AJSf OUTLINE 
 
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 c.l An outline of general 
 
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AN OUTLINE 
 
 OF 
 
 GENERAL GEOLOGY, 
 
 WITH COPIOUS REFERENCES. 
 
 DESIGNED FOR THE USE OF BOTH GENERAL AND SPECIAL 
 STUDENTS. 
 
 BY 
 
 THEO. B. COMSTOCK, B.Ag., B.S., 
 
 In Charge of Department of Geology, Paleontology and Economic Geology 
 in The Cornell University. 
 
 The laws of Nature are fixed and invariable. 
 Any given cause always produces the same effect 
 
 ITHACA, N. Y. 
 
 PRINTED FOR THE AUTHOR AT 
 
 THE UNIVERSITY PRESS, 
 1878 
 
5^ 
 
 << 
 
PREFACE. 
 
 This little volume is an amplification of a "Syllabus" of the 
 author's elementary lectures to a mixed class of students in the 
 Cornell University. In this institution, the subjects of Eco- 
 nomic Geology and Palaeontology are treated in more special 
 courses to which no student is eligible who has not passed the 
 examination in this general course. The class being made 
 up of members with quite various acquirements and purposes, 
 it has been a matter of no slight difficulty to arrange a Vade- 
 mecum intended both to meet the wants of those who aim at 
 the highest proficiency in General Geology and at the same 
 time to be sufficiently concise and simple for such as desire but 
 a cursory review of the subject as a means of general culture. 
 
 It is evident that this Outline will serve its best purpose 
 when used in connection with a course of lectures. The 
 author, in preparing it, has not been unmindful of the fre- 
 quent requests of teachers and others for a similar work, which 
 shall embody the best deductions and latest discoveries, with 
 references to authorities, without obliging the general student 
 to waste his time in unsuccessful efforts to collate the facts and 
 principles of the science, scattered through hundreds of works, 
 many of which are inaccessible. 
 
 The subject matter of the synopsis is arranged throughout 
 systematically in such a manner as to provide the student with 
 means of ready reference in the lecture-room and in the study, 
 but it cannot in any degree supply the place of collateral read- 
 ing, much as it may aid the memory in classifying what has 
 been read. Some subjects are much more minutely outlined 
 than others, and, as a rule, it may be regarded as desirable to 
 devote most attention in outside reading to those subjects 
 which are here least clearly explained. Many will find it un- 
 necessary to take full notes of the lectures, though nothing 
 should be left unrecorded which may require further study, or 
 
4 PREFACE. 
 
 which is of the nature of statistics or technicalities. In gen- 
 eral, the blank pages should be used for recording definition* 
 of technical terms, as they are explained, and for the copying 
 of such diagrams and other illustrations as may be placed up- 
 on the blackboard during the course. 
 
 No text-book will be necessary; several are recommended 
 as valuable for general use, and those who can afford it will do 
 well to purchase either Dana's "Manual of Geology" (Re- 
 vised Edition, 1874), or Le Conte's "Elements of Geology," 
 the latter being of special value in certain particulars. Other 
 general works, such as the best treatises on Physical Geogra- 
 phy, Jukes and Geikie's " Manual of Geology," Lyell's " Stu- 
 dents' Elements of Geology," etc., may be briefly reviewed be- 
 fore the class at the beginning of the course. 
 
 Works of reference for special topics, and, in many cases, 
 titles of papers in periodicals, even when not readily accessible 
 are given together in a list at the end of this volume, each with 
 an index number by which it is referred to at points in the 
 body of the Outline [R. 1, 2, 3, etc.] The occurrence of fig- 
 ures in black, type in the text indicates that the works sug- 
 gested are specially devoted to the subject under discussion in 
 that portion of the Outline. Some further hint as to the char- 
 acter of works is given in the List of References by printing 
 in Italics the titles of such works as are particularly adapted to 
 the needs of general students. At the same time the exercise of 
 some judgment will be required to prevent the overlooking of 
 works, which, though special in character, may contain matter 
 of importance to the most general students. To avoid this diffi- 
 culty references to particular pages have been introduced in 
 almost every case of the kind. 
 
 The author is conscious of many imperfections (the result 
 of pressing demands), which have made him hesitate to seek 
 for a wider field than is presented in his own lecture-room, but 
 he will be well pleased if his offering shall be found in some 
 slight degree serviceable to even a very few other teachers and 
 students. If the judgment be at all favorable, suggestions 
 concerning improvements in a later edition are respectfully 
 solicited. 
 
 THEO. B. COMSTOCK. 
 Ithaca, N. Y., Nov. 15, 1878. 
 
COURSE I.-GENERAL GEOLOGY. 
 
 Abbreviations are used as follows : H. for hardness : Gr. for specific gravity ; Comp. 
 for composition ; Sol. for soluble ; Insol. for insoluble ; Infus. for infusible ; Var. for 
 variety (or varieties) ; Cryst. for crystallization; CI. for cleavage; Temp, for tempera- 
 ture ; Ref. for general references ; R. for special references. 
 
 PART I.-INTRODUCTION. 
 
 i. Nature and Science; abuse of the terms. 
 
 2. Natural Science; its divisions: A. Cosmical; As- 
 tronomy. B. Telluric. I. Physical; Physics, Chemistry. 
 II. Geognostic ; Mineralogy, Geognosy. III. Biological ; Bot- 
 any, Zoology. IV. Geographical j Geography (Mathematical, 
 Physical). V. Historical / History, Archaeology. VI. Psy- 
 chical ; Psychology, Meta- Physiology. 
 
 3. Position and Relations of Geology in this system; 
 central, dependent on first three divisions, contributing to last 
 three. 
 
 4. Cultivating Power of Geology. 
 
 5. Scope of the science. 
 
 6. Divisions : A. Physiography. B. Geognosy. C. Dy- 
 namical Geology. D. Palaeontology. E. Stratigraphy. 
 
 F. Historical Geology, including Archaeology, in part. 
 
 G. Economic Geology. 
 
 7. Methods of Study and modes of reasoning. 
 
 8. Theories ; their uses and abuses, as illustrated by his- 
 tory. 
 
 g. Outline of present course; to include Physiography, 
 Geognosy, Dynamical Geology, and Historical Geology ; sep- 
 arate courses in Economic Geology and Palaeontology. 
 
 5 
 
6 GENERAL GEOLOGY. 
 
 PART II.-PHYSIOGRAPHY. 
 
 DIVISION A.-COSMICAE CONSIDERATIONS. 
 
 1. Physiography treats of earth's surface features, "forms 
 of relief," movements of air and water, distribution of life 
 forms, etc. ; in brief, review of exterior features and phenomena 
 of the globe. 
 
 2. Cosmical Relations of earth, a. Position in space. 
 b. Motions, (i) through space; (2) annual revolution; (3) 
 diurnal revolution, c. Solstices and equinoxes, d. Eccentricity 
 of orbit ; variations between circle and ellipse, e. Obliquity of 
 axis not constant, but changes slight and gradual, f. Preces- 
 sion of equinoxes. 
 
 3. General Conclusions based upon cosmical variations 
 in the past, as affecting climate and distribution of life. 
 
 4. Origin of Earth according to Nebular Hypothesis. 
 
 Ref. : — General works on Astronomy; also, R. 
 4, 6, 8, 11, etc. 
 
 DIVISION B.-CONCERNING THE EAND. 
 
 1. Shape of Earth. 
 
 2. Distribution of Land and "Water : a. 275 parts of 
 water to 100 parts of land, or nearly as 8 to 3. b. N. Hemi- 
 sphere about f land ; W. Hem. about \ land; N. Temp. Zone 
 \ land, \ water, c. Divide globe into hemispheres, taking An- 
 tipodes Is. and point near London as poles, and one hem. will 
 contain T V of all the land. d. Only gV of land has land an- 
 tipodes. 
 
 3. Coast Line : — Europe has -^h- of its area; Asia, ■&$', 
 Africa, ^ ; N. A., -g-b; S. A., ^; Australia, ^. 
 
 4. Homomorphism. a. Occident and Orient; orient = 
 2 Occidents ; Polynesia represents modern submergence of 
 tract connecting Australia with mainland, b. Occidents form- 
 ed by two triangles pointing southward, united by isthmus with 
 archipelago on one side, peninsula on other, c. Island (or 
 group) near extremity of peninsula, often to S. E. d. Gulf on 
 W. side of S. triangle, e. N. shores low, not deeply indented, 
 S. shores deep-cut, commonly with bold peninsulas ; promon- 
 tories more frequently pointing southward, f. Extreme N. and 
 extreme S. points of each continent nearly on same meridian. 
 
 5. Forms and Character of Land Surface, a. Dis- 
 

PHYSIOGRAPHY. 7 
 
 tribution and general character of (1) Lowlands, (2) Plateaus, 
 and (3) Mountains. b. Use of terms Serra (Portuguese), 
 Sierra (Span.), Peak, Mountain, Range, Cham, Cordillera, etc. 
 C. Distinctions between Hill, Mountain, Butte, Bench and 
 Mesa. d. Relations of plateaus to mountain systems, e. Ex- 
 amples : 
 
 (1) Lowlands : Mississippi Valley, Lower Conn. Valley ; (usually under 
 1000 ft.) (2) Plateaus: Gt. Basin, Utah, 5000 ft.; Colorado Desert, 
 Wyo., 7000 ft. ; N. Y. State largely a plateau, 1500 ft. to 2500 ft. ; Quitos 
 Plateau, 10,000 ft. ; Bolivia, 13,000 ft. ; Thibet (bet. Himalayas and Kuen 
 Lun Mts.), 11,500 ft. to 13,000 ft. ; Desert of Gobi, Mongolia, 4000 ft. ; 
 Sahara, 1500 ft. (3) Mountains various heights: Appalachians, 2000 ft. 
 to 6500 ft. : Rocky Mts., 9000 ft. to 14,500 ft. ; Andes, 13,000 ft. to 25,000 
 ft. ; Himalayas, even 29,000 ft. 
 
 6. Kinds of Mountains. (1) Narrow, with elevated 
 ridges, as Andes and Himalayas; (2) Broad, much folded, as 
 Jura and Appalachians; (3) Broad, with high plateaus, as 
 Rocky Mts. 
 
 7. Mountain Slopes ; often very gradual, seldom abrupt 
 except in peaks. 
 
 Examples : Rocky Mts., E. slope 8 ft. to 12 ft. per mile, W. slope not 
 much greater; Andes, E. 60 ft., W. 100 ft. to 150 ft. per mile; Appala- 
 chians, irregular. 
 
 8. Relief Systems. a. Laws of Vertical Config- 
 uration. 
 
 ( 1 ) Each continent has elevated borders and an interior basin. 
 
 (2) Highest land near middle of each border, lower southward, lowest 
 northward. 
 
 (3) Higher and steeper border faces larger oceatt [R. 13 (II, vols, iii, 398, 
 iv, 92, 1847, and xxii, 335, 1S56)]. 
 
 (4) Interior drainage system of each occide7it in a measure homologous, 
 and N. and S. triangles, each to each, more evidently related. 
 
 b. Laws of Horizontal Disposition. 
 
 (1) Every mountain chain belongs to one of two systems of trend — N.E. 
 XS.W. or N.IV.XS.E. 
 
 (2) Each continent has " N.E. system" on E. border, and "JV.JV. 
 system " on IV. border. 
 
 (3) Oceanic islands are arranged iti linear groups following one or other 
 of the two " systems of trend" ; (rule follows from the fact that the islands 
 are merely summits of submerged mountain chains). 
 
 (4) Outlines of continents lie in direction of great circles of the sphere 
 [R. 12, 13 (II, xxv, 130)]. 
 
 Ref. : — 1 (Part I), 4-5, 10 (Part I), 11, 12, 23. 
 
 DIVISION C— AS REGARDS THE WATER. 
 
 i. Comparison of Oceans: a. Areas and probable 
 depths: Atlantic, 2800 miles wide; Pacific, 6000 miles wide, 
 area to 62 S., 62,000,000 miles, b. Sources of error in sound- 
 
8 GENERAL GEOLOGY. 
 
 ing : (i) Pressure at great depths ; (2) Submarine currents ; (3) 
 Projecting ledges, c. Some forms of sounding apparatus ; 
 bathometer, d. Estimation of depth by means of earthquake 
 waves. 
 
 Depth quite variable; Atlantic along Telegraphic Plateau only from 
 6000 ft. to 15,000 ft. ; Gulf of Mexico, about 6000 ft. Earthquake-wave 
 calculations make N. and S. Pacific from 12,000 ft. to 13,000 ft., average. 
 Capt. Ross sounded 28,000 ft. without bottom, and Capt. Denham 46,000 — 
 ft., striking bottom, both in Pacific. Between India and E. Indies, aver- 
 age barely 300 ft. ; also same depth between Australia and adjacent islands 
 north ; N. Amer. and Asia separated by similar area 600 ft. in depth 
 [R. 14, 15 (II, ii., 278)]. 
 
 2. Sea Water ; a. Sp. gr. b. Specific heat ; effect on 
 climate, c. Temperature ; widely different on opposite sides 
 of same ocean (to be explained beyond). 
 
 3. Ocean Movements : Waves, Tides and Currents. 
 I. Waves; caused by winds and by earthquakes. II. Tides. 
 a. Cause of variation in height at different points, b. Progress 
 of Tidal Movement, c. Peculiarity seen on Amazonas; cur- 
 rent in same direction with rise and fall of tide. d. Effect of 
 wind upon tides, e. Theory of lunar action, with cause of 
 "neap" and "spring" tides. III. Currents x and Indraughts. 
 
 a. Equatorial Drift ; westward, caused by unequal velocity of 
 earth at poles and equator, partly, also, by uneven temperature. 
 
 b. Gulf Stream; 80 to 100 miles from coast, of great depth, 
 follows sinuosities of coast line ; surface velocity and cross- 
 section, c. Eastern Drift near 6o°, N. and S. Lat. d. Arctic 
 Indraught, e. Labrador Current, f. Rennel's Current, g. 
 Similar System in S. Atlantic and in other oceans. 
 
 4. Sargasso Sea. 
 
 5. Climate, as influenced by oceanic currents. 
 
 6. Circulation of Water from sea to land and return. 
 a. Drainage Systems, b. Peculiar Water-sheds : "Crown of 
 the Continent," in neighborhood of Yellowstone National 
 Park ; S. Pass, Rocky Mts. ; " Two-Ocean Pass ; " Orinoco and 
 Cassiquiari; Madeira and La Plata; Mississippi and Red 
 River of the North. 
 
 Ref.: — 1 (Part I), 4-8, 10 (Part I), n ; Dana, 
 J. D., in 12 (II, xxvi, 231)]. 
 
 1 Ocean currents are named according to direction towards which they flow; thus, an 
 eastern current flows eastward, a western current, westward, and so on. 
 
- 
 
 (\\X^^ /^v^ <*~\ p^X^ .UV^WV 
 
 C^^r^^ 9t<- C**~>*~&. dry dU . tffa "^i -' ' ^ 
 
i (1 ■ ' 
 
 * ■ \ ( ■ '■ ' • A... iX*. 
 
 
 
PHYSIOGRAPHY. 9 
 
 DIVISION D.-RELATING TO THE ATMO- 
 SPHERE. 
 
 1. Composition and Character, a. Normally con- 
 tains: O, 21 parts; N, 79 parts; C0 2 , -^ to T V; H 2 0, vari- 
 able, b. Thickness, as determined by observations of meteors, 
 by polarization of light (M. Liais), etc. c. Pressure; amount, 
 periodic variations, etc. d. Temperature ; radiation, effects 
 upon climate, e. Refraction; twilight, absence at equator. 
 f. Ozone in air. 
 
 2. Atmospheric Movements. 1 a. N.E. and S. E. 
 Trade winds and Counter-trades, b. Calms, c. High Western 
 Current, d. Summer and Winter changes, e. Some theories 
 regarding currents, f. Periodic Currents, g. Local Currents. 
 h. Storms. 
 
 Ref. : — Works on Physics and Meteorology ; 
 R. 1 (Part I), 4-8, 10, 11, 18, 23. 
 
 DIVISION E.— CEIMATIC CONDITIONS. 
 
 1. Climate; general considerations, a. Latitude alone 
 affects temperature, evaporation, precipitation. b. Land 
 modifies currents ; elevations induce precipitation ; in general, 
 land produces extremes, c. Water ameliorates conditions; 
 produces insular climate. 
 
 2. Fertility and Sterility, a. Forests; distribution 
 influenced by access of moist Trade Winds, b. Deserts; 
 occur in regions, mainly in interior, exposed to west drying 
 winds, c. Prairies ; more or less of desert character, but 
 probably often of different origin ; artificial. 
 
 3. Isotherms, a. Irregular lines, tending towards north 
 in passing westward over land, bearing parallelwise southwest 
 through ocean, b. Deflected southward in interior of conti- 
 nent, but irregularly, varying with season and modified by 
 topography. 
 
 4. Isobars, a. More regular than Isotherms, often con- 
 centrically disposed in ellipsoids transverse to Isotherms. 
 
 5. Review of U. S. Weather Reports; general conclu- 
 sions. 
 
 Ref. : — Works on Meteorology; R. 1 (pp. 43- 
 46), 4-8, 11, 18-21, 22, 23. 
 
 1 Atmospheric currents are named according to direction from which they flow ; thus 
 an eastern current flows westward, and vice versa. 
 
io GENERAL GEOLOGY. 
 
 DIVISION F.— LIFE ON THE GLOBE. 
 
 A. DISTRIBUTION OF PLANTS. 
 
 i. Latitude and Altitude ; comparative effects, a. i° 
 Lat. from equator equivalent to ioo ft. to 175 ft. elevation, with- 
 in limits fixed by special climatic conditions, b. Zones of Veg- 
 etation : I. Polar (88° to 78 ) ; Alpine Plants; at equator, 
 14,170 ft. II. Arctic (78 to 66°); Dwarf Willow and Alder, 
 Rhododendrons; 12,150 ft. III. Sub-Arctic (66° to 58 ) ; 
 Pines (ConifercB.) ; 10,140 ft. IV. Cold Temperate (5 8° to 45 ) ; 
 Deciduous Trees; 8,100 ft. V. Warm Tempo-ate (45 to 34 ) ; 
 Evergreens (Dicotyl.) ; 6,120 ft. VI. Sub- Tropical (34 to 
 23 ); Myrtle and Laurel; 4,050 ft. VII. Tropical (23 to 
 15 ); Figs and Tree Ferns; 2,020 ft. VIII. Equatorial 
 (15 to o°); Palms and Bananas; down to sea-level at equa- 
 tor. 
 
 2. Special Features, a. Retardation of flora of E. 
 Asia. b. Local distribution; peculiar cases, c. Co/if ervce, 
 etc., in hot springs. 
 
 B. DISTRIBUTION OF LOWER ANIMALS. 
 
 i. Sporadic Origin, etc. a. Specific Centres, b. 
 Generic Centres, c. Predominant Animals : Europe and Asia, 
 Ruminants; Africa, Land Tortoises ; N. Amer., Birds of Fas- 
 Cige; S. Amer., Edentates ? - Australia, Marsupials, d. Repre- 
 sentative Species : camel and llama — lion and puma — ostrich 
 and emu — crocodile, gavial, alligator, e. Transferred species ; 
 limit of distribution. Dog the only animal universally domes- 
 ticated, f. Zoological Provinces [R. 25, 1864], (Wallace and 
 Sclater): I. IVeo- Tropical— S. A., Mex., W. Indies. II. Ne- 
 arctic — Central Amer., U. S., Canada. III. Palcearctic — 
 Europe, N. Asia to Japan, Africa N. of Desert. IV. Ethio- 
 pian — Central and S. Africa, Madagascar. V. Lndian — S. 
 Asia, W. half of Malay Arch. VI. Australian — E. half of 
 Malay Arch., Australia, Pacific Is. (mainly), g. Zones of 
 Depth (Forbes) : I. Littoral — bet. high and low tides. II. 
 Circum-Littoral (Laminarian) — low water to 90 ft. III. Me- 
 dian [Coralline) — 15 fathoms (go ft.) to 50 fath. IV. Ln/ra- 
 Median [Deep-Sea Coral) — 50-300 fath. V. Abyssal — below 
 300 fath. (to 2500 fath., or more). 
 
 2. Special Features, a. Peculiarities of insular faunae. 
 b. Australian retardation, c. Remarkable fauna in Yellow- 
 stone Park. d. Mammoth Cave fauna, e. Deep-Sea fauna 
 [R. : — W. B. Carpenter, in 26, (vols, xviii, xix); 28, etc.] 
 
I 
 
 
 
 - 
 
 
PHYSIO GRAPHY. 1 1 
 
 C— DISTRIBUTION OF MAN. 
 
 i. Races and Minor Groups. I. Indo-European or 
 Caucasian, (i) Teutonic. (2) Celtic. (3) Sclavonic. (4) 
 Circassian. (5) Persian. (6) Arab. (7) Hindoo. Hab. : 
 S.W. Asia, Africa, nearly all of Europe, N. A., S. A., Austr., 
 etc. ; 500,000,000. Most refined ; features regular ; ample 
 hair and beard ; complexion fair; white. II. Mongolian. A. 
 Mongolian proper. (1) Japanese. (2) Chinese. (3) Siam- 
 ese. (4) Burmese. (5) Turks. (6) Tartars. (7) Thibetans. 
 (8) Siberians. (9) Finns. (10) Lapps. (n) Esquimaux. 
 Hab. : E. and Cent. Asia and Arctic sea-border; 490,000,000. 
 Civilization heretofore almost stationary, now progressive. 
 Head square, face broad, high cheek-bones, oblique eyes. 
 B. American, (i) S. A. Indians. (2) N. A. Indians; 16,- 
 000,000. Stationary or retrograding. Copper-colored, hair 
 black, nose aquiline. C. Malay, (i) Malays proper. (2) 
 Papuans. Hab. : Malaysia, Polynesia, Australasia ; Papuans 
 confined to Australia, New Guinea, New Hebrides and Feejee 
 Islands. (3) Maoris, New Zealand; 60,000,000 (without Pap- 
 uans, which are almost negroes). Brown. Papuans lowest 
 in scale of humanity. III. Ethiopian or Negro. Branches: 
 Gallas, Nubians, and Copts of Nile, Caffres and Hottentots 
 (who are more properly Mongolian). Hab. : Africa, S. of Sa- 
 hara, United States, West Indies and Brazil ; with Papuans, 
 100,000,000. Lowest race; black; skull narrow, forehead re- 
 treating, high cheek-bones, thick lips, broad, flat nose, project- 
 ing chin; hair short and woolly. 
 
 2. Population of Globe. 
 
 Av. per 
 
 Density per square mile. 
 
 China, 288 Greenland, -p^j 
 
 Japan, 233 Patagonia, T for 
 
 Brit. Islands, 245 Bas. of Amazon, -fa 
 Belgium, 438 Iceland, etc., 1.88 
 
 Bermuda, 477 Massachusetts, 157.00 
 Netherlands, 275 United States, II. 3 
 
 Population. sq. mi 
 
 Europe, 282,000,000 73 
 
 Asia, 711,000,000 40 
 
 Africa, 130,000,000 11 
 
 N. America, 50,000,000 6 
 S. America, 22,000,000 2>Yz 
 Oceanica, 20,000,000 £,y 2 
 
 (According to McTurk). 
 
 Ref. :— 1 (p. 609), 2 (p. 479 el sea.), 3 (p. 155), 4, 
 5, 6, 8, 11, 14, 15, 16, 17, 24. 
 
 liST Several topics, which naturally fall under the head of Physiography 
 (such as the general character and distribution of earthquakes, volcanoes, 
 hot springs, coral reefs, etc.), are omitted at this point for convenience of 
 discussion later in the course. Some few other subjects are ignored on 
 account of their slight importance, geologically considered. 
 
12 GENERAL GEOLOGY. 
 
 PART III.-GEOGNOSY. 
 
 I. Definitions, a. Geognosy; the study of earth's struct- 
 ure. A. Lithology, study of textural features (hand spec- 
 imens). B. Petrology, structural arrangement (in the field). 
 b. Mineral ; inorganic body, with (theoretically) definite form 
 and composition, c. Rock ; aggregation of mineral particles. 
 
 SECTION L— LITHOLOGY (Petrography, Germ). 
 
