to Hull ; a line 
 drawn thence to Peterborough ; thence one to Colchester ; 
 thence one to Reading ; and thence to Margate ; include 
 the secondary district, chiefly calcareous, and partly covered 
 by tertiary and alluvial depositions. The part between 
 Land's End and Bristol, and that between Bradford and 
 Scotland, are transition and primary. The strip between 
 Exeter and Derby, and the part included between Liver- 
 pool, Wales, Huddersfield* and Worcester, consist of inter- 
 mixed formations ; as also the Isle of Man. Cornwall 
 abounds with rocking-stones ; and many cavenious parts of 
 the rocks yield " Cornish Diamonds." Steatite occurs at 
 Lizard Point ; kaolin is afforded by the granite rocks ; 
 while slate and marble are supplied from the mountain 
 range But the chief treasures of this part of the island 
 are the ores of tin, copper, and lead ; besides which are ores 
 of silver, antimony, cobalt, bismuth, manganese, zinc, and 
 iron. Gold is occasionally found in the sands of rivulets. 
 
 Rich mines of lead, copper, and zinc, are also found hi 
 the mountain limestone of other parts of England. In the 
 mountains of Cumberland, occur beds of red unctuous fer- 
 ruginous clay and iron stone ; in one of which, above 
 Seathwaite, is found the celebrated graphite. The longest 
 mineral dyke, that has been traced, is the Cleveland, ex- 
 tending from Cock field to the sea, ten miles below Whitby. 
 It is about ten yards wide ; being a dark greyish brown 
 basalt. The transition limestone of the northern range is 
 rich in mines of lead and zinc. Extensive deposits of iron 
 often accompany the coal formation. Strata of the latter 
 extend from Berwick-on-Tweed to the Tees ; thence to the 
 Air. Another coal-field commences a little north of Leeds, 
 and extends in breadth, twenty-five miles, and in length, 
 about seventy. Small coal-fields are near Ashby-de-la- 
 Zouch, Tamworth, Atherstone, and Coventry. Bordering 
 the sea in Cumberland, is another ; as also in Lancashire, 
 Dudley, and Wolverhampton, Somersetshire, and Glouces- 
 tershire. 
 
 926. What minerals occur? 927. Where are the principal coal- 
 fields situated ? 
 
 13* 
 
291 GEOGRAPHICAL GEOLOGY. 
 
 , The chief repositories of gypsum, rocksalt, and the 
 strongest springs of brine, are situated in the red marie of 
 Cheshire and Droitwich, and the new red sandstone at 
 Northwich. 'Subterranean forests occur on the Lancashire 
 and Norfolk coasts, and in Yorkshire and Lincolnshire. 
 Thermal springs are in Bath, Derbyshire, and Somerset- 
 shire. At Matlock are two chalybeate springs. In the 
 London clay, the septaria produces the valuable Roman 
 Cement. Shropshire abounds in lead, copper, iron, lime- 
 stone, freestone, pipe-clay, bitumen, and coal ; Monmouth- 
 shire in limestone, coal, and iron ; Nottinghamshire in a 
 kind of stone resembling alabaster ; Derbyshire in lead, 
 iron, coal, marble, alabaster, millstones, barytes, and fluor 
 spar ; Staffordshire in copper, lead, coal, stone quarries, 
 alabaster, and limestone ; Worcestershire in coal and salt ; 
 Durham in coal, lead, iron, quarries of marble, slate, mill- 
 stone, firestone, limestone, grindstone, and freestone ; Lan- 
 cashire in cannel-coal ; Northumberland in lead, coal, iron, 
 salt, and limestone ; Cumberland in coal, lead, copper, iron, 
 graphite, and lapis calaminaris ; Westmoreland in lime- 
 stone and blue slate ; Suffolk in shell-marl. 
 
 WALES. This principality is mountainous ; the south- 
 ern coast being secondary, and the rest, primary and 
 transition. In South Wales, adjoining the Bristol Channel, 
 lies an almost exhaustless supply of coal and ironstone ; as 
 also in the north-east border. Anglesey abounds in copper 
 and sulphur ; Caernarvon in copper, lead, and blue slates ; 
 Denbigh in lead and coal ; Flint in lead, calamine, coal, 
 limestone, arid freestone ; Montgomeryshire in lead, slate, 
 arid lime ; Cardigan in lead and silver ; Caerrnarthen in 
 coal, lead, and lime ; Glamorgan in lead, coal, iron, and 
 limestone. In North Wales, gold occurs in quartz veins 
 
 SCOTLAND. The general aspect is rugged and mount- 
 ainous ; and the formations, primary, transition, arid the 
 secondary, as far as the cretaceous system, with a covering 
 of superficial accumulations. Sutherland abounds in iron- 
 si one, limestone, slate, lead ; Inverness in limestone, iron, 
 
 928. Where are the chief deposits of gypsum and rocksalt? 
 929. Give the geulogy of Wales. 980. What tor mat loan in Scotland i 
 
IRELAND. 296 
 
 and rock-crystal ; Fife in coal, iron, salt, lime, and free- 
 stone ; Argyle in copper, lead, and iron ; Aberdeen in 
 manganese, graphite, and quarries of granite, millstone, 
 and limestone ; Forfar in freestone and limestone ; Perth 
 in gold at Glen Turret ; Clackmaiian in coal and salt ; 
 Stirling in iron, coal, limestone, and basaltic rock; Edin 
 burgh in coal, iron, limestone, and marble ; Haddington in 
 coal ; Ayr in coal, freestone, limestone, iron, copper, and 
 lead ; Lanark in gold at Cumberhead ; Dumfries in coal, 
 lead, freestone, and limestone. Pearls and variegated 
 pebbles are also included in the mineral productions of 
 Scotland. The Brora coal, is poor, and said to be in oolite. 
 The Hebrides are noted for unstratified rocks. In Staffa is 
 the magnificent cave of Fingal, 200 feet long, bounded on 
 each side by splendid basaltic columns in perpendicular 
 ranges, and roofed by the fragments of others. Rich mines 
 of lead and gold occur at Lead Hills. 
 
 IRELAND. Here on an extensive scale occur all the 
 primary, transition, and older secondary formations. Be- 
 neath the trap, in succession, lie chalk, green sand, lias, 
 and variegated marls. The former is often changed into 
 granular limestone. Trap is the feature of Ulster in 
 area, 800 square miles, in thickness 545 feet. Antrim has 
 an astonishing work of nature the Giant's Causeway, 
 consisting of a vast number of perpendicular pillars of 
 basaltic rock, rising frem 200 to 300 feet above the water. 
 Carlo w of Leinster abounds in limestone ; Kilkenny in 
 coal, and quarries of white and black marble ; Kings in 
 limestone. The coal in Munster is chiefly anthracite. 
 Cork abounds in coal, iron, and lead ; Kerry in mineral 
 waters. Lead, silver, and salt are also found in Ireland ; 
 while the copper mines of Allihies, Coonbane, arid Tigrony, 
 are extensive. Gold occirrs disseminated in the beds of 
 the streams which descend from the northern flank of 
 Croghan Kinshela ; and Ballinvally, Killahurler, and Bal- 
 Ititemple, largely yield the precious metal associated with 
 magnetic iron-stone, iron-pyrites, wolfram, red and brown 
 
 'J31. What strata are found in Ireland ? 932. Describe the Giant's 
 933. Where does gold occur? ' 
 
206 GEOGRAPHICAL OHOLOGY. 
 
 haematite, manganese, tinstone, and quartz. Peat bogs 
 occupy an area of 2,000,000 of acres, and a thickness of 
 from 15 to 25 feet. 
 
 RUSSIA. The surface is generally level, bounded on the 
 south by the Silesian and Carpathian chains, and on the 
 north by the Ural. These, together with Russian Laplaud 
 and Finland, are primary, transition, and" lower secondary ; 
 yet tertiary arid alluvium chiefly predominate in the coun- 
 try. Old and new red sandstone, with the coal formation 
 intervening ; lias and other limestones, with green sand and 
 chalk, also occur. The diluvium is a deposit of clay, sand, 
 arid bowlders, containing relics of extinct land animals, and 
 brought from the north-east. Plutonic rocks are rare ; 
 though the Caucasus yields trachyte. The tertiary strata 
 correspond with those of Hungary.* The eastern slope of 
 the Ural has the greatest attractions for the miner ; but it 
 is towards the west that it offers to the geologist the most 
 complete and distinct stratigraphical succession. There is 
 here a great development of the Devonian system, and cop- 
 per abounds. In the empire medicinal and saline springs 
 (iron, copper, and silver) occur, and deposits of salt are 
 found in the new red sandstone with gypsum, while coal is 
 not extensive. In Russian Poland are, gold, silver, cop- 
 per, lead, iron, and marble ; also rubies, diamonds, crystals, 
 and other precious stones. At Sandomir are mines of 
 vitriol ; and in Riga iron. 
 
 SWEDEN AND NORWAY. The former is, in general, a 
 flat country ; the latter, rough and mountainous. Chalk 
 occurs, and, in Sweden, some recent tertiary strata ; but 
 the chief rocks are primary, transition, and lower secondary. 
 In Norway the formations of syenite arid porphyry are ex- 
 tensive ; and the mountains are mostly gneiss, with mica 
 and talcose slates. The diluvium, however, resembling 
 
 * The geology of the great north eastern angle is giren in the 
 new work of Count Keyserling, entitled, " Weisenschaftliche Beo- 
 bichtunfjen aaf einen Reise in das Petschor aland," with 23 elegant 
 4to plates of fossils, and two maps. 
 
 934. What formations in Russia ? 935. What is said of the Ural 
 range ? 906. What rooks in Sweden and Norway ? 
 
DENMARK. FRANCE. 297 
 
 that of New England, is the most remarkable. The east- 
 ern shore has risen from 100 to 200 feet, and is still rising. 
 The exports of Norway are, copper, silver, cobalt, iron, and 
 alum ; while extensive quarries of porphyry, granite, and 
 marble are worked. The iron usually accompanies gneiss. 
 The Swedish mines of silver (at Kongsberg), gold, and iron 
 are prolific. East Gothland has fine quarries of alum, stone, 
 and marble. 
 
 DENMARK. The surface is flat and lw, the soil sandy 
 and marshy, chiefly composed of weald, clay, and chalk, 
 covered by tertiary and superficial accumulations. The 
 surface of Iceland is mountainous, stony, and barren ; pre- 
 dominant rocks being ignigeuous of two epochs : 1. that of 
 greenstone or dolerite ; 2. that of modern volcanos. The 
 Snaefell Yokul is 4560 feet high. Mount Hecla, caldrons 
 of boiling mud, geysers, and sulphur springs are other nota- 
 bles. The Feroe Ides are of ignigenous rocks, with harbors 
 faced with tremendous precipices. They afford agate and 
 jasper, while the amygdaloidal rocks, as also those of Ice- 
 land^ produce beautiful zeolites. 
 
 FRANCE. The chief part is one widely-extended plain. 
 All rocks occur. Diluvium abounds, and is rich in fossil 
 extinct animals, particularly the pachydermata. There are 
 six large tertiary basins : chalk, oolitic limestone, and new 
 red sandstone form extensive tracts ; but the coal strata are 
 less than in England. Cantal is noted for its extinct vol- 
 canos ; the rocks being basalt, trachyte, and tufa. Brit- 
 tany is hilly, with extensive heaths. Coal, iron, lead, silver, 
 copper, manganese, antimony, vitriol, alum, marble, gyp- 
 sum, slate, flint, and burhstone abound ; while cobalt, 
 nickel, arsenic, and tin also occur in the Republic. The 
 surface of Corsica is mountainous ; the soil stony ; the 
 rocks chiefly primary and transition ; the whole rich in 
 iron, lead, copper, silver, alum, saltpetre, porphyry, jas- 
 per, amianthus, talc, emeralds, &c. ; and the south coast 
 abounds in beautiful coral. In the valley of the Rhine, 
 between Basle and Manheim, is a noted gold district. 
 
 937. Describe the surface of Denmark and Iceland ? 938. What 
 minerals in France and Corsica ? 
 
298 GEOGRAPHICAL GEOLOGY. 
 
 SPAIN. The surface is very mountainous ; arid usually 
 the axes of the Pyrenees and others are primary, transition, 
 and lower secondary rocks. Tertiary and recent secondary 
 strata to the chalk occur ; while middle secondary are often 
 of great altitude. Gold, silver, lead, mercury, iron, copper, 
 antimony, cobalt, cinnabar, graphite, sulphur, alum, ame- 
 thyst, agate, and chalcedony are found. Marble and alabas- 
 ter abound ; iii Catalonia are 117 varieties. The same 
 district also has beds of rock-salt, and around Olot is a 
 region 'of extinct volcanos. Asturias abounds in coal. The 
 Bahares are mountainous. The calcareous rock of the 
 Gibraltar promontory rises 1300 feet above the sea. 
 
 PORTUGAL. Portuguese geology resembles that of Spain. 
 There are mines of coal, iron, copper, tin. graphite, mercury, 
 and lead, and quarries of marble. St. TTbes is noted for its 
 salt-works ; and the sands of the Tagus are a little auri- 
 ierous. 
 
 GERMANY. Lofty primary mountains bound it on the 
 east and south-west. Secondary strata are less extensive 
 than in England ; yet most of the fossiliferous rocks of the 
 latter are in the same relative position in Germany. Dilu- 
 vial detritus from Scandinavia covers the tertiary rocks 
 which form the level of the north ; and all of four other 
 tertiary deposits occur in the United States of Central Eu- 
 rope. Indeed, near all Neptunian rocks here exist. The 
 primary Hartz abound in silver copper, lead, iron, zinc, 
 sulphur, vitriol, salt, and coal ; and the Erzhgeberge in 
 silver, iron, copper, tin, lead, cobalt, bismuth, and arsenic. 
 Bohemia abounds in gold, silver, copper, tin, iron, lead, and 
 mercury ; Tyrol in salt, gold, silver, and copper ; Wur- 
 temberg (at Halle) in salt ; Hesse in coal, iron, and copper ; 
 Westphalia in lead, iron, coal, and salt ; Brandenburg in 
 iron ; Silesia in coal, copper, lead, iron, antimony, sulphur, 
 nitre, mercury, alum, vitriol, agate, jasper, and some gems ; 
 &iyria in iron ; lllyria and Deux fonts in mercury. 
 
 SWISSERLAND. Here mountains tower to an immense 
 height,- between which are extensive glaciers, enormous 
 
 940. What metals are found in Spain? 941. What mine? in Por- 
 tugal 1 942. What is the geology of Germany? 
 
SWISSEKLAND. HUNGARY, &C. ITALY. 299 
 
 rocks, frightful precipices, terrific avalanches, roaming tor- 
 rents, and fertile vales. The centre of the Alps is of gneiss, 
 mica, hornblendie, and talcose slates, and limestone ; the 
 first often becoming protogine : e. g., Mount Blanc. On the 
 iiauks are deposits of new red sandstone, the oolitic system, 
 and tertiary strata, with a covering of diluvium. The ter- 
 tiary rise from 2000 to 4000 feet above the sea. The Alps 
 also contain granite, sienite, porphyry, and greenstone. 
 
 HUNGARY, TRANSYLVANIA, GALICIA, CROATIA, AND 
 SCLAVONIA. Neptunian and Plutonic rocks here occur ; 
 the latter including trachyte, trachytic porphyries, tufas, 
 and conglomerates. Hungary abounds in gold, silver, cop- 
 per, and iron ; Transylvania in gold, silver, lead, copper, 
 mercury, and tellurium ; one solfatara has also been found ; 
 (jalicia (at Wieliczka) in salt. 
 
 BELGIUM AND HOLLAND. The surface is nearly flat, 
 and much of it below the level of the sea. No rocks below 
 the transition occur. Clay-slate is the oldest ; above this 
 are the secondary, one or two tertiary basins and a coat of 
 diluvium. Belgium (chiefly at Mons,) abounds in bitumin- 
 ous coal and anthracite ; and Luxemberg in iron mines. 
 
 ITALY. Italy has the loftiest mountains and most 
 beautiful plains in Europe. The Appenines are of lime- 
 stone ; though in some parts are slate, euphotide, and 
 gabbro ; and the Sub-Appenine hills are tertiary, with 
 shells like those found in the Mediterranean. And the 
 whole chain evidently has been elevated some 4000 feet 
 since the tertiary formation. The Mediterranean shores are 
 alluvial ; and in the clefts and caves of the rocks bone 
 breccia is found. Marbles abound ; coal occurs ; iron, 
 silver, lead, copper, have been wrought. Naples contains 
 two volcanos and one solfatara. In Calabria granite, gneiss, 
 and mica-slate exist ; and most of the rocks of Sicily are 
 secondary and tertiary. The latter supplies Europe with 
 sulphur ; Cosenza abounds with salt. In the Isle of 
 Sardinia the chief rocks are primary, transition, and lower 
 
 943. What is said of Swis^erland ? 944. What is the surface of 
 Belgium and Holland? 945. Of what fi.nriHtion is the Appeuine 
 rmie ? 94rt. What rocks in Sicil? 
 
GOO GEOGRAPHICAL GT:OLOGT. 
 
 secondary ; Jura limestone occurs ; as also tertiary strata 
 covered by diluvium, with volcanic rocks. Tuscany yields 
 iron, alum, vitriol, marble, alabaster, porphyry, and min- 
 eral waters. Parma abounds in copper and silver GOTO 
 arid Malta are mostly made up of soft limestone ; the 
 Lipari Isles, Procida, and Jochia are of volcanic origin, 
 the first affording sulphur, alum, nitre, cinnabar, pumice, 
 &c. Iron abounds in Elba and Sardinia. 
 
 TURKEY. Here mountains are interspersed with fine 
 extensive valleys ; and the geology is similar to that of 
 Hungary. W^allachi abounds in fossil salt ; and its rivers 
 yield g Id. Some of the mountains are rich in iron ; also 
 rocks of mica, with copper and talc. Mount Pangeus, was 
 once famed for its mines of gold and silver. Marble and 
 potter's clay are found in the islands of the Archipelago. 
 
 GREECE. In its geological features is like unto Turkey. 
 Of the Ionian Republic, Zante has springs of petroleum ; 
 and St. Maura, salt. 
 
 NORTH AMERICA. 
 
 An immense chain of mountains stretches from north 
 to south, along the Pacific coast, through the whole extent 
 of the Western Continent ; called, in South America, the 
 Andes ; in Guatemala and Mexico, the Cordilleras ; and 
 thence to the Polar Sea, the Rocky Mountains. Parallel 
 to the Atlantic, the Appalachian chain traverses the North- 
 ern Continent, forms the Indies of the West, and joins the 
 Andes of Brazil. Hence arise three great divisions : the 
 Atlantic Slope, the Mississippi Valley, and the Plain beyond 
 the Rocky Mountains. 
 
 RUSSIAN AMERICA, AND GREENLAND. This desolate, 
 barren, and almost unknown region, contains two remark- 
 able mountains : St. Elias and Fairweather ; the former 
 17,900, the other, 14,796 feet above the Pacific. In the 
 
 947. What is said of Turkey and Greece ? ' 948. What mountain 
 chains in America? 949. What rocks in Russian America? 
 
THMTTSri AMERICA. MOl 
 
 North part of Greenland are the Arctic Highlands, and 
 cliffs, with red snow. 
 
 BRITISH AMERICA. The Rocky Mountains, which are a 
 continuation northward of the Cordilleras, are primary 
 flanked by secondary deposits, containing clay slate, grau- 
 wacke, and limestone. West of these is a volcanic strip, 
 the prolongation of a line 6000 miles long. Bowlders of 
 limestone, granite, porphyry, greenstone, &c., are scattered 
 over most of the northern region ; while clay slate with 
 a cover of trap compose the Arctic coast from Cape Lyon to 
 Coronation Gulf. Melville Island consists of sandstone with 
 relics of tropic coal plants. All classes of rocks, except 
 tertiary, are found around Hudson's Bay. Low ranges of 
 mountains, having a south-west direction, commence in 
 Labrador, become more elevated on the south shore of the 
 St. Lawrence, and form the northern termination of the 
 Afipalachian chain. Between Labrador and the Hudson 
 River, the rocks are chiefly primary ; but the coast of the 
 former is hypersthenic and feldspathose ; and along the St. 
 Lawrence is a deposit of black fossiliferous limestone. And 
 the north part of Nova Scotia is secondary limestone, with 
 trap above and clay slate beneath, and embracing gypsum 
 and saline springs ; wliile coal measures intervene between 
 the slate and sandstone. Coal, with grauwacke and clay 
 slate, has also 'been found in the interior of New Brunswick; 
 as also in Cape Breton. Iron also abounds in the penin- 
 sula of Nova Scotia. Primary rocks predominate in Up- 
 per Canada; but one north of the lakes, and the rocks in 
 the northern part of Lower Canada, are similar to those 
 on the Labrador coast. (Gold has lately been found in the 
 valley of Chaudiere, a ton of the raw material yielding $4.) 
 On the north side of, and parallel to, the St. Lawrence, run 
 two mountain ranges ; one 17, the other 200 miles distant. 
 They develope themselves in Essex county, New York ; 
 thence stretch to Kingston, where they connect with a low 
 range which extends along the shores of the lakes and boun- 
 
 950. What rocks are found in British America? 951. What mi- 
 nerals occur here ? 952. What rock* predominate in Canada ? 
 