 DIVISION A.-CHEMICAL ELEMENTS. 
 
 i. Elements Most Abundant in Rocks. Only 20 (of 
 6$ or 64) important as rock constituents, and only 12 occui 
 commonly, as below: I. Oxygen, a. Most abundant, com- 
 prising ^ (by weight) of earth's crust. Oxides, therefore, are 
 the most abundant compounds, b. Combines readily with all 
 elements but Fl. c. Quartz and gypsum more than } O. d. 
 Comprises .43 of 11 most common minerals, e. .23 of atmos- 
 phere, and .89 of H 2 0. f. -I of whole is combined with Si. 
 (See II, c). II. Silicon, a. About {- of weight of crust, b. 
 Found only in combination with 0, from which follow I, f, and 
 II, c. c. Combined with O (Silica), ^ weight of crust, d. 
 Compounds hard and durable. e. Rock compounds, with 
 some exceptions, insol. in water. III. Aluminium, a. About 
 iV weight of crust, b. Its oxide (Alumina), most common 
 base in silicates and siliceous minerals, c. Rock compound? 
 (except sulphate) insol. in water. IV. Calcium, a. Les? 
 than T V of crust, b. Found in various silicates, also as Carb. 
 and Sulph. c. Rock compounds insol. or sparingly sol. in 
 water. V. Magnesium, a. As Oxide (Magnesia) forms es- 
 sential base of durable silicates, hard and soft. b. Rock com- 
 pounds, some sol., some insol. in water. VI and VII. Potas- 
 sium and Sodium, a. Common, but less abundant than pre 
 ceding, b. Oxides (Potassa and Soda), important aids to 
 fusion and solution of silica, c. Compounds more or less sol. 
 in water, with few exceptions. VIII. Iron. a. Most widely 
 distributed; native in meteorites, b. Important agent in color- 
 ing and disintegrating rocks, c. Insol. and sol. rock com- 
 pounds (water). IX. Carbon, a. Widely disseminated; na- 
 tive (free) in coal, graphite, diamond, b. Prominent as life- 
 supporter and as vehicle of change, c. Rock compounds 
 
GEOGNOSY— LITHOLOGY. 13 
 
 generally insol. (except C0 2 and alkaline carbonates). X. 
 Sulphur. a. Native in volcanic regions ; small quantities 
 elsewhere, b. As sulphide in ores of various metals, c. As 
 sulphate in gypsum, etc. d. Rock compounds, some sol., 
 some insol. in water. XI. Hydrogen, a. Abundant as con- 
 stituent of H 2 and many other minerals, b. Ingredient of 
 all organic compounds. XII. Chlorine, a. Most abundant 
 in common salt. b. Compounds soluble in water, as a rule. 
 Ref. : — 1 (p. 48), 10 (Part II); general works 
 on chemistry. 
 
 DIVISION B.— MINERALS. 
 
 1. Scale of Hardness (Mobs). (1) Talc. (2) Gypsum. 
 (3) Calcite. (4) Fluorite. (5) Apatite. (6) Orthoclase. (7) 
 Quartz. (8) Topaz. (9) Corundum. (10) Diamond. 
 
 2. Principal Rock-forming Minerals. Of 1000 spe- 
 cies, 350 are of some geological interest, 40 are common as 
 rock constituents, while 12 make up bulk of earth's crust, viz. : 
 I. Quartz, a. Primary form, rhombohedron, but of different 
 shapes — often elongated — commonly hexagonal prism termin- 
 ated by 6-sided pyramids; H. 7; Gr. 2.5-2.8; insol. and 
 infus. (except with alkali) ; no cl. ; colorless to black, trans- 
 parent to opaque, b. Most abundant mineral; more than 40 
 var., including clear (or limpid), amethyst (violet), chalcedony 
 (translucent), agate (banded in colors), homstone, jasper, etc. 
 c. Comp., Si0 2 (silica). II. Feldspar, a. Cryst. oblique; 2 
 cl. at or near right angle; surface lustrous; white, flesh-red, 
 etc.; H. 6-7; Gr. 2.85; difficultly fusible, b. Very abun- 
 dant, 6 recognized forms equivalent almost to separate species. 
 C. Comp., alumina silicate, each species containing a charac- 
 teristic base or two of alkali or alkaline earth, as K 2 (ortho- 
 clase), NaO (albite), CaO (anorthite), Na 2 and CaO (oligo- 
 clase), CaO and Na 2 (labradorite). III. Mica. a. Elastic 
 folia; cl. basal; lustre brilliant; colorless to brown, etc., and 
 black, b. Abundant in granyte; 8 prominent species, c. 
 Comp., alumina silicate, with K 2 (muscovite), MgO (phlogo- 
 pite and biotite), Li 2 (lepidolite), etc. IV. Amphibole. a. 
 Oblique, prismatic crystals, sometimes truncated so as to ap- 
 proach regular hexagonal prism; also in long, thin crystals and 
 in bundles imbedded in rock, as well as in short, stout crys- 
 tals ; cl. parallel to faces ; black, green, white, brownish and 
 intermediate shades, b. Forms as follows: (1) Dark green 
 
i 4 GENERAL GEOLOGY. 
 
 to black, stout crystals {hornblende) ; (2) long, green prisms or 
 fibrous (actinolite) ; (3) grayish and brownish green, fibrous or 
 acicular (ant hop hy I lite) ; (4) long, white prisms or fibrous (trem- 
 olite) ; (5) delicate, flexible fibres (asbestos) ; (6) also in dissem- 
 inated grains in rocks, c. Comp., Si0 2 , MgO, CaO, FeO, 
 and, occasionally, A1 2 3 and MnO. V. Pyroxene, a. Cryst. 
 oblique, prismatic, nearly square in cross-section, often becom- 
 ing 8-sided prism by replacement of edges; cl. as in amphi- 
 bole, and color similar; H. 5-6; Gr. 3.23-3.5. b. Var., (1) 
 massive, cleavable, grayish-green (sahlite) ; (2) thin, foliated, 
 brownish -green or bronzen (hypersthene) , grass-green (diallage); 
 (3) common, black, etc. (ai/gite). c. Comp., very near am- 
 phibole. VI. Chrysolite (not chrysotile). a. In grains, masses 
 and rectangular crystals ; glassy, pale or dark green (olivine) ; 
 H. nearly that of quartz (7). b. Common in volcanic rocks; 
 olivine characteristic of basalt and other crystalline rocks, c. 
 Comp., magnesia silicate, often with considerable FeO. VII. 
 Chlorite, a. Resembles mica, but folia not elastic ; also mass- 
 ive with granular texture ; color olive-green, rarely approach- 
 ing white ; H. 2.5, easily cut with knife, b. Ingredient of 
 many schists. c. Comp., typical, MgFeSi0 4 , with varying 
 proportions of base, and considerable water; also var. with 
 AI2O3. VIII. Talc. a. Foliaceous or compact and massive ; 
 folia 7iot elastic ; color light to dark green and brownish ; H. 1 ; 
 greasy to touch, b. Var., (1) common as above; (2) granu- 
 lar or compact (steatite, soap-stone), c. Comp., MgSi0 3 , with 
 water; Si0 2 62.12, MgO 32.94, H2O 4.94 = 100. IX. Ser- 
 pentine, a. Usually massive, without cl., sometimes prismatic ; 
 delicately fibrous var. (amianthus, chrysotile). b. Abundant 
 as rock under certain circumstances. c. Comp., MgSi0 3 , 
 with water; Si0 2 43.6, MgO 43.4, H 2 13.0 = 100. X. Cal- 
 cite. a. Hexagonal, usually with perfect rhombohedral cl. ; 
 color white, yellow, reddish or even black ; effervesces with 
 acid; H. 3, easily scratched with knife; Gr. 2.69-2.75. b. 
 Principal ingredient of large proportion of limestones and of 
 all true marbles, as well as chief constituent of marls and hy- 
 draulic limestones, c. Comp., CaC0 3 ; C0 2 44.0, CaO 56.0 
 = 100. XI. Dolomite, a. Resembles calcite in form, but 
 differs slightly in interfacial angles (106 15'; bet. calcite 
 105 5', and magnesite [MgCo 3 ] 107 25') ; darker colors pre- 
 dominate; no effervescence unless heated; H. 3.5-4.5; Gr. 
 2.88-2.95. b. Occurs in many so-called limestones, and in- 
 directly yields serpentine under certain circumstances, c. 
 
GE GNOS Y—LITHOL OGY. 15 
 
 Comp., normal, CaC0 3 54.3 per cent., MgC0 3 45.7 per cent. 
 XII. Gypsum, a. Oblique prisms ; cl. very perfect in one di- 
 rection, affording non-elastic plates; also massive, compact, 
 etc.; white to dark, transparent to opaque; H. 1.5-2 ; affords 
 " Plaster of Paris " on heating, b. Abundant in various forms ; 
 var., (1) selenite, transparent, basal cl. ; (2) satin spar, fine 
 fibrous ; (3) alabaster, compact or saccharoidal. c. Comp. 
 CaS0 4 , 2H2O. XIII. Iron Ores, I. Magnetite, a. Cryst. 
 octahedral, etc. ; also found granular, compact, earthy, or as 
 fine sand ; black, with metallic lustre, giving black streak and 
 powder, b. In beds and veins, also in grains disseminated 
 through crystalline rocks, c. Comp., Fe 3 4 (ferroso-ferric ox- 
 ide). II. Haematite {Hematite, specular iron). a. Cryst. 
 hexagonal, often micaceous, also massive, compact, earthy, 
 fibrous, etc. ; lustre dull to sub-metallic and metallic; blood-red 
 streak and powder, b. In beds and veins and variously dis- 
 tributed through other rocks ; var., specular iron, lustre metal- 
 lic, crystallized ; red ochre, soft ; red chalk, with clay. c. 
 Comp., Fe 2 3 (ferric oxide, iron sesquioxide, iron peroxide). 
 
 III. Limonite [Brown Hematite), a. Cryst. indistinct, mam- 
 millaiy, botryoidal, stalactitic, fibrous, massive and earthy; 
 lemon-yellow streak and powder, b. In beds, etc., of later 
 date than preceding, now forming in bogs and by oxidation of 
 pyrites and iron carbonates ; bog iron ore and yellow ochre 
 prominent var. c. Comp., 2Fe 2 3 +3H 2 (orthic hydrate). 
 
 IV. Pyrite. a. Cryst., cubes, octahedrons, etc. ; brassy to 
 black, b. Var., several, c. Comp. (common), FeS 2 . XIV. 
 Graphite {Plumbago, wrongly Black Lead), a. Crystallized 
 and amorphous, commonly latter; lustre rather metallic, streak 
 black (used for lead pencils), b. Occurs in lumps and nests; 
 results from transformation of anthracite, c. Comp., C only, 
 when pure. 
 
 Ref. : — 1 (p. 52), 2 (chap. hi). 9, 10 (Part II), 
 29-31, 34. 
 
 ©IVIS30N C.-OBGAMC CONSTITUENTS. 
 
 I. Siliceous, a. Spicula of sponges, b. Remains of 
 Diatomacea;, Polycystinae, etc. c. Silicified shells and wood 
 produced by action of siliceous waters, d. Infusorial remains. 
 e. Products: bog iron ore (in part), infusorial earths (Tripoli 
 polishing slate, etc.), flint, opal (to some extent), etc. 
 
16 GENERAL GEOLOGY. 
 
 2. Calcareous, a. Various shells (calcite and aragonite). 
 
 b. Spines of Echini, c. Foraminiferal remains, d. Ccenen- 
 chyma of corals, e. Crinoidal columns, f. Skeletons of 
 Crustacea, g. Some plant remains (corallines), h. Products : 
 Marl, limestones, white chalk, coral reefs, etc. 
 
 3. Carbonaceous, a. Plant remains in general, b. 
 Some animal remains under peculiar conditions, c. Products : 
 Peat, lignite, jet, coals, anthracite, petroleum, asphalte, graphite, 
 resins, etc., diamond (?). 
 
 4. Phosphatic. a. Bones of Vertebrata. b. Scales of 
 fishes, etc. c. Enamel of teeth, d. Shells of Lingula and 
 allied genera of Mollusks. e. Products: Deposits of guano, 
 phosphatic nodules, bone-breccias, etc. 
 
 Ref. :— 1 (Part II), 2 (p. 382), 3 (p. 153), 10 
 (Part II), 35 (p. 327), 36 (pp. 22, 105, etc.), 
 37 (PP- 462, 759). 
 
 DIVISION ».— CONCERNING ROCKS. 
 
 A.— GENERAL CHARACTER. 
 
 1. Texture of Rocks, a. Homogeneous or heteroge- 
 neous, b. Var. : (1) crystalline; (2) granular, with rounded 
 grains; (3) crystalline-granular, crystalline grains; (4) crypto- 
 crystalline (compact) ; (5) earthy ; (6) friable, readily crumbled 
 in fingers; (7) glassy or vitreous ; (8) slaggy ; (9) schistose, di- 
 vided by alternating mineral layers; (10) foliated ; (n) por- 
 phyriiic, with distinct disseminated crystals in homogeneous 
 base; (12) vesicular, drawn out so as to produce numerous 
 cavities ; (13) amygdaloidal, with almond-shaped cavities, com- 
 monly filled with foreign minerals. 
 
 2. Difficulties in Rock Study, a. Close gradations 
 existing among rocks, b. Similarity of certain minerals in 
 form or composition, c. Fineness of texture in some rocks. 
 d. Want of ready means of ascertaining all components. 
 
 B.— DETERMINATION AND CLASSIFICATION. 
 
 1. Determination of Rocks, a. General value of 
 texture, b. Value of chemical analysis, and its disadvantages. ^ 
 
 c. Microscopic analysis, its uses and abuses, d. Electro- 
 magnet as accessory instrument. 
 
 2. Classification of Rocks, a. System of Zirkel, based 
 on species of feldspar, b. System of Durocher and Bunsen, 
 
GEOGNOSY— LITHOLOG Y 
 
 i7 
 
 proportions of silica, c. Convenient system for general pur- 
 poses, prepared by Theo. B. Comstock [R. 33]. based on 
 
 3. Scheme of Classification. 
 
 /. SERIES, representing mode of origin (Genesis). 
 
 II. CLASS, representing genetic conditions (Environment). 
 
 III. Division, representing secondary environment (Position). 
 
 IV. Family, representing dominant i7igredient (Structure). 
 
 V. sub-family, representing condition of mass (Character). 
 
 VI. Genus, representing mineral association (Type). 
 
 VII. Species, indicating special mineral combination (Quality). 
 
 VIII. Variety, indicating textural modification (Texture). 
 
 4. Systematic Arrangement of Most Common 
 Rocks. 
 
 SERIES I. 
 CLASS I.— 
 
 Fam. A. — Feldspathic. 
 
 Gen, 1. Graityte (quartz, feld- 
 spar, mica). 
 
 Gen. 2. Protogine (quartz, feld- 
 spar, talc). 
 
 Gen. 3. Granytine (quartz, 
 feldspar). 
 
 CLASS II.- 
 
 DlVISION I.' 
 
 Fam. A. — Feldspathic. 
 
 SUB-FAM. I. CRYSTALLINE. 
 
 Gen. 1. Porphyrine (basic feld- 
 spar). 
 
 Gen. 2. Felsyte (acidic feld- 
 spar, quartz occasional). 
 
 Gen. 3. Mica-trap (feldspar, 
 mica). 
 
 SUB-FAM. 2. FRAGMENTAL. 
 
 Gen. 1. Felsytic. 
 " 2. Porphyritoid. 
 
 Division 2. 
 Fam. A.— Trachytic (Acidic). 
 
 SUB-FAM. I. CRYSTALLINE. 
 
 Gen. 1. Trachyte (acidic feld- 
 spar, mainly). 
 
 IGNEOUS. 
 
 GRANYTIC. 
 
 Fam. B. — Hornblendic. 
 Gen. 1. Syenyte (quartz, feld- 
 spar, amphibole). 
 
 ERUPTIVE. 
 
 — Trappean. 
 
 Fam. B. — Pyroxenic. 
 
 SUB-FAM. I. CRYSTALLINE. 
 
 Gen. 1. Dioryte (feldspar and 
 hornblende; no labradorite). 
 
 Gen. 2. Melaphyrine (basic 
 feldspar and pyroxene). 
 
 SUB-FAM. 2. FRAGMENTAL. 
 
 Gen. 1. Diorytic. 
 " 2. Melaphyroid. 
 
 -Volcanic. 
 Fam. B. — Basaltic (Basic). 
 
 SUB-FAM. I. CRYSTALLINE. 
 
 Gen. 1. Basalt (labradorite, 
 augite, olivine, menaccanite). 
 
i8 
 
 GENERAL GEOLOGY. 
 
 Gen. 2. Trachoryte (acidic feld- 
 spar, etc., and hornblende). 
 
 Gen. 3. Phonolyte (glassy feld- 
 spar, nephelite, hornblende). 
 
 SUB-FAM. 2. FRAGMENTAL. 
 
 Genera dependent upon com- 
 position ; made up of ingre- 
 dients of Trachytic char- 
 acter. 
 
 Gen. 2. Amphigenyte, or Leii- 
 citophyr (labradorite and leu- 
 cite). Lava of Vesuvius. 
 
 Gen. 3. Nephefaiyte (nephelite, 
 augite, magnetite). 
 
 SUB-FAM. 2. FRAGMENTAL. 
 
 Genera dependent upon com- 
 position ; made up of ingre- 
 dients of Basaltic charac- 
 ter. 
 
 SERIES IL—METAMORPHIO 
 CLASS I.— HYPOGENIC. 
 
 Fam. A. — Micaceous. 
 Gen. 1. Granyte (same as 7, 1, 
 
 A, 1). 
 Gen. 2. Mica-schist (mica, 
 
 quartz, often feldspar). 
 
 Fam. C. — Feldspathic. 
 Gen. 1 . Felsyte (practically the 
 
 same as I, II, A, 1, 2). 
 Gen. 2. Euphotide (feldspar, 
 
 diallage). 
 
 Fam. B. — Hornblendic. 
 Gen. 1. Syenytine (includes 
 here syenytic forms which 
 would be separated in more 
 detailed classifications. 
 
 Fam. D. — Hydrous Mag- 
 
 NESIAN. 
 
 Gen. 1. Talcose (type, talc 
 schist). 
 
 Gen. 2. Serpentinous (type, ser- 
 pentine). 
 
 Gen. 3. Chloritic (type, chlo- 
 rite schist). 
 
 CLASS II.— METAMERIC. 
 
 Fam. A. — Quartzose. 
 Gen. 1. Qiiartzyte. 
 
 Fam. C. — Calcareous. 
 
 Gen. 1. Calciferous (altered 
 calcite). 
 
 Gen. 2. Dolomyiic (altered dol- 
 omite). 
 
 Gen. 3. Gypsiferous (altered 
 gypsum). 
 
 -Ferrous. 
 
 - (includes iron 
 
 Fam. B.- 
 Gen. 1. 
 
 ores). 
 
 Fam. D. — Argillaceous. 
 Gen. 1. Argyllyte (altered clay). 
 
 Fam. E. — Carbonaceous. 
 (Anthracite, graphite, etc.) 
 
 1 The sub-families of SERIES II are omitted here, being of no special import- 
 ance tc the general student. 
 
GEOGNOSY— PETROLOGY. 19 
 
 SERIES III.— AQUEOUS} 
 CLASS I.— MECHANICAL. 
 
 Comprises deposits formed by action of water on land, as 
 sand, mud, gravel, etc., and their consolidated forms, as sand- 
 stone, shale, conglomerate. 
 
 CLASS II.— CHEMICAL. 
 
 Includes accumulations as precipitates and other results of 
 chemical action in nature, as some limestones, geyserite, stalac- 
 tite, etc. 
 
 CLASS III.— ORGANICAL. 
 
 All natural collections of material directly formed by the ac- 
 tion of plants or animals, or by their decay, are to be regarded 
 as belonging to this group, as peat, coal, petroleum, some marls, 
 guano, phosphate beds, etc. 
 
 Ref. : — 1 (Part II), 2 (chaps, iv, v), 3 (parts of 
 chaps, ii, iii, iv), 9, 10 (Part II), 29, 32, 33, 
 47- 
 
 N.B. — It is impossible to give this portion of the lectures in full within 
 reasonable limits. As additional aids, students who desire to do so can 
 procure copies of R. 32 (price io cts.) and R. 33 (price 40 cts.) at the 
 Geological Laboratory, but this is not necessary. 
 
 SECTION II -PETROLOGY (Structural Geology). 
 
 DIVISION A.-GE^EEAL STRUCTURE OF 
 EARTH. 
 
 1. Form of Earth, a. Oblate spheroid, or spheroid of 
 rotation, b. Polar diam. = 7899.60 statute miles; equatorial 
 diam. = 7926.05 miles (M. Bessel). c. Nearly all of "relief" 
 of globe lies within an exterior protuberance beyond the 
 sphere having polar diam. d. Axis probably stable. 
 
 2. Density of Earth, a. Mean Gr. bet. 5 and 6, as 
 shown by: (1) Experiments of Ordnance Surv., Gt. Brit. (Col. 
 Sir H. James), on deflection of plumb-line [R. 39, 1856, vol. 
 
 1 For the purposes of this Course it is not necessary to classify the members of SE- 
 RIES III as fully as the preceding. In the lectures on Economic Geology considera- 
 ble attention is given to these details. 
 
2o GENERAL GEOLOGY. 
 
 cxlvi, p. 591]; (2) difference in times of oscillation of pendu 
 lums at top and bottom of deep mines [R. 39, vol. cxlvi, 1856, 
 P- 355] 5 (3) Hutton's observations of local attraction at 1000 
 points on Mt. Schehallien, Scotland [R. 39 (1821, p. 276)]; 
 (4) Cavendish's experiments (1798), with Michell's apparatus 
 (torsion balance), comparing earth's attraction with that of 
 mass of lead; (5) Bailey's similar experiments in 1842 (mean 
 Gr. 5.6604) [R. 40, p. 69]. b. Gr. of heaviest rock-masses 
 (as basalt) only 3.0; hence — c. Interior of earth much heav- 
 ier than at surface; estimated at 16.27 [R- 4 X > v °l- i y > P- 33\ 
 
 Gravity should increase wt. rapidly within, but if homogeneous, even 
 granyte (Gr. 2.5) would become heavier than 5 or 6 long before reaching 
 centre; air (Gr. =.0012+) would have density of water at 34 miles, 
 water density of iron at 200 miles, iron density of platinum at 175 miles, 
 and even cork (Gr. 0.24) would have Gr. at centre of earth equal to twenty 
 times earth's mean density. 
 
 3. Interior of Earth, a. Seat of expansive agent: (1) 
 follows from preceding; (2) also proven by temp, of deep 
 wells and mines; average increase of i°F. for each 55 ft. of 
 descent after first 100 ft. b. Internal fluidity doubtful and 
 improbable, though still believed by some geologists, c. 
 More or less local seas of molten material as shown by : (1) act- 
 ive volcanoes ; (2) old fissure eruptions, d. Probably more or 
 less of "honeycomb" structure, e. Sir Wm. Thomson's views 
 regarding solidity of earth [R. 42 (xxiii, 157)543 (xiv, 426), 13 
 (xii, 336, 1876)]; M. Delaunay [R. 44 (v, 507), 45 (Oct., 
 1867)]; Pratt [R. 26, 1870]; Hopkins [R. 39, 1839, and Brit. 
 Assoc. Rep't, 1847]; D. Forbes [R. 44 (iv), 45 (Oct., 1867)]; 
 T. S. Hunt [R. 45 (xx, 315)]. f. Composition of deep-seated 
 material dolerytic (iron bearing) ; Conn, trap ridges, g. Hints 
 from comp. of meteors. 
 
 4. Crust of Earth. a. Present application of term 
 "crust." b. Sources of knowledge : (1) Mines, wells, borings; 
 (2) exposures in cliffs, gorges, canons, etc.; (3) tilted rocks. 
 c. Known thickness 5 mi. (aver.) to 20 mi. (max.) 
 
 5. Relations of Form to Structure, a. Original form 
 commonly structural; Ex. : mountain folds, volcanic cones, etc. 
 b. Secondary action often obscures structure ; Ex.: valley be- 
 coming mountain by erosion, depressed fold filled with detritius. 
 
 Ref. : — 1 (p. 736), 2 (chap, xvi), 3 (Part II, 
 chap, i, p. 164), 10, 41. 
 