,>!):J GEOGRAPHICAL GKOLOGY. 
 
 dary of the United States to the Rocky Mountains. New- 
 foundland is mountainous and rugged. 
 
 UNITED STATED. The Appalachian chain occupies all 
 New England, crosses the Hudson, and forms four parallel 
 and lofty ranges of mountains in Pennsylvania, Maryland, 
 Virginia, the Carolinas, and Tennessee. The Allan iic 
 slope terminates at New York ; but the Central Valley 
 extends from the Gulf to the Polar Sea, and is bounded on 
 the east and west by primary rocks. The mountainous 
 region east, of the Hudson consists of gneiss, mica, and tal- 
 cose slates, quartz rock, and limestone, intersected and 
 upheaved by granite, sienite, greenstone, and porphyry ; 
 except : fossiliferous rocks appear in the east part of Miine, 
 pieces of transition rock containing anthracite in the east 
 part of Massachusetts and Rliode Island, and new red 
 sandstone with protruding greenstone in. the Connecticut 
 Valley. The same primary range continues through New 
 Jersey and Pennsylvania. The eastern belt passes near 
 New York City, Staten Island, and terminates at Perth 
 Amboy, where it is covered by red sandstone. 
 
 At Trenton it commences a second primary band, 90 
 miles wide, and parallel to the one ending in Pennsylvania, 
 a trough of red sandstone intervening. It passes through 
 Virginia, the Carolinas, Georgia, and, at the Alabama 
 River, under the alluvium ; while cretaceous and tertiary 
 strata cover its south-eastern flank. A range of Labrador 
 feldspar and hyperstheriic rock joins that on the west of 
 Lake Charnplain, occupies a large tract south of Lake Su- 
 perior, and probably reaches to the Mississippi. Transition 
 rocks rest on the primary over most of the valley. The 
 same red sandstone, commencing in Nova Scotia, forms a 
 wide belt below the Highlands ; and thence passes in a 
 south-east direction to North Carolina. Copper ores, bitu- 
 minous shale and limestones, and protruding greenstone are 
 associated with the deposit as far south as Virginia. 
 There it is very calcareous ; brecciated Potomac marble 
 being one of its lowest beds. The cretaceous system begins 
 
 953. What rocks east of the Hudson ? 954. Describe the primary 
 range. 955. What is the extent of the cretaceous system i 
 
VMTKD STATES. C03 
 
 at Nantucket, passes to New Jersey, and thence in a wide 
 belt to Alabama. It also embraces much in .Af&Sts&jgpt, 
 7V nttessee, Arkansas, arid Louisiana ; and extends from 
 Lake Eustis along the Missouri to Council Bluffs. 
 
 The tertiary group of deposits commences at Martha's 
 Vineyard ; reappears in the south-east part of New Jersey, 
 and passes through the Atlantic coasts of Delaware, Mary- 
 land. Virginia, and North Carolina and interruptedly 
 through South Carolina, Georgia, Alabama, Mississippi, 
 .and Louisiana. " The post-tertiary with shells of a highly 
 arctic character has been recognized in New York, and 
 Canada." The tertiary rocks are the chief occupants of 
 the level portion of the Southern States east of the Appa- 
 lachian range, aiid the south part of the Valley. The 
 erratic blocks of Barre and Fall River, Massachusetts, the 
 bursting of Long Lake in Vermont, the slide in the White 
 Mountains, and the transportation of primary pebbles on 
 the right bank of the Mississippi, are instances of diluvial 
 action. In Maine, the direction taken by the diluvium 
 was south; in Massachussets, a few degrees east of south ; 
 in eastern New York, the same ; in western, west of 
 south ; parts bordering on Pennsylvania and New Jersey 
 varied some degrees west from south, to south-east ; and 
 near New York city, north-west and south-east ; the fos- 
 siliferous region of western New York is strewed over 
 with bowlders, from western Michigan and from Upper 
 Canada north of the lakes ; on Long Island, the direction 
 corresponded to the rocks ; in Virginia, south-east ; in the 
 valley of the Missouri and Mississippi south-east ; on the 
 Coteau des Prairies, north. Few primary bowlders are 
 found south of Ohio river. 
 
 The Delta of the Mississippi is the greatest alluvial de- 
 posit, being 13,600 square miles in area. In these super- 
 ficial accumulations have been found : in New Jersey, 
 Maryland, South Carolina, Kentucky, and Mississippi, 
 the elephas primigenius ; in Connecticut, New York, 
 
 956. What parts of -the United States are tertiary? 967. What 
 course was taken by the diluvium in the several States ? 958. What 
 01 game remains have been found above the secondary fonnatiou? 
 
304 GEOGRAPHICAL GEOLOGY. 
 
 Ncic Jersey, Ohio, Indiana, Virginia, Kentucky, Ittis- 
 si$sij)pi, and most of the western States, the mastodon 
 maximus ; in Virginia and Kentucky, the megalonyx ; 
 in New Jersey and Kentucky, the cervus arnericanus ; in 
 Virginia, the walrus ; on Skiddaway Island, coast of 
 Georgia, the megatherium ; in Kentucky and Mississippi^ 
 the ox, (several species.) Since the protrusion of green- 
 stone, there are no signs of volcanic agency east of the 
 Rooky Mountains ; but thermal springs occur in the western 
 borders of Massachusetts, Seneca Falls, New Lebanon, 
 Saratoga, and Ballston, New York, Bath co., Virginia, 
 on the Wachitta, Arkansas, and in Buncombe co., North 
 Carolina. The carboniferous limestone extends northward 
 from Pennsylvania, to Falls of St. Anthony, arid westward 
 to Fort Leavenworth. Gypsum and salt are always found 
 in rocks below the coal beds. Along the south-east part of 
 the valley the coal is generally non-bituminous ; but ac- 
 quires bitumen as it recedes from the primary. Seams of 
 bituminous coal have been traced from Pennsylvania to 
 200 miles west of the Mississippi, and an outcrop of the 
 strata on the eastern flank of the Rocky Mountains. The 
 gold range extends along the Appalachian chain, chiefly on 
 its eastern slope from Maine to Alabama. 
 
 Maine is generally either undulating or hilly ; and 
 about the sources of the Kennebec and Penobscot, is 
 mountainous. Mineral resource granite on the coast. 
 
 In New Hampshire, the country, for 30 miles from 
 the coast, is diversified with hill arid dale, rising, in the 
 interior, into lofty mountains. Minerals iron and granite. 
 
 The face of the country in Vermont, when not mount- 
 ainous, is generally undulating. Minerals iron, lead, 
 copperas, marble, porcelain clay, and gold occurs (at Somer- 
 set,) in the quartz traversing talco-micacious slate 
 
 The west part of Massachusetts is crossed by the G reen 
 Mountains , east of the Connecticut it is hilly or undulat- 
 ing, except the south-east coasts, which are level and 
 
 959. What is the extent of the carboniferous lime-stone? 960. 
 "Where do the gold mines range 1 961. What minerals in the New 
 England States ? 
 
fXITF.D STATES. 305 
 
 sandy. Minerals (in Berkshire co., and other parts,) 
 iron, primary and transition marbles, granite, and porphyry, 
 (in Worcester,) anthracite, (in Southampton,) lead, and in 
 other parts, copper and tin. 
 
 RJwde Island, in the north part, is hilly ; in south 
 part, level. Minerals iron, coal, marble, and freestone. 
 
 Connecticut is generally hilly. Minerals iron (chiefly 
 in Litchfield co.,) copper, in trap and new red sandstone, 
 tin and anthracite. At Stafford is a mineral spring. 
 
 New York, in east parts, is mountainous, near the 
 Pennsylvanian boundary, hilly, and other parts level or 
 undulating. Minerals (in northern and other parts,) iron, 
 (in Rossie,) lead, (in western coasts and on Hudson river,) 
 gypsum and silver, tin, graphite, coal, and marble, in 
 various places, as also sulphur and salt springs. 
 
 In New Jersey, the south-east and southern parts are 
 low and sandy, in the central coasts, undulating, the north 
 section, mountainous. Minerals iron, copper, zinc, silver, 
 and marble. 
 
 Pennsylvania, on the west of the mountains, is hilly, 
 on the east it is undulating. Minerals (in the ridges and 
 mountains of the Alleghany range, and between the De- 
 laware and Schuylkill, chiefly,) coal, and (especially on the 
 Juniata,) iron. 
 
 The surface of Delaware is generally low, level, and 
 sandy. 
 
 The shores of Maryland include a low, level, and allu- 
 vial country ; the central and western parts are hilly and 
 mountainous. Minerals (in Alleghany co.,) coal and 
 iron, and 25 miles west of Baltimore, gold. 
 
 In Virginia, the alluvial tract extends from the ocean 
 and bay to the head of tide water. The surface rises 
 gradually towards the interior, and then becomes mountain- 
 ous and broken. Minerals (near Richmond and Wheel- 
 ing, and in Chesterfield and Prince Edward cos.,) coal, 
 (18 miles from Abingdon,) rock-salt and gypsum, (in the 
 
 962. What is the surface smd what are the mineral? of the Middle 
 States? 963. \Vhat mineral* are found in Virginia and North 
 Carolina "' 
 
306 GEOGRAPHICAL GEOLOGY. 
 
 primary strata from the Rappahannock to the Coosa m 
 Georgia and Alabama, also in the ditrital deposit,) gold, 
 often accompanied with silver, lead, and copper, the latter 
 is common in trap and new red sandstone ; iron, lead, 
 graphite, marble, limestone, freestone, porcelain clay, and 
 chalk also abound, as also sulpher, hot and salt springs. 
 
 North Carolina, on the seacoast, is low ; in the interior, 
 hilly, in the western part, mountainous. Minerals gold 
 and ircn abound, coal and lead occur. The veins of gold 
 are found both in hilly and low grounds, and vary . in 
 width from a few inches to several feet ; the best having a 
 dip of 45 to the horizon. This gold range commences in 
 Virginia, and extends south-west through North Carolina 
 along the northern part of South Carolina into Georgia, 
 thence north-east into Alabama and Tennessee. 
 
 In South Carolina, the country on the coast is level for 
 100 miles towards the interior, after which is a range of 
 sand hills, and beyond these it is undulating. 
 
 Georgia is level and marshy on the sea-coast, and 
 mountainous in the north. 
 
 Florida is level, and not much elevated above the sea. 
 In the w r est part it is limestone, and cavernous in its struc- 
 ture. 
 
 Alabama is undulating in the south and central parts, 
 and mountainous in the north. Minerals coal, iron, arid 
 gold. 
 
 Mississippi is undulating, containing several ranges of 
 hills of moderate elevation. 
 
 Some parts of Louisiana are hilly, others flat and 
 sandy ; arid in the south-west parts of the State are exten- 
 sive prairies. 
 
 The eastern part of Arkansas is low and marshy, the 
 interior and northern, elevated. The mountains contain 
 iron, lead, coal, salt, and sulphur. 
 
 The face of the country in east Tennessee is bold and 
 mountainous ; the west, undulating. Minerals iron, lead, 
 gold, gypsum, burhstone, white, grey, arid red marble, and 
 
 964. What minerals in Alabama? 965. What in Arkansas and 
 Tennessee ? 
 
UNITED STATES. 307 
 
 nitrous earth. Salt springs, caves, petrified trees, bones of 
 mammoths, and other organic relics, occur. 
 
 Kentucky in the east part is hilly and undulating; in 
 the west, level. Beneath the mountains it rests on a bed 
 of limestone, usually 8 feet below the surface, which the 
 rivers have excavated several hundred feet in depth.. The 
 limestone country also abounds in subterranean caves and 
 sink holes, the former impregnated with nitre. Salt springs 
 also abound. 
 
 Indiana, south of the White and its east Fork, is hilly 
 and rough ; in the north, level or undulating. Minerals- 
 coal, iron, lime, and salt ; and epsom salts are found near 
 Corydon. 
 
 The face of the country in Ohio presents a large surface 
 of table- land, sloping towards Lake Erie on the north, and 
 the Ohio river on the south. The most hilly parts are in 
 the south-east and east sections, where coal and salt abound. 
 Iron is obtained in the same regions, and also in the west- 
 ern reserve counties. Gypsum is found near Sandusky, 
 and limestone, freestone, marble, and mineral springs 
 abound in many parts. 
 
 Michigan is level, or gently rolling. Copper and coal 
 abound ; the former south of the Lake Superior ; and 
 south of this district masses of the metal occur in the di- 
 luvium over an area of several thousand square miles. 
 These fragments are derived from ores traversing greenstone, 
 amygdaloid, and an overlying conglomerate. 
 
 Iowa is generally level, and in the northern part is a 
 high table-land ; lead, coal, iron, and limestone abound ; 
 the first embraces a strip of townships. 
 
 Wisconsin is generally hilly, with the exception of 
 some prairies, and the north part is mountainous. Lead, 
 copper, zinc, and iron abound. The lead region of this 
 part of the United States is 87 miles long from east to 
 west, and 54 broad, and is chiefly in "Wisconsin. At Mi- 
 neral Point, great quantities of copper and zinc occur. 
 
 Missouri is low and swampy in the south-east part. 
 
 966. What is said of Kentucky I 967. Describe the surface of 
 Ohio ? 968. W hat is the extent ot the lead region ? 
 
SOS GEOGRAPHICAL GEOLOGY. 
 
 Beyond the highlands, which mark the boundary of this 
 tract, the country rises and extends to the mountainous 
 lead region, and the banks of the Osage, then comes a 
 broken and hilly tract, and finally, in the western part, are 
 extensive prairies. Minerals lead iron, coal, salt, zinc, 
 antimony, graphite, silver, copper, chalk, and flint. The 
 deposits of specular iron ore are connected with porphyry, 
 while a stratum of granite with trap dykes, 6 miles in 
 width, separate them from the mountain limestone. Iron 
 Mount, 350 feet high and two miles in circuit, is entirely, 
 and Pilot Knob, 600 feet high and three miles in circuit, is 
 partly, composed of this ore. The centre of the lead 
 mines is from 50 to 70 miles miles south-west of St. Louis. 
 At Boone's Lick, St. Genevieve, and Herculaiieum, are 
 salt springs. 
 
 Prairies cover two-thirds of the surface of Illinois ; the 
 north part is hilly and broken ; the margins of the rivers 
 are usuall alluvial, bounded at a short distance by bluffs 
 or banks, which at the height of 100 or 150 feet, spread 
 out into table-lands. Coal is found in nearly every county ; 
 and iron, copper, and chalybeate, sulphur, and salt springs 
 abound. The lead district occupies 10 townships, the ore 
 lying in horizontal strata, and yielding 75 per cent. 
 
 Texas, consists chiefly of vast prairies, and the mountains 
 abound in silver, gold, and other valuable minerals. In 
 the southern part is the Mustang Desert, containing a salt 
 lake ; and a like lake occurs at the head of the Brazos. 
 The northern part contains a portion of the great 
 Desert. 
 
 The Indian and Missouri Territories are vast wilder- 
 nesses, consisting of extensive prairies. On the western 
 frontier rise the Rocky Mountains to a great height. A 
 few miles up Muddy River, (long. 111, lat. 4U,) Fre- 
 mont collected a beautiful series of specimens of fossil 
 ferns, associated with which were found several beds of 
 coal. 
 
 In the mountainous region of Oregon, occur many basaltic 
 
 ?69. What metals abound in Missouri ? 970. What is said of 
 H)ii'ji>? 971 What i* th* extent of the lead district in Illinois '', 
 
TTCITED STATES, 309 
 
 or volcanic rocks. The whole country from Ctueen Char- 
 lotte's Island on the north, to California on the south, and 
 from the mountains on the east to the ocean on the west, 
 is. no doubt, of igneous formation. The channel of the 
 Columbia, in many places, is walled up on its ' sides, and 
 studded with basaltic islands, rising from 20 to 200 feet in 
 height, and the same river passes through a basaltic mount- 
 ain of more than 1000 feet in height. Indeed, the whole 
 is a region of extinct volcanoes ; for lava, trachyte, basalt, 
 massive, and columnar, and other volcanic productions, 
 occur along many of the rivers and other parts. Beds of 
 rock-salt are found (particularly at the head of Salmon 
 River,) and epsom salts on both sides of the Rocky Mount- 
 ains. A gold mine of great extent is reported to exist in 
 this territory, lying in the vicinity of the Rocky Mountains, 
 chiefly on the Powhattan River. The metal is found not 
 only in the sands of the streams flowing from the mount- 
 ains, but upon the mountains mixed with quartz, and in 
 the rocky strata. If this is true, we have then two gold 
 ranges, one following the Appalachian chain, the other, 
 the Rocky or Cordilleras. It is very probable also that 
 coal exists on Vancouver Island. 
 
 California. We now come to a realized El Dorado 
 a veritable terra (Toro, towards which the tide of emigra- 
 tion is now setting frojn all quarters of the earth. Upper 
 California, or that part of Western America recently ceded 
 to the United States, is embraced between lat. 32 and 42 
 north, and between long. 109 west and the Pacific Ocean, 
 containing about 400,000 square miles. That part east 
 of the Colorado, whose southern boundary rests on the 
 Gila, is entirely occupied by broken mountain ranges, with 
 narrow valleys intervening. The general features of the 
 central part, lying between the Colorado and the Sierra 
 Nevada, are those of a semi-desert, the north part forming 
 a " Great Basin," which is 400 miles in extent from east 
 to west, by 250 from north to south, and elevated some 
 
 972 Of what formation is Oregon ? 973. What volcanic produc- 
 tions are found t 974. What ie the extent of California ? 975. 
 Describe the Great Basin ? 
 
 14 
 
310 GEOGRAPHICAL 
 
 5000 feet above the ocean, having a succession of isolated 
 mountain ranges, running north and south, their general 
 outline being sharp and rugged.* This great valley con- 
 tains the Great Salt Plain, which is 40 miles broad, and 
 1 50 long, with a snow-like incrustation of saline and alka- 
 line bodies, and very compact and hard on its eastern bor- 
 der. The crust is from \ to .' an inch thick, beneath which 
 is a stratum of damp whitish sand and clay intermingled ; 
 fragments of " white shelly rock" are strewn over the en- 
 tire plain, arid imbedded in the salt and sand. To the 
 west the soil becomes softer, being composed of clay, sand, 
 and salt.f 
 
 Within the area of the Basin are : the Timporiogos or 
 Great Salt, and Yutah Lakes lying on the east ; the Pyra- 
 mid, Walker, and Carson Lakes on the west. The first is 
 about 70 miles long, arid 40 to 60 wide. The water is 
 exceeding salt and bitter, the chloride of sodium com- 
 prising 97.80 parts in 100. To the south-east lies the 
 fresh water lake, Yutah, which empties its waters into the 
 former. It is 20 miles long and 6 wide. Between these 
 lakes and the mountains in which the Sacramento rises, is 
 a vast valley, supposed to consist chiefly of sandy plains, 
 from which no egress for water has been discovered, the 
 rivers losing themselves in the sand. Approaching the 
 mountains from Pyramid Lake, volcanic appearances in- 
 crease, the plains being covered with scoriae, and the 
 mountain ridges composed of black basaltic rocks. Nu- 
 merous warm springs, impregnated with salt, sulphur, and 
 magnesia, occur on the flanks. The ascent of the Sierra 
 Nevada begins at the lake ; reddish and brown sandstone 
 are first met with, then conglomerates, granites, and, above 
 all, basalt. J 
 
 The mountain masses of Old California extend, undi- 
 vided, to the peak of San Bernardino, where they separate 
 into the two principal ranges the Sierra Nevada and 
 
 * Wilkes. f Bryant. \ Wilkes. 
 