 •JUSprUS [BJ3U33 31{1 oj aaire 
 
 -jjodun repsds ou jo 2upq 'ajaq psjjiuio aiE jj S3IH3S i° saniwvj-ans aqx i 
 
U * ^l> dL^-^JJ^-^ , , / to -'H^c4„ 
 
GEOGNOSY— PETROLOGY. 21 
 
 DIVISION B.— STRUCTURE OF ROCK MASSES. 
 A.— GENERAL ARRANGEMENT. 
 
 i. Mode of Occurrence. A. Igneous, a. Position: (i) 
 beneath other terranes ; (2) protruding as nuclei of various 
 mountain ranges ; (3) above or between other terranes (inter- 
 bedded) ; (4) occupying fissures in other rocks. b. Strictly 
 unstratified. c. Common structures: Massive, columnar, 
 platy. A. I. Granytic. a. Position and relation to Aqueous 
 Rocks; intrusive, b. Rarely cuboidal or columnar. A. II. 
 Trappean. a. (1) Intrusive; in sheets, veins, dikes, necks; 
 (2) interbedded. A. III. Volcanic, a. Position chiefly at 
 surface. B. Metamorphic. a. Beneath Aqueous Rocks; 
 otherwise nearly as in C. b. Special structural features, as 
 cleavage. C. Aqueous, a. Nearest surface, b. Stratified. 
 
 2. Unstratified Terranes. a. All Igneous rocks, strictly 
 speaking, b. Material filling fissures and intrusive veins [see 
 B, 4. Igneous Dikes], c. More or less homogeneous in text- 
 ure : crystalline or amorphous. 
 
 3. Stratified Masses, a. Consolidated sediments main- 
 ly, b. Aqueous and Metamorphic rocks, c. Crystalline or 
 fragmental. 
 
 B.— FEATURES COMMON TO ALL ROCKS. 
 
 1. Fissures, a. Frequently miles in length, many feet 
 wide, of unknown depth, b. Commonly in parallel series fol- 
 lowing trends of mountain systems, c. Also accompanied by 
 smaller transverse systems, d. Variously inclined, vertical to 
 low angle. 
 
 2. Faults, a. Non-adjustment of two sides of fissures. 
 b. More apparent in stratified rocks [see beyond, C, 3. Dislo- 
 cations], c. Very common in mountainous regions, often of 
 great extent horizontally (250 miles) and vertically (20,000 
 ft.) d. "Hade." e. "Throw." 
 
 3. Joints, a. Division planes in two or more directions. 
 b. Parallelwise to minor ridges or folds, c. Courses vary ac- 
 cording to character of rocks, producing blocks of different 
 shapes and sizes : 
 
 In basalt and other Igneous rocks, columnar or prismatic ; in granyte, 
 large, irregular, columnar or cuboidal ; in limestone, regular, cubical ; sand- 
 stone, more or less prismatic (quadrangular) ; shale, commonly rectangu- 
 lar ; in Metamorphic rocks, often rhomboidal, small. 
 
 4. Igneous Dikes, a. Fissures suddenly filled by Trap- 
 pean ejections b. Mainly ancient choked-up fissures, c. 
 
22 GENERAL GEOLOGY. 
 
 Occur in crystalline or amoqjhous masses, d. Offsets (" igne- 
 ous veins" and "cotemporaneous veins.") e. Granyte dikes 
 and "elvans." f. Structural features of dikes : 
 
 (i) Traversed commonly by two series of joint-planes meeting at right 
 angles; (2) often columnar (as basalt) with columns commonly perpendic- 
 ular to walls of dike; (3) edges frequently, and inner portions occa- 
 sionally, streaked with tachylite ; (4) selvage of decomposed material not 
 infrequent; (5) adjacent rocks often much altered. 
 
 f. Necks; ( 1 ) occupy throats of extinct volcanoes ; (2) crys- 
 talline or fragmental [R. 44 (iii, 243)]. 
 
 5. Mineral Veins, a. Fissures, crevices or patches more 
 or less filled by material slowly accumulated, b. Extent and 
 direction dependent on size of fissure, c. Kinds : (1) veins of 
 infiltration, usually siliceous or calcareous; (2) veins 0/ segrega- 
 tion, no definite walls — same, in effect, as concretions, explained 
 beyond; (3) fissure veins, commonly metalliferous, d. Struct- 
 ure commonly banded, e. Leaders and feeders. \Full dis- 
 cussion given i?i Course LI, — Economic Geology]. 
 
 6. Concretions. A. Congenital. I. Lgnigenous. a. 
 In Igneous rocks; as (1) "druses" in granyte; (2) spheroids 
 in doleryte and dioryte. b. In Metamorphic rocks ; (1) patches 
 of foreign or other crystals in gneiss, etc. B. Secondary. 
 a. In all rocks, but chiefly in Aqueous [see D, 1. Concretions], 
 
 7. Slaty Cleavage, a. Most common in Metamorphic 
 rocks. 1 
 
 C— SPECIAL FEATURES OF STRATIFIED ROCKS. 
 
 i. Regular Arrangement, a. Planes of stratification ; 
 use of terms stratum, formation, b. Original horizontal posi- 
 tion of beds proven by: (1) composition of beds; (2) positions 
 of trees and other entombed remains, c. Inclined strata, d. 
 "Dip"; measurement and sources of error, e. "Strike"; at 
 right angle to dip. f. "Conformity." g. Association of beds. 
 
 2. Irregular, or Secondary Arrangement, a. "Over- 
 lap." b. Foldings: (1) major folds; (2) minor folds; (3) con- 
 tortions; (4) plications. c. Use of terms anticlinal, syncli- 
 nal, uniclinal, qua-qua-versal. d. " Unconformity," real and 
 apparent, e. Inversion of strata. 
 
 3. Dislocations [see ante, B, 2. Faults], a. Kinds: (1) 
 vertical; (2) inclined; (3) trough; (4) step; (5) reversed 
 (not common), b. Simple and compound faults, c. Varia- 
 
 1 The full discussion of the subject of cleavage in rocks will be more advantageously 
 taken up under the head of JE. — Paiticular Structure of Metamorphic Rocks, later in 
 the course. 
 

 
 ^-^^v ", V^^jL-JS ^ 
 

GEOGNOSY— PETROLOGY. 23 
 
 tions, due to (1) nature of beds; (2) inclination of beds. d. 
 Faults in anticlinals and synclinals, e. Strike faults, etc. f. 
 Distortions, etc. g. Resulting fissures and cavities, h. Meth- 
 od of determining thickness of faulted beds. i. Rules and 
 conclusions : 
 
 ( 1 ) Acute aiigle very rarely occurs with surface of given bed on both sides 
 of fault. 
 
 (2) Hade is commonly in direction of down-throw. 
 
 4. Lamination, a. Planes of lamination, b. Regular 
 lamination. c. Oblique lamination ("false-bedding"). d. 
 "Rolls," "swells," etc. e. Lateral extent of beds : 
 
 ( 1 ) 7 lie finer the particles the more extended and more regular (in thick- 
 ness) the beds, and vice versa. 
 
 (2) Limestone liable to extend farthest, shale next, then sandstone, con- 
 glomerate shortest distance. 
 
 J).— PECULIARITIES OF AQUEOUS ROCKS. 
 
 1. Concretions, a. Really veins of segregation [ante, 
 B, 5, c, (2)]. b. Found in all rocks, but especially charac- 
 teristic of Aqueous, c. In Aqueous rocks, always of second- 
 ary origin, d. Forms of nodules : globular, lenticular, annu- 
 lar, botryoidal, and various, e. Hollow, solid, honey-combed, 
 partitioned, radiated, etc. f. Often have fossil or crystal as 
 nucleus, g. Comp. : 
 
 (1) In sandstone CaC0 3 , FeS 2 or F&2O3 ; (2) in shale CaC0 3 (septaria), 
 FeCOs (clay iron-stone), FeS^ (Catalina stone) ; (3) in limestone SiOj 
 (chert, flint, etc.), also in dolomite; (4) dolomite itself also sometimes nod- 
 ular. 
 
 2. Petrifactions, a. Include remains of plants and ani- 
 mals, generally hard parts, b. State of preservation varies 
 greatly ; structure commonly apparent, sometimes only outline. 
 c. Replacement (pseudomorphism), d. Casts and moulds. 
 
 3. Peculiar Markings, a. Wave marks, b. Ripple 
 marks, c. Rill marks, d. Rain prints, e. Mud cracks. 
 f. Traces left by flowing mud. g. Tracks of animals. 
 
 E.— PARTICULAR STRUCTURE OF METAMORPHIC 
 ROCKS. 
 
 i. Slaty Cleavage, a. Not necessarily confined to Met- 
 amorphics, but more common than in Aqueous or Igneous. 
 b. Divisional planes more or less transverse to bedding, c. 
 Course of planes parallel to main axes of elevation, d. Lam- 
 ination often obliterated by cleavage planes, e. Planes often 
 extend through great series of beds. f. Surface bending of 
 
24 GENERAL GEOLOGY. 
 
 planes, g. Sedgwick's conclusions [R. 48 (vol. iii, On Struct- 
 ure of Large Ati?ieral Masses)] : 
 
 (1) Strike of cleavage planes (when well developed and extending through 
 mountain-masses) coincides nearly with strike of beds. 
 
 (2) Dip of planes (in amount and direction) not affected by changes in 
 beds, even when latter are contorted. 
 
 2. Foliation, a. Darwin and Sharpe regard it as extreme 
 degree of slaty cleavage, b. Geikie considers it result of met- 
 amorphism. c. Prof. Geikie's view receives support from 
 common direction of folia (coincident with bedding). 
 
 Ref. : — 1 (pp. 79-114), 2 (chaps, vi-xv), 3 (Part 
 II, chaps, ii-v, mainly), 9, 10, 47. 
 
 PART IV -DYNAMICAL GEOLOGY. 
 
 1. Scope, a. Treats of geological agents and their present 
 operations, b. Comprises chiefly chemical and physical geology. 
 
 2. Divisions. I. Subterranean Agencies. II. Sur- 
 face Agencies, including Aqueous, Atmospheric and Organic. 
 III. Morphogony, or origin of surface outlines. 
 
 SECTION I -SUBTERRANEAN AGENCIES. 
 
 1. Causes of Disturbance, a. Subject but little under- 
 stood, b. Local bodies of molten material within the crust. 
 C. Contraction of crust, d. Access of water through fissures 
 to heated caverns in interior mass. e. Sir Humphrey Davy's 
 idea of oxidation of metallic bases of earths and alkalies [R. 49]. 
 
 2. General Effects, a. Sudden movements of crust as 
 exhibited in earthquakes, b. Slow elevations and subsidences. 
 
 c. Ejection of molten material through fissures and craters. 
 
 d. Physical and chemical changes in rocks; as (1) expansion; 
 (2) contraction; (3) folding; (4) slaty cleavage; (5) foliation; 
 (6) concretions; (7) mineral veins, e. Phenomena of hot 
 springs and geysers. 
 
 DIVISION A.— ACTION OF HEAT. 
 
 A.— SOURCES OF TERRESTRIAL HEAT. 
 
 i. Heat from Sun, etc. a. Nearly 40 per cent, ab- 
 sorbed by atmosphere, b. Penetrates crust 50 to 100 ft." c. 
 
SUBTERRANEAN AGENCIES. 25 
 
 Amount received varies; (1) with seasons; (2) with eccentricity 
 of orbit, d. Daily invariable isogeother?n but two or three ft. 
 underground, e. First constant isogeotherm an irregular line ; 
 from less than 2 ft. under heat equator to more than 100 ft. 
 at poles — varying in submergence according to amount of an- 
 nual variation, and representing temp, near mean annual iso- 
 therm at surface, f. Heat from fixed stars very important, 
 nearly | of amount from sun. 
 
 2. Interior Heat. a. Invariably increases in descending 
 below limit of surface action, b. Rate of increase varies ac- 
 cording to locality, mainly owing to varying conductivity of 
 rocks, as in table on next page. c. Annual loss of heat not 
 great, owing to low conductivity of materials of crust ; Thom- 
 son estimates enough to melt 777 cu. miles of ice, equal to 
 earth-envelope of only .0085 mm. 
 
 3. Chemical Action, a. Possible source of some im- 
 portance, but not easily estimated, b. Result of decomposi- 
 tion (oxidation). 
 
 4. Mechanical Sources, a. Movement in crust, chief- 
 ly, b. Mallet's experiments [R. 42, 1862 (Paper on "Vol- 
 canic Energy")], epitomized in following table: 
 
 Heat Produced by Crushing. 
 
 Z cu. ft. of crushed produces Temp. {F.) of sp. heat. 
 
 (1) Syenyte or granyte Ilo°.oo-2I3 .25 0.181-0.186 
 
 (2) Slate I32°.85 0.201 
 
 (3) " I44°.2Q 0.218 
 
 (4) Sandstone 32°.84 0.238 
 
 (5) " 47°-79 0.233 
 
 (6) " 86°.i3 0.215 
 
 (7) Limestone (compact) 20°.o8 0.245 
 
 (8) " " 26°.28 0.265 
 
 (9) Marble (Devonshire) H4°.68 0.203 
 
 B.— EXPANSION AND CONTRACTION IN ROCK'S. 
 
 i. Col. Totten's Experiments [R. 13 (vol. xxii, 1833, 
 p. 136), 46 (vol. ii)]. a. Ratio of expansion in: (1) fine- 
 grained granyte, (2) granular limestone, (3) red sandstone = 
 1 : 1.78: 1.99, respectively, b. Amount of expansion in 1 in. 
 cubes: (1) .000004825 ; (2) .000005668; (3) .000009532. c. 
 Lyell calculates that 50 miles in thickness of crust, with increase 
 of 6oo° F. to 8oo° F., would cause elevation of 1000 ft. to 
 1500 ft. 
 
 2. Bischof s Experiments, a. In passing from glassy 
 condition to crystalline, rocks shrink in volume: (1) Basalt, 
 
26 
 
 GENERAL GEOLOGY. 
 
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S UB TERRANEAN A GENCIES. 2 7 
 
 0702; (2) Trachyte, .0786; (2) Granyte, .1580. b. From 
 fluid state to crystalline, shrinkage in: (1) Basalt, .1040; (2) 
 Trachyte, .1813; (3) Granyte, .2519. c. Results somewhat 
 remarkable and not all confirmed [D. Forbes, R. 45 (xviii, p. 
 191)]. 
 
 3. Experiments of Delesse and Deville [R. 53 (II, 
 iv, pp. 1312, 1380)]. a. From fluid to solid, contract: (1) 
 Granyte, Quartz-porphyry, etc., .09 to .11; (2) Syenyte, .08 to 
 •°9j (3) Porphyrine forms, .08 to .10; (4) Greenstones, .06 to 
 .08; (5) Melaphyr, .05 to .07 ; (6) Trappean rocks, .03 to .05 ; 
 (7) Volcanic rocks, .00 to .04. b. Conclusions of M. Delesse 
 for Igneous rocks. 
 
 ( 1 ) From crystalline to glassy state, rocks increase in volume (decrease in 
 density*) more rapidly in proportion to quantity of SiOa and alkali (Acidic 
 Series). 
 
 (2) Rocks increase in volume less rapidly in proportion to amount of iron, 
 CaO and A1 2 > 3 (Basic Series). 
 
 (3) Igneous rocks most deeply seated (ancient) generally of first group 
 (acidic) ; those near surface (modern) commonly of second group {basic). 
 
 (4) Order of increase of volume almost exactly the inverse of order of fu- 
 sibility. 
 
 4. Production of Columnar Structure in Rocks. 
 
 C— VOLCANOES AND VOLCANIC PHENOMENA. 
 
 i. Form and Structure of Volcanoes, a. More or 
 less conical, built up of material ejected from below through 
 one or more shafts communicating with highly-heated portion 
 of earth's crust, b. Truncated above, with basin-shaped pit, 
 or crater, surrounding orifice of shaft, c. Much variety in 
 shape and structure, d. Structure commonly complicated by 
 irregular alternations of lava, ash and cinders, e. Height even 
 14,500 ft.; breadth of crater variable, even 3 miles; depth of 
 crater as great as 1000 ft. 
 
 2. Kinds of Volcanic Cones. A. Eruptive. Most 
 common ; formed by successive ejections of molten or other 
 material. I. Lava-cones, a. Slope at low angles (6° to 8°) ; 
 Ex. : ^Etna, cones of Hawaii (Sandwich Is.) b. Crater in 
 form of pit, with nearly vertical walls; lavas often stratified. 
 II. Tufa-coties. a. Wet cinders or flowing mud. b. Slope 
 1 5 to 30 . c. Inward slope of walls of crater towards cen- 
 tral shaft, making bowl-shaped depression. III. Cinder-cones. 
 
 a. Slope of 40 or less. b. Crater restricted, with narrow 
 rim. IV. Mixed cones, a. Slope from 8° to 35 , dependent 
 upon proportions and alternations of lava, tufa and cinder. 
 
 b. Crater liable to simulate that of cinder-cotie. B. Elevated. 
 
28 GENERAL GEOLOGY. 
 
 Caused by swelling and bursting of earth's crust; probably 
 form part of some cones. 
 
 3. Present Distribution, a. Almost wholly limited to 
 oceanic islands or to borders of continents near the sea. b. 
 Nearly all oceanic islands are volcanic, c. Two-thirds of all 
 volcanoes are on oceanic islands, d. Mainly confined to bor- 
 ders of Pacific Ocean and equatorial seas. e. Arranged in 
 groups or linear series [R. 1 (p. 703)]. f. Pacific Ocean al- 
 most completely encircled by main belt. g. Note of much im- 
 portance : Active volcanoes most common in geologically 
 modern strata, h. Number of existing volcanoes, 1200 or 
 more; goo in archipelago about Borneo, i. Extinct volcanoes 
 very numerous, even in regions away from present coast. 
 
 4. Products. A. Liquid, a. Liquidity dependent upon : 
 (1) amount of heat ; (2) conditions of fusion (aqueous or aqueo- 
 igneous); (3) nature of material, b. Special forms of lava 
 produced by cooling, as: (1) Pele's hair; (2) pumice; (3) ob- 
 sidian (volcanic glass); (4) vesicular lava; (5) volcanic sand. 
 c. Igneous fusion occurs with great heat (2500 or more) and 
 limited amount of water, d. Aqueo-igjieous fusion requires 
 abundant supply of water but not greatest heat (only 8oo°). 
 e. Fcldspathic (acidic) lavas less fusible than augitic (basic). 
 B. Solid. I. Volcanic ash, forming tuffs. II. Cinders. III. 
 Fragmentary masses, a. From walls of chimneys, b. Ce- 
 mented into breccias, agglomerate, or conglomerate. C. Gas- 
 eous. I. Steam, a. Escapes with ash and cinders in explo- 
 sive eruptions, b. Not abundant in lava ejections, c. Largely 
 from surface waters. II. Carbonic Acid. a. Rather secondary. 
 b. From limestone, and possibly other sources. III. Chlor- 
 hydric Acid. a. From sea- water, mainly, b. Converts oxides 
 to chlorides. IV. Sulphurous Vapors, a. Sulphur deposited 
 secondarily, b. S0 2 vapor not rare ; produces sulphates event- 
 ually, c. H 2 S rather common. V. Nitrogen. VI. Hydrogen. 
 
 5. Association of Basic and Acidic Lavas, a. Old 
 opinion of relative age ; basic group newer, b. Richthofen's 
 views as to order of succession in Rocky Mountain region : (1) 
 Propylyte, (2) Afidesyte, (3) Trachyte, (4) Rhyolyte, (5) Basalt 
 [R. 54, 55 (pp. 186, 187)]. c. Bunsen's double or triple sets 
 of "volcanic foci." d. Durocher's double "magmas." e. 
 Lyell's counter-statement regarding trachytic lavas overlying 
 dolerytic in Madeira [R. 46, (vol. ii, p. 52)]. f. Association 
 well marked in ancient (Trappean) as well as modern (Vol- 
 canic) accumulations, g. Relations of both basic and acidic 
 
S UB TERRANEAN A GENCIES. 2 9 
 
 lavas to sedimentary beds, suggesting possible cause of associa- 
 tion of former. 
 
 6. Phenomena Accompanying Eruption. A. Lava 
 Flows. I. Ebullition, a. Jets of thirty ft. in most liquid 
 lavas, b. In viscid lavas resistance much greater, and burst- 
 ing of bubbles sometimes throws material very high (10,000 ft., 
 Vesuvius, 1779, Sir Wm. Hamilton), c. Circulation from 
 centre towards sides of crater. II. Hydrostatic Pressure, a. 
 Increases 8^ atmospheres for every 100 ft. in depth, b. Heat 
 causes vaporizable substances to ascend, inflating mass in con- 
 duit, making general rise in craters, c. Produces fractures in 
 sides of cones. III. Outflow, a. Sometimes over brim of 
 crater, but usually through coincident fractures, b. Common- 
 ly quiet, unless affected by vapors, c. Superficial extent de- 
 pendent on liquidity of lava and topography of region ; often 
 many sq. mi. in area, from 100 ft. to 600 ft. in depth [R. 1 (p. 
 712), 46 (vol. ii, p. 52)]. d. Scoriaceous crust formed at sur- 
 face long (even 10 years) before solidification of subjacent 
 mass. e. Production of dikes, mounds, clinkers, etc. B. Solid 
 Ejections, a. Huge fragments thrown out in explosive erup- 
 tions, often to great distances (from Cotopaxi, one mass of 211 
 tons, 9 miles), b. Earthquakes ordinarily occur at same time. 
 C. Vapor Emissions, a. Ordinarily associated with explo- 
 sive eruptions, b. Important effects on weather, causing rains, 
 etc. c. Scrope [R. 58] considers mobility of lavas due to im- 
 pregnating steam. 
 
 7. Process of Cone-formation, a. Successive steps: 
 
 (1) Opening of vent; (2) growth of primary cone by accumulation of 
 ejectamenta; (3) bursting-out of side-vents ; (4) production of dikes; 
 
 (5) building-up of secondary cones ("parasitic cones " or "monticules ") ; 
 
 (6) formation of central crater by bursting or melting off of top of main 
 cone; (7) rebuilding of cones over central area ("cone-within-cone " 
 structure). 
 
 b. LeConte's simile of exogenous wood [R. 3, p. 89]. c. 
 Remarks on great age of certain volcanoes. 
 
 8. Periodicity of Eruptions, a. Active, dormant, ex- 
 tinct volcanoes, b. Intervals sometimes rather irregular, but 
 commonly not so. 
 
 9. Explanation of Volcanic Action. A. Require- 
 ments, a. Necessary to account for : (1) force of ejection and 
 (2) heat of fusion. 
 
 (1) Amount of force required to raise lavas (Gr. 2.5-3.) to bottom of 
 crater = wt. of column in conduit= 156.25 lbs. to 187.5 ^ Ds * P er cu - ft- = 
 I atmosphere for each vertical 12 ft. (12ft. 10 in. to loft. 8 in. ) of column. 
 This, in Vesuvius (3900 ft. above sea) = 325 at. ; in ^Etna (11,000 ft.), 
 
3 o GENERAL GEOLOGY. 
 
 I083 at. ; in Mount Loa (craters 10,000 ft. to 13,000 ft. ), 833 at. to 1083 at.; 
 Cotopaxi (20,000 ft.), 1666 at. (2) Quiet eruptions demand exercise of 
 maximum force and maximum heat, while explosive eruptions may occur 
 under minimum of force and heat, owing to presence of superheated water. 
 
 B. Theories. I. Eruption, a. Generally agreed that ejec- 
 tion is mainly due to imprisoned vapors, chiefly steam. II. 
 Fusion, a. Source of heat somewhat in dispute ; several theo- 
 ries, as below : 
 
 (1) Internal Fluidity. Supposes existence of molten interior, throb- 
 bing in response to crust movements which permit access of surface 
 waters through new fissures. \_Relic of early geology]. 
 
 (2) Gaseous Evolution (subterranean). Superheated gases in interior 
 of earth expanding near surface, melting rocks and forcing them out- 
 wards ; appeals to sun for support. \_Kev. O. Fisher, 1868 [R. 44 (Nov.), 
 67], 1875 [R. 61 (vol. xii)]; N. S. Shaler, 1868 [R. 44 (Nov.), 67]. 
 
 (3) Rise of Heat through Crust, locally transforming subjacent sedi- 
 ments, by aqueo-igneus fusion, into material sufficiently elastic to produce 
 volcanic phenomena. [Sir jfohn Herschel, [R. 66, (vol. xi, p. 548)]. 
 
 (4) Aqueo-Igneous Belt. Thought to be result of action given in (3), 
 producing continuous belt of fused material between central mass and 
 outer crust. [Compromise bet-ween (1) and (2)]. 
 
 (5) Oxidation of Inferior Mass, above "limit of volcanic water," 1 de- 
 veloping heat enough for effects observed in volcanoes. Sir Humphrey 
 Davy suggested particular form of oxidation (see p. 24). \_Few hold this, 
 perhaps, as chief source of heaf\. 
 
 (6) Contraction of Interior more rapidly than the crust, causing suffi- 
 cient horizontal pressure in latter to produce local volcanic action. [ Mal- 
 let's view [R. 39, 1872] now accepted by many of best authorities], 
 
 C. Discussion. I. Theory of Internal Fluidity, a. Based 
 upon hypothesis now but little supported, b. Limits thickness 
 of" crust more than seems warranted by results of recent phys- 
 ical research, c. Effects too local for support of this theory, 
 in toto. d. "Limit of volcanic waters" probably far above 
 isogeotherm of 8oo° F. (temp, of aqueo-igneous fusion); hence, 
 surface waters could not penetrate to igneous interior, e. Ad- 
 vocates adopt modifications ("local thinnings," and "honey- 
 combed remains" within crust separated from interior mass), 
 which practically revoke theory as regards volcanoes. II. Sub- 
 terranean Gases, a. Sun generally considered as now in con 
 dition of earth at an earlier stage ; from former vapors abun- 
 dantly emitted, b. Volcanic activity formerly greater on the 
 earth, c. Lavas usually charged with vapors, d. Action of 
 this kind may take place far below limit of volcanic waters. 
 e. This view may be held as accessory to theory (6), though 
 Fisher opposes latter. III. Ascent of heat. a. Deposition of 
 
 1 Phraseology suggested by Le Conte [R. 3 (p. 92)] to indicate point where action of 
 jravity on surface waters balances reverse action of interior heat. 
 
S UB TERRANEAN A GENCIES. 3 1 
 
 sediments causes gradual upward movement of isogeotherms, 
 possibly sufficient to account for certain volcanic phenomena, 
 as mud-throws and some explosive ejections, b. Increase of 
 temp, too slight and too slow for igneous fusion, c. Receives 
 some apparent support from occurrence of active volcanoes 
 mainly in recent strata. IV. Zone of Aqueo-igneous Fusion, a. 
 Open to objections under I and III. V. Chemical Theory, a. 
 Probably explains certain phenomena and rightly accounts for 
 part of heat. b. Sir Humphrey Davy's special modification 
 almost purely hypothetical, c. Oxidation not only chemical 
 source of heat. 
 
 Much heat is disengaged in formation of chlorides. bro77iides, iodides and 
 snip/tides, and, contrary to general rule, heat is also given off in decomposi- 
 tion of nitrous oxide and hydrogen peroxide [R. 59]. 
 
 VI. Mechanical Theory, a. Explains not only volcanoes 
 but also other kinds of igneous, as well as sub-igneous, action. 1 
 b. Accords well with commonly accepted theories of earth's 
 general history. 
 
 Earth, in cooling, first formed thin, solid crust, acting as non-conduct- 
 ing envelope to fluid mass within. Interior magma, in cooling, contracted 
 and still contracts more rapidly than crust, because coefficient of contraction 
 is greater at high temperature and because temperature of crust has be- 
 come nearly stationary. Result must be horizontal pressure from yielding 
 of crust to adjust itself. 
 
 c. Two prominent modifications of theory: (1) arching of 
 strata by the pressure, allowing portions of interior mass to 
 escape; (2) more common view of crushing of material and 
 final mechanical fusion of subjacent portion. 
 
 D.— IGNEOUS ACTION NOT VOLCANIC. 
 
 i. Nature of Trappean Ejections, a. Distribution 
 same as volcanoes, but also common in regions of extinct vol- 
 canoes, b. Produced by eruption through fissures, c. Mate- 
 rial similar to volcanic masses, but more compressed. 
 
 2. Interbedded, or Contemporaneous Traps, a. 
 Characterized by: (1) position among stratified beds, conform- 
 able with overlying sediments; (2) unaltered condition of su- 
 perimposed layers ; (3) occurrence of tuffs, etc. ; (4) slaggy, 
 or scoriaceous, character at top and bottom of lava sheets, b. 
 Material both crystalline and fragmental, former somewhat re- 
 stricted, latter of all varieties. 
 
 Dioryte, hyperyte, quarts-porphyry, etc., not known as interbedded trap, 
 though meldphyr and felsyte are not uncommon, also some rocks of Vol- 
 canic Division. 
 
 1 This theory will be more fully examined under head of Mountain Elevation (p. 38). 
 See also remarks under Slaty Cleavage beyond (p. 37). 
 
32 GENERAL GEOLOGY. 
 
 c. Structure and texture of sheets similar to modern lava 
 flows from volcanoes, with induced modifications resulting from 
 age and pressure, d. Sheets occur in series alternating with 
 sedimentary beds. e. Tuffs of given series commonly resem- 
 ble lavas of same group, f. Sedimentary masses enclosed in 
 tuff. g. Illustrations from contemporaneous traps of " the great 
 Northwest lava-flood" extending from Big Horn Mts. to Pacific 
 Ocean (area nearly 175,000 sq. mi.) h. Some European 
 fissure-eruptions 
 
 3. Intrusive, or Subsequent Traps (see Igneous 
 Dikes, p. 21). a. Material filling fissures in rocks previously 
 arranged, b. Occur in dikes, offsets, bosses, sheets and necks, 
 always following lines of least resistance, c. Sometimes, in 
 sheets and offsets, may appear contemporaneous, locally, d. 
 Crystalline, of all Trappean varieties ; fragmental varieties 
 normally wanting, represented, however, by agglomerate necks. 
 e. Dikes rarely formed of diotyte or members of Feldspathic 
 Family, f. Examples of intrusive traps : 
 
 (1) Amorphous Masses more or less abundant in Scotland, Wales and 
 elsewhere: (2) dikes well represented in U. S. by trap ridges of Conn. 
 Valley, Mt. Tom and Holyoke Mts., N. J. Highlands and Lake Superior 
 bluffs ; elsewhere common, as Giant's Causeway and Fingal's Cave j (3) 
 sheets, necks and offsets, more local. 
 
 4. Igneous Granytes. a. Subject of much discussion ; 
 formerly considered fundamental or part of original crust, b. 
 All granyte regarded as igneous until recently; greater portion 
 now considered metamorphic. c. Position and relations to 
 other rocks indicate cooling at great depths under pressure. 
 d. Growing opinion that Granytic rocks are rarely or never true 
 igneous deposits, e. Abundant proof of Aqueo-igneous origin. 
 For arguments on both sides, see Hunt [R. 13, (New Series, 
 vol. i, pp. 82, 182), 56 (pp. s, ss, 43, 65, 183, 189-191)]; 
 Scrope [R. 65 (vol. xii, p. 326)]; Scheever and others [R. 53 
 (II), vol. iv, pp. 468, 1018, 131 2 ; vi, 644 ; vii. 275 ; vii, 500] ; 
 Sorby [R. 62 (February, 1858)]; Rose [R. 62 (xix, p. 32)]; 
 Delesse [R. 63 (vol. vii, p. 190)]; Jukes and Geikie [R. 2 
 (chap, xii)]; Le Conte [R. 3 (p. 217)]. f. Notes of personal 
 observations on granytes of Rocky Mts. and region in Brit. 
 Amer. N. W. of Lake Superior. 
 
 E.—SECONDAR Y IGNEOUS ACTION. 
 
 I. Geysers, a. Intermittent explosive thermal springs. 
 b. Occur in Iceland, New Zealand and Yellowstone Park, 
 U. S., associated with ancient volcanic outflows, c. Great 
 
S UB TERRANEAN A GENCIES. 33 
 
 Geyser, Iceland: Bunsen [R. 86 (lxxii, 1847, pp. 159-170)]; 
 Bischof [R. 72, p. 225 (quoted in R. 73, 187 1, p. 129)]. d. 
 New Zealand geysers [R. 71, p. 432 (quoted in R. 73, 187 1, 
 p. 128)]. e. 1 Yellowstone (rather, Madison,) geysers; some 
 account of explorations; (1) Lieut. G. C. Doane [Rep't upon 
 Yellowstone Expedition of '1870 (Sen. Ex. Doc, 51, 4.1st Cong., 
 3d Sess.)\ ; (2) Capts. Barlow and Heap [Reconnaissance of 
 Sources of Yellowstone River, 187 1 [Sen. Ex. Doc, 66, 42^ 
 Cong., 2d Sess.)] ; (3) Hayden, Peale, etc. [R. 73, 1871, 1872, 
 1877, 1878]; (4) Jones, Heizmann, Comstock, 1873 [R. 55]; 
 (5) Ludlow, Grinnell, E. S. Dana, 1875 [Carroll, Montana, to 
 Yellowstone Park (War Dep't)]. f. Personal observations; 
 descriptions of leading geysers, as White Dome, Clepsydra, 
 Fountain, Impulsive, etc., of Lower Fire Hole — Old Faithful, 
 Castle, Giant, Giantess, Bee-hive, Grotto, Grand and Fan gey- 
 sers of Upper Basin — with remarks on phenomena and de- 
 posits JR. 55 (pp. 241-259), 74, 76, 78 (1875, B, p. 97)]. g. 
 Periodicity of geysers, h. "Sympathy" between separated 
 geysers [R. 74]. 
 
 2. Theory of the Geyser [R. 3 (p. 99)]. I. Origin. 
 a. Relation to volcanic activity, b. Produced by infiltration, 
 through fissures, of meteoric water, c. Only formed by sili- 
 ceous waters, d. Waters always contain alkaline carbonates. 
 e. Bunsen's theory of formation of tube and chimney. II. 
 Eruption, a. Mackenzie's theory of subterranean caverns, 
 adopted by Bischof [R. 72, 73 (1871, p. 129)] for New Zeal- 
 and, and applied by the author to certain geysers of Yellow- 
 stone Park [R. 55, p. 225 et sea.], b. Bunsen's theory of 
 eruption (unequal heating at different depths) sufficient to ex- 
 plain prominent facts and capable of experimental verification. 
 
 3. Thermal Springs in Volcanic Districts. 2 a. 
 Non-eruptive or sometimes eruptive, b. Antecedents or con- 
 sequents of geysers; often siliceous, c. Deposits [see M 9 1. 
 Geysers, e.]: (1) siliceous, in form of chimneys of opal or 
 quartz (rarely); (2) calcareous cones and basins of travertine 
 along bottoms of streams, even forming limestones of considera- 
 ble local extent (Gardiner's River, Yellowstone Park); (3) sul- 
 phurous, as sulphur incrustations, and (4) resulting products, 
 such as alum, gypsum, etc. d. Solfataras; commonly in 
 
 1 All references under e may be found in the Cornell University Library. 
 
 2 Certain classes of springs in which the action of heat is commonly coincident if not 
 essential, might properly be discussed here, but it is thought best to consider them under 
 the head of Stibterrancan Water beyond (p. 41). 
 
34 GENERAL GEOLOGY. 
 
 Trachytic rocks, e. Salses and mud-volcanoes, f. Fumar- 
 oles. g. Carbonated springs, h. Personal observations at 
 other points in Yellowstone Park. 
 
 Ref. : — i (pp. 697-723), 2 (chaps, xvi, xix, and 
 xx to p. 358), 3 (pp. 76-104), 4-6, 8-12, 27, 
 41, 46, 47, 49, 55, 56, 58, 60, 71, 72, 73 
 (1871, 1872, 1877, 1878), 74, 76, 79, 82, 84. 
 
 DIVISION B.— MOVEMENTS IN EARTH'S 
 CBTJST. 
 
 A.— EARTH Q UAKE PHENOMENA. 
 
 i. Character and Distribution, a. Mallet's definition 
 [R. 88 (1847, Part 2, p. 30; 1850, pp. 1-87; 1851, pp. 272- 
 
 3 2 °)]- 
 
 Earthquake consists of "waves of elastic compression, from vertical to 
 horizontal, in any azimuth, through crust of earth, from any centre of 
 impulse, or more than one, and which may be attended with sound- 
 waves and sea-waves, depending on impulse and circumstances of posi- 
 tion." 
 
 b. Average recorded number 575 per annum, but greater 
 number not catalogued ; earth probably never wholly free from 
 quakings. c. Most common in volcanic districts [see R. 79 
 (PI. X) or any good Physical maps, as in R. 4, etc.] 
 
 2. Relation to Volcanic Action, a. Eruptions rarely 
 occur without earthquakes, before and during ejection, b. 
 Especially characteristic of explosive eruptions. c. Earth- 
 quakes not unfrequently cease upon eruption of neighboring 
 volcanoes, and vice versa. 
 
 3. Cosmical Relations. a. Earthquakes occur more 
 commonly in winter than in summer; difference trifling, b. 
 C. More liable to occur under diminished atmospheric pressure. 
 Alexis Perrey's laws of lunar action : 
 
 (1) Earthquakes most frequent with moon on meridian (flood-tide). 
 (2) At syzygies (new and full moon, high flood-tide) a little more fre- 
 quent than at quadratures (half-moon). (3) Somewhat more frequent in 
 perigee (moon nearest earth, highest flood-tide) than in apogee (moon 
 farthest from earth). 
 
 4. Phenomena and Effects, a. Sudden movements 
 (undulatory) in earth's crust, producing temporary and perma- 
 nent displacements; alteration of drainage. b. Vorticose 
 movements, c. Production of fissures, d. Inundations, e. 
 Shocks in mines, f. Destruction of life and property, g. 
 Storms, h. Earthquake-" bridges." i. Peculiar sounds. 
 
^ UB TERRANEAN A GENCIES. 3 5 
 
 5. Seismographs and Seismometers [R. 3, p. 122]. 
 a. Palmieri's telegraphic seismograph [R. 60, p. 141]. b. 
 Cavalleri's pendulum seismometer [R. 62, xix, 1866, pp. 102— 
 116]. c. Simple forms sometimes employed, as basin of mo- 
 iasses, etc. 
 
 6. Mallet's Laws of Earthquake Motion [R. 85]. 
 
 I. "Earth-wave of shock''' is result of sudden impulse, a. 
 May be: (1) volcanic eruption; (2) cracking of rock under 
 tension; (3) generation of steam from spheroidal state of 
 water; (4) condensation of steam. II. Transmitted with 
 great velocity, affecting a?iy spot but momentarily. a. Veloc- 
 ity dependent upon nature of rock, etc. b. Mallet's exper- 
 iments [R. 3, p. ni[ with artificial earthquakes, c. Mallet's 
 observations (1857) on Calabrian earthquakes; mean velocity 
 of 789 ft. per second (658 ft. to 989 ft., extremes). III. 
 Waves travel in spheroidal shells, spreading in irregular closed 
 
 curves (" coseismal lines "), widening in proportion to distance 
 from central impulse, a. "Coseismal lines" modified by: (1) 
 form and dimensions of central impulse; (2) variations in 
 hardness, density, texture and structure of rocks ; (3) sudden 
 changes in rocks, producing return waves. IV. "Angle of 
 emergence = 90 (seismic vertical) over central impulse, decreas- 
 ing with distance from seismic vertical, a. Destructive effects 
 commonly decrease inversely as "angle of emergence"; be- 
 cause overthrowing power increases as angle decreases. V. 
 " Velocity of shock" not rapid, but "transit of wave" about half 
 as rapid as cannon-ball. a. "Velocity of shock" only 10 ft. 
 to 15 ft. per second, b. "Amplitude" of wave usually but a 
 few inches. 
 
 7. Explanation and Discussion. I. Explosive earth- 
 quakes, a. Velocity of shock very great, owing to very sud- 
 den and strong impulse, b. Position of central impulse (focus) 
 not very deep, otherwise height of wave and velocity of shock 
 would be too much diminished to produce such violent effects. 
 
 II. Vorticose earthquakes, a. Less common than often sup- 
 posed ; vorticose movements frequently produced by ordinary 
 vibrations, b. Mainly due to concurrence and interference of 
 waves, produced by : 
 
 (1) Unequal velocity of different waves (probably not a common cause 
 in earthquakes) ; (2) reflection of waves in passing through media of 
 varying density. 
 
 III. Spreading earthquakes, a. Coseismal lines will be : (1) 
 Circular, when waves pass through material of uniform elas- 
 ticity ; (2) elliptical, when elasticity of rock differs considerably 
 
36 GENERAL GEOLOGY. 
 
 in directions mutually transverse ; (3) linear, when structure is 
 such as to produce effect of non-elastic material in two opposite 
 directions. This last result is most frequently due to wave-re- 
 flection in passing through strata of varying density ; hence 
 linear earthquakes are most common along mountain axes. 
 IV. Sea-wave. a. Velocity due to size of wave; much less 
 than earth-wave, though often from 300 mi. to nearly 500 mi. 
 per hour. b. Distance traversed very much greater than 
 earth-wave, because : 
 
 (1) Earth-waves, being spherical, diminish in oscillation as square of 
 distance, while water-waves (circular) diminish only in proportion to dis- 
 tance. (2) Earth-waves traverse heterogeneous medium, causing abnor- 
 mal reduction in oscillation, by reflection and refraction, and loss of effect 
 from fractures and transformation of energy. 
 
 c. Reduction in velocity due to decrease in depth of water; 
 measurement of depth. 
 
 Great size of sea-wave causes it to "drag bottom" in comparatively deep 
 water. Principle is established that every wave traverses its own length 
 during time of one oscillation. Length of wave thus ascertained from ob- 
 served velocity and time of oscillation, depth of sea is calculated from dif- 
 ference between free velocity and actual retarded velocity [A. D. Bache, R. 
 83, 1862, p. 238]. 
 
 B.-SECULAR MOVEMENTS. 
 
 i. Relation to Sea-Level, a. Changes of level in land 
 must ordinarily affect water-level, hence : 
 
 (1) Actual amount of any movement of elevation is less than apparent 
 by just the amount of coincident depression of sea-level. (2) Depression 
 of land is greater than apparent by an amount equal to coincident elevation 
 of sea-level. But (3) actual additions to land surface being (apparently) 
 inappreciable, sea-level may be regarded, for convenience, as a fixed plane. 
 b. Cosmical causes may change level of sea alone, but 
 these effects are commonly compensated [Croll, R. 62 (April, 
 1866; June, 1867; 1868, p. 382)]. 
 
 2. Proofs of Elevation of Land [Lyell, R. 46, 89]. a. 
 Raised rocks, reefs, old sea-beaches, etc. : 
 
 Examples : (1) Scandinavian Peninsula, N. of Stockholm (and part of 
 Russia), '■'raised beaches" 50 to 70 miles inland, at height of 100 to 700 
 ft., with barnacles and shells attached; (2) South America, Chili and 
 southward, beaches, 1180 miles on E. coast, and 2075 miles on west, 100 
 ft. to 3000 ft. ; (3) Siberian Coast for 600 miles ; (4) Mediterratiean Sea- 
 coast in places (Bay of Naples, 20 ft.), Temple of Jupiter Serapis. 
 
 b. Old caves formed at sea-level, now 8 ft. to 100 ft. above, 
 as along coasts of Scotland, c. Terraces along sea-border. 
 d. Human works, as piers, etc., and Swedish commission 
 guages. 
 
 3. Evidences of Depression, a. Submerged forests. 
 
S UB TERRANEAN A GENCIES. 3 7 
 
 b. Growth of coral islands, c. Fjords. 1 d. River deltas, e. 
 Encroachment of sea on land over wide areas. 
 
 Examples: (i) Southern Sweden, gradual approach of streets to sea- 
 level, stone set by Linnseus in 1749, 100 ft. nearer sea in 1S36. (2) IV. 
 Coast of Greenland for 600 miles, submerging huts and boat-poles. 
 
 4. Theoretical Considerations, a. Areas of subsid- 
 ence commonly in regions of great accumulation of sediments. 
 b. Consequent rise of isogeotherms, basis of: 
 
 (1) Babbage's Theory [R. 66, vol. II, p. 73]. Expansion of crust ver- 
 tically, causing elevation. [Conflicts with fact given under a]. 
 
 (2) HerscheTs Theory [R. 66, vol. ii, pp. 548, 596]. Result of rise of 
 isogeotherm, subsidence, due to chemical change and aqueo-igneous fusion. 
 
 c. Commonly accepted opinion that movements are due to 
 contraction of earth from secular cooling. 
 
 Ref. : — 1 (p. 741), 2 (chaps, xvii, xviii), 3 (pp. 
 104-132), 4-6, 8-1 1, 27, 35, 41, 46, 47, 79, 
 80, 81, 84, 85, 87. 
 
 DIVISION C ! -LATEEAL PRESSURE FROM 
 CONTRACTION. 
 
 i. Foldings, Contortions, etc. a. Plainly due (on 
 large scale) to subsidence of crust, b. Modified by texture 
 and structure of included terranes. c. Fractures least com-- 
 mon in contorted strata, d. Slaty cleavage associated with 
 flexures. 
 
 2. Joints, Fissures, Faults, a. Mainly due to eleva- 
 tion of portions of earth's crust, b. Result of non-elastic 
 nature of material, c. Indicate cleavage-structure in crust 
 transverse to pressure. 
 
 3. Slaty Cleavage, a. Theory of Sharpe [R. 65, vol. 
 iii, p. 87] deduced from distortion of fossils, etc. b. Sorby's 
 experiments with foreign particles in clay [R. 62, 2d Ser., vol. 
 xi, p. 20]. c. Tyndall's experiments and conclusions [R. 62 
 (2d Ser., vol. xii, p. 35), 92 \appendix)\ d. Contraction hori- 
 zontally in direction of pressure, extension vertically, no change 
 in direction of strike. e. Ratio of compression and exten- 
 sion averages nearly 6 : 1 (from 2:1 to n : 1). 
 
 4. Elevation of Mountains, a. Foldings, contortions, 
 
 1 The proofs of subsidence afforded by coral reefs and fjords will be better appreciated 
 by the student later in the course. 
 
 2 The argument of the subject of this DIVISION is given in the later text-books 
 [R. 1 (p. 73s, et seq.), 2 (pp. 358-360), 3 (p. 252)]. See also J. M. Wilson [R. 44, v, p. 
 2o6j, and R. in the text. 
 
38 GENERAL GEOLOGY. 
 
 plications and slaty cleavage always associated with mountain 
 chains, b. Strata 20,000 ft. to 40,000 ft. thick in moun- 
 tainous regions ; hence where slaty cleavage is prominent, 
 mountain chains now 100 mi. broad originally extended 250 
 mi. horizontally, and elevation of central portion is wholly ex- 
 plained by lateral pressure. c. Much folded and greatly 
 cleaved mountains result of subsidence ; those resulting from 
 crust elevation commonly less folded and little cleaved, but 
 much fractured and faulted, d. Mechanical theory [(6), p. 30; 
 VI, p. 31] of volcanic action, therefore, applies here. e. Prog- 
 ress of mountain elevation illustrated : 
 
 (1) Sinking of large area of crust (geosynclinal) by contraction of mass 
 within, produces foldings, contortions, and finally slaty cleavage ; com- 
 pression greater in synclinals, hence synclinoritim is more permanent 
 mountain chain, as Jura and portions of Appalachian Mts. 
 
 (2) Elevation of large tract (geanticlinal) produces tension in strata 
 and consequent fissures and faults of great extent. This form (anticli- 
 norium) of mountain chain therefore less permanent, as Rocky Mts., etc. 
 
 5. Formation of Continents and Oceanic Depres- 
 sions, a. Continents represent first cooled areas with sub- 
 sequent additions, b. Oceanic basins later cooled areas of 
 greater subsidence, c. General remarks on growth of conti- 
 nents. 
 
 Ref. :— 1 (pp. 735-754), 2 (pp. 35 8 -3 6o )> 3 (PP- 
 240, 252, etc.), 13 (II, xxii, 1856), 56 [Index). 
 
 DIVISION D.- ALTERATIONS OF TEXTURE 
 
 AND COMPOSITION. 
 
 1. Metamorphism. a. Effects: (1) consolidation ; (2) 
 change of color; (3) loss of vaporizable ingredients; (4) ob- 
 literation of fossils; (5) crystallization; (6) foliation, b. Caused 
 by chemical action induced or modified by heat, pressure, 
 moisture and alkalies. 
 