 976. Describe the Salt Plain ? 977. What lakes within the Basiu ? 
 978. What occur on the east flanks of the Sierra I 
 
T'MTED STATES, 31 1 
 
 Coast Range, which include an extensive valley. The 
 eastern chain runs nearly parallel to the coast, at the dis- 
 tance of 130 to 150 miles, and extends from the 42nd to 
 the 35th degree of north lat. The mountains ascend gra- 
 dually from the valley, and become more and more preci- 
 pitous, rising like pyramids from a lofty plateaux to the 
 height of 14,000 or 17,000 feet. The collection of rugged 
 mountains or spurs, which form the Coast Range, run ge- 
 nerally parallel to the coast, rise to the height of 4,000 feet, 
 and join the Shaste Mountains towards their northern ter- 
 mination. On the eastern side, this range declines into 
 rolling hills, while, on the west, they present a perpendicu- 
 lar or rock-bound shore, thus reversing the order of the 
 Sierra Nevada.* 
 
 The section west of the California range, comprising 
 re of the territory, and to which the world's attention is now 
 turned by the discovery of its mineral riches, embraces 
 three valleys the Sacramento, San Joachin, and San Juan. 
 The first extends from 40 30' north to the south 1 80 miles, 
 and is an inclined prairie of alluvial, rising about four feet 
 to the mile, and divided into two distinct terraces through- 
 out its length, called the upper and low prairies. The low 
 undulating hills which form the upper prairie, project into 
 the lower prairie to various distances, and gives its bound- 
 ary an irregular outline ; the heig i! of this upper prairie 
 above the lower is about 60 feet, the slope varying, and, in 
 some instances, is very steep. The upper prairie is about 
 250 feet above the level of the river, and inclines to the 
 south. Its undulating hills consist of a clayey and sandy 
 loam, gravel, and pebbles, while the soil of the lower prai- 
 rie is rich alluvial. The Bute Hills rise to the height of 
 1794 feet above the plain, the base being nearly on a level 
 with the upper prairie. The valley of San Joachin is 140 
 miles long and 50 wide ; its lower prairie is almost want- 
 ing, yet it has two distinct elevations, the difference in level 
 
 * Wilkes. 
 
 979. Describe the mountain ranges? 980 Dp-rril^ the valley 
 of the Sacramento! 081. U'Jiat it, taid of tin* tan JuaUiin va!le\"? 
 
312 GEOGRAPHICAL GEOLOGT. 
 
 averaging 40 feet. The valley is 300 miles long and 60 
 broad, being elevated only a few hundred feet above the 
 level of the sea. The surface along the lakes, arid river 
 consists of level plains, changing into undulating ground 
 nearer the foot hills of the mountains. Both lakes are 
 surrounded by extensive sloughs, the earth being a rich al- 
 luvial deposite from the surrounding mountains. The val- 
 ley of San Juan is situated at the south of San Francisco 
 Bay, being 60 miles long, from 15 to 20 in width. It is 
 apparently a level plain, but ascends gradually towards the 
 south ; the plain extends to the foot of the high hills on 
 the east, but on the west, it has the undulating hills of the 
 Sacramento valley, but not their irregular outline.* 
 
 A volcanic range on the Ocean side of the Peninsula runs 
 parallel to a similar and loftier series on the continental 
 side, and the two, terminating northwards in an elevated 
 plateau, gradually combine and culminate in the lofty 
 mountain of San Bernardino. They again diverge, form- 
 ing the two chains enclosing the aforesaid valleys. The 
 eastern the Sierra Nevada carries on the chain of high- 
 lands as far as Oregon, and there meets with another and 
 transverse group of mountains, extending from Cape Men- 
 docino north east, and culminating at Mount Shaste. Near 
 the sea, the rocks are primitive, arid probably porphyries of 
 varied character, like those in the Rocky Mountains, and 
 also further south. 
 
 About 70 miles north-east from the Bay of San Fran- 
 cisco, a spur is given off from the chain of the Sierra Ne- 
 vada, which contains an active volcano. In the main chain 
 of mountains to the south, porphyries and limestones form 
 the flanks ol the chief elevations, and of the whole central 
 ridge ; these have been elevated often to considerable 
 heights, arid often there appear rocks more distinctly volca- 
 nic, presenting either true cvultes of lava or trachytic 
 
 * Ansted. 
 
 982. Where is the valley of the San Juan situated? 983. What 
 is the extent of the volcanic range? 984. What is the geological 
 character of the mountain chain to the south ? 
 
T'MTF.T) STATES. 313 
 
 rocks, which, on the plateau, occupy vast tracks by the 
 side of the porphyries. Extensive lacustrine deposits re- 
 pose on these, consisting of rounded flints, covered by marls 
 and handsome clays. On the Pacific coast granite comes 
 more into view, while further north than Mexico, trachytic 
 rocks, occasionally metalliferous, are crossed at various 
 points by lava currents. As they advance further north, 
 in the same direction, the distinctly volcanic products are 
 gradually less nearly in contact, while altered schists, dior- 
 ites, and metamorphic limestones appears, and are traversed 
 by veins of quartz containing gold, and often silver. It 
 appears, also, that the alluvia derived from these veins is, 
 throughout the range, chiefly on the western side. * 
 
 The Sierra Nevada range is primary, granite fonning the 
 backbone rock. The group of porphyritic formations, 
 non-metalliferous, reposes on primary rocks ; the other, 
 often metalliferous, rests on clay-slate or on talcose slate 
 with transition limestone Entering the Shaste Mount- 
 ains, trachytic rocks will be found to be abundant ; but 
 talcose rocks constitute the greater part of the ridges along 
 the upper part of the Sacramento valley. The Shaste 
 Peak is one of the lofty volcanos of the Cascade range. 
 Fronting the Peak, the plain is covered with hillocks of a 
 porphyritic lava ; and to the east of it, occurs a very hot 
 spring. Obsidian is said to exist in the same region. The 
 granite of the Shaste region is mostly albitic ; and no true 
 gneiss is seen in the mountains. Compact hornblendic 
 rocks, which occur upon the Shaste river, and the syenites 
 pass into a compact hypersthenic rock, which abounds 
 along Destruction River in the Shaste Mountains. The 
 talcose rocks of this region are generally compact and irre- 
 gularly fissured ; and it appears that the jasper and prase 
 rocks are closely connected with the series. Serpentine is 
 largely developed in high ridges to the north-west of the 
 Shaste Mountains, the general color being a dark green. 
 
 * Ansted. 
 
 985. Of what formation is the Sierra Nevada? 986. What rocks 
 abound iu the Shaste mountains ? 
 
3 1 4 GEOGI! A P H 1C A L < I F.OLOO Y 
 
 There are also seams of amianthus. The rock is also 
 found in the Shaste Mountains. " The talcose forma- 
 tions," says Professor Dana, in his Geol. Ex. Ex., " was 
 first met with travelling south from the Umpqua ; next 
 \ve came upon syenite, then true granite, upon the Shaste 
 River. After passing a region of basalt and sandstone, in 
 the vicinity of the Klamet, we crossed a prairie, covered 
 in many parts with pebbles from the talcose formation ; 
 then the foot of a ridge of serpentine ; and then entered 
 into a region of syenite at the foot of the Shaste Mountains. 
 For 20 miles in the mountains, these rocks were interrupt- 
 ed by trachytes. Boulders of talcose rock and syenite oc- 
 curred abundantly along the head waters of the Sacra- 
 mento ; and within a mile, granite boulders were inter- 
 mingled. A mile beyond, granite became the prevailing 
 rock ; and at the centre of the granite region, lofty pin- 
 nacles and needle peaks peered above the forests around, 
 to a height of 3,000 feet. We next passed successively 
 to hornblende rocks, talcose and prasoid rocks, with proto- 
 gine and some serpentine. Talcose rocks and slates were 
 again met with near San Francisco. Large beds of con- 
 glomerates and sandstone were found in the Shaste Mount- 
 ains. Following down Destruction River, we travelled for 
 1 8 miles before reaching the Sacramento plains. The 
 slate appears to be the lower member of the series in the 
 Shaste Mountains, and the puddingstone the upper." 
 
 The upper part of the Sacramento valley is 100 miles, 
 long, the lower, 200 The terrace is mostly about 60 feet 
 high; but the upper plain gradually rises to 150 or 200 
 feet. On the plains nothing but mineral deposits are met 
 with until reaching the Sacramento Bute, which is an an- 
 cient crater, consisting of trachyte arid trachytic porphyry. 
 It will become valuable for its stone quarries. The gold 
 district lies north of San Francisco, being a broad tract en- 
 closed on the east by a lofty arid recently elevated tract, 
 partly volcanic, partly trachytic but every where exhibit- 
 ing igneous rocks. The metal has hitherto been obtained 
 
 987. What does Dana say concerning the talcose formation? 988. 
 How high is the terrace ? 989. Describe the gold district ? 
 
UNITED STATES. 31 5 
 
 from alluvial sand and gravel, being mixed with and form- 
 ing part of quartz rock and pebbles, occurring in the mud 
 and gravel which form the present beds of streams, and 
 also iii the former and now dry beds of such streams. The 
 crevices of rocks also contain a good supply.* 
 
 The gravel of the district is the rock ready pulverized by 
 natural causes. The streams washing over the soil, still 
 farther aid in the preparation, by collecting the gold into 
 the bottom of the valleys, and carrying off the light gravel 
 and sand, thus leaving the grains of metal along the beds 
 of the streams and the bottoms of ravines. The region 
 covered by the debris of the mountains is as wide as the 
 vast prairies of its long-reaching rivers, and the slopes that 
 rise into the ranges on either side. The gravel of these 
 slopes, and the stratified earth and gravel of the plains 
 may therefore contain gold ; but the parts more nearly in 
 the vicinity of the particular auriferous rocks, naturally 
 prove most productive. Compact, slightly glistening, slaty 
 rocks, of various dark colors, the talcose, more or less 
 greasy in look or feel, and often greenish, and chloritic, 
 mostly of a darker olive green color, contain often beds or 
 veins of quartz in which the gold is found. t Dikes or 
 beds of quartz rock, many feet in thickness, and often of 
 great length, are numerous, and generally among nearly 
 vertical strata of some form of slate or gneiss rock. The 
 diluvium, where the diggings have been carried on, varies 
 from half a foot to several feet in thickness, and rests, un- 
 conformably, on a bed of agillite or gneiss, running about 
 north north-west and south south-east, and dipping nearly 
 perpendicularly. The clay-slate presents a very irregular 
 surface, with abundant little pockets for retaining the 
 gold, which is found most plentifully on its surface and in 
 its crevices. Where the gold is dug from the ravines, the 
 underlying rock is some form of this slate ; and on the 
 river, the gold stratum rests on a stratum of coarse granitic 
 sand. The richest excavations have been in the bottoms 
 * Ansted. t Dana. 
 
 990. What rocks prove most productive? 991. Describe the di- 
 luvium ? 992. Where and how does the gold occur f 
 
316 GEOGRAPHICAL GEOLOGY. 
 
 of dry ravines, though gold is found on the slopes, and 
 even on the summits of hills.* 
 
 The "dry diggings," which is an upland marsh, is con- 
 sidered preferable to the " wet." In the former, the metal 
 is found in lumps, and in the crevices of rocks, and lies 
 from a few inches to three or four feet below the surface : 
 In the latter, it occurs in flakes or scales. In the streams, 
 the usual process of procuring it is by throwing up dikes 
 and turning the water from its channel, or drawing por- 
 tions of the river's bed. In the eddies of the main stream, 
 it can be seen in great abundance, an at a depth of 25 or 
 30 feet in many places. 
 
 Auriferous districts and mountains are rarely limited to 
 small areas, and the fact that no part of the world con- 
 tains a greater mass of porphyrines than the cordillera 
 renders probable the existence of a considerable tract over 
 which similar repositories exist. It is reported that gold 
 occurs near Tule lake, near Monterey, on the east side of 
 the Sierra Nevada ; and that a rich placer has been dis- 
 covered near the boundary line between California and 
 Oregon. The porphyraceous chain, of which the range 
 in California is a part, extends almost in the direction of a 
 meridian, 7500 miles from one hemisphere to the other, 
 and throughout its whole length appears highly metalli- 
 ferous ; but amidst many indications of aureate deposits, 
 no mine has yet been discovered which can be compared 
 in richness to those of the wide and more than Pactolian 
 plains, 
 
 Where Sacramento floats the desert lands, 
 And leaves a rich manure of golden sands. 
 
 But great as are the discoveries of gold, they are equalled 
 by those of mercury. It is found in various places, even 
 within three miles of San Francisco. Forbes' mine is sit- 
 uated near San Juan, in a spur of the mountains, 1,000 
 feet above the level of the bay of San Francisco. The 
 
 * Lyman. 
 
 993. What is said of auriferous districts ? 994. What other me- 
 tal* are found? 
 
MEXICO. CENTRAL AMERICA. 317 
 
 cinnabar occurs in a large vein dipping at a strong angle 
 to the horizon. Lead mines exist at Sonoma. The other 
 metals are platinum, silver, copper, iron, and tin. Sul- 
 phur, nitre, muriate and carbonate of soda, and bitumen, 
 abound ; bituminous coal is known to exist. 
 
 From official analyses, we learn that the gold dust yields 
 983 pure gold ; the melted metal yielding within 6, 1000, 
 or $6 in the $1000, of the mint standard of 900. In the 
 assays of the melted gold, the results showed a variation 
 in fineness from 892 to 897 thousandths ; the average of 
 the whole being 894. The average value per ounce of 
 the bullion assayed, before melting, was $18. 05.}; that of 
 the same in bars, after melting, $18.50 The specimens of 
 cinnabar yielding nearly one-third of their weight in mer- 
 cury. 
 
 MEXICO. Mexico consists mainly of a vast and very 
 elevated table-land, being, in fact, a flattening down of the 
 Andes on the south, and the Rocky Mountains on the 
 north. This vast plain, 1,500 miles over, is occasionally 
 diversified by an elevated insulated peak, which is often a 
 volcano, recent or extinct. The basis of the country seems 
 to be primary rocks ; such as gneiss and granite ; but its 
 upper portion is covered with porphyry and trachyte. Se- 
 condary sandstone and limestone also occur. A line of 
 volcanos, of which there are five principal vents, traverse 
 Mexico from east to west, about in the lat. of the capital. 
 The rocks are rich in silver and gold. They occur in veins 
 traversing clay-slate, and talcose slate, transition lime- 
 stone, grauwacke, and porphyry. Silver mines number 
 3,000. Tin, copper, lead, mercury, and iron abound, as 
 also beds of rock-salt on the Colorado. The gold is 
 mixed with silver or iron, and generally in the sulphurets 
 of these metals. Oaxaco contains the only auriferous 
 veins worked as gold mines in Mexico. 
 
 CENTRAL AMERICA. This country is, for the most part, 
 mountainous, and abounds in volcanos. Its geology is 
 
 995. State the result of the analysis of the gold dust ? 996. 
 What rocks in Mexico? 997. What minerals does Mexico produce? 
 998. What in raid of Central America? 
 14* 
 
318 GEOGRAPHICAL GEOLOGY. 
 
 similar to that of Mexico, on the north, and of New G ra- 
 nada, on the south. Silver and sulphur exist 
 
 WEST INDIES. These islands are formed by the Ap- 
 palachian chain, and many contain mountains, which in 
 Cuba, Hayti, and Jamaica, are about 9,000 feet high. 
 The highest in Cuba, consist of mica-slate, arid sieriite, 
 gneiss, and granite, project through the secondary forma- 
 tions of the lower regions. Copper, gold, and silver occur ; 
 and coal exists in a vein. There is a granitic mountain 
 in the south part of Hayti. Grauwacke with trap chiefly 
 makes up the highest part of Jamaica. Over this lie red 
 sandstone, marl, limestone, trap, porphyry, arid superficial 
 accumulations. The eastern of the Caribbee Isles are 
 mostly limestone. Antigua " consists of grauwacke, re- 
 cent calcareous dep>* U\ and trap. Lying above the first, 
 is a silicious deposit r i bracing an immense number of 
 silicified trees, along with vast quantities of shells. These 
 form splendid agates. In St. Croix are grauwacke, and 
 tertiary and alluvial limestone ; but no uristratified rocks. 
 The tertiary is mostly indurated limestone, abounding in 
 corals and shells. In the recent deposit on the shores 
 were found human skeletons. The western parts of the 
 Caribbee group are chiefly volcanic ; extinct craters are 
 visible, and trachytic and basaltic rocks are common. 
 Trinidad is a continuation of the continent, being mostly 
 primary. Here is the Pitch Lake, three miles in circum- 
 ference and of unknown thickness." 
 
 SOUTH AMERICA. 
 
 Every rock is here developed on a magnificent scale. 
 The chalk formation sometimes rises 13,000 feet. Gra- 
 nite and gneiss, for the most part, form the basis of 
 the Andes ; but are covered by an immense deposit 
 of ancient volcanic rocks. The elevated table-lands 
 
 999. What rocks abound in the West Indian isles? 1000. What 
 is said of the geology of South- America? 
 
NEW GKAXADA. VENEZUELA. 319 
 
 near the range are covered in a measure by fossiliferious 
 limestone, which occurs from 9,000 to 14,000 feet above 
 the sea ; and by new red sandstone, embracing copper and 
 gypsum. The lower table-land is covered by diluvial de- 
 tritus, embracing gold. The mountains in the central 
 parts of America, lying east of the principal Cordilleras, 
 are in a measure composed of various slates with quartz 
 rock and sandstone ; the central axis being usually prim- 
 ary, and the slopes the older secondary. The plains be- 
 tween the diflerent chains are extensively covered by 
 tertiary strata.* 
 
 In NEW GRANADA, are very fine copper mines, near 
 Palma ; and at Choco, gold, platinum, and titanium occur. 
 The whole of the Isthmus of Panama, excepting the schis- 
 tose channel, which crosses it in the meridian of the 
 Boqueron, and the granitic line between Pequeni and San 
 Bias, is composed of porphyritic and hornblendic rocks, 
 which gradually pass from one to the other, and run in 
 large layers, more or less, in a northerly direction. In the 
 Boqueron and the Cascajal, the schistose rocks are largely 
 developed, and the laminated structure of the hornblende 
 rocks is well denned ; there is a great deficiency of lime 
 and silica in the latter. Though generally speaking, the 
 porphyritic hornblende is auriferous, the gold is very spar- 
 ingly disseminated ; four rials a-day being the maximum 
 quantity obtained, and that by excessive labor. The gold- 
 washings of Santa Rita are situated between the rivers 
 Clara and Grande, and are the product of decomposed 
 rocks. Iron abounds occasionally in great quantities in 
 the state of the peroxyd and protoxyd ; also hepatic. f 
 
 In VENEZUELA, mountains skirt the northern shore, and 
 savannas extend from the base of the chain to the Orinoco. 
 All the rivers of Caraccas to 10 north lat., flow over 
 golden sands. 
 
 The Colombian States also afibrd some diamonds, and 
 
 * Hitchcock. 
 
 t V. Bogat Gazette, September 9th, 1847. 
 
 1001. Give the geology of the Isthmus of Panama ? 1002. What 
 t * said of Venezuela ? 
 
320 GEOGRAPHICAL GEOLOGY. 
 
 'many other precious stones. Gold, silver, mercury, cop- 
 per, tin, and rock-salt, abound. The Pacos de Oro con- 
 sists of ores of iron and copper oxides with much gold. 
 
 GUYANA has more of a flat than mountainous aspect. 
 
 BRAZIL is mountainous on the coast ; in the centre are 
 the llanos which rise into lofty chains of mountains. It is 
 most celebrated for its gems, especially its diamonds. 
 Gold is found on both sides of the Brazilian Andes, from 
 the 5th to 30th degree south lat. It is found chiefly in 
 the affluents of the Francisco. The rocks are granite in- 
 clining to gneiss, with some hornblende arid often mica. 
 The gold mostly lies in cascalhas. In Villa Rica, Minas 
 Geraes, Cuyaba, and Gongo Soco,- are noted gold mines. 
 Tejuco is the capital of the diamond district. Copper 
 also abounds, and deposits of nitre and salt occur. 
 
 J'ERU, in the western part, is intersected by the Andes 
 and their Cordilleras ; the eastern part consists of llanos. 
 ] iic hiding BOLIVIA, it is one of the most remarkable regions 
 on the globe for the precious metals. The silver moun- 
 tain of Potosi is eighteen miles in circumference. Mer- 
 cury abounds, especially at Huanca Velica. One mine is 
 70 feet thick. The other mines of gold and silver are 
 numerous. Mines of copper, lead, tin, arid rock-salt also 
 exist. Most of the mines are situated in the eastern range 
 of the Andes, which consists of mica-slate, sienite, por- 
 phyry, new red sandstone, arid oolite.* In Huailas and 
 Patz, the gold is mined in veins of quartz, variegated with 
 red ferruginous spots, traversing primary rocks. 
 
 CHILI is enriched with valuable mines of gold, silver, 
 copper, iron, tin, and lead. Coquimbo is rich in mines of 
 the first three metals. Extensive coal-fields have been 
 discovered at Conception, and between Valparaiso and 
 Santiago. 
 
 The ARGENTINE REPUBLIC, in the north parts, is moun- 
 tainous ; the central and south parts are generally low 
 
 Hitchcock 
 
 1003. What rocks and mines in Brazil ? 1004. What is said of 
 Peru and Bolivia ? 1006. What metals <loe s Chili afford J 
 
PATAGONIA- 321 
 
 and level, terminating in llanos. The mountains yield 
 gold and silver ; and salt abounds in the eastern plains. 
 
 T he chief part of PATAGONIA appears to be a desert 
 region. Tertiary stra-ta with white marl analogous to 
 the lower chalk, and a resemblance to the green sand, are 
 well developed on its shores. Coal has been discovered 
 at the Magellan Straits. 
 
 The Smith American Islands are sterile regions, with 
 rugged and barren shores. 
 
 [The history of Geology in the United States dates as 
 early as 1807, when William McClure, a native of Scot- 
 land, undertook a geological survey of the United States, 
 prompted by a love of science, and a patriotic devotion to 
 his adopted country. Possessed of ample fortune, and an 
 indomitable industry in scientific researches, he traversed 
 nearly every State in the Union, personally inspecting the 
 most remote districts, and enduring incredible hardships 
 and privations in the then unsettled state of much of the 
 country. His pedestrian excursions with his hammer in 
 his hand, and his employment in breaking rocks, the frag- 
 ments of which he examined so minutely, and preserved 
 with so much care as valuable treasure, led to his being 
 often suspected and avoided by those who witnessed his 
 solitary avocations, as a lunatic escaped from his keepers. 
 But he persevered in his investigations, devoting many 
 years of toil to the work, and in 1809 commenced the pub- 
 lication of his researches in the "Transactions" of the 
 American Philosophical Society, which enlisted the atten- 
 tion of scientific men at home and abroad. 
 
 De Witt Clinton, as early as 1814, urged upon the atten- 
 tion of the legislature of New York " the importance of 
 employing men of observation and science to explore the 
 State, with a view to its geology, mineralogy, botany, zoo- 
 logy, and agriculture." Scientific associations in Pennsyl- 
 vania, New York, and Massachusetts, by the publication 
 of their transactions, enlightened the public mind on the 
 importance of geology and mineralogy, in which they were 
 
 1006. What is said of Patagonia? 
 
322 CONCLUDING KEMARKS. 
 
 aided by the circulation of Mr. Featherstonhaugh's " Ame- 
 rican Monthly Journal of Geology." 
 
 In 1819, De Witt Clinton, then Governor of New York, 
 again recom friended that the Board of Agriculture, estab- 
 lished by the legislature at his instance, should be autho- 
 rized to make a statistical and geological survey of the 
 State, in the hope that coal might be found, and he recom- 
 mended that premiums might be offered for its discovery. 
 
 In 1820, the late Stephen Van Rensaellaer employed at 
 his own expense, Drs. Eaton and Beck to explore the county 
 of Albany, and subsequently Professor Eaton extended his 
 survey under the same patronage throughout the region 
 traversed by the Erie canal, and published his report of the 
 strata from Boston to Buffalo, in 1824. 
 
 Thus it was that the impulse was given to the State 
 surveys which have since been made with such brilliant 
 results. To North Carolina belongs the honour of having 
 first sent geologists in the field, and Professor Olmstead's 
 report for that State appeared in 1825, since which time 
 most of the older States have been explored. 
 
 In 1836, the State of New York authorized her survey, 
 the results of which have been published in successive vol- 
 umes, and are honourable to the able gentlemen who have 
 completed it. And although it has been thus ascertained 
 that coal is not to be found within the wide extent of the 
 ^tate, as had been confidently anticipated, yet this destitu- 
 tion has been compensated by the discovery of rich depo- 
 sits of salt, lime, marl, peat, and gypsum, as well as plum- 
 bago, copper, zinc, lead and iron, which have been found 
 in numerous localities, demonstrating the economical and 
 practical value of geology, as has been done in every in- 
 stance in which similar surveys have been made. 
 
 The importance of this science, then, should inspire our 
 youth with an ardent desire for its early acquisition, apart 
 from the intrinsic attractions of the subject itself.] 
 
 THE END. 
 
APPENDIX. 
 
 To PARAGRAPH L Professor Hitchcock divides the science into : 
 1 . Economical Geology, or an account of rocks with reference to their 
 pecuniary value, or immediate application to the wants of society ; 
 "2. Sceuographical Geology, or an account of natural scenery ; 3. Scien- 
 tific Geology, or the history of rocks in their relation to science or 
 philosophy. 
 
 To PARAGRAPH LXXIIL Taking the specific gravity of lava at 
 2.8, the following table, made by the same geologist, will show the 
 force requisite to cause it to flow over the tops of the several vol- 
 
 Name. 
 
 Height in 
 
 Force exerted upon . 
 the Lv. 
 
 Initial velo- 
 city p'r Sec'd. 
 
 Stromboli, (highest peak,) 
 Vesuvius, 
 Jorullo, 
 Hecla, 
 Etna, 
 Teneriffe, 
 Mouna Kea, 
 Popocatapetl, 
 Mount Elias, 
 Cotopaxi; 
 
 2168 
 
 3874 
 2942 
 6106 
 10892 
 12464 
 14700 
 17712 
 18079 
 18869 
 
 176 Atmospheres, 
 314 
 319 
 413 
 882 
 1009 
 1191 
 1435 
 1465 
 1492 
 
 371 feet. 
 496 
 602 
 570 
 832 
 896 
 966 
 1062 
 1072 
 1104 
 
 Vesuvius has launched scoria 4000 feet above its summit. Coto- 
 paxi has projected matter 6000 feet above the summit ; and once it 
 threw a stone, of 109 cubic yards in volume, to the distance of nine 
 miles. 
 
 To PARAGRAPH CXIL We usually find a fossiferous formation 
 of any considerable thickness divided into many distinct beds of dif- 
 ferent thickness. At the bottom, perhaps, will be a layer of argil- 
 laceous or siliceous rock, with few or no remains ; then will succeed 
 a layer, perhaps calcareous, full of them in a perfect state ; next a 
 layer of sand or clay, or limestone containing none ; then a laver 
 made up of the fragments of rocks, animals, and plants, more or fesu 
 comminuted ; next a layer of fine clay ; then a layer abounding in 
 remains. And thus shall we find a succession of changes to the top 
 of the series. HitcJicork. 
 
324 APPENDIX. 
 
 The thickness in feet of the fossiliferous strata in Great Britain ie 
 thus given by Professor Phillips : 
 
 Tertiary Strata, 1350 
 
 Chalk, 600 
 
 Green Sand, 480 
 
 Wealden Group, 900 
 
 Oolite, (mean thickness,) 1 230 
 
 Lias, 1050 
 
 New Red Sandstone, 900 
 
 Magnesian Limestone, 300 
 
 Coal Measures, 3000 
 
 Millstone Grit, 900 
 
 Carboniferous Limestone, 1800 
 
 Old Red Sandstone, 9900 
 
 Silurian Rocks, 7470 
 
 Cambrian System, 9000 
 
 Professor Rogers makes the fossiliferous rocks in this country be- 
 low the coal measures inclusive, 40,000 feet thick. 
 
 In the Andes and Himalayas, rocks, 1 6,000 feet above the sea, 
 abound in organic remains. Gerard found ammonites in Chinese 
 Tartary at the height of 16,200'feet; and, in Thibet, he found mil- 
 lions of shells 17,000 feet above the sea. 
 
 According to Hitchcock, all of two thirds of the surface of our 
 existing continents are composed of fossiliferous rocks. 
 
 In the Cambrian and Silurian Systems, Old Red Sandstone, Car- 
 boniferous Limestone, New Red Sandstone Group, and Cretaceous 
 Group, all the organic remains are of marine origin ; in Tertiary 
 Strata, they are marine and fresh water ; and in the Oolitic Group, 
 the marine predominate. In Diluvium, the relics are terrestrial. In 
 the Coal Measures, the deposits are terrestrial estuary ; in Wealden 
 Rocks, estuary. 
 
 To PARAGRAPH CXIX. Koferstein makes the whole number of 
 fossil species 9620 : the number of 
 
 Mammalia being .... 270 
 
 Birds 20 
 
 Reptiles 104 
 
 Fishes .386 
 
 Insects 247 
 
 Spiders, Crustaceae, Xyphosura, Ento- > , . 
 mostracea, Isophoda, Myriopoda ( 
 
 Mollusca 6056 
 
 Annelides 214 
 
 Radiata 411 
 
 Polypina 907 
 
 Vegetables . . . . .803 
 
 About half of this number are found above the secondary strata. 
 
 The older the rock, the more unlike in general are its organic 
 remains to existing species ; and the relics in northern parts of the 
 globe correspond more nearly to existing tropical plants and animals 
 than to those now living in the same latitudes. It is probable that, 
 during the deposition of the older fossiliferous rocks, the climate was 
 
APPENDIX. 325 
 
 ultia-troptcal It is the opinion of Agaseiz, that a fall of tempera- 
 ture took place near the close of each great geological period. 
 Hitchcock. 
 
 To PARAGRAPH CXX. According to M. GBppert, the numerical 
 distribution of the fossil plants in the various rocks is as follows : 
 
 Paleozoic. . . 52 
 
 Carboniferous . .819 
 
 Permian . . .58 
 
 Triassic . . .86 
 
 Oolitic . . .234 
 
 Wealden . . .16 
 
 Cretaceous - . .62 
 
 Tertiary . . .454 
 
 Unknown . .11 
 
 1792 
 
 To PARAGRAPH CLXXXI. Agassiz now reckons more than 1700 
 species of fossil fish. All the great rock formations, from the grau- 
 wacke upwards, contain fishes ; but not one species has been found 
 that is now living, or is common to any two of the formations. 
 
 To PARAGRAPH CCXXII. Professor Phillips now enumerates 274 
 species of ammonites, distributed as follows : In grauwacke, 17 ; car- 
 boniferous system, 33; poikilitio system, 3; 'oolitic system, 164; 
 cretaceous system, 57. Brochant enumerates 270 species. It is 
 sometimes called cornu Ammonis. Vide Pliny, 37, 10. 
 
 To PARAGRAPH CCXLVL All the fossil relics of birds are distri- 
 buted as follows : 20 species in diluvium ; 10 in the tertiary strata ; 
 and one in the Wealden formation. 
 
 Agassiz observes, that the tracks of birds may be invariably dis- 
 tinguished by the number of joints of the several toes; the hind toe 
 having uniformly two joints, the inner three, the middle four, the 
 outer five. 
 
 To PARAGRAPH CCXLVIL With few exceptions, all fossil mam- 
 malia occur in tertiary strata and diluvium. There is reason to 
 believe that the Marsupial Mammalia appeared earlier on the globe 
 than any other animals of this class. Hitchcock. 
 
 To PARAGRAPH CCCXII. Stromboli appears to have been in 
 ceaseless activity for 2000 years. Kiranea. and the volcano in *he 
 island of Nicaragua, are said to be constantly active. Many volcauos 
 are in a state of moderate activity, with occasional paroxysms, until, 
 finaily, a violent eruption gives vent to the force. Vesuvius was 
 thus from the commencement of the 19th century to October, 1822, 
 and from 1767 to 1779. In 1805, '09, '11, '12, and '19, ^Etna was 
 eruptive with intermediate agitations, but both these volcano* have 
 had periods of long repose. Popocatepetl ha. c been active ever since 
 the conquest of Mexico, and that of Sangay has been in incessant 
 
3C6 APPENDIX. 
 
 activity for about a century. As instances of remarkable volcanic 
 paroxysms, there are those of Vesuvius, A.D. 79, 203, 472,512, t-,86, 
 993, 1036, 1139, 1306, 1631, 1760, 1794, and 1822. ./Etna, in 1169, 
 1329, 1535 ; this latter eruption lasted two years " with terrific vio- 
 lence," and occurred after a quiescence of nearly 100 years. Tenerifte, 
 in 1 704, 1797-8. San Georgio, in 1808. Palma, in 1558, 164G, 1777. 
 Lanzerote, in 1730. Kattlagia Jokuhl, in 1 755. which lasted a year. 
 Skaptar Jokuhl, in l7&3.Silliman. 
 
INDEX. 
 
 |7" The figures in the columns beneath indicate the paragraphs of the 
 text in which the particular term or subject is fully explained ; and the letter 
 n refers to the notes accompanying the section in which the paragraph 
 occurs. 
 
 PARA. 
 Actynolite ...................... 97 
 
 Adipocere ................... 115, n 
 
 ^ tna, Viewof .................. 68 
 
 A tna, Eruptions ol .............. 73 
 
 Agriculture aided by Geology 331 
 Alabaster .............. n. page 254 
 
 Alluvial ...................... 62. n 
 
 Alluvial Land .......... n. page 52 
 
 Alps, Age of ................ ---- 243 
 
 Alum ........................... 229 
 
 Amber .......................... 249 
 
 -Amianthus ...................... 150 
 
 Ammonites (figured) ............ 222 
 
 Ammonites Catena ...... n, page 179 
 
 A morphous ..................... 95 
 
 Amygdaloid .................. 117. n 
 
 A nimal Life, Effects of ........ 84-80 
 
 A nimals. Classification of ....... 121 
 
 Anthracite .................. 192, n 
 
 Ant: clinical Axis ............. 108. n 
 
 Aqueous Action .............. 38. n 
 
 AQUEOUS AGENTS ............. 53. n 
 
 Architecture aided by Geology- 332 
 Arenaceous .............. n. page 120 
 
 Argillaceous Compounds ...... 140, n 
 
 Artesian Wells ................ 21, n 
 
 Articulated Animals ............ 121 
 
 Asaphus (figured) ............... 163 
 
 Asbestus ....................... 150 
 
 Asphalte ........................ 289 
 
 Asphalte. Uses of ............... 290 
 
 Asterophy llites (figured) ........ 194 
 
 Astraea, Fossil (figured .......... 163 
 
 Astra-a, Recent (figured) ........ 300 
 
 ATMOSPHERE, CONSTITUTION OF--- 33 
 Atmosphere, Pressure of ..... 33, n 
 
 Atmosphere, Utility of 
 
 34 
 
 PARA. 
 
 ATMOSPHERIC AGENTS 39. n 
 
 Atolls, or Circular Coral Reefs 304 
 
 Augite 97 
 
 Auiacaria (fossil) 194 
 
 Auvergne, Trap Hills of 243 
 
 Avalanche n, page 34 
 
 Avalanches, Effects of 43 
 
 BarbadoesTar 289 
 
 Basalt 198,199 
 
 Basin-Form of Coal-Fields 201 
 
 Beaches, Ancient, or Raised 78, 264 
 
 Beaches, Travelling 269 
 
 Beetle Stones 192 
 
 Beetles. Fossil 223 
 
 Belemnites 233, n 
 
 Bellerophon (figured) 190 
 
 Birds. Fossil 246 
 
 Bitumen n. page 87 
 
 Bitumens. Varieties of n, page 157, 289 
 Bitumenization. Process of- 115. n 
 
 Botryoidal 296 
 
 Boulder Group 252, * 
 
 Boulders, where found 254 
 
 Bovey Coal 249 
 
 Brine Springs 213 
 
 BRITISH DEPOSITS, TABLE OF 128 
 
 Burr Stone 249 
 
 Calamites (figured) 
 
 Calcareous Compounds- 
 
 Calc-Sinter 
 
 Calc-Tuff 
 
 Calymene (figured) 
 
 CannelCoal 191 
 
 Caoutchouc. Mineral n, page 157 
 
 Carbonate of Lime 97 
 
 83 
 
 194 
 140, n 
 
 2*7 
 .. 287 
 
 ... 183 
 
328 
 
 INDEX. 
 
 PARA. 
 
 Carbonate of Magnesia 97 
 
 Carbonic Acid Gas. Wasting 
 
 Powers of 50 
 
 Carboniferous Compounds 140, n 
 
 Carboniferous Limestone 186 
 
 CARBONIFEROUS SYSTEM 184 
 
 Cartilaginous Fishes 181 
 
 Catenipora (figured) 161 
 
 Caverns in Limestone n, page 157 
 
 Caverns, Ossiferous 261 
 
 Cellular Texture 95 
 
 Central Heat 21 
 
 Central Material of Globe 14 
 
 Cephalaspis (figured) 174 
 
 Cestration of Australia 224 
 
 CHALK FORMATION 230, n 
 
 Chalk Rock - 231 
 
 Chalybeate Springs 58 
 
 Chemical Action 38, n 
 
 Chemical Solution 30 
 
 Chloride of Sodium 97 
 
 Chlorite 97 
 
 Choke Damp n, page 157 
 
 Cidaris (figured) f. 222 
 
 Clay-Slate Fossils 160, 161 
 
 CLAY-SLATE SYSTEM 153 
 
 Cleavage 158, n 
 
 Clinkstone, or Phonolite 198 
 
 COAU MEASURES 192 
 
 Coal, Varieties of 192 
 
 Coal, Formation of 1 96, 197 
 
 Coal, where found 202 
 
 Coal, Utility of- 204 
 
 Coccosteus (figured) 174 
 
 Cocoa Nuts (fossil) 245 
 
 Columnar 95 
 
 Conformable Strata 108 
 
 Contorted Strata- 107 
 
 Copper, where found 169, 213 
 
 Coprolites 191. n 
 
 Coral. Uses of n, page 254 
 
 Coral Animalcule (figured) 300 
 
 CORAL REEFS 85, 300-306 
 
 Coral Reefs, Composition of 302 
 
 Coral Reefs, Formation of 303 
 
 Coral Reefs, Various Forms of- 304 
 
 Coral Reefs, Growth of 306 
 
 Coralloidal 206 
 
 Cornbrash n, page 179 
 
 Cornish Clay 139 
 
 Cornstqne 171 
 
 Crag Limestone .... - 241 
 
 Crater 68, n 
 
 CRETACEOUS SYSTEM 230 
 
 Crinoid Zoophytes 188 
 
 Crust of the Earth 2. n 
 
 Crust of the Earth, Causes Modi- 
 fying ' 4,5 
 
 Crust of the Earth, Thickness of 20 
 Crust of the Earth, Mineral Sub- 
 stances Composing 92 
 
 PARA- 
 
 Ctenoid Fishes 182 
 
 Cuboidal Structure 95 
 
 Currents, Oceanic 64, 65 
 
 Cyathophyllum, 161 
 
 Cyathophyllum Basaltiforme 
 
 (figured) 189 
 
 Cycadeae Fossil 220 
 
 Cycloid Fishes 189 
 
 Debacle n, page 231 
 
 Debris 56, r. 
 
 Degradation 52. n 
 
 Degrading Causes 90 
 
 Deinothenum (figured) 247 
 
 Deltas, Formation of 62 
 
 Deltas of Principal Rivers 279-2^1 
 
 Deltoid Deposits, Nature of 277 
 
 Density of the Globe 13, n 
 
 Denudation n, page 44 
 
 Deposits, Varieties of n, page 52 
 
 Devonian System n. page 133 
 
 Dialage Rock 97 
 
 Didelphidae, Fossil 224 
 
 Diluvium, Diluvial Drift 252. n 
 
 Dip 97 
 
 Dirt- Bed of Portland 221 
 
 Dislocation 111, n 
 
 Disrupting Masses 110, n 
 
 Divisional Planes 186 
 
 Dolerite 313 
 
 Dolomite 205 
 
 Downs, Formation of 41 
 
 Downthrow 111,201 
 
 Drainage, Natural 284 
 
 Dyke Ill, n 
 
 EARTH, SURFACE CONFIGURATION 
 
 OF 23 
 
 Earthquakes and their Effects. 74-76 
 Earthquakes, Examples of ...... 31C 
 
 Echinidse (figured) 23S 
 
 Edentata, Fossil 247 
 
 Edge Strata 107 
 
 Elaterite, elastic mineral pitch 
 
 n, page 157 
 
 Electrical Action 38. n 
 
 Electricity, Effects of 47 
 
 Elementary Bodies 100 
 
 Elevating Causes 90 
 
 Elevating Forces, Gradual 77 
 
 Embouchure n, page 231 
 
 Encrinital Limestone 188 
 
 Encrinite (figured) 188 
 
 Encrinites, Varieties of 18S, n 
 
 Engineering aided by Geology 3'3() 
 
 Entrochi n, page 157 
 
 Eocene n, page 97. 245 
 
 Erratic Block Group 252 
 
 Erratic Blocks, where found 254 
 
 F,c carpment 10? 
 