 (1) Metamorphism in dry way illustrated by effects of igneous protru- 
 sions on adjacent rocks ; (2) effect of pressure shown by formation of 
 marble from calcite without loss of CO2 [Sir James Hall's experiments 
 (R. 42, vol. vi, p. 95)]; (3) combined water of rocks probably sufficient 
 for changes observed; (4) alkalies assists fusion and solution. 
 
 c. Cycles of metamorphism. d. Sorby's study of " Micro- 
 scopical Structure of Crystals" [R. 65, vol. xiv, p. 453]. 
 
 2. Pseudomorphism [R. 57 (vol. i, p. 53), 29 (p. 222), 
 56 (Index)], a. Alteration of composition without change of 
 
SURFACE AGENCIES. 39 
 
 form, in minerals, b. Due to transfer of particles by solutions 
 (replacement), c. Petrifaction essentially same process. 
 
 Ref. :— 1 (p. 724), 2 (pp. 50, 360), 3 (p. 215), 
 9, 10, 29, 46, 47, 56, 87. 
 
 SECTION II -SURFACE AGENCIES. 
 
 DIVISION A.— ACTION OF WATER. 
 
 A.— THE OCEAN AND INLAND SEAS. 
 
 i. Erosion of Land. a. Maximum effect produced 
 along shore, but probably more or less of sub-marine denuda- 
 tion in shallow water elsewhere, b. Erosive action progress- 
 ing on all coasts, but most abundant in Scotland and Norway, 
 Cape Horn, etc.; more extensive in high latitudes, c. Steven- 
 son [R. 42, xvi, pp. 25, 28], found force of breakers on coasts 
 of Scotland : 
 
 (1) In summer, 611 lbs. per sq. ft. ; (2) in winter, 2086 lbs. ; (3) during 
 heavy storms as much as 6000 lbs. 
 
 d. Effects vary with : ( 1 ) height of tides ; (2) force of waves; 
 (3) outline of coast; (4) texture and structure of rocks; (5) in- 
 clination of strata; (6) direction of prevalent winds, e. "Shore 
 platform," or line of no erosion, just above low tide. f. Line 
 of greatest erosion somewhat above half-tide. g. Bays formed 
 in yielding strata, headlands left of tougher rocks, h. Caverns, 
 "blow-holes" and undermining of coast, i. Examples : 
 
 (1) Cliffs, headlands, "spectral islands," caverns, bays, etc., Norway, 
 Brit. Is., and elsewhere; (2) washing away of old towns on English 
 coast; (3) U. S. coast from N. of Boston to Charleston, S. C, appreciably 
 wasting (9 ft. per annum at Cape May) ; (4) numerous instances of bays, 
 coves, cliffs, etc., along shores of Great Lakes, as "Pictured Rocks," L. 
 Superior, bluffs of L. Erie, etc. ; (5) shores of Australia, and peculiar 
 forms in Bay of Islands, New Zealand [Dana]. 
 
 2. Transportation, a. Ocean currents carry masses of 
 "Gulf-weed" and included life, also fine mineral particles, b. 
 Waves move immense masses, but only short distances, c. 
 Bache's statement concerning transportation of siliceous sand 
 to S. extremity of Florida, d. Landward movement of waves 
 limits transportation of detritus seaward, e. Density of sea- 
 water enables it to carry material farther, or larger particles. 
 
 3. Mechanical Deposition, a. Probably much mate- 
 rial is deposited by oceanic tides and currents [see Leconte (R. 
 13, vol. xxiii, p. 46, 1857)]. b. Examples: 
 
4 o GENERAL GEOLOGY. 
 
 (i) Banks of Newfoundland, formed by meeting of Gulf Stream with 
 cold Arctic current; (2) Bahama banks and other shoals formed by ma- 
 terial received from Amazonian current; (3) submarine banks off coasts 
 of German Ocean ; (4) pebbles have been brought up off Cape of Good 
 Hope, in 100 fathoms, some miles from land [Jukes and Geikie]. 
 
 C. Soundings show large portion of ocean bed to be covered 
 with non-transported ooze. d. Waves produce detrital islands 
 along coasts by pushing up material of submarine banks. 
 
 4. Chemical Deposits, a. Sea contains less CaC0 3 
 than most rivers, hence deposition must occur, b. Precipita- 
 tion rather local, as shells, etc., abstract very considerable 
 quantity, c. Salt lakes, 
 
 (1) Formed by excessive evaporation or by disjunction from sea; (2) 
 deposits alkaline (from alkaline carbonates) in volcanic regions, or in re- 
 gions covered by volcanic waste, as in Mono Lake and elsewhere in W. 
 U. S. ; (3) precipitate saline (from alkaline chlorides) in regions of ordi- 
 nary sediments ; gypsum first deposited, then common salt, leaving MgCl s 
 as menstruum finally, as in Dead Sea;Gt. Salt Lake, Utah, still deposit- 
 ing NaCl ; (5) Dilution of inland lakes once arms of the sea, illustrated 
 by L. Champlain [R. 72, 104 (G. K. Gilbert, 1872)]. 
 
 'B.— CIRCULATION OF WATER UPON LAND.* 
 
 1. Action of Rain. I. Mechanical, a. Washes off fine 
 material, exposing new surfaces to weathering influences, b. 
 Scores out gullies in uncompacted strata ; forms earth-pillars 
 beneath protecting stones, c. Adds to power of streams by 
 freshets. II. Chemical, a. Due to presence of C0 2 , increas- 
 ing solvent power, b. Assists chiefly in disintegration. 
 
 2. Rivers, Creeks, etc. I. Character, a. Size varies 
 according to: (1) area of drainage; (2) amount of precipita- 
 tion ; (3) evaporation ; (4) physiography of hydrographic basin ; 
 (5) geological structure, b. Pitch depends mainly on charac- 
 ter of surface and amount of water, modified by geological 
 structure ; varies between high and low water, c. Velocity is 
 determined by pitch and depth. II. Erosion, a. Cascade 
 portion, b. Torrent area. c. River portion, d. Flood- 
 ground, e. Ground plan and profile, f. Potholes, g. 
 Causes of variations in Ithaca gorges, h. Striking examples 
 of erosion : 
 
 1) Colorado canons, 300 miles, vertical walls, 3000 ft. to 6000 ft. ; (2) 
 Yellowstone canons and others, 2000 ft. and more, worn in volcanic rocks ; 
 (3) Niagara gorges, ancient and modern, 7 miles, 600 ft. to 1200 ft. wide, 
 200 ft. to 300 ft. deep. 
 
 1 For a full appreciation of the importance of this subject, consult: Hutton's Theory 
 of the Earth [R. 42, vol. i, 1785, p. 209 (also enlarged and separately issued in 1795)]; 
 \Vhitaker [R. 44, vol. iv, p. 447 (bibliography to 1867)] ; also R. 46, 57, 87, q^. o±. 
 
SURFACE AGENCIES. 4 i 
 
 III. Transportation, a. Force of current increases as sixth 
 power of velocity, b. Transportive power increased by loss 
 of wt. (| to |) of rock in water, c. Experiments show : 
 
 (i) Fine clay is moved when current attains velocity of 900 ft. per hour ; 
 (2)Jine sand moves in water with velocity of 1800 ft. per hour; (3) coarse 
 sand (size of linseed) requires velocity of 2400 ft. per hr. ; (4) gravel, 
 3600 ft. ; (5) pebbles, 1.364- miles per hr. ; (6) angular stones (size of 
 hen's egg), 2.045+ miles. 
 
 d. Effects due to sudden changes in velocity, e. Amount 
 of silt carried by rivers varies greatly. 
 
 Mississippi carries annually to Gulf of Mexico 406,250,000 Ions of sedi- 
 ment = T8 L tfff °f w t- an d Woo" °f v °l ume °f tne water, also pushes 44.500,- 
 000 tons sea-ward. Ganges discharges annually 378,100,000 tons, brought 
 from a basin of less than £ the area of the Mississippi. [Humphreys and 
 Abbott.) 
 
 Hoang Ho transports yearly 1,040,250,000 tons. 
 
 Dr. Livingstone describes rivers of moving sand. [ Travels in S. Africa, 
 p. 598.] _ 
 
 IV. Deposition, a. Alluvial tracts in river-bottoms, b. 
 Natural levees. c. Deltas. d. Deposits in estuaries. e. 
 Bars at river-mouths, f. Peculiarities of Amazonian deposi- 
 tion. 
 
 &— SUBTERRANEAN WATER. 
 
 i. Chemical Action. A. Springs. I. Ordinary, a. 
 Solvent power mainly due to C0 2 or alkali, b. Remove cer- 
 tain ingredients, thus leaving cavities, c. Effect replacement 
 (pseudomorphism), d. Emerge at surface as calcareous, siliceous 
 ox ferruginous (chalybeate) springs, e. Leave deposits of 
 travertine, stalactite, etc. f. All rocks contain more or less 
 moisture originally abstracted from ocean; average 2.5 per 
 cent. [Hunt, R. 13, II, xxxix, 193; Durocher, R. 53, x, 1853, 
 431; De Lesse, ibid., xviii, 1861, 64. Quoted in 1, p. 656J. 
 II. Thermal. [See E.— SECONDARY IGNEOUS AC- 
 TION, ante, p. 32]. a. Contain greater proportion of min- 
 eral ingredients than ordinary springs, b. Commonly asso- 
 ciated with folds or deep fissures. c. Products : sulphates, 
 chlorides, sulphur, silica, etc. d. Examples : Hot Springs, 
 Arkansas ; Bath Springs, Camp Brown, Wyo. ; warm springs 
 of Bath, England, etc. ; deep artesian wells. B. Streams. 
 a. Same chemical effects as in springs, but on larger scale, as 
 in Mammoth Cave, Ky., etc. 
 
 2. Mechanical Effects. I. Caverns, a. Most common 
 in limestone regions, b. Formed by corrosion and erosion on 
 part of underground streams, c. Examples of streams and 
 caves : 
 
42 GENERAL GEOLOGY. 
 
 (i) In central Penn. and elsewhere large creeks frequently sink sudden- 
 ly and reappear miles beyond ; in same region are numerous caves. 
 
 (2) Mammoth Cave, Ky., represents portions of ancient and modern 
 channels of Green River, the several chambers and passages lying one 
 above another, the whole system being comprised within comparatively 
 narrow limits horizontally. Numerous other caverns in vicinity. Echo 
 River and Styx still connect with Green River. 
 
 (3) Basins of extinct thermal springs, Yellowstone Park, afford some 
 fine examples of large caves. 
 
 d. Special features of Mammoth Cave and vicinity, as il- 
 lustrating cave-history in general. 
 
 (1) Slalactitic formations scarce in main cave, and mainly confined to 
 certain chambers, an effect due to protection of limestone by sandstone 
 capping, preventing free access of water; (2) in domes, where fissures ex- 
 ist, water enters freely and forms stalactite, finally choking up the cavity; 
 (3) same effect in adjacent caves with no sandstone capping; (4) domes 
 in Mammoth generally formed by subsidence of roof of cave. 
 
 II. Sink-holes, a. Basin-like depressions in surface rocks 
 produced by falling-in or yielding of roofs of caverns, b. Very 
 common and remarkably large in parts of Ky. ("Cavern lime- 
 stone" of Owen), and general in other regions. III. Land- 
 slides, a. Produced in several ways : 
 
 (1) By slipping of wet soil held together by trees, etc., as in cases of 
 slide of Aug., 1826, on White Mts. and rather frequent landslips in Rocky 
 Mountain region. 
 
 (2) Inclined strata, underlaid by soft layers, often glide down over sub- 
 jacent beds, particularly on steep mountain slopes, as in the destructive 
 slide of the Rossberg, Switzerland, 1806, and in other recorded cases [R. 
 46, vol. i]. 
 
 (3) In horizontal strata underlaid by wet clay, pressure may be sufficient 
 to displace latter and allow superincumbent mass to subside, as commonly 
 occurs on shores of L. Erie and elsewhere, and occasionally at points on 
 Hudson River. 
 
 b. Slides cause scratching and polishing of rocks beneath, 
 and sometimes produce contortions in clayey layers. IV. Mud- 
 lumps, a. Low heaps noticed near mouth of Mississippi, b. 
 Produced by pressure upon layer of mud beneath surface de- 
 posits [Hilgard, R. 13, III, i]. 
 
 J).— FROST, SNOW AND ICE. 
 
 i. Action of Frost, a. Expansion of water from 39^° 
 F. to 32 F. produces remarkable mechanical effects [see R. 
 96-98]. b. Explains absence of talus at foot of cliffs in trop- 
 ics, c. Examples from various localities. 
 
 2. Snow. a. Protects land from erosion, b. Very de- 
 structive in sliding masses {avalanches), c. Holds back pre- 
 cipitated moisture to cause increased destruction by rapid melt- 
 ing. 
 
 3. Glaciers [R. 92, 96-103]. I. General Character, a. 
 
SURFACE AGENCIES. 43 
 
 Ice-streams descending valleys below snow-line. b. Exist only 
 in regions of abundant precipitation where mountains extend 
 above limit of perpetual snow and where alternate freezing and 
 thawing occur, c. Mainly confined to higher latitudes, d. 
 Occupy transverse valleys of erosion. II. Structure, a. 
 Veins; marginal, transverse and longitudinal, b. Crevasses; 
 marginal, transverse, longitudinal, c. Moraines; lateral and 
 terminal, d. " Glacier tables." III. Motion, a. Rate varies 
 from 1 in. to 60 ft. per day. b. Rate varies according to : (1) 
 amount and frequency of precipitation; (2) obstructions in 
 valley ; (3) slope of surface ; (4) point of observation, c. 
 Laws : 
 
 (1) Velocity greatest along median line, as in water-streams. [Friction 
 against sides.] 
 
 (2) Motion most rapid at top, least at bottom. [Atmospheric friction not 
 appreciable ] 
 
 (3) Velocity increases directly as angle of slope. 
 
 (4) Motion varies with thickness (depth of stream). 
 
 (5) Degree of fluidity materially affects progress. [Summer and winter 
 changes]. 
 
 (6) Rate of flow in tortuous channels follows laws of river-motion, except 
 that greater viscosity of ice-sheet overcomes greater resistances. 
 
 d. Theories of glacier-motion : 
 
 (1) Forbes' Theory regards ice as viscous-brittle substance flowing under 
 its own weight, on principle of slowly applied pressure. 
 
 (2) TyndalPs Theory of ttflracture and regelation?' 1 based on fact that 
 slow pressure in small masses causes fracture, while fragments are re- 
 united by pressure. 
 
 IV. Transportation, Erosion, Deposition, a. Effects much 
 greater than in case of water, owing to buoyant action of ice, 
 and greater resistance opposed to obstructions, b. Transpor- 
 tation of material, c. Grooving and polishing of strata, d. 
 Rounded hills, roches moutonnees, parallel valleys, etc. e. En- 
 largement of valleys, f. Formation of " Drift " deposits. 
 
 4. Icebergs, a. Fragments broken from lower end of 
 glacier by buoyant power of water, etc. 
 
 Sp. gr. of ice =0.918 (32 F.), hence exposed mass of iceberg is about 
 T^- of total weight, when solid. Actually nearly \ above water, and some 
 icebergs 300 ft. visible. 
 
 b. Effects; scoring of rocks (irregularly), erosion of gullies, 
 deposits of boulders. 
 
 5. Anchor-ice and Shore-ice. a. Produce effects of 
 some importance occasionally. 
 
 Ref. : — 1 (pp. 635-696), 2 (chaps, xxiii-xxv), 3 
 (pp. 9-76), 4-6, 8-1 1, 23, 27,46, 55 (pp. 155- 
 167), 56 {Index, water), 57 (vol. i), 68, 69, 87, 
 92—103, 106, 118, 119. 
 
44 GENERAL GEOLOGY. 
 
 DIVISION B.— ATMOSPHERIC ACTION. 
 
 i. Protective, a. Preservation of human works and 
 other remains by blown sand. 
 
 2. Formative, a. Production of soil (and boulders) by- 
 disintegration of rocks, as in "driftless" regions, b. Trans- 
 portation of seeds by wind. c. "Dust-showers" and "blood- 
 rains" [R. 13, (II, xi, p. 372), 105]. d. Sand-hills, dunes, etc. 
 
 3. Destructive, a. Weathering of rocks, b. Effects of 
 wind : 
 
 (1) Erosion of rocks, as by sand-blast, in Colorado and elsewhere; (2) 
 obliteration of land-marks by shifting sands ; (3) denudation of sand-fLts 
 and hummocks where not protected by vegetation ; (4) overthrowing of 
 forest trees. 
 
 c. Atmospheric electricity; fulgurites [R. 48, vol.. II, 1814, 
 p. 528J. d. Ozone in windy localities, as near S. Pass, Wyo. 
 [R. 55, p. 178J. e. Marked variations in atmospheric pressure 
 causing fluctuations in level of Great Lakes. [See Col. Chas. 
 Whittlesey's papers in R. 78, 1873 (B, p. 42), 1874 (A, p. 139), 
 and in Canadian Naturalist, April, 1875.] 
 
 Ref. :— 1 (pp. 630-635), 2 (chap, xxi), 3 (pp. 
 3-8), 4-6, 8-1 1, 23, 35, 41, 46, 47, 68, 84, 87, 
 90 (1867), 91 (1867), 105, 107 (chap, vi), 108. 
 
 DIVISION C— ACTION OF LIFE. 
 
 A.— VEGE TA TION. 
 
 i. Protective Influences, a. Turf, roots of trees, etc., 
 bind soil and prevent erosion to some extent [special cases, R. 
 55, pp. 170-173]- 
 
 2. Deposits of Peat. a. Most common in northern re- 
 gions, where climate is moist, as in Ireland, N. U. S., etc. b. 
 Formed from mosses [sphagnum, Hyptium, etc.), and sometimes 
 from other plants, as in Dismal Swamp, N. Car. (from leaves). 
 C. Peat-bogs commonly antiseptic, d. Similar formations in 
 Central N. Y. e. Bogs probably ordinarily originate from 
 prostration of timber, f. Coal results from decomposition and 
 more or less complete metamorphism of peat, or more often of 
 woody tissue. 
 
 3. Drift-wood Accumulations, a. Represented by 
 famous Red River and other " rafts." 
 
 4. Bog-iron Ore Deposits, a. Produced by: 
 
 (1) Deoxydation of Fe 5 3 in presence of decaying organic matter; (2) 
 combination of resulting FeO with nascent Co. 2 , and (3) final conversion 
 of FeCOj, by oxydation, into Fe 2 3 , 3H 2 {limonile). 
 
SURFACE AGENCIES. 45 
 
 5. Destructive Effects, a. Through force exerted by 
 growing roots in crevices, b. Vegetation holds back moisture 
 in soil, thus facilitating disintegration, c. Landslides rendered 
 more destructive by binding effect of trees and turf. d. Dam- 
 age increased in tornados, etc., by overthrow of trees. 
 
 B.— ANIMAL FORMATIONS, ETC. 
 
 i. Siliceous Deposits [ante, p. 15]. a. Ehrenberg's es- 
 timate : 
 
 (1) 17,946 cu. ft. of siliceous organisms annually forming in one harbor 
 in Baltic ; (2) he collected from the mud one pound in one hour = 700, 
 000,000,000 individuals; (3) his estimate of increase of single individual 
 for one month = enough to form bed of silica of 18,480,000 cu. ft. =more 
 than 1,600,000,000,000,000,000,000 individuals. 
 
 b. Commonly found segregated in layers or nodules (chert, 
 flint, etc.) c. In all parts of the ocean and even living in ice. 
 d. Some noted accumulations : 
 
 (i) Polycystine sandstone, Barbadoes ; (2) Polycystine deposits, Sea of 
 Kamtchatka [R. 13, II, xxii, PI. I], Nicobar Is. (100 species, Ehr.), Bar- 
 badoes (282 sp., Ehr.) 
 
 2. Oaze, Marls and Shell-Deposits, a. More CaCOj 
 in rivers than in ocean ; abstracted from latter by organisms : 
 
 (1) Foraminiferal remains make up bulk of deep-sea ooze and finally 
 produce chalk. 
 
 (2) Shells of Mollnsca in ponds or near shores of lakes and seas form 
 marls (as near Cortland and Cayuga in N. Y. State), and these and corals 
 after attrition and comminution by waves, produce oolyte. 
 
 3. Coral Reefs and Coral Islands, a. Distribution 
 of reef-builders : 
 
 (1) Limited by "isocryme" of 68° F., averaging Lat. 30 N. and S. , 
 [on W. coast of Africa and E. coast of Asia forced back to Lat. 15°, W. 
 N. Amer. to 23^°, by cold currents, and on E. coasts of Africa (Cape of 
 Good Hope) and N. America (Bermuda) extended to nearly 32 by warm 
 currents] ; (2) cannot grow in water deeper than 100 ft. ; (3) require clear 
 salt water; (4) most kinds flourish best in rough water; (5) volcanic 
 action prevents growth. 
 
 b. Formation of "fringing reefs" about islands, c. "Barrier 
 reefs." 
 
 (1) Formed outside of fringing reefs, leaving channel between of vary- 
 ing dimensions (from very shallow and narrow to considerable depth, and 
 breadth of even 60 miles) ; (2) channel kept open by fresh-water streams, 
 tidal and local currents or depth of water. 
 
 d. " Atolls," or coral islands : 
 
 (1) Formed by growth of corals to low-tide level; (2) then by wave- 
 action, irregular encircling reef is raised about a central "lagoon"; (3)- 
 vegetation finally grows from transported seeds; (4) small atolls some- 
 times fill up lagoon. 
 
 e. Kinds of coral rocks [R. 1, p. 620]. 
 
46 GENERAL GEOLOGY. 
 
 (i) Compact, tough limestone, non-fossiliferous ; (2) compact oolyte, 
 generally non-fossiliferous; (3) like (1), but with fragments of shells and 
 corals imbedded ; (4) coarse conglomerate of firmly cemented masses of 
 coral; (5) corals in situ, with interstices filled in with sand, mud, etc. 
 
 4. Theories of Atolls and Barrier Reefs. A. State- 
 ment, a. Often. extend to enormous depths, while corals can- 
 not live below cir cum- littoral zone (ante p. 10). b. Formerly 
 explained by crater theoiy, but Darwin's subsidence theory now 
 commonly received : 
 
 ( 1 ) Crater Theory. Regards atoll as built upon rim, lagoon as occupy- 
 ing basin, of extinct volcanic crater. 
 
 (2) Theory of Stibsidenee [C. Darwin, R. 48 (1840, pp. 505-510), 65 
 (vol. xii, pp. 115-119), 66 (II, 1838, p. 552), 84 (pp. 465-482), 86 (lxiv, 
 1845, p. 563), ill; Dana, R. 109, also 1; outline of argumetit in R. 2 
 (PP- 335' 336)> 3 (P- 144 et seq.)\ Supposes gradual subsidence of fring- 
 ing reef and inclosed island, not more rapid than growth of corals, on 
 average, and at no time during its formation submerging reef more than 
 100 ft. 
 
 B. Discussion. I. Crater, a. Submarine banks, probably 
 offering conditions suitable for atoll growth, are sometimes pro- 
 duced by volcanic action, b. Barrier reefs, though of similar 
 origin, not explained by this theory, c. Atolls more extensive 
 (even 10 mi. to 90 mi. wide) and more precipitous (5o°-6o°) 
 than volcanic cones. II. Subsidence, a. Accounts for barrier 
 reefs and all features of atolls, b. Lyell's early views : 
 
 In 1st edition of "Principles" states that amount of subsidence in Pacific 
 is greater than elevation, as area of land is small compared with formative 
 agents (coral-growth and volcanic action). 
 
 c. Evidences of subsidence given by nearly all travelers 
 among coral islands of Pacific, d. This theory explains ab- 
 sence of corals from an area of 2,000,000 sq. mi. in mid-Pacific, 
 where all conditions are favorable except depth. 
 
 C. Remarkable Exceptions, a. Florida reefs, occupying 
 lower half of State (20,000 sq. mi.), example of increase of land. 
 b. No evidence of subsidence or of growth about volcanic 
 area. c. Probable agency of Gulf Stream [see Leconte (R. 
 3, pp. 149-153) for admirable statement and argument]. 
 