 Estuary Deposits 2>' 
 
INDEX. 
 
 329 
 
 Euomphalus (figured) 
 
 Exfoliate 
 
 Exuviae 
 
 PARA. 
 
 .. 163 
 
 n, page 66 
 
 Fault 111.201 
 
 Fauna, Fossil n, page 87 
 
 Felspar 97 
 
 Fibrous Structure 95 
 
 Fire-Clay 204 
 
 Fire-Damp n, page 157 
 
 Fissile - 95 
 
 Flagstone 172, 180 
 
 Flint, Uses of 237 
 
 Flint, Formation of- 238 
 
 Flora, Fossil n, page 87 
 
 Foliated Structure 95 
 
 Forests, Submarine 265 
 
 Forests, Subterranean 292 
 
 Fossiliferous Strata n, page 97 
 
 Fossils, Nature of- 112 
 
 Freshets, or Land-Floods n, page 231 
 
 Friable 95 
 
 Frosts. Effects of 42,43,n 
 
 Fuller's Earth 229 
 
 Ganges. Delta of- 281 
 
 Ganoid Fishes 188 
 
 Garnet, 97. 150 
 
 Gault. or Golt, Clay 231 
 
 Geodes 180, n 
 
 Geognosy n, page 17 
 
 Geography, Physical 6 
 
 Geology, Definition of 1, n 
 
 Geology, Objects of 3 
 
 Geology, Importance of 327 
 
 GLOBE. STRUCTURE AND CONDI- 
 TIONS OF 9 
 
 Globe. Figure of 10,11 
 
 Globe, Density of- 13 
 
 GLOBE, CAUSES MODIFYING 
 
 THE 37,38 
 
 Globe, Surface, Configuration 
 
 of 
 
 23 
 
 GXEISS SYSTEM .................. 140 
 
 Gneiss, Composition of ....... 141-1 43 
 
 Gold, where found ......... 169, 204 
 
 Granite composition of .......... 133 
 
 Granite, where found ........... 137 
 
 Granite. Uses of ............... 139 
 
 Granitic Crust, or Basis ......... 131 
 
 Granitic Rocks ............. 129-133 
 
 Granitic Districts, Aspect of ---- 138 
 
 Granular Texture .............. 95 
 
 Graphic Granite ................ 133 
 
 CTRAUWACKK SYSTEM ............ 154 
 
 Green Earth .................... 97 
 
 Green-sand Formation .......... 231 
 
 Greenstone ..................... 198 
 
 Gryphaea (figured) .............. 222 
 
 Gypsum (sulphate of liuie) ---- 249 
 
 Gyrgonites .................... 345 
 
 PARA. 
 
 Hamite n, page 179 
 
 Harnites (figured) 233 
 
 Hatchetine. mineral tallow n, page 157 
 
 Heat, Central 21 
 
 Heat. Solar Effects of 44, 45 
 
 Heliopora (figured) 161 
 
 Heterocercal Fishes 183 
 
 Hitch 111,201 
 
 Holoptychius (figured) 174 
 
 Horizontal Strata 107 
 
 Hornblende 97 
 
 Hypogene Rocks n, page 101 
 
 Iceberg n, page 34 
 
 Icebergs, Effects of 4a 255 
 
 Ichnites 209, n 
 
 Ichth) odorulite 174 
 
 Ichthyolite n. page 133 
 
 Ichthyosaurus, Skeleton of 223 
 
 Igneous Action 38, n 
 
 IGNEOUS AGENCIES 66, 67 
 
 Inoceramus (figured) 190 
 
 Interstratified Masses 110 
 
 Interstraiificauon. Pseudo 110 
 
 Iron, Oxide and Sulphuret of 97 
 
 Ironstone 184 
 
 Ironstone, Value of 204 
 
 Jet 
 
 Joints, or Backs 
 Jungles 
 
 186 
 291 
 
 Kaolin 139 
 
 Kupfer-schiefer 213, n 
 
 Lacustrine Deposits 283 
 
 Lagoon n, page 231 
 
 Laminar 95 
 
 LAND AND WATER, DISTRIBUTION 
 
 OF 25 
 
 Land and Water, Proportions of 26, n 
 
 Lapis Ollaris 150 
 
 Lava 71, n; 313 
 
 Lead Ore 204 
 
 Lepidodendron (figured) 194 
 
 LIAS GROUP 217, n 
 
 Lias Limestone 229 
 
 Light, Effects of 44,45 
 
 Lignite (wood-coal) 192, 249 
 
 Lithographic Limestone 213 
 
 Lituite n, page 179 
 
 London, Tertiary-Basin 241 
 
 Magnesian Limestone 206 
 
 Mammillary Structure 206 
 
 Man and his Works, found Fossil, 
 
 286, 295, 324 
 
 Marble 169, 204, 213, 249, Ac. 
 
 Marine Silt 267 
 
 Marl. Varieties of 285 
 
 Mastrve Structure 05 
 
330 
 
 INDEX. 
 
 PARA. 
 
 Mechanical Action 33, n 
 
 Mechanical Suspension 3 
 
 Megatherium (figured) 257 
 
 Meiocene n, page 97, 245 
 
 Metallization, Process of = 117 
 
 Metamorphic Rocks n, page 108 
 
 Mica.-.! 97 
 
 Mca. Uses of 139 
 
 MICA SCHIST SYSTEM 142 
 
 Millstone Grit 187 
 
 Mineralogy. Science of- 6 
 
 Mineral Springs 58 
 
 Minerals the most Abundant 97 
 
 Mining aided by Geology 329 
 
 Mississippi, Rafts of 62 
 
 Mississippi, Delta of 279 
 
 Molluscous Animals 121 
 
 Monkeys, Fossil 233 
 
 Moraines 255, n 
 
 MOUNTAIN LIMESTONE 186 
 
 Muschelkalk 207 
 
 Naphtha 289, n 
 
 Neptunian Rocks n, page 97 
 
 NEW RED SANDSTONE 205, n 
 
 New Red Sandstone, where found 211 
 
 Niger, the Delta of ' 280 
 
 Nile, Delt; 
 
 taof 
 
 Non-Fossiliferous Strata -n, page 97 
 
 Obsidian 313, n 
 
 Ocean, Depth of 26 
 
 OCEAN, CONSTITUTION OF 30 
 
 Ocean, Pressure of 32, n 
 
 Ochre 204 
 
 OLD RED SANDSTONE SYSTEM ' 170, n 
 Old Red Sandstone, Fossils of 173- 175 
 Old Red Sandstone, where found 178 
 
 Olivine 198 
 
 OOLITIC SYSTEM 216 
 
 Oolitic System, where found 226 
 
 Organic Action 38. n 
 
 ORGANIC AGENTS- 80 
 
 Ornithichnites n, page 166 
 
 Orthoceratite (figured) 1 90 
 
 Oryctology 6, w; 112 
 
 Osseous Breccia 259, n 
 
 Osseous Fishes 1 81 
 
 Ossiferous Sands and Gravels 257 
 Ossiferous Caves and Fissures 260 
 
 Osteolepis (figured) 174 
 
 Ostrea (figured) 222 
 
 Outcrop 108 
 
 Outliers 108 
 
 Overlying Masses 110 
 
 Oxygen, Wasting Effects of 50 
 
 Palaeontology 6, n 
 
 Palaeotherium (figured) 247 
 
 Pampas, Formation of 284. n 
 
 Parallel Road* < 273 
 
 PAfv. 
 
 Paris Tertiary Basin '. 
 
 Peal- Mosses 291-296 
 
 Peat, Uses of 290 
 
 Peat, Varieties of 29y 
 
 Pecopteris (figured) 194 
 
 Pecten (figured) 233 
 
 Permian System n, page 165 
 
 Peroxide of Iron 167. n 
 
 Petrifaction, Process of ' 113, 114 
 
 Petroleum 289 
 
 Pisiform Iron Ore - 217 
 
 Pitch, Mineral 289 
 
 Placoid Fishes 182 
 
 Plagiostoma (figured) 233 
 
 Plane Strata 107 
 
 PLANETARY RELATIONS OF THE 
 
 GLOBE 35 
 
 Plants, Cellular and Vascular 120 
 
 Plaster of Paris 249 
 
 Plastic Clay 249 
 
 Pleiocene n, page 97, 245 
 
 Pleistocene n, page 97, 245 
 
 Plesiosaurus 
 
 223 
 
 Plutonic Rocks n, page 97 
 
 Po. the Delta of the 279 
 
 Poikilitic System 205 
 
 Porous 95 
 
 Porphyry n, page 1:33 
 
 Post-Tertiary 251 
 
 Potstone 150 
 
 Prairies, Formation of- 284. n 
 
 Primary Districts 149 
 
 Primary Strata 144 
 
 Primary Strata, Origin of 146 
 
 Primary Strata, where found 148 
 
 Primary Strata, Uses of 150 
 
 Producta (figured) 190 
 
 Protogine 13-3 
 
 Pterichthys (figured) 174 
 
 Pterodactyle 221 
 
 Puddingstone 172. n 
 
 Purnicestone 313 
 
 Pyrites n, page 120 
 
 97 
 251 
 
 Quartz 
 
 Quaternary System 
 
 Radiated Animals 121 
 
 Rain, Effects of 54 
 
 Rai sed Beaches 264 
 
 Resins, Mineral n, page 157 
 
 Retepora (figured) 1 89 
 
 Rhone, the Delta of 279 
 
 Ripple-Mark 176 
 
 Rivers, Action of 60, 61 
 
 ROCK FORMATIONS, CLASSIFIED 
 
 124-130, n 
 
 Rock, Definition of 125 
 
 Rock-Salt 213 
 
 Rocks, Stratified, Aqueous, or Se- 
 di memary J>3 
 
IfCDEX. 
 
 331 
 
 Rocks, Unstratified, Igneous, or 
 
 Volcanic 92,129 
 
 Rocks, Mechanical Structure of-. 9 
 Rocks, Mineral Composition of 96 
 
 Rocks, Varieties of- 98 
 
 Rocks, Chemical Character of 99 
 
 Roesione 216 
 
 Roofing-Slate 169 
 
 Rothe-todte-1 iegende 207, n 
 
 Saccharoid Texture 95 
 
 Saddle-Back 108 
 
 Saliferous System 205 
 
 Salt-Rock, Formation of 214 
 
 Salt Springs 213 
 
 Sand-Drift 268 
 
 Sauroid Animals n, page 179 
 
 Sauroidichnites n, page 166 
 
 Savannah, Formation of 284, n 
 
 Scaphite n. page 179 
 
 Scaphites (figured) - 233 
 
 Schistose 95 
 
 Schorl n, page 70 
 
 Scoriae n, page 59, 313 
 
 Screwstones (encrinites) n, page 156 
 
 Sea,Depthof 28 
 
 Secretion n,page 66 
 
 Sections, Natural and Artificial 
 
 105, 106 
 
 Sediment- 30 ; n, page 52 
 
 Selenite (crystallized gypsum) 206 
 
 Septaria 192 
 
 Serpentine 133 
 
 Shell-Beds 298,299 
 
 Shell-Fish, Effects of 87 
 
 Shingle-Beaches 269 
 
 Sigilfaria (figured) 184 
 
 Silicious Compounds 140, n 
 
 Silicious Sinter 288 
 
 Silt n, page 51; 61, n 
 
 Silt, Marine 267 
 
 SiLCRiAS SYSTEM 155 
 
 Silurian, why called - n, page 120 
 Silurian System, Fossils of 162, 163 
 
 Silver, where found 169, 204 
 
 Slips 111,201 
 
 Snow. Effects of 54 
 
 Soil, Formation of- 51,308 
 
 Soils, Varieties of 309 
 
 Solar Heat, Effects of 44, 45 
 
 Solar Light, Effects of 44, 45 
 
 Sphagnum Palustre 291 
 
 Sphenopteris (figured) 194 
 
 Spiritera (figured) 169 
 
 Springs, Effects of 67, 58 
 
 Springs, Salt 213 
 
 Springs ' Belles of 56 
 
 Squamose 95 
 
 St. Cuthbert's Beads n. page 157 
 
 Staffa. Basa'tic Columns of 200 
 
 Stalactite ai 4 Stalagmite 2W 
 
 MBA. 
 
 Steatite - 07 
 
 Steppes, Formation of 284, n 
 
 Stigmaria (figured) 194 
 
 Stratification, Forms of- 107 
 
 Stratum n, pagt: 17 
 
 Subcolumnar n, page 156 
 
 Subcrystalline n, page 156 
 
 Submarine Deposits 271 
 
 Subsoils 307 
 
 Sulphate of Lime (gypsum) 97 
 
 Sulphur n, page 261 
 
 SUPERFICIAL ACCUMULATIONS 251 
 
 Supraposition of Rocks 130 
 
 Surface Configuration 23, n 
 
 Syenite 133 
 
 Synclinal Axis 108, n 
 
 Syringipora (figured) 189 
 
 Talc 97 
 
 Talc, Usesof 139 
 
 Temperature of the Globe- -16-22, n 
 Temperature of the Earth's Surface 17 
 Temperature of the Earth's Crust 18 
 Temperature of Central Parts 21 
 
 Terebratula (figured) 161, 163 
 
 Terraces in Valleys 273 
 
 TERTIARY BASINS 242 
 
 Tertiary Strata 239 
 
 Tetiapodichnites n, page 166 
 
 Thames Tertiary Basin (figured) 241 
 
 Theroid Animals 247, n 
 
 Tides, Effects of 172,180 
 
 Tilestone 180 
 
 Tilted Up 107 
 
 Tin. where found 169 
 
 Toadstone n, page 133 
 
 Trachyte 313 
 
 Trade-Winds 40 
 
 Transition Districts, Features of 168 
 Transition Districts, Scenery of- - 168 
 
 Transition Rocks 130, 156 
 
 Transition Rocks, Succession of 159 
 
 Trap Tuff 198 
 
 Trappean Rocks 129 
 
 Travertine 287 
 
 Triassic System n, page 165 
 
 Trigonia (figured) 222 
 
 Trilobites (figured) 173 
 
 Tripoli 288 
 
 Trough Form of Coal-Fields .... 201 
 
 Unconformable Strata 108 
 
 Upthrow 111,201 
 
 Valley Deposits 275 
 
 Valleys, Varieties of n, page 231 
 
 Vegetable Classification 120 
 
 Vegetable Growth, Effects of- 81-83 
 
 Veins Ill 
 
 Vertebrated Animals 121 
 
 Vesicular Texture 96 
 
332 
 
 INDEX. 
 
 PARA 
 
 Vital Action 38, n 
 
 Volcanic Forces,Elevating powers 
 
 of 73 
 
 Volcanic Forces, Effect3 of 70, 311, 312 
 
 Volcanic Rocks 129 
 
 Volcanoes, Causes of- 314 
 
 Volcanoes, Definition of- 68 
 
 Volcanoes, Extinct, Dormant, and 
 
 Active 311, n 
 
 Volcanoes, Products of- 313 
 
 PARA 
 
 Water, Action of * 53, n 
 
 Waves, Effects of 64,65 
 
 WKALDEN GROUP 217 
 
 Weathering 39,49 
 
 Winds 40, n 
 
 Winds, Effects of 41 
 
 World, Map of page 27 
 
 Zechstein 
 
 207, 
 
 INDEX TO GEOGRAPHICAL GEOLOGY. 
 
 PAGE. 
 
 Afghanistan 284 
 
 AFRICA 289 
 
 African Islands 291 
 
 Arabia 283 
 
 Argentine Republic 326 
 
 ASIA 281 
 
 Australia 288 
 
 Ballogistan 284 
 
 Barbary 289 
 
 Belgium 299 
 
 Boliva 320 
 
 Brazil 320 
 
 British America 301 
 
 Central America 317 
 
 Chili 320 
 
 China 287 
 
 Circassia 282 
 
 .299 
 
 Denmark 297 
 
 Eastern Africa 291 
 
 England 292 
 
 EUROPE 292 
 
 France 297 
 
 Galicia 299 
 
 Georgia, 282 
 
 Germany 298 
 
 Greece 300 
 
 Greenland 300 
 
 Guyana 320 
 
 Holland 299 
 
 Hungary 299 
 
 India 285 
 
 Ireland 295 
 
 Italy 299 
 
 Japan, 287 
 
 Malaysia 
 Mexico 
 
 PAOI 
 
 .319 
 
 New Granada 319 
 
 NORTH AMERICA 300 
 
 Norway 296 
 
 Patagroni a 32 1 
 
 Persia.. ...284 
 
 Peru . 320 
 
 Polynesia 289 
 
 Portugal 298 
 
 Region of the Nile 290 
 
 Russia 296 
 
 Russian America 300 
 
 Sc lavonia 299 
 
 Scotland 294 
 
 Sibera 281 
 
 Soudan 291 
 
 SOUTH AMERICA 318 
 
 South American Islands 321 
 
 Southern Africa 291 
 
 Spain 298 
 
 Sweden 2% 
 
 Swisserland 298 
 
 Tartary 285 
 
 Thibet 285 
 
 Terkey (in Asia) 282 
 
 Turkey (in Europe) 300 
 
 Transylvania 299 
 
 United States, including 
 
 California 302 
 
 Venezuela 319 
 
 Wales... ...294 
 
 Western Africa 290 
 
 West Indies 313 
 
 Zaoara 290 
 
Davits' System of Mathematics. 
 
 TO THE FRIENDS OF EDUCATION. 
 
 The publishers of this series of mathematical works by Professor 
 CHARLES DAVIES, beg leave respectfully to ask of teachers and the 
 friends of education a careful examination of these works. It is 
 not their intention to commend, particularly, this Course of Math- 
 ematics to public favor ; and especially, it is not their design to 
 disparage other works on the same subjects. They wish simply 
 to explain the leading features of this system of Text- Books the 
 place which each is intended to fill in a system of education the 
 general connection of the books with each other and some of the 
 advantages which result from the study of a uniform series of math- 
 ematical works. 
 
 It may, perhaps, not be out of place, first, to remark, that the 
 author of this series, after graduating at the Military Academy, 
 entered upon the duties of a permanent instructor in that institution 
 in the year 1816, and was employed for the twenty following years 
 in the departments of scientific instruction. At the expiration of 
 that period he visited Europe, and had a full opportunity of com- 
 paring the systems of scientific instruction, both in France and 
 England, with that which had been previously adopted at the Mili- 
 tary Academy. 
 
 This series, combining all that is most valuable in the various 
 methods of European instruction, improved and matured by the 
 suggestions of more than thirty years' experience, now forms the 
 only complete consecutive course of Mathematics. Its methods, 
 harmonizing as the works of one mind, carry the student onward 
 by the same analogies and the same laws of association, and are cal- 
 culated to impart a comprehensive knowledge of the science, com- 
 bining clearness in the several branches, and unity and proportion 
 in the whole. Being the system so long in use at West Point, and 
 through which so many men, eminent for their scientific attain- 
 ments, have passed, it may be justly regarded as our NATIONAL 
 SYSTEM OF MATHEMATICS. Scholars and students who have pur- 
 sued this course, will everywhere stand on the highest level with 
 reference to the estimates which themselves and others will form 
 of this part of their education. 
 
 The series is divided into three parts, viz. : First ARITHMETI- 
 CAL COURSE FOR SCHOOLS. Second ACADEMICAL COURSE. Third 
 COLLEGIATE COURSE. 
 
 (3) 
 
Davies* System of Mathematics. 
 
 The Arithmetical Course for Schools. 
 
 I. PRIMARY TABLE-BOOK. 
 II. FIRST LESSONS IN ARITHMETIC. 
 III. SCHOOL ARITHMETIC. (Key separate/* 
 
 PRIMARY TABLE-BOOK. 
 