 5. Rate of Growth of Coral-formations, a. Average 
 increase in height less than .10 in. (Dana's estimate .0625 in.) 
 per annum =120 yrs. per ft. b. Some existing deposits (now 
 growing) fully 2000 ft. thick, have required from 240,000 yrs. 
 to 384,000 yrs. c. With subsidence more gradual than growth- 
 rate, time would be increased proportionately. 
 
 Ref. : — 1 (pp. 606-626), 2 (chap, xxii), 3 (pp. 
 ^-^SX 4-6, 8-1 1, 13, 27, 28, 36, 41, 46, 
 47, 68, 69, 84, 105, 108-113, 120. 
 
S URFA CE A GEN CIES. 47 * 
 
 SECTION III -M0RPH0GONY (Supplementary). 1 
 
 1. Hills and Mountains, a. Relations of form to struct- 
 ure illustrated, b. Hills of upheaval; characteristic forms, c. 
 Hills of deposition, how produced, d. Hills of circum-denu- 
 dation. e. "Outliers" and "escarpments." 
 
 2. Plains and Plateaus, a. Plains of deposition, b. 
 Plains of denudation, c. Table-lands. 
 
 3. Valleys and Ravines, a. Of erosion, b. Of de- 
 pression, c. Formed by circum-deposition. d. Longitudinal 
 valleys [R. 94, p. 160, figs. 55, 56, 58]: (1) synclinal ; (2) 
 monoclinal ; (3) anticlinal, e. Transverse valleys [R. 94, p. 
 160, figs. 53, 54, 57] : (1) cataclinal ; (2) anaclinal ; (3) dia- 
 clinal. 
 
 4. Lakes and Ponds, a. In basin of erosion or of cir- 
 cum-deposition. b. Dammed-up by superficial deposits, caused 
 by: 
 
 (1) Streams of lava ; (2) terminal moraines of glaciers ; (3) land-slides ; 
 (4) sand-bars drifted ; (5) irregular deposition ; (6) work of beavers. 
 
 5. Mountain Passes, a. Produced by erosion, b. Re- 
 sult of faults, c. Synclinal passes (depressed). 
 
 6. Fjords, or Sea-lochs, a. Generally regarded as 
 former glacial valleys, now partially submerged. 
 
 7. Caverns, a. Subterranean (already discussed), b. 
 Along sea-coasts, c. From landslides or tumbling of large 
 masses from cliffs. 
 
 8. Cliffs, a. Of erosion, b. Of displacement. 
 
 9. Canons, Alcoves and Amphitheatres, a. Gen- 
 eral remarks. 
 
 Ref. : — 2, chap, xxvi, is admirable ; Powell, R. 
 94, gives very much valuable and interesting 
 description of valleys, canons, alcoves, cliffs, etc. 
 
 1 It would be quite proper under this head to discuss several subjects, such as Mount- 
 ain Elevation, Special Forms of Erosion above and below surface, Fornlation 0/ Coral 
 Islands, etc., but each of these has already been considered in a more convenient place. 
 
48 GENERAL GEOLOGY. 
 
 PART V.-PALiEONTOLOGY. 
 
 I. Definitions and Divisions, a. Literally, discourse 
 about ancient beings, b. As here restricted, treats mainly of ex- 
 tinct forms of life preserved as fossils and of their relations to 
 existing plants and animals. 1 
 
 BIVISION A.-BIOLOGICAL RELATIONS. 
 
 I. Convenient Classification of Plants and Ani- 
 mals. A. Vegetable Kingdom. 2 I. Cryptogamia. a. 
 
 Multiplying by spores containing no embryo, b. Subdivisions: 
 Class I. — Thallogens. Fronds spreading, commonly with no dis- 
 tinct axis; composed wholly of cellular tissue. Sub-class I. — ALG/E. 
 Ex. : Fucoids (leathery sea-weeds), Confervacea:, Dialomacece, Coral- 
 lines, Coccoliths, Nullipores. Sub-class II. — Mycetales. Ex. : 
 Lichens, Fungi. 
 Cla.SS II* — Anogens. Cellular tissue, with short, leafy axis more 
 
 or less developed. Ex. : Mosses, Liverworts. 
 Class III* — Acrogens. Vascular tissue, in part, growing from 
 apex; ascending and descending axes prominent. Ex. : Ferns, Tree- 
 ferns, Lycopods, Equisetacece. 
 
 II. Phanerogamia. a. Distinct flowers; multiplying by 
 seeds containing embryo, b. Subdivisions : 
 
 Class I. — Endogens. Single cotyledon, endogenous in growth. 
 Division I. — Glumace^E. Ex. : Grasses, Sedges, Reeds, etc. DIVI- 
 SION II. — Petaloide^:. Ex. : Palm, Lily, Banana, etc. 
 
 Class II. — GymnosperMS. Often polycotyledonous, exogenous, 
 seeds naked. Division I. — Conifer/E. Ex. : Pine, Fir, Cypress, 
 Cedar, Araucaria-. Division II. — Cycade.'E. Ex. : Cycads (Palm- 
 like and acrogenous). 
 
 Class III. — Angiosperms. Dicotyledonous, exogenous, enclosed 
 seeds. Division I. — Monochi.amyde>e (Apetalous). Ex. : Oak, 
 Beech, Birch, Walnut, Chestnut. Division II. — Corolliflor/E 
 (Monopetalous). Ex. : Ash, Thistle, Honeysuckle, Rhododendron. 
 Division III. — Calyciflor^: (Polypetalous, stamens perigynous). 
 Ex. : Rose, Apple, Pear, Cherry, Cactus, Hemlock. Division IV. — 
 Thalam I florae (Polypetalous, stamens hypogynous). Ex.: Maple, 
 Balsam, Mahogany, Orange, Tea, Geranium. 
 
 B. Animal Kingdom. 3 I. Protozoa, a. Simple or com- 
 
 1 In the present course of lectures, this subject is meiely outlined as a necessary intro- 
 duction to Historical Geology (Part VI). 
 
 1 This outline scheme of the Vegetable Kingdom is, in part, based upon a "Synopsis" 
 prepared several years ago by Dr. W. H. Harvey for Professor Jukes (published in R. 2, 
 p. 760), but several quite important modifications, with fuller descriptions, are here in- 
 troduced. 
 
 3 The main features of this outline scheme of the Animal Kingdom correspond to 
 Professor Huxley's published systems, with certain modifications, not material, intro- 
 duced merely for the purposes of this course of lectures. Duly qualified members of the 
 class should require such a scheme only as a check upon the memory. Those who have 
 
PALjE ONTOLOG Y. 49 
 
 pound, generally minute, b. Body composed of structureless 
 "sarcode." c. Subdivisions: 
 
 Class I. — Rhizopods. Possess power of prolonging sarcode in 
 shape of pseudopodia; fossil forms protected by calcareous or sili- 
 ceous "test." Order i. — Foraminifera. Ex. : Nummulites, 
 Urbitoides, Fusulina, Eozoon. Order 2. — Radiolaria. Ex. : Poly- 
 cyslina (various). 
 Class II. — Sponges. Compound; sarcode supported by net-work 
 of siliceous or calcareous spicules. 
 
 II. Ccelenterata. a. Body composed of 2 layers, b. ali- 
 mentary canal communicating freely with body-cavity. c. 
 Subdivisions : 
 
 Class I. — Hydrozoans (Acalephs). Digestive tract and body-cavity 
 coincident. Order i. — Tubularida (Corynida). Order 2. — 
 Sertularida. Order 3. — Graptolitid.^e. Ex. : Graptolites (ex- 
 tinct), [^//fossil forms are of Sub-class I. — Hydrophora]. 
 
 Class II. — Actinozoans. Digestive sac, opening below into cham- 
 bered body cavity with radiating septa. Order i. — Zoantharia. 
 Corallum sclerodermic (occasionally sclerobasic) ; tentacles simple, 
 multiple of 5 or 6. Ex. : Aladrepores, Star-corals, Brain-corals. 
 Order 2. — Alcyonaria. Corallum sclerobasic; tentacles fringed, 
 multiple of 4. Order 3. — Rugosa (all extinct). Corallum sclero- 
 dermic; parls in multiples of 4, transverse tabulae commonly uniting 
 septa. 
 
 III. Mollusca. a. Body soft, commonly covered by a 
 shell, b. Heart (when present) on dorsal aspect, nervous sys- 
 tem in one ganglion, or scattered pairs, c. Sub-divisions : 
 
 PROVINCE A. — Molluscoida. Heart absent or imperfect; 
 single ganglion or one pair of ganglia. 
 
 Class I. — Poi.YZOANS (Bryozoans). Compound, generally not con- 
 nected internally ; 2 coats ; retractile muscle. 5 Orders. 
 
 Class II. — Tunicates (Ascidians). Simple or compound ; leathery 
 "test," lined by muscular coat; 2 anterior openings ; respiratory sac ; 
 simple, open tubular heart; one ganglion, orally placed. 
 
 Class III. — Brachiopods. Simple; shell bivalve {ventral and dor- 
 sal) ; inequivalve (ventral v. usually larger), opened and closed by 
 muscles, commonly fixed by muscular stalk passing through aperture 
 in beak of ventral v. , or between valves or attached to substance of 
 ventral v. ; 2 fringed arms about mouth, commonly coiled, supported 
 by framework. Order 1. — Inarticulata. Ex. : Lingula, Crania, 
 Discina. Order 2. — Articulata. Ex. : Terebralula, Spirifera, 
 Ori/iis, Producla, Rkynchonella, Athyris. 
 
 PROVINCE JB. — Mollusca Proper. Nervous system, 3 pairs 
 of ganglia, heart with at least 2 chambers. 
 
 Class IV. — Lamellibranchs. Bivalves, shells equivalve (usually), 
 inequilateral, closed by muscles, opened by ligament; respiration by 
 lamellar branchiae (gills). Ex. : Oyster, Clam, etc. 
 
 Class V. — Gasteropods. Shell (when present) never bivalve ; oc- 
 
 little or no familiarity with zoology will find all necessary information upon this subject 
 in either one of R. 114, 115, or 116. \N. B. — Only such groups as are 0/ geological im- 
 portance are here given.] 
 
50 GENERAL GEOLOGY. 
 
 casionally multivalve, commonly univalve, whorled more or less 
 spirally. Sub-class I. — Branchifera. Respiration by gills, aquatic. 
 
 7 Provisional Orders. Ex. : Limpet, Whelk, Periwinkle. Sub- 
 class II. — Pulmonifera. Aerial respiration by pulmonary sacs ; 
 terrestrial or amphibious. Order I. — Operculata. Order 2. — 
 Inoperculata. 
 
 Class VI. — Pteropods. Winged appendages at mouth, for swim- 
 ming. Large forms extinct. 
 
 Class "VII. — Cephalopods. External shell (if present) usually 
 chambered, straight or coiled in a plane, siphuncle passing through 
 partitions. Order i. — Dibranchiata. 2 gills, 10 arms or less, 
 with suckers ; little or no external shell. Sub-order i. — Octopoda. 
 
 8 arms. Ex. : Octopus, Paper Nautilus. Sub-order 2. — Deca- 
 PODA. 10 arms. Ex. : Squid, Calamary. Order 2. — Tetra- 
 BRANCHIATA. 4 gills ; arms more than 10, without suckers ; exter- 
 nal, many chambered shell. Ex. : Orthoceras, Ammonite, Goniatite. 
 
 IV. A?inuloida. a. Alimentary canal entirely distinct from 
 body-cavity, b. "Water-vascular" system present, c. Sub- 
 divisions : 
 
 Class I. — Echinoderms. Ambulacral system communicating with 
 exterior, commonly employed in locomotion ; integument of calcare- 
 ous plates or leathery, with imbedded grains, spines or tubercles. 
 Order i. — Crinoidea. — Fixed (almost always) by jointed stem; 
 central cup or disk of calcareous plates with 5 or more radiating (often 
 branching) arms from margin. Order 2. — Blastoidea (Pentre- 
 mitids). Attached, body ovoidal; 5 petaloid ambulacra meeting at 
 summit, no true arms. Order 3. — Cystoidea. Plates not regularly 
 radiated; arms absent, rudimentary or few, not marginal; "pectin- 
 ated rhombs" bet. ambulacral areas. Order 4. — Asteroidea. 
 Star-shaped; central disk with 5 or more arms radiating, containing 
 prolongations of stomach; integument leathery. Ex.: Star-fish. 
 Order 5. — Ophiuroidea. Central disk covered with calcareous 
 plates ; arms locomotive and prehensile, without internal prolonga- 
 tions of stomach. Ex. : Brittle stars. Order 6. — Echinoidea. 
 Body spherical to discoidal ; covered by test jointed immovably 
 (mostly). Order 7. — Holothuroidea. Leathery, etc. (recent 
 and fossil forms rare). 
 
 V. Annalosa. Articulated body; limbs (when present) 
 turned towards side on which nervous system predominates. 
 
 PROVINCE A. — Anarthropoda. Limbs, when present, not 
 jointed or articulated to body. 
 
 Class. I — Annelids. Body segmented, with lateral appendages of- 
 ten in pairs. Order i. — Tubicola. Branchiate, secreting mem- 
 branous or calcareous tube. Ex. : Serpula, Spirorbis. 
 
 PROVINCE 15. — Arthropoda. Articulated, jointed appendages. 
 
 Class II. — Crustaceans. More or less aquatic; 2 prs. antennae; 
 limbs on thorax and abdomen (usually). Order i. — Decapoda 
 (Podophthalmia). 5 prs. legs, eyes stalked. Sub-order i. — Ma- 
 crura. Tail well developed, long. Ex. : Lobster. Sub-order 2. 
 — Brachyura. Tail short and turned under. Ex. : Crab. Order 
 2. — Isopoda. Head distinct, eyes sessile. Ex. : Wood-lice. Or- 
 der 3. — Merostomata. Legs about mouth used as jaws, paddles, 
 
PALEONTOLOGY. 51 
 
 etc. Ex. : Limulus, Eurypterus. Order 4. — Trilobita. Body- 
 divided laterally into 3 lobes. Order 5. — Cirripedia (Pectostraca). 
 Multivalve shell. Ex. : Barnacle, Acorn-shell. Order 6. — Ostra- 
 CODA. Bivalve shell. Ex. : Cypris. etc. 
 Class III. — Arachnids. Head and thorax united (cephalo-thorax) ; 
 terrestrial; legs never exceeding 4 prs., none on abdomen. Ex.: 
 Spiders, Scorpions. 
 Class IV. — Myriapods. Head distinct, thorax not distinct from 
 abdomen ; segments more than 20 (one exception) ; legs more than 
 8 prs. ; one pr. antennae. Ex. : Centipede, Millipede. 
 Class V. — Insects. Head, thorax and abdomen distinct; legs (on 
 thorax) never more than 3 prs. Order i. — Hemiptera. Ex.: 
 Cicada, Aphis. Order 2. — Orthoptera. Ex. : Cricket, Locust, 
 Grasshopper. Order 3. — Neuroptera. Ex. : Dragon-fly, Caddis- 
 fly. Order 4. — Diptera. Ex. : Ely, gnat. Order 5. — Lepid- 
 uptera. Ex. : Butterfly, Moth. Order b. — HYMENOPTERA. Ex. : 
 Wasp, Bee, Ant. Order 7. — Coleoptera. Ex. : Beetle. 
 VI. Ve?'tet>rata. Body of definite segments ; often an exo- 
 skeleton of scales or bony plates ; limbs ventral, turned away 
 from side on which nervous system predominates. Vertebral 
 column (cartilaginous or osseous) usually present in adult. 
 
 PKOVlftCfi A. — Ichthyopsida. Branchiae present permanently 
 or at least during tirst stages of growth. 
 
 Class I. — Fishes. Group illy defined; median fins (interspinous) 
 probably always present, and always provided with fringe of fin-rays, 
 as are paired fins. Order I. — Marsipobranchii. Skull and ver- 
 tebral column cartilaginous ; mandible and cranial bones wanting ; no 
 clavicle, no limbs ; gills saccate, non-ciliated. Ex. : Lamprey. 
 Order 2. — Elasmobranchii. Skull well developed, vertebral col- 
 umn varying ; mandible present, no cranial bones ; no clavicle, 2 prs. 
 fins, supported by multiple cartilages ; gills pouched. Ex. : Shark, 
 Ray. Order 3. — Teleostei. Skeleton bony, as in modern fishes ; 
 vertebral column more or less completely ossified; clavicle, 2 prs. 
 fins, ventral varying in position; guls tufted or pectinate, protected 
 by bony coverings. Ex. : Perch, Cod, Salmon. Order 4. — Ga- 
 NOIDEI. Osseous skull ; vertebral column varying; clavicle present, 
 2 prs. fins, posterior near anus. Order 5. — Dipnoi. Skull bony, 
 vertebral column cartilaginous ; clavicle, 2 prs. filiform fins, each sup- 
 ported by jointed cartilaginous rod; posterior pr. close to anus. Ex. : 
 Lepidosiren. 
 Class II. — Amphibians. Median fins, when present, not fringed 
 with fin-rays ; 2 occipital condyles ; basi-occipiial unossified. Order 
 I. — Labyrinthodonta. Salamandroid body, weak limbs, long tail; 
 skull somewhat as in Fishes ; dorsal vert, bi-concave ; teeth "labyrin- 
 thine " in cross section. Order 2. — Ophiomorpha (Gymnophiona). 
 Worm-like body, no limbs or tail ; scales imbedded in integument ; 
 dorsal vert, bi-concave. Ex.: Ccecilia, etc. Order 3. — Batrachia 
 ( Anoura). Exoskeleton absent or represented rarely by dorsal derm- 
 al ossifications; dorsal vertebrae proccelous (concavo-convex), ribs 
 rudimentary; radius united with ulna, tibia with fl bu la. Ex.: Frog, 
 Toad. Order 4. — Urodela. No exoskeleton; dorsal vert, am- 
 phiccelous (bi-concave) or opisthoccelous (convexo-concave), ribs 
 short. Ex. : Newt, Salamander, Axolotl (Siredon), Siren (mud-eel). 
 
52 GENERAL GEOLOGY. 
 
 PROVINCE B.— Sauropsida. No branchiae during life ; single 
 occipital condyle partly made up of ossified basi-occipital ; mandibular 
 ramus complex, articulated to skull by quadrate bone. 
 
 Class III. — Reptiles. Horny exoskeleton commonly in form of 
 broad plates or overlapping scales ; flying apparatus (when present) 
 not bird-like. Order i. — Ichthyosauria. Ex. : Ichthyosaurus. 
 Order 2. — Chelonia. Ex. : Tortoise, Turtle. Order 3. — Ophid- 
 ia. Ex. : Rattlesnake, Boa, etc. Order 4.— Pythonomorpha. 
 Ex.: Clidastes, Liodon, Edestosaurus, Mosasaurus. Order 5. — 
 Lacertilia. Ex. : Lizard, Blindworm. Order 6. — Plesiosauria. 
 Ex. : Plesiosatirus. Order 7. — Crocodilia. Ex.: Crocodile, Al- 
 ligator, Teleosaurus. Order 8. — Dicynodontia. Ex.: Dicynodon, 
 Oudenodon. Order 9. — Pterosauria. Pterydactylus, Rhampho- 
 rhyncus. Order 10. — Dinosauria (Ornithoscelida). Ex. : Igua- 
 nodon, Megalosaurus, Scelidosaurus, Thecodontosaurus, Poikilo- 
 pleuron. 
 Class IV. — Birds (Aves). Feathery covering produced by conver- 
 sion of dermal cells into horn : fore-limbs acting as wings, metacar- 
 pal bones often anchylosed, metatarsals and distal tarsal also ("tarso- 
 metatarsus "). Order i. — Saurur^e. Tail longer than trunk; 
 metacarpals free. Ex. : Arclucopteryx. Order 2. — Ratit/E. Tail 
 shorter than trunk ; metacarpals anchylosed ; sternum without crest. 
 Elx. : Ostrich, Emu, Apteryx, Dinornis. Order 3. — Carinat^s. 
 Tail short, terminated by "plough-share" bone; metacarpals anchy- 
 losed ; sternum with keel. Ex. : Penguin, Goose, Pigeon, Parrot, 
 Eagle, Heron, Snipe, etc. Order 4. — Dentaive (Odontornithes 
 [Subclass] Marsh). Birds with teeth. Sub-order i. — Odontolc^. 
 Vertebrae as in ordinary birds ; sternum without keel ; wings rudi- 
 mentary ; teeth in grooves. Ex. : Uespero?-nis regalis Marsh. Sub- 
 order 2. — Icjithyornithes. Vertebra; bi-concave ; sternum with 
 keel ; wings well developed. Ex. : Jchthyornis dispar Marsh. 
 PROVINCE C. — Mammalia. Hairy appendages developed from 
 dermal cells ; young nourished by milk secretion ; 2 occipital condyles : 
 ramus of lower jaw simple, articulating directly with squamosal bone. 
 Class V. — Mammalia. 1 Characters of Province C. Order i. — 
 Monotremata. Ex. : Echidna, Urnilhorhynchus. Order 2. — 
 Marsupialia. Ex. : Opossum, Kangaroo, Myrmecobius. Order 
 3. — Edentata. Ex. ': Sloth, Armadillo, Megatherium, Megalotiyx, 
 Mylodon, Glyptodon. Order 4. — Cetacea. Ex. : Whale% Zeug- 
 lodon, Squalodon. Order 5. — SlRENlA. Ex. : Manatee, Halilhe- 
 rium, Rhylina. Order 6. — Ungulata. Sub-order i. — Peris- 
 SODACTYLA. Ex. ." Horse, Tapir, Orohippus, Pala'osyops, Rhinoce- 
 ros. Sub-order 2. — Artiodactyla. Ex. : Ox, Pig, Deer, Cam- 
 el, Anoplotherium, Platygonus. Order 7. — Amblypoda (Cope). 
 Ex. : Dinoceras, Uintatherium, Loxolophodon. Order 8. — Probo- 
 SCIDEA. Ex. : Elephas, Mastodon. ORDER 9. — Toxodontia. 
 Ex. : Toxodon, Nesodon. Order 10. — Tillodontia. Ex. : Tillo- 
 therium, Anchippodus. Order 1 1. — Rodentia. Ex.: Rat, Squir- 
 
 1 In arranging this group it has been necessary to introduce several divisions com- 
 prising recently discovered American fossil forms. These groups are largely provi- 
 sional, and it is probable that further study will cause extensive changes in the classifi- 
 cation. The outline here given is probably as satisfactory as is possible without over- 
 turning old systems. Cope brings together into new Orders, through intervening 
 fossil forms, members of groups here widely separated. 
 
PALAEONTOLOGY. 53 
 
 rel, Hare, Beaver, Castoroides. Order 12. — Carnivora. Ex. : 
 Lion, Tiger, Bear, Seal, A/achairodus. Order 13. — Insectivora. 
 Ex. ; Mole, Hedgehog, etc. Order 14. — Cheiroptera. Ex. : Bat, 
 Nyctilesles. Order 15. — Primates. Ex. : Lemur, Ape, Man. 
 
 2. Plants best Adapted for Fossilization. a. 
 Aquatics and marsh plants more apt to meet with proper con- 
 ditions of burial, b. Lowest orders, as Algae and Lichens, ap- 
 proach most closely to mineral kingdom, hence most readily 
 produce rocks, c. Nullipores and Corallines secrete CaO, 
 hence well preserved. 
 
 3. Animals and Animal Tissues most Permanent, 
 a. Soft parts, as impressions, or as interstitial tissue or even 
 (rarely) as adipocere, occasional, b. Mineral oil or coal some- 
 times left by decomposition of membranes and other soft por- 
 tions, c. Bones, scales and hard parts generally, preserved 
 mainly in proportion to amount of earthy matter; hence teeth 
 more commonly, d. Insects, birds, reptiles, etc., living in or 
 near water or marshes ; hence Neuropiera, Natatores, Grallat- 
 ores, Amphibians, etc., more common as fossils, e. Inverte- 
 brates more common, owing to small proportion of animal tis- 
 sues in exoskeletons. f. Vertebrates less common, owing to 
 large amount of animal tissue in hard parts. 
 
 4. Biological Causes of Extinction of Types, a. 
 Species inhabiting shallow water more liable to extermination 
 by changes of level, b. Terrestrial forms more liable to suffer 
 from climatal changes, c. Forms most removed from domi- 
 nant type succumb in "struggle for existence," if antagonistic 
 or beneficial to " fittest." 
 
 Ref. :— 1 (pp. 113-135, etc.), 10, 114, 115, 116, 
 117, 125. 
 