 The leading feature of the plan of this work is to teach the reading of figures 
 that is, so to train the mind that it shall, by the aid of the eye alone, catch in- 
 stantly the idea which any combination of figures is intended to express. 
 
 The method heretofore pursued has aimed only at presenting the combinations 
 by means of our common language : this method pioyoses to present them pure- 
 ly through the arithmetical symbols, so that the pupil shall not be obliged to pause 
 at every step and translate his conceptions into common language, and then re- 
 translate them into the language of arithmetic. 
 
 For example, when he sees two numbers, as 4 and 8, to be added, he shall not 
 pause and say, 4 and 8 are 12, but shall be so trained as to repeat. 12 at once, as is 
 always done by an experienced accountant. So, if the difference of these num- 
 bers is to be found, he shall at once say 4, and not 4 from 8 leaves 4. If he de- 
 sires their product, he will say 32 ; if their quotient, 2 : and the same in all simi- 
 lar cases. 
 
 FIRST LESSONS IN ARITHMETIC. 
 
 The First Lessons in Arithmetic begin with counting, and advance step by step 
 through all the simple combinations of numbers. In order that the pupil may be 
 impressed with the fact that numbers express a collection of units, or things of 
 the same kind, the unit, in the beginning, is represented by a star, and the child 
 should be made to count the stars in all cases where they are used. Having once 
 fixed in the mind a correct impression of numbers, it was deemed no longer 
 necessary to represent the unit by a symbol ; and hence the use of the star was 
 discontinued. In adding 1 to each number from 1 to 10, we have the first ten 
 combinations in arithmetic. Then by adding 2 in the same way, we have the 
 second ten combinations, and so on. Each ten combinations is arranged in a 
 separate lesson, throughout the four ground rules, and each is illustrated either 
 by unit marks or a simple example. Thus the four hundred elementary combi- 
 nations are presented, in succession, in forty lessons, a plan not adopted in any 
 other elementary book. 
 
 SCHOOL ARITHMETIC. 
 
 This work begins with the simplest combination of numbers, and contains all 
 that is supposed to be necessary for the average grade of classes in schools. It 
 is strictly scientific and entirely practical in its plan. Each idea is first presented 
 to the mind either by an example or an illustration, and then the principle, or 
 abstract idea, is stated in general terms. Great care has been taken to attain 
 simplicity and accuracy in the definitions and rules, and at the same time so to 
 frame them as to make them introductory to the higher branches of mathematical 
 science. No definition or rule is given until the mind of the pupil has been 
 brought to it by a series of simple inductions, so that mental training may begin 
 with the first intellectual efforts in numbers 
 
 4 
 
Davies' System of Mathematics. 
 
 The Academic Course. 
 
 I. THE UNIVERSITY ARITHMETIC. (Key separate.) 
 II. PRACTICAL GEOMETRY AND MENSURATION. 
 
 III. ELEMENTARY ALGEBRA. (Key separate,) 
 
 IV. ELEMENTARY GEOMETRY. 
 
 V. DAVIES' ELEMENTS OF SURVEYING. 
 
 Those who are conversant with the preparation of elementary 
 text-hooks, have experienced the difficulty of adapting them to the 
 wants which they are intended to supply. The institutions of in- 
 struction are of all grades from the college to the district school, 
 and although there is a wide difference between the extremes, the 
 level in passing from one grade to the other is scarcely broken. 
 Each of these classes of seminaries requires text-books adapted to 
 its own peculiar wants ; and if each held its proper place in its 
 own class, the task of supplying suitable text-books would not be 
 so difficult. An indifferent college is generally inferior, in the 
 system and scope of instruction, to a good academy or high-school ; 
 while the district-school is often found to be superior to its neigh- 
 boring academy. 
 
 Although, therefore, the University Arithmetic and the Practical 
 Geometry and Mensuration, have been classed among the books 
 appropriate for academies, they may no doubt be often advantage- 
 ously studied in the common-school ; so also with the Algebra and 
 Elementary Geometry. The Practical Geometry and Mensura- 
 tion, containing so much practical matter, can hardly fail to be a 
 useful and profitable study. 
 
 DAVIES' UNIVERSITY ARITHMETIC. 
 
 The scholar in commencing this work, is supposed to be familiar with the oper- 
 ations in the four ground rules, which are fully taught both in the First Lessons 
 and in the School Arithmetic. This being premised, the language of figures, 
 which are the representatives of numbers, is carefully taught, and the different 
 significations of which the figures are susceptible, depending on the places in 
 which they are written, are fully explained. It is shown, for example, that the 
 simple numbers in which the unit increases from right to left according to the 
 scale of tens, and the Denominate or Compound Numbers, in which it increases 
 according to a different scale ; belong in fact to the same class of numbers, and 
 that both may be treated under a common set of rules. Hence, the rules for No- 
 tation, Addition, Subtraction, Multiplication, and Division, have been so con- 
 structed as to apply equally to all numbers. This arrangement is a new one, and 
 is deemed an essential improvement in the science of numbers 
 
 Ifl developing the properties of numbers, from their elementary to their highest 
 combinations, great labor has been bestowed on classification and arrangement. 
 It has been a leading object to present the entire subject of arithmetic as forming 
 
Davies' System of Mathematics. 
 
 a series of dependent and connected propositions ; so that the pupil, while ac- 
 quiring useful and practical knowledge, may at the same time be introduced to 
 those beautiful methods of exact reasoning which science alone can teach. 
 
 Great care has been taken to demonstrate fully all the rules, and to explain the 
 reason of every process, from the most simple to the most difficult. The demon- 
 stration of the rule for the division of fractions, on page 147, is new and consid- 
 ered valuable. 
 
 The properties of the 9's, explained at page 93, and the demonstration of the 
 four ground rules by means of those properties, are new in their present form, 
 and are thought worthy of special attention. 
 
 In the preparation of the work, another object has been kept constantly in 
 view ; viz., to adapt it to the business wants of the country. For this purpose, 
 much pains have been bestowed in the preparation of the articles on Weights 
 and Measures, foreign and domestic on Banking, Bank Discount, Interest, Coins 
 and Currency, Exchanges, Book-keeping, &c. In short, it is a full treatise on 
 the subject of Arithmetic, combining the two characteristics of a scientific and 
 practical work. 
 
 Recommendation from the Professors of the Mathematical Department of the 
 
 United States Military Academy 
 
 In the distinctness with which the various definitions are given the clear and 
 strictly mathematical demonstration of the rules the convenient form and well- 
 chosen matter of the tables, as well as in the complete and much-desired appli- 
 cation of all to the business of the country, the " University Arithmetic" of 
 Prof. Davies is superior to any other work of the kind with which we are ac- 
 quainted. These, with the many other improvements introduced by the ad- 
 mirable scientific arrangement and treatment of the whole subject, and in par- 
 ticular those of the generalization of the four ground rules, so as to include 
 " simple and denominate" numbers under the same head, and the very plain 
 demonstration of the rule for the division of fractions both of which are, to us, 
 original make the work an invaluable one to teachers and students who are de- 
 sirous to teach or study arithmetic as a science as well as an art. 
 
 (Signed,) D. H. MAHAN, Prof. Engineering. 
 
 W. H. C. BARTLETT, Prof. Nat. Phil. 
 A. E. CHURCH, Prof. Mathematics. 
 United States Military Academy, Jan. 18, 1847. 
 
 PRACTICAL GEOMETRY AND MENSURATION. 
 
 The design of this work is to afford schools ana academies an Elementary 
 Text-Book of a practical character. The introduction into our schools, within 
 the last few years, of the subjects of Natural Philosophy, Astronomy, Mineralo- 
 gy, Chemistry, and Drawing, has given rise to a higher grade of elementary 
 studies ; and the extended application of the mechanic arts calls for additional 
 information among practical rnen. In this work all the truths of Geometry are 
 made accessible to the general reader, by omitting the demonstrations altogether, 
 and relying for the impression of each particular truth on a pointed question arid 
 an illustration by a diagram. In this way it is believed that all the important 
 properties of the geometrical figures may be learned in a few weeks ; and after 
 these properties have been once applied, the mind receives a conviction of their 
 truth little short of what is afforded by rigorous demonstration. The work is 
 divided into seven books, and each book is subdivided into sections. 
 
 In Book I., the properties of the geometrical figures are explained bv questions 
 and illustrations. 
 
Davies* System of Mathematics. 
 
 In Book II. are explained the construction and uses of the various scales ; and 
 also the construction of geometrical figures. It is, as its title imports, Practical 
 Geometry. 
 
 Book III. treats of Drawing. Section I., of the Elements of the Art ; Section 
 II., of Topographical Drawing ; and Section III., of Plan Drawing. 
 
 Book IV. treats of Architecture explaining the different orders, both by de- 
 scriptions and drawings. 
 
 Book V. contains the application of the principles of Geometry to the Mensu- 
 ration of Surfaces and Solids. A separate rule is given for each case, and tho 
 whole is illustrated by numerous and appropriate examples. 
 
 Book VI. contains the application of the preceding Books to Artificers' and Me- 
 chanics' work. It contains full explanations of all the scales the uses to which 
 they are applied and specific rules for the calculations and computations which 
 are necessary in practical operations. 
 
 Book VII. is an introduction to Mechanics. It explains the nature and proper- 
 ties of matter, the laws of motion and equilibrium, and the principles of all the 
 simple machines. 
 
 ELEMENTARY ALGEBRA. 
 
 This work is intended to form a connecting link between Arithmetic and Alge 
 bra, and to unite and blend, as far as possible, the reasoning on numbers with the 
 more abstract method of analysis. It is intended to bring the subject of Algebru 
 within the range of our common schools, by giving to it a practical and tangible 
 form. It begins with an introduction, in which the subject is first treated men- 
 tally, in order to accustom the mind of the pupil to the first processes ; after 
 which, the system of instruction assumes a practical form. The definitions and 
 rules are as concise and simple as they can be made, and the reasonings are as 
 clear and concise as the nature of the subject will admit. The strictest scientific 
 metiiods are always adopted, for the double reason, that what is learned should 
 be learned in the right way, and because the scientific methods are generally the 
 most simple. 
 
 ELEMENTARY GEOMETRY. 
 
 This work is designed for those whose education extends beyond the acquisi- 
 tion of facts and practical knowledge, but who have not the time to go through 
 a full course ofrnathematical studies. It is intended to present the striking and 
 important truths of Geometry in a form more simple and concise than is adopted 
 in Legendre, and yet preserve the exactness of rigorous reasoning. In this sys- 
 tem, nothing has been omitted in the chain of exact reasoning, nothing has been 
 taken for granted, and nothing passed over without being fully demonstrated 
 The work also contains the applications of Geometry to the Mensuration of Sur 
 faces and Solids. 
 
 SURVEYING. 
 
 In this work it was the intention of the author to begin with the very elemems 
 of the subject, and to combine those elements in the simplest manner, so as to 
 render the higher branches of Plane Surveying comparatively easy. All the in- 
 struments needed for plotting have been carefully described, and the uses of those 
 required for the measurement of angles are fully explained. The Conventional 
 Signs adopted by the Topographical Bureau, and which are now used by the United 
 States Engineers in all their charts and maps, are given in full. An account is also 
 given of the manner of surveying the public lands ; and although the method is sim- 
 ple, it has nevertheless been productive of great results. The work also contains 
 a Table of Logarithms a Table of Logarithmic Sines a Traverse Table, and a 
 Table of Natural Sines being all the Tables necessary for Practical Surveying 
 
 CT1 
 
Dames' System of Mathematics. 
 
 The Collegiate Course. 
 
 I. DAVIES' BOURDON'S ALGEBRA. 
 II. DAVIES' LEGENDRE'S GEOMETRY AND TRIGONOMETRY. 
 
 III. DAVIES' ANALYTICAL GEOMETRY. 
 
 IV. DAVIES' DESCRIPTIVE GEOMETRY. 
 
 V. DAVIES' SHADES, SHADOWS, AND PERSPECTIVE. 
 VI. DAVIES' DIFFERENTIAL AND INTEGRAL CALCULUS. 
 
 The works embraced under the head of the " Collegiate Course," 
 were originally prepared as text-books for the use of the Military 
 Academy at West Point, where, with a single exception, they are 
 still used. Since their introduction into many of the colleges of 
 the country, they have been somewhat modified, so as to meet the 
 wants of collegiate instruction. The general plan on which these 
 works are written, was new at the time of their appearance. Its 
 main feature was to unite the logic of the French School of 
 Mathematics with the practical methods of the English, and the 
 two methods are now harmoniously blended in most of our systems 
 of scientific instruction. 
 
 The introduction of these works into the colleges was for a 
 long time much retarded, in consequence of the great deficiency in 
 the courses of instruction in the primary schools and academies : 
 and this circumstance induced Professor Davies to prepare his 
 Elementary Course. 
 
 The series of works here presented, form a full and complete 
 course of mathematical instruction, beginning with the first com- 
 binations of arithmetic, and terminating in the higher applications 
 of the Differential Calculus. Each part is adapted to all the 
 others. The Definitions and Rules in the Arithmetic, have 
 reference to those in the Elementary Algebra, and these to similar 
 ones in the higher books. A pupil, therefore, who begins this 
 course in the primary school, passes into the academy, and then 
 into the college, under the very same system of scientific in- 
 struction. 
 
 The methods of teaching are all the same, varied only by the 
 nature and difficulty of the subject. He advances steadily from 
 one grade of knowledge to another, seeing as he advances the con 
 nection and mutual relation of all the parts : and when he reacnej 
 the end of his course, he finds indeed, that " science is but know 
 ledge reduced to order." 
 
 (8) 
 
Dames 9 System of Mathematics. 
 
 DA VIES' BOURDON. 
 
 The Treatise on Algebra by M. Bourdon, is a work of singular excellence 
 and merit. In France it is one of the leading text-books. Shortly after its first 
 publication it passed through several editions, and has formed the basis of every 
 subsequent work on the subject of Algebra. 
 
 The original work is, however, a full and complete treatise on the subject of 
 Algebra, the later editions containing about eight hundred pages octavo. The 
 time given to the study of Algebra in this country, even in those seminaries where 
 the course of mathematics is the fullest, is too short to accomplish so volumin- 
 ous a work, and hence it has been found necessary either to modify it, or to 
 abandon it altogether. The Algebra of M. Bourdon, however, has been regarded 
 only as a standard or model, and it would perhaps not be just to regard him as 
 responsible for the work in its present form. 
 
 In this work are united the scientific discussions of the French with the prac- 
 tical methods of the English school, so that theory and practice, science and art, 
 may mutually aid and illustrate each other. A great variety of examples have 
 also been added in the late editions. 
 
 DAVIES' LEGENDRE. 
 
 Legendre's Geometry has taken the place of Euclid, to a great extent, both in 
 Europe and in this country. In the original work the propositions are not 
 enunciated in general terms, but with reference to, and by the aid of, the par- 
 ticular diagrams used for the demonstrations. It was supposed that this de- 
 parture from the method of Euclid had been generally regretted, and among the 
 many alterations made in the original work, to adapt it to the systems of in- 
 struction in this country, that of enunciating the propositions in general terms 
 should be particularly named ; and this change has met with universal acceptance. 
 
 To the Geometry is appended a system of Mensuration of Planes and Solids 
 a full treatise on Plane and Spherical Trigonometry and a table of Logarithms, 
 and Logarithmic Sines, Tangents, and Secants. The whole forms a complete 
 system of Geometry with its applications to Trigonometry and Mensuration, 
 together with the necessary tables. 
 
 ANALYTICAL GEOMETRY. 
 
 This work embraces the investigation of the properties of geometrical figures 
 oy means of analysis. It commences with the elementary principles of the sci- 
 ence, discusses the Equation of the Straight Line and Circle the Properties of 
 the Conic Sections the Equation of the Plane the Positions of Lines in Space, 
 and the Properties of Surfaces. 
 
 DESCRIPTIVE GEOMETRY. 
 
 Descriptive Geometry is intimately connected with Architecture and Civil 
 Engineering, and affords great facilities in all the operations of Construction. 
 
 As a mental discipline, the study of it holds the first place among the various 
 branches of Mathematics. 
 
 SHADES, SHADOWS, AND PERSPECTIVE. 
 
 This work embraces the various applications of Descriptive Geometry to 
 Drawing and Linear Perspective. 
 
 DIFFERENTIAL AND INTEGRAL CALCULUS. 
 
 This treatise on the Differential and Integral Calculus, was intended to supply 
 the higher seminaries of learning with a text-book on that branch of science. It 
 is a work after the French methods of teaching, and in which the notation of tlu 
 French school is adopted. 
 
 (9) 
 
Parker's Natural Philosophy. 
 
 NATURAL AND EXPERIMENTAL PHILOSOPHY 
 
 FOR SCHOOLS AND ACADEMIES, 
 
 BY R, G, PARKER, A, M. 
 
 PRINCIPAL OF THE JOHNSON GRAMMAR SCHOOL, BOSTON, AUTHOR OF AIDS 
 TO ENGLISH COMPOSITION, ETC., ETC. 
 
 I. PARKER'S FIRST LESSONS IN NATURAL PHILOSOPHY. 
 II. PARKER'S COMPENDIUM OF NATURAL AND EXPERIMENTAL 
 PHILOSOPHY. 
 
 PARKER'S FIRST LESSONS IN NATURAL PHILOSOPHY, 
 
 Embracing the Elements of the Science. Illustrated with numerous 
 
 engravings. Designed for young beginners. Price 38 cts. 
 
 It is the design of this little book, to present to the minds of the 
 youth of the country a view of the laws of Nature as they are 
 exhibited in the NATURAL WORLD. 
 
 Reading books should be used in schools for the double object of 
 teaching the child to read, and storing his mind with pleasant and 
 useful ideas. 
 
 The form of instruction by dialogue, being the simplest, has 
 been adopted and by means of the simple question and the ap- 
 propriate answer, a general view of the laws of the physical uni- 
 verse has been rendered so intelligible, as to be easily understood 
 by children who are able to read intelligibly.' 
 
 It is confidently believed that this book will form an important 
 era in the progress of common-school education 
 
 PARKER'S COMPENDIUM OF NATURAL AND EXPERIMENTAL 
 
 PHILOSOPHY. 
 
 Embracing the Elementary principles of Mechanics, Hydrostatics, Hy- 
 draulics, Pneumatics, Acoustics, Pyronomics, Optics, Astronomy, 
 Galvanism, Magnetism, Electro-Magnetism, Magneto-Electricity, 
 with a description of the Steam and Locomotive Engines. Illustrated 
 by numerous diagrams. Price $1.00. 
 
 The use of school apparatus for illustrating and exemplifying 
 the principles of Nacural and Experimental Philosophy, has, with- 
 in the last few years, become so general as to render necessary a 
 work which should combine, in the same course of instruction, the 
 theory, with a full description of the apparatus necessary for illus- 
 tration and experiment. 
 
 The work of Professor Parker, it is confidently believed, fully 
 rpnets that requirement. "U is also verv full in the general facts 
 
 (12) 
 
Parker's Natural Philosophy. 
 
 which it presents clear and concise in its style, and entirely 
 scientific and natural in its arrangement. The following features 
 will, it is hoped, commend the work to public favor. 
 
 1. It is adapted to the present state of natural science ; embraces 
 a wider field, and contains a greater amount of information on the 
 respective subjects of which it treats, than any other elementary 
 treatise of its size. 
 
 2. It contains an engraving of the Boston School set of philo- 
 sophical apparatus ; a description of the instruments, and an ac- 
 count of many experiments which can be performed by means ot 
 the apparatus. 
 
 3. It is enriched by a representation and a description of the 
 Locomotive and the Stationary Steam Engines, in their latest and 
 most approved forms. 
 
 4. Besides embracing a copious account of the principles ol 
 Electricity and Magnetism, its value is enhanced by the introduc- 
 tion of the science of Pyronomics, together w r ith the new science 
 of Electro-Magnetism and Magneto-Electricity. 
 
 5. It is peculiarly adapted to the convenience of study and of 
 recitation, by the figures and diagrams being first placed side by 
 side with the illustrations, and then repeated on separate leaves at 
 the end of the volume. The number is also given, where each 
 principle may be found, to which allusion is made throughout the 
 volume. 
 
 6. It presents the most important principles of science in a 
 larger type ; while the deductions from these principles, and the 
 illustrations, are contained in a smaller letter. Much useful and 
 interesting matter is also crowded into notes at the bottom of the 
 page. By this arrangement, the pupil can never be at a loss to 
 distinguish the parts of a lesson which are of primary importance ; 
 nor will he be in danger of mistaking theory and conjecture for fact. 
 
 7. It contains a number of original illustrations, which the author 
 has found more intelligible to young students than those which he 
 has met elsewhere. 
 
 8. Nothing has been omitted which is usually contained in an 
 elementary treatise. 
 
 9. A full description is given of the Magnetic Telegraph, and the 
 principles of its construction are fully explained. 
 
 10. For the purpose of aiding the teacher in conducting an ex- 
 amination through an entire subject, or indeed, through the whole 
 book, if necessary, all the diagrams have been repeated at the 
 end of the work, and questions proposed on the left-hand page im- 
 mediately opposite. This arrangement will permit the pupil to 
 use the figure, in his recitation, if he have not time to make it on 
 the hlac.k-board, and will also enable him to review several lessons 
 and recall all the principles by simply reading the questions, and 
 analyxing the diagrams. 
 
Parker's Natural Philosophy. 
 
 From the Wayne County Whig. 
 
 After a careful examination of this work, we find that it is well calculated for 
 the purpose for which it is intended, and better adapted to the state of natural 
 science at the present time, than any other similar production with which we 
 are acquainted. The design of the author, in the preparation of this work, was 
 to present to the public an elementary treatise unencumbered with matter that is 
 .not intimately connected with this science, and to give a greater amount of in- 
 formation on the respective subjects of which it treats, than any other school- 
 book of an elementary character. The most remarkable feature in the style of 
 this work is its extreme brevity. In the arrangement of the subject and the man- 
 ner of presenting it, there are some peculiarities which are, in our opinion, de- 
 cided improvements. The more important principles of this interesting science 
 are given in a few words, and with admirable perspicuity, in a larger type ; while 
 the deductions from these principles, and the illustrations are contained in a 
 smaller letter. Much useful and interesting matter is also given in notes at the 
 bottom of the page. 
 
 This volume is designed expressly to accompany the Boston School Set of Philo- 
 sophical Apparatus ; but the numerous diagrams with which it is illustrated, are 
 so well executed and so easily understood, that the assistance of the Apparatus 
 is hardly necessary to a thorough knowledge of the science. The trustees of the 
 Lyons Union School having recently procured a complete set of the above Ap- 
 paratus, this work will now be used as a text-book in that institution. 
 
 LEICESTER ACADEMY, April 12, 1848. 
 MESSRS. A. S. BARNES &. Co.: 
 
 Sirs : I have examined Parker's Natural Philosophy, and am much pleased 
 with it. I think I shall introduce it into the academy the coming term. It seems 
 to me to have hit a happy medium between the too simple and the too abstract. 
 The notes containing facts, and showing the reasons of many things that are of 
 common occurrence in every-day life, seem to me to be a valuable feature of the 
 work. 
 
 Very respectfully, yours, B. A. SMITH. 
 
 From the New York Evening Pojt. 
 
 Professor Parker's book embraces the latest results of investigation on the sub- 
 'ects of which it treats. It has a separate title for the laws of heat, or Pyronora- 
 ics, which have been lately added to the list ol sciences, as well as electro mag- 
 netism and magneto electricity. The matter is well arranged, and the style of 
 statement clear and concise. The figures and diagrams are placed side by side 
 with the text they illustrate, which is greatly for the convenience of the student. 
 We cheerfully commend the book to the favorable attention of the public. 
 
 From the Albany Spectator. 
 
 'I his is a school-book of no mean pretensions and of no ordinary value. It is 
 admirably adapted to the present state of natural science ; and besides contain- 
 ing engravings of the Boston school set of philosophical apparatus, embodies 
 more information on every subject on which it treats than any other elementary 
 w-jrk of its size that we have examined. It abounds with all the necessary helps 
 :u prosecuting the study of the science, and as its value becomes known it can- 
 not f ail to be generally adopted as a text-book. 
 
 14 
 
Parker's Natural Philosophy. 
 
 From the Newark Daily Advertiser. 
 
 A work adapted to the present state of natural science is greatly needed in all 
 our schools, and the appearance of one meeting all ordinary wants must be hailed 
 with pleasure by those who feel an interest in the cause of education. Mr. Par- 
 ker's work embraces a wider field, and contains a greater amount of information 
 on the respective subjects of which it treats, than any other elementary treatise 
 of its size, and is rendered peculiarly valuable by the introduction of the science of 
 Pyronomics, together with the new sciences of Electro- Magnetism and Magneto 
 Electricity. We have seldom met with a work so well adapted to the conveni- 
 ence of study and recitation, and regard as highly worthy of commendation the 
 care which the author has taken to prevent the pupil from mistaking theory and 
 conjecture for fact. We predict for this valuable and beautifully printed w 
 the utmost success. 
 
 From the New York Courier and Enquirer 
 
 " A School Compendium of Natural and Experimental Philosophy," by Richard 
 Green Parker, has just been issued by Barnes & Co. Mr. Parker has had a good 
 deal of experience in the business of practical instruction, and is, also, the author 
 of works which have been widely adopted in schools. The present volume strikes 
 us as having very marked merit, and we cannot doubt it will be well received. 
 
 NEW YORK, May, 1848. 
 MESSRS. A. S. BARNES & Co.: 
 
 Gent. .I have no hesitation in saying that Parker's Natural Philosophy is the 
 most valuable elementary work I have seen : the arrangement of the subjects 
 and the clearness of the definitions render it an excellent adjunct to a teacher. 
 For the last seven years I have used it in various schools as a text-book for my 
 lectures on Natural Philosophy, and am happy to find that in the new edition 
 much important matter is added, more especially on the subjects of Electricity 
 and Electro-Magnetism. 
 
 With respect, Gentlemen. 
 
 Your obedient servant, 
 
 GILBERT LANGDON HUME, 
 Teacher of Natural Philosophy and Mathematics in N. Y. city. 
 
 NEW YORK, May 2, I84a 
 
 We have used Parker's Compend of Natural Philosophy for many years, and 
 consider it an excellent work on the various topics of which it treats. 
 
 Yours, &LC. FORREST & McELLIGOTT, 
 
 Principals of the Collegiate School. 
 
 From the Lynchburg Virginian. 
 
 The volume before us strikes us as containing more to recommend it than any 
 one of its class with which we are acquainted. It is adapted to the present state 
 of natural science ; embraces a wider field, and contains a greater amount of in- 
 formation on the respective subjects of which it treats, than any other elementary 
 treatise of its size. It contains descriptions of the steam-engine, stationary and 
 locomotive, and of the magnetic telegraph. It embraces a copious account of 
 the principles of electricity and magnetism, under all their modifications, and is 
 embellished by a vast number of illustrations and diagrams. There is appended 
 a series of questions for examination, copious and pertinent 
 
 15 
 
Gillespie's Manual of Road-Making. 
 
 ROADS AND RAILROADS. 
 
 A MANUAL OF ROAD-MAKING: 
 
 Comprising the principles and practice of the Location, Construc- 
 tion, and Improvement of ROADS, (common, macadam, paved 
 plank, &c.,) and RAILROADS. By W. M. GILLESPIE, A. M., 
 Professor of Civil Engineering in Union College. Price $1.50. 
 
 Recommendation from Professor Mahan. 
 
 I have very carefully looked over Professor Gillespie's IVlanual of Road- 
 Making. It is, in all respects, the best work on this subject with which I am ac- 
 quainted ; being, from its arrangement, comprehensiveness and clearness, equally 
 adapted to the wants of Students of Civil Engineering, and the purposes of per- 
 sons in any way engaged in the construction or supervision of roads. The ap- 
 pearance of such a work, twenty years earlier, would have been a truly national 
 benefit, and it is to be hoped that its introduction into our seminaries may be so 
 general as to make a knowledge of the principles and practice of this branch of 
 engineering, as popular as is its importance to all classes of the community. 
 (Signed,) 
 
 D. H. MAHAN, 
 
 Professor of Civil Engineering in the Military ) 
 Academy of the United States. \ 
 
 From a Report of a Committee of the American Institute. 
 
 This work contains in a condensed form, all the principles, both ancient and 
 modern, of this most important art ; and almost every thing useful in the great 
 
 mass of writers on this subject Such a work as this performs a great 
 
 service for those who are destined to construct roads by showing not only what 
 ought to be done, but what ought not to be done ; thus saving immense outlay of 
 money, and loss of time in experiments The committee therefore, recom- 
 mend it to the public. 
 
 From the American Railroad Journal. 
 
 The views of the author are sound and practical, and should be read by the 
 people throughout the entire length and breadth of the land. . . . We recom- 
 mend this Manual to the perusal of every tax-payer for road-making, and to the 
 young men of the country, as they will find useful information in relation to each 
 department of road-making, which will surely be useful to them in after-life. 
 
 From Silliman's American Journal of Science. 
 
 If the well-established principles of Road-Making, which are so plainly set 
 forth in Prof. Gillespie's valuable work, and so well illustrated, could be once 
 put into general use in this country, every traveller would bear testimony to the 
 fact that the author is a great public benefactor. 
 
 From the Journal of the Franklin Institute. 
 
 This small volume contains much valuable matter, derived from the best 
 authorities, and set forth in a clear and simple style. For the want of informa- 
 tion which is contained in this Manual, serious mistakes are frequently made, 
 and roads are badly located and badly constructed by persons ignorant of the true 
 
 (16) 
 
GiUcspie's Manual of Road-Making. 
 
 principles which ought to govern in such cases. By the extensive circulation of 
 such books as that now before us, and the imparting of sound views on the sub- 
 ject to the students of our collegiate institutions, we may hope for a change for 
 .he better in this respect. 
 
 From the Albany Cultivator. 
 
 The author of this work has supplied a desideratum which has long existed. 
 Perhaps there is no subject on which information is more needed by the country 
 in general than that of Road-Making. Prof. Gillespie has taken up the subject 
 in a proper manner, beginning the work at the right place, and prosecuting it in 
 systematic order to* its completion. 
 
 From the New York Tribune. 
 
 It would astonish many " path-masters" to see how much they don't know 
 with regard to the very business they have considered themselves such adepts in. 
 Yet all is so simple, so lucid, so straight forward, so manif^tly true, that the 
 most ordinary and least instructed mind cannot fail to profit by it. We trust this 
 useful and excellent volume may find its way into every village library if not 
 into every school library, as well as into the hands of every man interested in 
 road-making. Its illustrations are very plain and valuable, and we cannot doubt 
 that the work will be a welcome visiter in many a neighborhood, and that bad 
 roads will vanish before it. 
 
 From the Newark Daily Advertiser. 
 
 This elaborate and admirable work combines in a systematic and symmetrical 
 form the results of an engineering experience in all parts of the Union, and of an 
 examination of the great roads of Europe, with a careful digestion of all acces- 
 sible authorities. The six chapters into which it is divided comprehend a 
 methodical treatise upon every part of the whole subject ; showing what roads 
 ought to be in the vital points of direction, slopes, shape, surface, and cost, and 
 giving methods of performing all the necessary measurements of distances, di- 
 rections, and heights, without the use of any instruments but such as any 
 mechanic can make, and any farmer use. Bridges, Railroads, and City Streets 
 are also treated of at length and with good sense. 
 
 From the Vermont Chronicle. 
 
 To selectmen and others who may have any thing to do with these improve- 
 ments, we would earnestly recommend the book named above. The author is a 
 man of science, (Professor of Civil Engineering at Union College,) and his work 
 embraces a full discussion of both the principles anrf practice of Road-Making 
 A little study of this work may often lead to results of importance to whole towns 
 and counties. 
 
 From the Home Journal. 
 
 The author of this book holds a quill so skilful and dairtv in light literature, 
 that we were not prepared with laurels to crown him for a scientific work ; but 
 we see, by the learned critics, that this fruit of his study of his profession as an 
 engineer, is very worthy of high commendation, and a valuable addition to the 
 useful literature of the day. 
 
 (17) 
 
Willard's Series of School Histories and Charts. 
 
 MRS. EMMA WILLARD'S 
 SERIES OP SCHOOL HISTORIES AND CHARTS, 
 
 1. WILLARD'S HISTORY OF THE UNITED STATES, OR RE- 
 PUBLIC OF AMERICA, 8vo. Price 91. 50. 
 
 II. WILLARD'S SCHOOL HISTORY OF THE UNITED STATES. 
 III. WILLARD'S AMERICAN CHRONOGRAPHER, $1.00. 
 A CHART OP AMERICAN HISTORY. 
 
 I. WILLARD'S UNIVERSAL HISTORY IN PERSPECTIVE. 
 II. WILLrtRD'S TEMPLE OF TIME, fl.25. 
 A CHART OF UNIVERSAL HISTORY 
 
 W I L L A R D'S 
 HISTORY OF THE UNITED STATES. 
 
 The large work is designed as a Text-Book for Academies and 
 Female Seminaries : and also for District School and Family 
 Libraries. The small work being an Abridgment of the same, is 
 designed as a Text-Book for Common Schools. The originality 
 of the plan consists in dividing the time into periods, of which 
 the beginnings and terminations are marked by important events ; 
 and constructing a series of maps illustrating the progress of the 
 settlement of the country, and the regular advances of civilization. 
 The Chronographic Chart, gives by simple inspection, a view of 
 the divisions of the work, and the events which mark the be- 
 ginning and termination of each period into which it is divided. 
 A full chronological table will be found, in which all the events ot 
 the History are arranged in the order of time. There is appended 
 to the work the Constitution of the United States, and a series ot 
 questions adapted to each chapter, so that the work may be used 
 in schools and for private instruction. 
 
 The Hon. Daniel Webster says, of an early edition of the above work, in a letter 
 to th author, " 7 keep it near me, as a Book of Reference, accurate in facts and dates." 
 
 (18) 
 
WillanVs Series of School Histories and Charts. 
 
 W I LL ARD'S 
 AMERICAN CHRONOGRAPH ER, 
 
 DESIGNED TO ACCOMPANY WILLARD's HISTORY OF 
 THE UNITED STATES. 
 
 To measure time by space is universal among civilized nations -, 
 and as the hours, and minutes, and seconds of a clock measure th& 
 time of a day, so do the centuries, tens, and single years of this 
 Chronographer, measure the time of American History. A 
 general knowledge of chronology is as indispensable to history, as 
 a general knowledge of latitude and longitude is to geography. 
 But to learn single dates, apart from a general plan of chronology 
 addressed to the eye, is as useless as to learn latitudes and longi- 
 tudes without reference to a map. The eye is the only medium 
 of permanent impression. The essential point in a date, is to 
 know the relative place of an event, or how it stands in time com- 
 pared with other important events. The scholar in the school- 
 loom, or the gentleman in his study, wants such a visible plan of 
 time for the study of history, the same as he wants the visible 
 plan of space, viz., a map for the study of geography, or of books 
 of travels. Such is the object of Willard's Chronographer oj 
 American History. 
 
 Extract from a Report of the Ward School Teachers 1 Association 
 of the City of New York. 
 
 The Committee on Books of the Ward School Association respectfully report : 
 
 That they have examined Mrs. Willard's History of the United States with 
 peculiar interest, and are free to say, that it is in their opinion decidedly the best 
 treatise on this interesting subject that they have seen. * * 
 
 As a school-book, its proper place is among the first. The language is remark- 
 able for simplicity, perspicuity, and neatness ; youth could not be trained to a 
 better taste for language than this is calculated to impart. The history is so 
 written as to lead to geographical examinations, and impresses by practice the 
 habit to read- history with maps. It places at once, in the hands of American 
 youth, the history of their country from the day of its discovery to tne present 
 time, and exhibits a clear arrangement of all the great and good deeds of their 
 ancestors, of which they now enjoy the benefits, and inherit the renown. The 
 struggles, sufferings, firmness, and piety of the first settlers are delineated with a 
 masterly hand. 
 
 The gradual enlargement of our dominions, and the development of our na- 
 tional energies, are traced with a minute accuracy, which the general plan of the 
 work indicates. 
 
 The events and achievements of the Revolution and of the last war, are 
 brought out in a clear light, and the subsequent history of our national policy 
 and advancement strikingly portrayed, without being disfigured by that tinge 
 
 ' 
 
Willard's Series of School Histories and Charts. 
 
 ol party bias which is so difficult to be guarded against by historians of their own 
 times. 
 
 The details of the discovery of this continent by Columbus, and of the early 
 settlements by the Spaniards, Portuguese, and other European nations, are all ol 
 essential interest to the student of American history, and Will be found sufficiently 
 minute to render the history of the continent full and complete. The different 
 periods of time, together with the particular dates, are distinctly set forth with 
 statistical notes on the margin of each page, and these afford much information 
 without perusing the pages. 
 
 The maps are beautifully executed, with the locality of places where particular 
 events occurred, and the surrounding country particularly delineated. These 
 are admirably calculated to make lasting impressions on the mind. 
 
 The day has now arrived when every child should be acquainted with the his- 
 tory of his country ; and your Committee rejoice that a work so full and clear can 
 be placed within the reach of every one. 
 
 The student will learn, by reading a few pages, how much reason he has to be 
 proud of his country of its institutions of its founders of its heroes and states- 
 men : and by such lessons are we not to hope that those who come after us will 
 be instructed in their duties as citizens, and their obligations as patriots 7 
 
 Your Committee are anxious to see this work extensively used in all the schools 
 in the United States. 
 
 (Signed,) 
 
 SENECA DURAND, 
 EDWARD McELROY, 
 JOHN WALSH. 
 
 The Committee would respectfully offer the following resolution : 
 Resolved, That Mrs. Emma Willard's History of the United States be adopted 
 by this Association, and its introduction into our schools earnestly recom- 
 mended. 
 
 At a meeting of the Board of the Ward School Teacners' Association, January 
 20th, 1847, the above Resolution was adopted. (Copied from the Minutes.) 
 
 From the Boston Traveller. 
 
 We consider the work a remarkable one, in that it forms the best book for 
 general reading and reference published, and at the same time has no equal, in 
 our opinion, as a text-book. On this latter point, the profession which its author 
 has so long followed with such signal success, rendered her peculiarly a fitting 
 person to prepare a text- book. None but a practical teacher is capable of pre- 
 paring a good school-book ; and as woman has so much to do in forming our 
 early character, why should her influence cease at the fireside why not en- 
 courage her to exert her talents still, in preparing school and other books foi 
 after years ? No hand can do it better. 
 
 The typography of this work is altogether in good taste. 
 
 From the Cincinnati Gazette. 
 
 Mns. WILLARD'S SCHOOL HISTORY OF THE UNITED STATES. It is one of those 
 rare things, a good school-book ; infinitely better than any of the United States 
 Histories fitted for schools, which we have at present. It is quite full enough, 
 and yet condensed with great care and skill. The style is clear and simple- 
 Mrs. Willard having avoided those immense Johnsonian words which Grirnshaw 
 and other writers for children love to put into their works, while, at the same 
 time there is nothing of the pap style about it. The arrangement is excellent, 
 
 (20) 
 
Willard 1 s Series of School Histories and Charts. 
 
 the chapters of a good length ; every page is dated, and a marginal index makes 
 reference easy. But the best feature in the work is its series of maps ; we have 
 the country as it was when filled with Indians ; as granted to Gilbert ; as di- 
 vided at the time the Pilgrims came over ; as apportioned in 1643 ; the West 
 while in possession of France ; the Atlantic coast in 1733 ; in 1763 ; as in the 
 Revolution, with the position of the army at various points ; at the close of the 
 Revolutionary War; during the war of 1812-15; and in 1840: making eleven 
 most excellent maps, such as every school history should have. When we 
 think of the unintelligible, incomplete, badly written, badly arranged, worthless 
 work of Grimshaw which has been so long used in our schools, we feel that 
 every scholar and teacher owes a debt of gratitude to Mrs. Willard. Miss 
 Robins has done for English History, what Mrs. Willard has now done for 
 American, and we trust these two works will be followed by others of as high or 
 higher character. We recommend Mrs. Willard's work as better than any vre 
 know of on the same subject ; not excepting Bancroft's abridgment. This work, 
 followed by the careful reading of Mr. Bancroft's full work, is all that would be 
 needed up to the point where Bancroft stops ; from that point, Pitkin and Mar- 
 shall imperfectly supply the place, which Bancroft and Sparks will soon fill. 
 
 From the United States Gazette. 
 
 Mrs. Willard is well known throughout the country as a lady of high attain 
 ments, who has distinguished herself as the Principal of Female Academies, that 
 have sent abroad some of the most accomplished females of the land. 
 