 DIVISION B.-OEOLOGICAL RELATIONS. 
 
 i. Extinction by Geological Agents, a. Changes of 
 level of land (shore-travel), producing changes in: (1) depth 
 of water ; (2) amount and character of deposition ; (3) temper- 
 ature of water; (4) land climate, b. Approach or recession 
 of glaciers, causing climatal changes, etc. 
 
 2. Life-record in the Rocks, a. Importance of "cycles 
 of deposition" as affecting interpretation [see Ramsay's ad- 
 dresses (R. 65, vols, xix, xx), and Hull on "Ternary Classifica- 
 tion" (R. 122, 1870)]. b. Method of reading record : 
 
 (1) Not vertically through rocks, but in zig-zag manner, following move- 
 ments of shore-line. 
 
54 
 
 GENERAL GEOLOGY. 
 
 (2) Generally speaking, lineal descendants of given types should be sought 
 in similar strata 0/ succeeding cycles rather than in superimposed layers. 
 
 (3) il Line of descent" most continuous and nearest vertical (stratigraph- 
 ically) in strata of most uniform composition, i. e., in cycles of greatest du- 
 ration. 
 
 c. Chronological gaps, caused by complete denudation of 
 strata or by absence of fossils in certain rocks, d. Value of 
 negative evidence in Palaeontology, e. Relation of Palaeon- 
 tology to hypothesis of " Natural Selection." 
 
 Ref. :— 1 (pp. 763, 764), 2 (pp. 484, 485, 492, 
 495-5° 8 )- 
 
 PART VI.-HISTORICAL GEOLOGY (STRA- 
 TIGRAPHY). 
 
 1. Scope, etc. a. Includes history of earth from its ori- 
 gin to beginning of human records, b. Treats of physiographic 
 and geognostic results and dynamical action, with examination 
 of life-record, of successive epochs in the past. 
 
 2. Divisions. A. Nomenclature. I. Era. a. Broad- 
 est division of geological time. b. Based upon prominent 
 characteristics of life. II. Age. a. Sub-division of Era. b. 
 Characterized by dominant group of animals or plants, III. 
 Period, a. Sub-division of Age. b. Represents history of 
 one "cycle of deposition" (in effect, not always). IV. Epoch. 
 a. Sub-division of Period, b. Not uniformly defined. 
 
 DIVISION A.-GENEBAL CONSIDERATIONS. 
 
 i. Value of Historical Divisions, a. No well marked 
 lines of separation, b. Strata at present classified somewhat 
 arbitrarily, c. System convenient, but complicated and more 
 or less illogical, d. Best divisions those in which strata and 
 fossils lead to same conclusions, and those which also are syn- 
 chronous with distant beds. e. Distinction between synchron- 
 ism and " ho?notaxis" [Huxley, R. 65, vol. xviii, p. xlvi], or 
 parachronism [R. 55. p. 143]. 
 
 2. Tests of Age of Strata, a. By order of succession 
 in conformable layers, b. By structure in unconformable beds. 
 
HISTORICAL GEOLOGY. 55 
 
 c. By means of fossils, d. Limited value of color and litho- 
 logical character as comparative tests. 
 
 3. Basins of Independent Progress, a. Outlined 
 almost by earliest depressions and elevations of crust, b. 
 Boundaries of N. American areas : 
 
 (1) Eastern Border. Includes whole of region E. and N. E. of Green 
 Mts. 
 
 (2) Appalachian. From Quebec, through Green Mts., S. along Appa- 
 lachian Chain. 
 
 (3) Interior Continental. Between Appalachians and Rocky Mts., oc- 
 cupying greater portion of Mississippi Valley. 
 
 (4) Cordillera. Region W. of Missouri River to near base of Pacific 
 slope. 
 
 (5) Western Border. Portions of California, etc. W. of coast ranges. 
 
 (6) Arctic Border. Not clearly defined. 
 
 4. Subdivisions in Geological History, a. Each 
 group is named from region of earth where its rocks are best 
 developed or from character of most abundant fossils, b. 
 General classification of sedimentary strata, beginning with 
 earliest. 
 
 I— ARCHAEAN ERA. 
 
 AGE A.— AZOIC (Lifeless). Period 1. Nebular. Period £. 
 Crustific 
 
 AGE B.— EOZOIC (Life-dawn). Period 1. Phytogenic. Pe- 
 riod 2. Laurentian. Periods. Huronian. Period 4. 
 Keewenawian (T. B. Brooks). 
 
 II.— PALAEOZOIC ERA. 
 
 AGE C— LOWER SILURIAN (Brachiopods and Trilobites). Pe- 
 riod 1. Cambrian. EPOCH I. Acadian. EPOCH II. Pots- 
 dam. Period 2. Canadian. EPOCH I. Calciferous. EPOCH 
 
 II. Quebec. EPOCH III. Chazy. Period 3. Trenton. 
 EPOCH I. Trenton. EPOCH II. Utica. EPOCH III. Cin- 
 cinnati. 
 
 AGE D.— UPPER SILURIAN (Invertebrates). Period 1. Ni- 
 agara. EPOCH I. Medina. EPOCH II. Clinton. EPOCH 
 
 III. Niagara. Period 2. Salina. Period 3. Helderberg. 
 
 Transitional Period. Oriskany. 
 AGE E.— DEVONIAN (Fishes). Period 1. Corniferous. 
 
 EPOCH I. Cauda-galli. EPOCH II. Schoharie. EPOCH III. 
 
 Corniferous. Period 2. Hamilton. EPOCH I. Marcellus. 
 
 EPOCH II. Hamilton. EPOCH III. Genesee. Period 3. 
 
 Chemung. EPOCH I. Portage. EPOCH II. Chemung. Pe- 
 riod 4. Catskill. 
 AGE F.— CARBONIFEROUS (Amphibians, Acrogens). Period 
 
 1, Sub-carboniferous. EPOCH I. Lower S. C. EPOCH II. 
 
 Upper S. C. Period 2. Carboniferous. EPOCH I. Carb. 
 
 Conglomerate (Millstone Grit). EPOCH II. Lower Coal Measures. 
 
 EPOCH III. Upper Coal Measures. Period 3. Permian. 
 
56 GENERAL GEOLOGY. 
 
 III.-MESOZOIC ERA. 
 
 AGE G.— REPTILIAN. Period 1. Triassic. EPOCH I. 
 Bunter-sandstein {gres bigarre). EPOCH II. Muschelkalk {Cal- 
 caire coquillier). EPOCH III. Kenper {Marne irisee). Period 
 £. Jurassic. EPOCH I. Lias. EPOCH II. lower {Bath) 
 Oolite. EPOCH III. Middle {Oxford) Oolite. EPOCH IV. Up- 
 per {Portland) Oolite. EPOCH V. Wealden. Period 3. Cre- 
 taceous. EPOCH I. Lower Cret. EPOCH II. Middle Cret. 
 EPOCH III. Upper Cret. (In N. A.— I. Earlier. II. Later.) 
 Traiisitional(!) Period. Lignitic. 
 
 IV.-CMNOZOIC ERA. 
 
 AGE H.— TERTIARY (Mammals). Period 1, Eocene. Pe- 
 riod 2. Miocene. Period 3. Pliocene. 
 
 AGE I.— QUATERNARY (Man). Period 1. Glacial (Drift). 
 Period 2. Champlain. EPOCH I. Dihivian. EPOCH II. 
 Alluvian {Loess). Period 3. Recent. EPOCH I. Reindeer. 
 EPOCH II. Modern. EPOCH III. Historical. 
 
 Ref. : — i (pp.4-6, 101-107, 136-146), 2 (chaps, 
 xxvii, xxviii, xxix), 3 (pp. 266-271), 47, 116, 
 117, 123 (tome 1, Introd.) 
 
 DIVISION B.-AKCH^AN ERA. 
 
 A.— AZOIC AGE. 
 
 1. Nebular Period, a. Hypothetical, based on nebular 
 hypothesis, b. From evolution of earth from sun until con- 
 densation of vaporous mass. 
 
 2. Crustific Period, a. Globe cooling at centre and 
 finally forming crust at surface, b. Temperature of earth not 
 reduced below 200 F. c. Geosynclinals formed but proba- 
 bly of little permanence. 
 
 2. General Remarks on Azoic, a. Rocks not certain- 
 ly known. 
 
 B.—EOZOIC AGE. 
 
 1. Phytogenic Period, a. Reduction of temperature 
 sufficient to admit of growth of lowest Cryptogamia (not above 
 200 F.) b. Thickening of crust, formation of geosynclinals 
 and geanticlinals. c. Probably small areas of dry land before 
 close, d. No rocks certainly known. 
 
 2. Laurentian Period. a. Distribution : V-shaped 
 area, apex N. of Great Lakes, running N. E. to Labrador, 
 N. W. to Arctic; in Appalachians, Rocky Mts., etc., etc. b. 
 Character of rocks (not always readily separated from Huro- 
 nian) : 
 
HISTORICAL GEOLOGY. 57 
 
 30,000 ft. of: (1) granyte, gneiss and mica schist; (2) syenyte, etc.; 
 (3) crystalline limestone ; (4) quartzyte, etc. ; (5) labradorite ; (6) chrys- 
 olite (common); (7) iron ores, except limonite ; (8) graphite, etc. 
 
 c. Arrangement and structural features, d. Original condi- 
 tion of beds, sedimentary, e. Alterations and disturbances. 
 f. Life: 
 
 (1) Plants indicated by graphite and ores of iron ; (2) Eozoon Canadense 
 and allies ; (3) Archmospherince ; (4) Palczohvchis (doubtful); (5) An- 
 nelids perhaps indicated by tubes, etc. 
 
 3. Huronian Period, a. N. of L. Huron, S. of L. 
 Sup'r(?), N. of L. Sup'r and N. W. ; elsewhere doubtful, b. 
 Nature of rocks : 
 
 15,000 ft. to 20,000 ft. of: (1) slates, limestones and conglomerates; 
 (2) metamorphics, etc., as chert, jasper, dioryte, chlorite schist, etc. 
 
 c. Paucity of fossils, d. Carbon abundant, e. A. A. 
 Julien reports indistinct Fucoidal (?) markings [R. 124, vol. 
 
 H.P-S]- 
 
 4. Keewenawian Period. (?) a. Name suggested by 
 
 Major Brooks for copper-bearing series of L. Superior. 
 
 5. General Remarks on Eozoic Age. a. In Europe: 
 N. W. Scotland, Bavaria, Bohemia, Norway, Sweden, Finland, 
 features identical with N. A. rocks, b. Basins outlined in 
 earliest ages. c. General character of earliest life ; supposi- 
 tions as to forms not yet recognized as fossils, d. Discussion 
 concerning nature of Eozoon. 
 
 C.—CONCL USIONS. 
 
 i. Length of Archaean Time. a. Azoic age alone 
 probably at least of as great duration as all succeeding time. 
 b. Calculations : 
 
 (1) Sir Wm. Thompson estimates, from loss of heat of globe, that crust 
 must have been formed at least 20,000,000 yrs. ago, and not more than 
 400,000,000 yrs. ago. More lately he gives 100,000,000 yrs. [R. 2, p. 
 
 3 2 5]- 
 
 (2) Helmholtz, from cooling of lavas, estimates time required for earth 
 to pass from 2000° C. to 200 C. at 350,000,000 yrs. [R. I, p. 147]. 
 
 (3) Temperature at close of Archaean probably not above 40 C. ; hence 
 at least 30,000,000 yrs. to 50,000,000 yrs. more necessary, and tempera- 
 ture at beginning probably much above 2000 C. 
 
 2. Relations of Archaean Basins to N. American 
 Continent, a. "V" follows two main systems of trends. 
 b. Other regions exposed near axes of prominent ranges. 
 
 Ref. :— 1 (pp. 146-161), 2 (pp. 523-525), 3 
 (pp. 272-276), 10, 37, 116, 117. 
 
58 GENERAL GEOLOGY. 
 
 DIVISION C.-PAt^OZOIC ERA. 
 
 A.— LOWER SILURIAN AGE. 
 
 1. Cambrian Period. A. North America, a. Flank- 
 ing Archaean ranges and in some distant spots in interior, b. 
 Sandstones, shales, etc. ; limestones more local ; some meta- 
 morphics. I. Acadian Epoch, a. S. New Br., at St. John ; S.E. 
 Newfoundland, b. Shales and slates. II. Potsdam Epoch. 
 a. Labrador and Newfoundland, Vt. ; Appal, region (3000 ft.), 
 S. to Va. and E. Tenn. ; Int. Cont., from St. Lawrence Co., 
 N. Y., to Can., S. shore of L. Sup'r (" Pictured" and " Pillared" 
 rocks) into Wis., Minn, and Iowa; borings show it in Ohio, 
 Ky., etc.; Texas; Rocky Mts., base of Black Hills, Dak., Big 
 Horn, Wind River, Wahsatch, Teton and other ranges, b. 
 Red and whitish sandstone, shales and some limestone ; from 
 60 ft. (N. Y.) to 5000 ft. (Appal, region), c. Markings, indi- 
 cations of near coast origin. B. Life. a. All marine : 
 
 (1) PLANTS: Fucoids. 
 
 (2) ANIMALS: Protozoa — Rhizopods indicated by "green sand," 
 Wis. and Tenn. Ccelenterata — Hydrozoans, Dendogroptus Hallianus. 
 Annuloida — Crinoid stems, Minn. Mollusca — Brachiopods, Lingn- 
 lella antiqua, Lingnlepis prinuzforviis, Discina acadica, Orthis Billingsii ; 
 Pteropods, Hyalites gregarius ; Gasteropods, 4 or 5 forms ; Cephalopods, 
 2 sp. of Orthoceras, Can. Annui.OSA — Crustaceans — Trilobites, Paradox- 
 ides (several sp.), Agnostus, Conocoryphe. 
 
 C. Foreign Cambrian, a. Wales and eastward. I. Har- 
 lech grits and Longmynd slates. II. Meneviati Group (Acadi- 
 an). III. Lingula flags (nearly Potsdam), b. Lapland, Nor- 
 way, Sweden, Bavaria, Bohemia; schists, conglom., etc. c. 
 Life very similar to American, but, as yet, more varied. D. 
 General Remarks, a. Shallow seas. b. Climate uniform 
 over globe; eyes of Trilobites indicate sunlight, c. Disturb- 
 ances at close of Acadian in Newfoundland, possibly at close 
 of Potsdam in Idaho and eastward, d. Extinctions of species 
 among Trilobites. 
 
 2. Canadian Period. A. N. America. I. Calciferous 
 Epoch, a. N. N. Y. and Can., S. W. Newfoundland (2000 ft. 
 of Up. Calcif., above N. Y. Calcif.); Appal., "Lower Magne- 
 sian Limestone" of Mo., Iowa, Wis., and Upper Mississippi 
 Valley, b. Calcareous sandstone to dolomite; geodes of 
 quartz (Middleville, N. Y., etc.) II. Quebec Epoch, a. E. 
 Can., S. along W. base of Green Mts., N. W. Newfoundland; 
 E. of Hudson R. (Poughkeepsie), Tenn. ; Rocky Mts., north- 
 ward, b. 1500 ft. to 6500 ft., sandstone and shales, limestone 
 westward. III. Chazy Epoch, a. Range same as Calcif., 
 
HISTORICAL GEOLOGY. 59 
 
 often not readily separated ; also in Arctic, b. Less than 
 1000 ft. ; limestone, magnesian southward and in Arctic. B. 
 Life. a. Fucoids, Rhizopods, Sponges, Graptolites, few Ac- 
 tinozoans, Mollusca (of all groups), Worms and many Trilo- 
 bites. C. Foreign Canadian, a. Difficult "homotaxis." 
 b. Agrees best with lower part of foreign Lower Silurian. 
 D. General Remarks, a. Deep seas in Int. Co///., shal- 
 lower northward, b. Alternations bet. deep and shallow seas. 
 
 3. Trenton Period. A. N. America, a. E. of Green 
 Mts. ; Appal., Trenton Falls, N. Y. and southward; O., Ind., 
 111., Wis. ("Galena Limestone"), etc.; Arctic, b. Mainly 
 limestone, from 100 ft. to 2000 ft. I. Trenton Epoch (Bird's- 
 eye, Black River and Trenton groups). II. Utica (shale) 
 Epoch. III. Cincinnati Epoch (Hudson River and Cincinnati 
 groups), a. Mt. Washington, etc. ; S. W. Ohio, through Ky. 
 into Tenn. (Nashville), b. Slates, shales, etc. B. Life. a. 
 Same group as before, with addition of many Corals, Crinoids, 
 Cystids, Mollusca (all fossil groups, but Brachiopods still 
 most abundant) ; Trilobites very common. C. Foreign, a. 
 Brit. Is., Bohemia, Scandinavia, etc. b. Lower part of Ca?-a- 
 doc atid Bala Group. D. General Remarks, a. Forma- 
 tion of limestones over wide area in Int. Cont. indicates pres- 
 ence of barrier along E. Bo)'d. during Trenton Epoch, b. Part 
 of barrier submerged during Cinn. Epoch, while waters became 
 shallower in Int. Cont. c. Cumberland sandst. in Ky. repre- 
 sents gradual transition to Up. Silurian. 
 
 4. Review of Lower Silurian, a. Appal., thickest de- 
 posits; shallow water beds; greatest changes of level, b. 
 Ocean climate not diversified, c. Probable absence of very 
 high land. d. Land area limited, if absence of terrestrial fos- 
 sils be criterion. 
 
 5. Disturbances at Close of Lower Silurian, a. 
 Green Mts. ; extensive geosynclinal, with faults in positions of 
 eroded anticlinals of the synclinorium. b. Cincinnati geanti- 
 clinal, less marked and less ruptured, c. Beds of succeeding 
 AGE overlie these unconformably in Europe; disturbances 
 not general. 
 
 B.— UPPER SILURIAN AGE. 
 
 i. Niagara Period. A. North America. I. Medina 
 Epoch (Oneida congl., Medina sandstone), a. N. Y., Upper 
 Can., W. Mich, Penn. and Tenn. b. About 400 ft. to 2000 
 ft., congl. and sandstone. II. Clinton Epoch, a. N. Y., 
 through Can. to Mich., Wis., Ind., Ohio, Penn., Va., Tenn. 
 
60 GENERAL GEOLOGY. 
 
 b. Shales, sandstone, limestone, iron ore {hematite). III. Ni- 
 agara Epoch, a. Anticosti, Brit. Amer., Arctic, N. Y. ; Rocky 
 Mts., far west and south, b. Mainly limestones, 300 ft. to 
 1500 ft. B. Life. a. Medina and. Clinton: Fucoids ; Sponges, 
 Corals {Favosites, Halysites etc.), Crinoids (star-Jish), Brachio- 
 pods, Lamellibranchs. b. Clinton and Niagara limestones: 
 Corals, Crinoids, few Lamellibranchs, Trilobites. C. Foreign. 
 a. Similar in features, b. Limestones less abundant in Gt. 
 Britain. D. General Remarks, a. Shore-line moving west- 
 ward, elevating E. N. Y. in earlier epochs, finally deepening 
 waters in interior, b. E. Bord. somewhat independent in 
 progress. 
 
 2. Salina Period [Onondaga Salt Group). A. N. Amer- 
 ica, a. N. N. Y., (S. of Erie Canal), bet. Niagara River and 
 L. Huron, Mich., W. Ohio, S. W. Va. b. 700 ft. to 1000 ft. 
 in N. Y., shales and marly beds, with salt (Syracuse). B. Life. 
 Rare. C. * * * * . D. General Remarks, a. Interior 
 
 a. 
 
 
 shallow sea, with sand flats and marshes, b. Thickness of 
 beds indicates subsidence. 
 
 3. Helderberg Period. A. N. America, a. N. Y., 
 Penn., Md., Va., Ohio, S. 111.; E. Border, b. 350 ft. to 2000 
 ft., limestone {Lower Water-lime Group). B. Life. a. 
 Abundant ; 300 sp., same Fam. and Gen. as before, but new 
 species, b. Corals, Crinoids, Cystids, Worms, new Crustaceans 
 {Eurypterus, Bterygotus, Ceratiocaris), Trilobites, Ostracoids, 
 etc. 
 
 4. Foreign Upper Silurian, a. Less wide spread than 
 L. Sil., but extensive; Europe (except Spain and France), 
 Asia, Africa, Australia, Brazil, b. Terrestrial life: (1) Plants 
 — Lepidodendron, Brototaxites, Bachytheca, etc.; (2) Animals — 
 Invert, similar to American; First Vert. {Fishes), Bteraspis, 
 Cephalaspis, Coccosleus, Bterichthys, Elasmobranchs. 
 
 5. Review of Upper Silurian, a. E. Bord. still more 
 distinct, even in character of Life. b. Land mainly submerged, 
 except at north, c. Seas warm and rather uniform, d. Ex- 
 tinctions : (1) Graptolites ; (2) several genera of Trilobites. 
 e. Special features of life: (1) Spirifers broader winged than 
 before; (2) Lamellibranchs and Gasteropods chiefly of siphon- 
 less divisions. 
 
 Oriskany (Transitional) Period. 
 A. N. America, a. Narrow belts in N. Sc, through Me. 
 and Vt., southwestward ; Oneida Co., N. Y., S. W. along Appal., 
 W. through Can., Ohio, Ind., 111. and Mo. b. Limestone, E. 
 
HISTORICAL GEOLOGY. 61 
 
 Bord. ; sandstone, N. Y., with some limestone westward. B. 
 Life. a. Algae; Lycopods (Psilophyton princeps Dawson) in 
 Can. ; Crinoids : Spirifer arenosus, Rensselaeria ovoides and 
 other Brachiopods ; Lamellibr., Gasteropods and Ceph. C. 
 Foreign, a. In Europe, "Tilestones" are beds of passage 
 bet. U. Sil., and Devonian ; elsewhere transition also gradual. 
 D. General Remarks, a. Probably interior seas opening 
 southeastward, Green Mts. and Archaean Highlands being out 
 of water, b. Elevation in E. N. Y. of land previously sub- 
 merged, c. Allied to U. Sil. by character of life, by structure 
 of rocks, etc., to 
 
 C— DEVONIAN AGE. 
 
 i. Corniferous Period. A. N. America. I. Cauda- 
 galli Epoch, and II. Schoharie Epoch, a. Both in Appal., E. 
 half of N. Y. b. Grits. III. Corniferous Epoch, a. Vt. 
 and Mass., Can. and westward, southward in Ky., etc. b. 
 Limestone (Onondaga and Corniferous), 50 ft. to 300 ft, with 
 chert. B. Life. a. Desmids, Diatoms, Algae (Spirophyton 
 cauda-galli), Lycopods, Ferns, Tree-ferns (Ohio), Conifers (Pro- 
 totaxites) : Sponges, Cyathophylloid corals and others (Eavo- 
 sites, etc.), forming reefs, as at Falls of Ohio, Louisville; Blast- 
 oids (Nucleocrinus), Brachiopods [first Productd), Gasteropods, 
 Pteropods (Tentaculites scalaris), Cephal. (Orthoceras, Cyrtoce- 
 ras, etc.), Trilobites ; Fishes (first Vert, in Amer.), Elasmobr. 
 and Ganoids, representing all subdivisions given in foot note l 
 [R. 128, Palaeont., vol. i, pp. 264-268]. Ex. : Holocephali — 
 Rhynchodus [R. 128, loc. cit., PI. 28, 29]; Plagiostomi — Psam- 
 modus (Cestraciont), Machaeracanthus and Cyrtacanthus (Hybo- 
 dont) ; Placoganoidei — Acanthaspis, Cephalaspis, Macropetal- 
 ichthys; Lepidoganoidei — Onychodus. C. Foreign, a. 
 Lower Dev. and part of Middle Dev. of Europe. D. Gen- 
 eral Remarks. a. Climate not greatly diversified over 
 globe. b. Considerable increase of land. c. Deep sub- 
 mergence of E. N. Y. during Corniferous Epoch, as shown by 
 hornstone and corals, d. Some reason for belief that this form- 
 ation occurs in Arctic [R. 13, II, xxvi, 120]. 
 