 The plan of the authoress is to divide the time into periods, of which the be- 
 ginning and the end are marked by some important event, and then care has 
 been taken to make plain the events of intermediate periods. The style is clear, 
 and there appears no confusion in the narrative. In looking through the work, 
 we do not discover that the author has any early prejudices to gratify. The 
 book, therefore, so far as we have been able to judge, may be safely recom- 
 mended as one of great merit, and the maps and marginal notes, and series of 
 questions, give additional value to the work. 
 
 From the Xewburyport Watchman. 
 
 Air ABRIDGED HISTORY or THE UNITED STATES: By Emma Willard. We 
 think we are warranted in saying, that it is better adapted to meet the wants of 
 our schools and academies in which history is pursued, than any other work of 
 the kind now before the public. 
 
 The style is perspicuous and flowing, and the prominent points of our history are 
 presented in such a manner as to make a deep and lasting impression on the mind. 
 
 We could conscientiously say much more in praise of this book, but must content 
 ourselves by heartily commending it to the attention of those who are anxious 
 to find a good text-book of American history for the use of schools. 
 
 From the Albany Evening Journal. 
 
 WILLARD'S UNITED STATES. This work is well printed on strong white paper, 
 and is bound in a plain substantial manner all-important requisites in a school- 
 book. The text is prepared with equal skill and judgment. The memory of the 
 youthful student is aided by a number of spirited illustrations by no means un- 
 important auxiliaries while to lighten the labors of the teacher, a series of ques- 
 tions is adapted to each chapter. Nor is its usefulness limited to the school-room 
 As a book of reference for editors, lawyers, politicians, and others, where dates and 
 facts connected with every important event in American History may be readily 
 found, this little book is truly valuable. 
 
 21 
 
Wizard's Series of School Histories and Charts. 
 
 WILLARD'S 
 UNIVERSAL HISTORY IN PERSPECTIVE, 
 
 ILLUSTRATED WITH MAPS AND ENGRAVINGS. 
 
 THIS WORK IS ARRANGED IN THREE PARTS, VIZ : 
 
 ANCIENT, MIDDLE, AND MODERN HISTORY. 
 
 1. ANCIENT HISTORY is divided into six periods comprising 
 events from the Creation, to the Birth of our Saviour. 
 
 2. MIDDLE HISTORY, into five periods, from the Christian Era, 
 to the Discovery of America. 
 
 3. MODERN HISTORY, into nine periods, from the Discovery of 
 America, to the present time. Each period marked by some im- 
 portant event and illustrated by maps or engravings. 
 
 The following resolution was offered and adopted at a meeting of the Ward 
 School Teachers' Association of the City of New York, January 20th, 1847. 
 
 Resolved, That the Ward School Teachers' Association of New York con- 
 siders Willard's Universal History as a book essentially adapted to the higher 
 classes of schools on account of its vivacity, lucidness, and intelligent mode of 
 arrangement, of dates and questions, and that such a work has long been wanted, 
 and as such will endeavor to introduce it into their respective schools, aud 
 warmly recommend it to public patronage. 
 
 Extract of a Letter from Mr. Elbridge Smith, late Principal of the English 
 
 High School of Worcester, Mass. 
 
 I have recently introduced " Willard's Universal History in Perspective," into 
 the school under my care. I am much pleased with it, and think it superior to 
 any other work of the kind. 
 
 (Signed,) 
 
 ELBRIDGE SMITH. 
 Worcester, June 5, 1847. 
 
 From Professor Charles B. Haddock of Dartmouth College, and School Commissioner 
 
 of the State of New Hampshire. 
 
 I am acquainted with Mrs. Willard's Histories, and entertain a high opinion of 
 them. They are happily executed, and worthy of the long experience and emi- 
 nent character of their author. 
 
 (Signed,) 
 
 CHARLES B. HADDOCK. 
 Dartmouth College, Hanover, Dec. 11, 1846. 
 
 22 
 
Fulton <& Eastman's Principles of Penmanship. 
 
 FULTON & EASTMAN'S PENMANSHIP, 
 
 Illustrated and expeditiously taught by the use of a series of Chirographic 
 Charts, a Key, and a set of School Writing- Books, appropriately ruled. 
 
 I. 
 CHIROGRAPHIC CHARTS, 
 
 IN TWO NUMBERS. (Price 5.00.) 
 
 Chart No. 1, EMBRACES PRIMARY EXERCISES, AND ELEMENTARY PRINCIPLES 
 
 IN WRITING. 
 
 Chart No. 2, EMBRACES ELEMENTARY PRINCIPLES FOR CAPITALS COMBINED, 
 AND ELEMENTARY PRINCIPLES FOR SMALL LETTERS COM- 
 BINED. 
 
 II. 
 
 KEY TO CHIROGRAPHIC CHARTS ; 
 
 Containing directions for the position at the desk, and manner of holding 
 the pen. Also for the exact forms and proportions of letters, with Rules 
 for their execution. (Price 25 cents.) 
 III. 
 
 SCHOOL WRITING-BOOKS. 
 IN FOUR NUMBERS. (Price 12$ cents each.) 
 
 From the Trustees of the Union School, Lyons, JV. Y. 
 
 The undersigned, trustees of the Union District School of the town of Lyons, 
 take this method of expressing their approval of " Fulton's Principles of Pen- 
 manship." They have seen the system in operation, during the past year, in the 
 school with which they are connected, and are fully satisfied of its great superi- 
 ority over all other systems heretofore used. The " Chirographic Charts," upon 
 which are drawn in large size the different letters and parts of the letters of the 
 alphabet, proportioned in accordance with the rules laid down by the author for 
 the formation of each letter, and which, when suspended, can be seen from all 
 parts of a school-room of ordinary size, they regard as an especial improvement 
 upon, and advantage over, other modes of teaching this art. While the labor of 
 the teacher is by this means lightened a hundredfold, from the fact that the direc- 
 tions and rules thus illustrated, can be explained to a whole class at once, the 
 benefit to the scholar is proportionally increased. The charts being made the 
 property of the district, a uniformity is established in this branch of instruction, 
 and the continual changes in books and methods of teaching, which have hereto- 
 fore given occasion to so much just complaint on the part of parents and guard- 
 ians, and which have been so prejudicial to the pupil, are entirely avoided. * 
 
 The brief space necessarily allotted to a notice of this kind, will not permit the 
 undersigned to say all they might say with truth in praise of Mr. F.'s system of 
 instruction. They therefore conclude with the remark that it meets their entire 
 approbation, and they cordially commend it to the favorable notice of the friends 
 of education generally, and would recommend its adoption by academies and 
 common schools in this and in other states. 
 
 A. L. BEAUMONT 
 ELI JOHNSON, 
 
 Dottd Lyons, N. Y., April 5th, 1847. DE WITT PARSHALL, 
 
 25 
 
Fulton & JEastman's Principles of Penmanship. 
 
 NEWARK, March 3, 1848. 
 
 I have examined with much care Fulton's System of Penmanship, lately pub- 
 lished by Messrs. A. S. Barnes & Co., of New York. My attention has been called 
 to the subject of teaching penmanship in our public schools, from the very mani- 
 fest want of any system that seemed at all suited to the character of our Ward 
 Schools. Mr. Fulton's system I deem to be the best I ever saw, and I have no 
 hesitation in recommending it. There is an exactness about Mr. F.'s method of 
 teaching this art, which seems to defy the possibility of pupils becoming any 
 thing but accomplished proficients. 
 
 I have taken means to procure the introduction of one set of the charts and a 
 number of the copy-books in our schools as an experiment, and so well satisfied 
 am I that the system is what we need, that I shall use early measures to have 
 them introduced more extensively. 
 
 Yours, &c., JNO. WHITEHEAD, 
 
 Commissioner of Public Schools for the city of Newark 
 
 From the Superintendent oj Monroe County, West District. 
 MR. LEVI S. FULTON: 
 
 Dear Sir : I am well pleased with the examination of your series of " Chiro- 
 graphic Charts, for the purpose of illustrating and teaching the principles of Pen- 
 manship." One of the greatest obstacles in the way of the scholar's improve- 
 ment in our schools, is the frequent change of teachers. Under the instruction 
 of every new teacher, the scholar commences to learn a new hand, by attempting 
 to copy that of the teacher : the consequence is, that he rarely obtains a good 
 permanent hand. His efforts so often failing of success, he becomes discouraged, 
 Mid ready to abandon the exercise as a vexatious and hopeless task. 
 
 By the use of your charts, applying the principles as taught in your book, the 
 teacher and pupil will be very much aided in the exercise ; the teacher illustra- 
 ting the principles from the chart, and the pupil practising upon them. 
 
 I rejoice that you have so arranged these principles, that the art of good pen- 
 manship will be placed within the reach of all who desire to attain this necessary 
 accomplishment, and I will indulge the hope, that your works may obtain that 
 extensive circulation which their merits so richly deserve. 
 
 Desiring your best success in this praiseworthy undertaking, I shall ever re- 
 main your most obedient and humble servant, 
 
 JULIUS A. PERKINS, 
 County Superintendent, Monroe co., West District. 
 
 Spencerport, Dec. 26, 1846. 
 
 LEVI S. FULTON, Esq. : 
 
 Dear Sir : Your theory and practice of Penmanship, which I have had several 
 opportunities to see tested and applied, is, in my opinion, truly philosophical, and 
 fully justifies the high estimate formed of it by all to whom it has been exhibited. 
 
 I have examined the plan of your proposed publication, and entirely approve 
 of it. It seems to me that such a work is greatly needed, and that its adoption as 
 a text-book would greatly facilitate the acquisition of a beautiful but hitherto vex 
 atious branch of education. 
 
 REV. 0. R. HOWARD, A. M., 
 (Late) Principal of Fairfield Academy. 
 
 Lyons, Dec. 1, 1846. 
 
 PENFIELD, Jan. 31, 1848. 
 
 Dear Sirs : It is with pleasure I inform you that your Chirographic Charts aro 
 in use in th Union School of this village, with admirable success. Serious diffi- 
 
 26 
 
Fulton <k Eastman's Principles of Penmanship. 
 
 culties which presented themselves to the learner of writing by the old system 
 (imitation merely) are entirely overcome. 
 
 The fixed rules for the formation of each principle separately, and most espe- 
 cially the general arrangement of your Charts, are desiderata hitherto unreached 
 Dy any system of penmanship with which I am acquainted. 
 
 In my humble opinion, they must meet with universal approbation. 
 
 Very respectfully, yours, &c., WM. D. SHUART. 
 
 MESSRS. FULTON &. EASTMAX : 
 
 Dear Sirs : I have carefully examined your Chirographic Charts and Key, and 
 am pleased to find your system of penmanship one that at once recommends it- 
 self by its perfection and simplicity requisites indispensable to successful ap- 
 plication in our schools, and for a lack of which, others have proved failures. 
 As teachers themselves are not unfrequently inferior penmen, and have gained 
 their own knowledge of this branch of education by a random practice, they are 
 wholly unable to impart it to their pupils. Your system obviates this difficulty, 
 by giving the teacher a resource from which to supply his own deficiency, and 
 hints for the successful application of whatever knowledge of the art he may 
 possess. 
 
 Your chart? are in use in the Union and Select schools of this village, and also 
 in other schools of this town and county, and with the happiest success. The 
 scholars, charmed with the novelty which the system continually presents, and 
 the ease with which they master its principles, vie with each other in their efforts 
 to excel, and are rewarded by acquiring a beautiful " hand" and neat mechanical 
 execution and at the same time, the teacher is relieved from the perplexing 
 practice of random teaching, so universal in our schools. 
 
 JAMES M. PHINNEY, 
 County Superintendent, Monroe Co., East Dist. 
 
 Penfield, Nov. 1, 1847. 
 
 From the Rochester Monthly Educator. 
 
 We believe that Mr. Fulton is the first author who has attempted to teach the 
 Art of penmanship by rule. Heretofore, imitation has been almost the sole princi- 
 ple used to direct the student in acquiring a knowledge of chirography, and as 
 every teacher has a system peculiar to himself, no uniform plan of instruction 
 could be successfully introduced into our common schools. Mr. Fulton has ren- 
 dered an essential service to the cause of education, in perfecting a system which 
 does not, at every change of teacher, require a variation in the handwriting ot 
 the pupil. One advantage which must result to the teacher from the use of these 
 charts, is the great amount of time and labor that will be saved thereby the old 
 method of writing separate copies for each scholar being entirely dispensed with 
 We feel confident that teachers and parents who will take time to examine this 
 system of penmanship must be convinced of its superiority over all others. 
 
 27 
 
Fulton & Eastman's Book- Keeping. 
 
 FULTON SL EASTMAN'S BOOK-KEEPING. 
 A PRACTICAL SYSTEM OF BOOK-KEEPING BY SINGLE ENTRY' 
 
 Containing three distinct forms of books, adapted for the 
 Farmer, Mechanic, and Merchant to which is added a va- 
 riety of useful forms for practical use, viz. : Notes, Bills, 
 Drafts, Receipts, &c. &c. : also a Compendium of Rules ot 
 Evidence applicable to Books of Account, and of Law in 
 reference to the Collection of Promissory Notes, &c. By 
 LEVI S. FULTON and G. W. EASTMAN, authors of a complete 
 System of Penmanship. 
 
 ROCHESTER, Feb. 12, 1848 
 L. S. FULTON, Esq. : 
 
 Dear Sir : I have examined with much satisfaction your System of Book-Keep- 
 ing, and take pleasure in recommending its adoption to my immediate friends 
 and others. 
 
 It is simple and easily reduced to practice, and possesses a peculiar adaptation 
 to the wants of the community for which you design it. 
 
 The plan for Merchants' Books, which I examined more critically than other 
 portions of the work, is very neat, compact, and economical, and must ensure a 
 great degree of accuracy in keeping accounts. 
 I believe your work will meet the present wants of community. 
 
 Very respectfully, your friend, ELIJAH BOTTUM, 
 
 Book-keeper for John M. French & Co., 
 Rochester, N. Y. 
 
 I have examined Messrs. Fulton & Eastman's " Practical System of Book- 
 Keeping by Single Entry," and am pleased with the work. As a branch of Edu- 
 cation, Book-Keeping is well deserving a high estimation ; and, I will add, there 
 is none of equal importance and utility more generally neglected, particularly in 
 our public schools. 
 
 The work above alluded to, is plain, simple, and comprehensive, and well 
 adapted to meet the wants of the business community. In many respects I deem 
 it superior to any other work of the kind with which I am acquainted. I shall 
 recommend it to the schools under my charge. 
 
 JOHN T. MACKENZIE, 
 
 Lyons, May 8, 1848. Town Superintendent. 
 
 FULTON & EASTMAN'S BOOK-KEEPINO. We had supposed that, in the multi- 
 plicity of works on Book-Keeping, hardly any thing valuable remained to be 
 suggested by later authors, should any such present themselves. But we have 
 been convinced of our short-sightedness in examining the work with the above 
 title, now before us. The work is principally designed for schools for common 
 schools but should be, in the hands of every Farmer, Mechanic, and Merchant 
 in the land. It opens with a system of account-keeping for farmers, followed by 
 one for mechanics, and this, in turn, by an admirable and comprehensive system 
 of mercantile Book-keeping, which, for its simplicity, and time and labor savir 
 
 28 
 
Fulton <& Eastman's Book-Keeping. 
 
 properties, possesses advantages over all other systems with which we are ac- 
 quainted. These advantages are thus set forth by the authors in their preface, 
 and an examination of the work will convince any man competent to judge, that 
 they are not over-estimated : 
 
 " It [the system spoken of] saves more than one-third of the time in journal- 
 izing, and at least three-fourths of the labor in posting. It requires but twelve 
 lines in the Ledger to post a year's business, while in the ordinary way as many 
 pages may be necessary. In settling with a person at the end of a year, you have 
 only to refer back to twelve places in the Journal to show him all the items of 
 his account, whereas in the ordinary manner of keeping books you might have to 
 refer to five hundred." 
 
 Part II. of the work, which was prepared by a distinguished member of the 
 bar, comprises " rules of evidence and general rules of law in relation to bills of 
 exchange, promissory and chattel notes, checks, books of account, &c., together 
 with a large number of forms useful to all classes of business men ; such as deeds, 
 bonds, mortgages, bills of sale, powers of attorney, bills of exchange, notes, re 
 ceipts. &c. 
 
 This invaluable work contains 232 pages of duodecimo, is printed in the best 
 style of Messrs. A. S. Barnes & Co., of New York, on an excellent quality of pa 
 per, and is afforded at the very low price of 51) cents per copy. Wayne Co. Whig 
 
 LYONS, May 8, 1848. 
 
 I have examined " Fulton & Eastman s Book-Keeping," and regard it as a use- 
 ful work on the subject of which it mainly treats. Its methodical arrangement, 
 its simple and ready modes of keeping accounts, adapted to the business of the 
 Farmer, Mechanic, or Merchant respectively, and the neat style in which it is 
 executed, recommend very strongly its use in primary institutions of learning, 
 and especially in common schools. It is to be hoped that its general introduction 
 as a school-book, will cause the art of Book-keeping to be regarded as one of the 
 indispensable requisites of what is termed a good English education. 
 
 JAMES C. SMITH. 
 
 From the Albany Spectator. 
 
 FBLTON & EASTMAN'S BOOK-KEEPING. New York : A. S. Barnes & Co., 
 1848. 
 
 We are very much pleased with the design and execution of this work. It is 
 exceedingly practical ; .being by single entry, containing three different forms ot 
 books, for the Farmer, the Merchant, and Mechanic. To these are added notes, 
 bills, drafts, receipts, and a compendium of rules of evidence applicable to books 
 of account, and of law in reference to the collection of promissory notes. A 
 work of such a character, and of so much practical value, speaks for itself, and 
 stands in need of no commendation from us to ensure it a large sale among all 
 classes. 
 
 29 
 
Clark's English Grammar. 
 
 SCIENCE OF THE ENGLISH LANGUAGE. 
 
 CLARK'S NEW ENGLISH GRAMMAR. 
 
 A Practical Grammar, in which WORDS, PHRASES, and SENTENCES 
 are classified, according to their offices, and their relation to 
 each other : illustrated by a complete system of Diagrams. By 
 S. W. CLARK, A. M. Price 50 cts. 
 
 From the Rahway Register. 
 
 It is a most capital work, and well calculated, if we mistake not, to supersede, 
 even in our best schools, works of much loftier pretension. The peculiarity of its 
 method grew out of the best practice of its author (as he himself assures us in its 
 preface) while engaged in communicating the science to an adult class ; and his 
 success was fully commensurate with the happy and philosophic design he lias 
 unfolded. Technicality, as technicality, our author unceremoniously discards, and 
 substitutes on the pupil's part rational practice in ascertaining the office of words in 
 sentences, rather than the usual mode of perplexing his memory with their mere 
 names and forms. 
 
 From the New York Tribune. 
 
 " The Science of the English Language A Practical Grammar, in which 
 Words, Phrases, and Sentences are classified according to their offices and their 
 relation to each other. Illustrated by a complete system of Diagrams. By S. W 
 Clark, A. M.," is a new work which strikes us very favorably. Its deviations from 
 older books of the kind are generally judicious and often important. We wish 
 teachers would examine it. 
 
 From the Courier and Enquirer. 
 
 " A Practical Grammar of the English Language" by S. W. Clark, A. M., has 
 just been published by Barnes & Co. It is prepared upon a new plan, to meet diffi- 
 culties which the author has encountered in practical instruction. Grammar and 
 the structure of language are taught throughout by analysis, and in a way which 
 renders their acquisition easy and satisfactory. From the slight examination, 
 which is all we have been able to give it, we are convinced it has points of very 
 decided superiority over any of the elementary works in common use. We com- 
 mend it to the attention of all who are engaged in instruction 
 
 From A- R. Simmons, Ex- Superintendent of Bristol. 
 MR. CLARK: 
 
 Dear Sir : From a thorough examination of your method of teaching the Eng 
 lish language, I am prepared to give it my unqualified approbation. It is a plan 
 original and beautiful well adapted to the capacities of learners of every age and 
 stage of advancement. Believing that the introduction into our Common Schools 
 and Academies of a text-book on grammar containing your SYSTEM and METHOD 
 will greatly facilitate the acquisition of the science of the English language, I re 
 spectfully suggest that it be permitted to come before the public. 
 Respectfully 
 
 Grammar Teachei 
 
 Bristol, August 28, 1847 ir ' 
 
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