 1 See ante, p. 51, (VI, Prov. A, CI. I). Order 2. — Elasmobranchii. Sub-order i. 
 — Holocephali (Genus Chim&ra). Mouth at end of head ; single external gill slit, 
 operculated. Sub-order 2. — Plagiostomi. Mouth transverse on under side of head; 
 several non-operculated gill slits on each side of neck. Family a. Cestracionts. Mas- 
 ticatory apparatus — bony pavement. Ex. : Port Jackson (Australia) .--hark, Acrodus. 
 family b. Selachians. Hybodont or Squalodont dentition, "placoid" scales. Ex.: 
 Sharks. Order 4. — Ganoidei. Sub-order i. — Placoganoidei (Placodermi). Part- 
 ly or wholly covered by polygonal ganoid plates. Ex. : Pteraspis, Pterichthys, 
 Cephalaspis. Sub-order 2. — Lepidoganoidei. Ganoid scales like living forms. Ex.: 
 Amia, Lepidosteus, Hoicptychius, etc. 
 
62 GENERAL GEOLOGY. 
 
 i. Hamilton Period. A. N. America. I. Marcellus 
 Epoch; II. Hamilton Epoch; III. Genesee Epoch. a. E. 
 fiord., similar to Cornif. ; Hudson River, through Cent. N. Y., 
 across L. Erie into S. Mich., W. Penn., E. Ky., etc., O., Iowa, 
 S. W. Minn., E. Dakota, northward, b. Mainly shales, with 
 sandstone in E. fiord, c. Ripple-marks, septaria, etc., as on 
 Cayuga Lake, N. Y. d. Joints, etc. B. Life. a. Lycopods 
 (Psilophyta, Lepidodcndron, Sigillaria, Stigmaria), Ferns, Equi- 
 setaceae (Catamites, Asterophyllites), Charoz ; Gymnosperms 
 (Coniferce) 1 ; Brachiopods abundant, Lamell., Gaster., Cephal. 
 (first Goniatites); Trilobites. First Insects, May-Fly ; Fishes 
 (Dinkhthys, Paltzonisciis, Cephalaspis). C. Foreign, a. Up- 
 per part of Middle Dev. D. General Remarks, a. Shallow 
 water E., deeper W. b. Genesee quite wide spread, indicating 
 shallow sea in Int. Cont. c. Land frequently exposed, as 
 shown by terrestrial plants and insects, marsh dwellers. 
 
 3. Chemung Period. A. N. America. I. Portage 
 Epoch; II. Chemung Epoch, a. E. fiord., same as Hamil- 
 ton ; Hudson River, S. W. along Appal., through N. Y., W. 
 Pa., Cent. Ohio, along shores of L. Erie. b. Less than 3500 
 ft., shallow water beds, sandstone and shales. B. Life. a. 
 Plants as before, b. Animals characteristic, but similar to 
 Cornif. c. Local features about Ithaca. C. Foreign. # # # 
 D. General Remarks, a. Continuation of previous condi- 
 tions northward, b. In Ky. and other parts of Int. Cont., 
 wholly absent, 2 indicating elevation of land out of water. 
 
 4. Catskill Period. A. N. America, a. N. N. Y., 
 Penn., Appal. ; E. fiord, as in previous periods, b. Reddish 
 sandstones and shales, 5000 ft. to 6000 ft. B. Life. a. Not 
 very abundant; Plants, Fishes, etc.; no Corals, Crinoids, 
 Brachiopods or Trilobites. C. Foreign, a. Homotaxis not 
 apparent. D. General Remarks, a. Eastward movement 
 of shore-line, followed by movement southward. 
 
 5. Review of Devonian Age. A. Geography, a. 
 Land-area considerably increased, b. Large rivers of north (as 
 Hudson and Conn.) probably existing towards close to near 
 present extent, c. In Europe more diversified land and water 
 areas. B. Life, etc. a. Terrestrial plants, Insects, Fishes 
 
 1 For descriptions of Dev. Plants, see J. W. Dawson, R. 37 (1871), 65 (xv, 483; xviii, 
 296; xix, 458; xxvii, 270); Ch. Fred Hartt, R. 127 (Bailey's N. B. Reft, 1865). 
 
 2 In Ky. a thick mass of " Devonian Black Shale" represents, probably Genesee 
 Epoch, but may be synchronous with part of Chemung Period also. Dr. J. S. New- 
 berry regards parachronous beds in Ohio as the equivalent of both Genesee and Portag* 
 in N. Y. 
 
HISTORICAL GEOLOGY. 6 3 
 
 most prominent, b. Broad-winged Spirifers ; increase in size 
 of Proditcta. c. New types introduced, as (i) Producta, (2) 
 Goniatites, (3) Nucleocrinus, all culminating later and becoming 
 extinct in Palaeozoic Era. d. Extinctions : (1) Cystids 1 (Oris- 
 kany) ; (2) several genera of Corals, Crinoids, Brachiopods. 
 e. Climate but little changed from preceding Ages. 
 
 6. Disturbances at Close of Devonian, a. E. Bord. t 
 extensive, permanently elevating Maine; less marked in Conn. 
 Valley and in N. Y. State, b. N. Europe, but not below 
 Cent. France. 
 
 J).— CARBONIFEROUS AGE. 
 
 i. Sub-carboniferous Period. A. N. America. I. 
 Lower S. C. Epoch ; II. Upper S. C. Epoch, a. N. S., N. B. ; 
 Va., Ala. ; Tenn., Ky., N. E. Miss., Mo., Iowa, Ind., O., Mich., 
 Wyo. (??), Mont., Idaho, Wahsatch, Humboldt and other 
 ranges, N. Calif, b. Rocks: 
 
 E. Boni., — Lower, sandstone, congl., albertite, coal, etc. {Horion) — 
 Upper, limestone (fossil), marls, with gypsum { Windsor) — together 6000 
 ft.; Penn. — Lower {Vespertine), 2000 ft., sandstone and congl. — Upper 
 ( Umbral), 3000 ft. shales, reddish ; Ohio ( Waverley), sandstone, thin 
 beds of shale and limestone; Tenn., 1200 ft. — Lower, siliceous — Upper, 
 calcareous; 111., 1500 ft., 1 {Kinderhook, 250) sandstone and shales, 2 
 {Burlington, 200) limestone, 3 {Keokuk, 250) limestone and quartz ge- 
 odes, 4 {St. Louis, 250) limestone, oolyte, etc., 5 {Chester, 600) limestone. 
 Ky., thick, synchronism doubtful; Keokuk, St. Louis, Chester prominent ; 
 Iowa, 500 ft. (no Chester). 
 
 B. Life. a. Plants abundant, genera as before, b. Increase 
 of Corals, Echinoderms, Polyzoans, Lamellibr., Gasteropods, 
 Ceph., Crustaceans, Insects and Fishes, c. Culmination of 
 Crinoids, Blastoids, Spirifera, Producta, Goniatites, etc. d. In- 
 troduction of beaked Gasteropods, 2 new genera of Trilobites, 
 Amphibians. C. Foreign, a. Similar to American in Gt. 
 Brit., Belgium, Russia, etc. b. Trap ejections in Gt. Brit., 
 also in New Br. c. Eusulina (Rhizopod) common in Europe, 
 not known in Amer. Sub-carb. I). General Remarks, a. 
 Limestone forming seas in all regions, b. Overlap (?) in 111., 
 Iowa and Mo. c. Unconformity with overlying beds in Ba- 
 varia and in S. and Cent. France, d. Remarkable parallelism 
 in life throughout the world. 
 
 2. Carboniferous Period. 2 A. N. America. I. Car- 
 boniferous Conglomerate [Millslofie Grit) j II. Lower Coal 
 Measures ; III. Upper Coal Measures {Carboniferous Lime- 
 
 1 One now living in depths of Atlantic (Loven). 
 
 * This Period being always discussed at length in text-books, it is here less fully 
 outlined than its importance would otherwise necessitate. 
 
64 GENERAL GEOLOGY. 
 
 stone), a. S. W. Newfoundland, N. S. and N. B., R. I., Mass, 
 S. N. Y., Penn., Va., VV. Va., Ky., Tenn., Ala.; Ohio, Lower 
 Penin. of Mich., Ind., 111., Iowa, Mo., E. Miss., Texas, Ark., 
 Kansas, Neb.; Colo., Wyo., Mont., Nev., Utah, Calif.; Arctic. 
 b. 9000 ft. (Penn.) to 14,500 ft. (N. S.) ; I. Congl. and sand- 
 stone; II. Sandstone, congl. and coal (from papery to 40 ft.) 
 B. Life. a. Plants remarkably abundant, same fades as De- 
 vonian, b. First Cycads, some evidence of Fungi, c. Fusu- 
 lina • Corals and Crinoids diminish ; Lamellibr., Brachiopods 
 abundant, land Gasteropods; few Orthoccras, Goniatites, etc.; 
 a few Worms and Trilobites; Crustaceans — Decapoda (Ma- 
 crura) and Merostomata ; several Orders of Insects ; numer- 
 ous ancient Fishes, Hypodont Sharks abundant ; Amphibians, 
 few Reptiles. C. Foreign, a. Very similar to American. D. 
 General Remarks, a. Period of oscillation, with excess of 
 elevation eastward, of deep submergence largely in far west. 
 
 b. Marshes for growth of coal plants, c. Coal result of accu- 
 mulation, decomposition and compression of vegetable matter 
 not in direct contact with atmosphere, d. Note : 
 
 It is impossible to treat this subject as it deserves within the limits of 
 this work, even synoptically. Students should roughly note during the 
 lecture the topics which seem most important, afterward directing their read- 
 ing towards the general principles of the discussion, without devoting 
 much time to special facts and conclusions, which will be taken up in the 
 course of lectures on Economic Geology. 
 
 e. Temperature of water over globe not below 68°F., as 
 Corals of this Period are found even in Arctic, f. Climate 
 moist, g. Air must have had more C0 2 , as coal now repre- 
 sents C then abstracted by plants. 
 
 3. Permian Period. A. N. America, a. Kansas and 
 E. slope of Rocky Mts. b. Less than 1000 ft. at utmost, lime- 
 stones, shales, marls, sandstone. B. Life. a. Fossils few, 
 marine ; Mollusca, some teeth of Fishes, etc. C. Foreign. 
 a. Rocks similar, with red sandstone, b. Breccia in Lower 
 Perm, of Engl., perhaps indicates iceberg action (Ramsay). 
 
 c. Life rather abundant; plants similar to Upper C. M. ; ani- 
 mals more or less characteristic, d. Introduction of Theco- 
 dont Reptiles (Crocodilia, with affinities to Deinosauria), 
 as Proterosaurus. e. Extinctions: (1) among Brachiopods, 
 Ort/iis, Producta and other genera; (2) cyathophylloid Corals 
 (nearly); (3) heterocercal Ganoids (mainly). D. General 
 Remarks, a. Movement of interior sea westward by previous, 
 elevation of Mississippi Valley, b. Similar relation in Europe 
 to Volga Riv. and Ural Mts. c. Continuation over restricted 
 
HISTORICAL GEOLOGY. 65 
 
 area of Carboniferous conditions, d. Transition to Mesozoic 
 conditions. 
 
 E.—COiVCL USIONS. 
 
 i. Thickness of Palaeozoic Strata, a. Maximum 
 over 50,000 ft.; L. Sil., from 700 ft. (111.) to 15,000 ft. (E. 
 Tenn.) ; Up. Sil., 90 ft. (Mich.) to nearly 10,000 ft. {Appal.) , 
 Dev., 130 ft. (Mo.) to more than 1400 ft. {Appal.); Carb., 
 850 ft. (Mich.) to 14,570 ft. (N V S.) b. In Appal., 45,000 ft. 
 (sandstone, shales, etc.) ; Int. Cont., only 3000 ft. to 6000 ft. 
 (limestone largely). 
 
 2. Estimate of Length of Palaeozoic Time. a. 
 From thickness of strata : 
 
 (1) Dana (R. i, p. 381) gives ratio of L. Sil., U. Sil., Dev., Card. 
 and Potsdam, respectively ; 3.5 : .62+ : 1 : 1 : I. 
 
 (2) Allowing extremely rapid rate of accumulation (average of 10 ft. per 
 century), Potsdam Epoch alone 80,000 yrs., and PALAEOZOIC ERA 
 about 590,000 yrs. 
 
 3. Life of Era. a. Review of general progress, b. 
 " Comprehensive types." c. Palaeozoic flora and fauna char- 
 acterized by great size. d. Animals have often degraded 
 features of colonization, multiplicity of parts, immobility, e. 
 Parallel groups co-existent. f. Palaeozoic Molluscan genera 
 now living, as Lingula, Terebratula (late Pal.), Ostrea, etc. 
 
 4. Disturbances at Close, a. Elevation of Appalach- 
 ians (except previously formed Green Mts.) and exposure of 
 land over area E. of Mississippi Riv. b. In Europe extensive 
 disturbances, partly bet. Carb. and Perm. c. Examples of 
 remarkable faults, as in Ky. Tenn. and Va. 
 
 Ref. :— 1 (pp. 162-402), 2 (pp. 520-610), 3 (pp. 
 276-304), 9, 10, 47, 117, 127, 128, 129. 
 
 DIVISION D— MESOZOIC ERA. 
 
 A.— REPTILIAN AGE. 
 
 1. Triassic Period. A. N. America, a. N. S.„ Pr. 
 Edw. Is. ; Conn. Valley, Palisade belt, (S. E. N. Y. to Rich- 
 mond, Va.) and Deep River (N. C.) ; Blk. Hills, Wahsatch, 
 Uintah, Wind River ranges, etc.; Calif., Alaska, b. 3000 ft. 
 to 5000 ft, sandstone, commonly reddish, with gypsum in 
 northwest (Wind River Valley). B. Life. a. Very few re- 
 mains in U. S. except in W. Bord. b. Plants; Tree-ferns, 
 Cycads, Conifers, c. Animals ; mingling of Palaeozoic forms 
 {Spirt/era, Orthoceras, Goniatites) with Mesozoic {Ceratites, 
 5 
 
66 GENERAL GEOLOGY. 
 
 etc.) ; Ostracoids, Neuropters ; Ganoids [heterocercal, homo- 
 cereal and protocercal); Labyrinthodonts, Deinosaurs, "bird 
 [Deinosaur?] tracks" of Conn. Valley, Crocodilia (Theco- 
 donts Belodon, etc.) ; Lacertilia (Rhynchosaurus, also allied 
 to Chelonia); Marsupial (Insectivorous (?) Dromatherium). 
 C. Foreign. (See Epoehs given a?ite, p. 56). a. Deposits, Life, 
 etc., remarkably similar to American. D. General Remarks. 
 a. Markings in beds, showing shallow-water origin, b. Ameri- 
 can in rocks and life, European in life, rather closely related 
 (though transitional) to Jurassic, c. Disturbances; eruption 
 of N. J. trap ridges, but in such manner as to show previous 
 tilting of sandstone. d. American coast line farther seaward 
 than now. e. Climate less uniform than before, but still not 
 much differentiated. 
 
 2. Jurassic Period. A. N. America, a. Undefined, 
 except in Rocky Alts. b. Limestone, etc. B. Life. a. New 
 forms of animals, as Gryphcea, Belemniies (endo-skeleton, Di- 
 branchiata), fragments of uncertain Reptiles. C. Foreign. 
 (See ante, p. 56, for division into Epochs), a. Life similar to 
 Triassic, with additions; Rhizopods [Orbitolites, Nummulites), 
 Sponges, Corals (some Zoantharia), Crinoids (some free), 
 characteristic modern Brachiopods (old forms die out, as Spirif- 
 era, etc.), Terebratula, Rhynchonella, special Lamellibr., Gas- 
 teropods, Ammonites abundant, Dibranch. Ceph. ; Annelids, 
 Crustaceans, Arachnids, all groups of Insects ; Ganoids (none 
 heteroccrcal) Elasmobr., (first Squalodonts) first Teliosts; Ich- 
 thyosaurus, Plesiosaurus, Pliosaurus, Teleosawus, Rhynchosau- 
 rus, Rhamphorhynchus ; Crocodilia (Cetiosaurus, etc., first 
 Crocodihis), Deinosauria (Megalosaurus, Iguanodon, etc.), 
 Pterosauria {Pteiydactylus, etc.) Chelonia; Birds [Archoz- 
 opteryx); Mammals all Marsupials, niostly Insectivorous, but 
 2 sp. of Plagiaulax, allied to Kangaroo-rat (Rodent-Marsup.), 
 and one (Galastes) Predaceous. D. General Remarks, a. 
 Absence of strata along present Amer. coast indicates eastward 
 extension of Jurassic shore-line. b. Climate somewhat more 
 differentiated than before, but still temperate even in Arctic, c. 
 Disturbances: (1) elevation of Sierra Nevada and Wahsatch 
 Mts., Uintah Mts. [see R. 55 (pp. 99, 154), 130 (Geol. vol. i), 
 131 (vol. ii, also vol. iii, p. 4)]. 
 
 3. Cretaceous Period. A. N. America. I. Earlier 
 Cretaceous Epoch (Dakota, Benton, Niobrara groups); II. 
 Later Cretaceous Epoch (Fort Pierre, Fox-Hills groups), a. 
 N. J. (below Sandy Hook) to S. C, Gulf States, Miss. Valley, 
 

i*£ fo^l 
 
 
 
 ■ ■ • i . 
 
 . 
 
 - ' 
 
HISTORICAL GEOLOGY. 67 
 
 Rocky Mts., Coast Ranges, Brit. Amer., Arctic, etc. b. Max- 
 imum over 10,000 ft. (9000 ft. in Wyo., Utah and Col.), sili- 
 ceous and calcareous. B. Life. a. Coccoliths, first Angio- 
 sperms — Oak, Poplar, Maple, Willow, Beech, Sassafras, Syca- 
 more, Liriodeudron. b. Foraminifera (Orbitoliua, Nummu- 
 lites) ; Terebratulids, Ostreidae, Rudistes group (aberrant and 
 characteristic, not found later) ; Belemnites, numerous, often 
 very large Ammonites (coiled, partly coiled and even straight) ; 
 Fishes numerous, yf/'^/Teliosts in N. America, Selachians (Squal- 
 odonts, last of Hybodonts) more abundant than Cestracionts. 
 Deinosaurs very abundant, Crocodilia, first Amer. Che- 
 lonia {Trionyx, Atlantochelys, some very large in higher beds), 
 Plesiosauria [Pliosaurus, etc., not Plesiosanrus and Ichthyo- 
 saurus in N. Amer.), Pterosauria (large forms, wings spread- 
 ing 10 ft. to 25 ft.); 1 first Amer. Birds (Odontomithes, and 
 other extinct forms, largely aquatic) ; no Mammals yet discov- 
 ered (1878), probably some living in Cretaceous, however. 
 C. Foreign. a. Sandstone, marls, chalk, "green-sand," etc. 
 b. S. American Cretaceous (Prof. Hartt's discoveries), c. Life 
 as in Amer., and very abundant, d. Besides Amer. Plants : 
 Desmids, Diatoms, Palms, and some characteristic Phanero- 
 gams, e. Animals special: Chalk Foraminifera, Sponges; 
 Ichthyosaurs and Plesiosaurs, Pterydactyles. D. General 
 Remarks, a. Extension of American coast line southward. 
 b. Review of geography during Cret. times; Miss, and Ohio 
 rivers discharged into bay near present mouth of latter, Del- 
 aware Riv. reached ocean near Trenton, N. J. ; Missouri hy- 
 drographic basin mainly submerged, etc. ; Andes, Alps, Hima- 
 layas more or less submerged, etc. c. Climate probably more 
 rigorous than before in polar regions. 
 
 4. Disturbances at Close of Cretaceous, a. Eleva- 
 tion of Rocky Mts. b. European elevations. 
 
 Lignitic (Transitional ?) Period. 
 A. N. America, a. Perhaps at Brandon, Vt. ; Tenn., Miss., 
 Ark.; Texas; Fort Union, Judith Basin; Brit. Amer. b. 
 Sandstone and clays, with lignite, coal and even anthracite. B. 
 Life. a. Plants: 200 sp. of forms even more modern than 
 undoubted Cretaceous, b. Animals of Cret. types : Free Crin- 
 oids, Ostrea congesta, Inocera??ius problematicus, Anomia sp., 
 Fishes (Lepidotus, etc.), Deinosaurs, Megalosaurs, Crocodilus, 
 
 1 These forms, of genera Pteranodon and Nyctosaiinis, are now placed in a distinct 
 order of Reptiles, known as Pteranodontia (literally winged-toothless) , by Marsh. 
 
68 GENERAL GEOLOGY. 
 
 Chelonia (Trionyx, Emys, etc.) c. Animals upon which ref- 
 erence to Eocene Tertiary is based by some authorities (Les- 
 quereux, etc.) : mainly Mollusca of brackish water and fresh 
 water types, d. Ammonites become extinct, also Deinosaurs. 
 e. Note: 
 
 The question concerning the age of the " Lignite Group " is still under 
 discussion. Its settlement now rests almost wholly upon data furnished 
 by the life of the Period. For the argument, consult (i) various papers in 
 R. 73 (every year from 1868 to present), especially vol. for 1874 (pp. 141- 
 146, 15 1— 1 55 ), where Dr. A. C. Peale gives important summaries and ref- 
 erences to authorities ; (2) papers by Hayden, Lesquereux and others in 
 R. 132 (since 1873); (3) articles by various authorities in R. 13 [those 
 previous to 1874 recorded by Dr. Peale {loc. cit. )]; (4) the views of the 
 author, based on some study of the lignite beds in N. W. Wyoming are 
 given in R. 55, pp. 120, 121, 132, 133 (see also, Stratigraphic Chart 
 opposite p. 103) — at that date the relation of the Fort Union group to the 
 Green Riv. coal series was not so clearly indicated as now. 
 
 C. Foreign, a. Similar history to American. D. Gen- 
 eral Remarks, a. Peculiar association of Tertiary flora with 
 Cretaceous fauna, b. Proof of gradual elevation of Rocky 
 Mts. ; change from marine to fresh-water beds not abrupt, c. 
 Cretaceous advocates : E. D. Cope, O. C. Marsh, J. S. New- 
 berry (originally Miocene in part), Clarence King, Bannister, 
 F. V. Hayden (in part), Joseph Leconte (in part), J. J. Steven- 
 son, Engelmann, F. B. Meek (in part), Theo. B. Comstock 
 (Green River coal series and coal and lignite beds of Wind 
 River Valley, Shoshone Plateau and canon of Buffalo Fork of 
 Snake River), d. Tertiary advocates : F. V. Hayden, F. B. 
 Meek (in part), Jos. Leidy, G. M. Dawson, Leo Lesquereux, 
 Joseph Leconte (originally in Colorado). e. Text-books; 
 Dana follows Hayden (Eocene), Le Conte adopts Cretaceous. 
 
 Ref. :— 1 (pp. 403-488, 490, 493, 501, 508), 2 
 (chaps, xxxv, xxxvii), 3 (pp. 404-475), 10, 13 
 (1868, 1874), 47, 55, 65 (Hector, vol. xvii), 
 73, 116, 117, 123, 131, 132-134. 
 
 DIVISION E.— CiErVOZOIC ERA. . 
 A.— TERTIARY (MAMMALIAN) AGE.. 
 
 i. Eocene Period (Alabama, nearly). A. N. Amer- 
 ica. I. C/aibome Epoch; II. Jackson Epoch; III. Vicks- 
 burg Epoch ; also I. Wahsatch Epoch {Coryphodon, Marsh); 
 II. Gree?i River Epoch (Dinoceras) ; III. Uintah Epoch 
 (Diplacodon). a. S. C, Va., in patches; Miss., Ala., Georgia; 
 Rocky Mts., Uintah, San Juan and Green River basins, b. 
 
, / ^' ' ' tv -cf 
 
HISTORICAL GEOLOGY. 69 
 
 10,000 ft. and more; coast areas marine; Rocky Mts. fresh- 
 water, lacustrine ; varying greatly, sands, clays, marls, lime- 
 stones, more or less imperfectly consolidated. B. Life. a. 
 5 to 10 per cent, of shells now living, Mammals all extinct. 
 
 b. Palm, Willow, Oak, Grass, Sedge, etc.; genera modern, 
 species mostly extinct, c. Rhizopods {Nummulites, Orbitoides, 
 etc.), modern genera of Molluscs, Crustaceans and Insects; 
 Elasmobr. (Holocephali, Squalodonts and a few Batides, or 
 Rays) and Ganoids (with many Lepidoganoidei,/ Teliosts) ; 
 Amphibians few, modern ; Crocodilia (mainly Crocodilus, but 
 some with affinities to Alligators), Ophidia (allied to Boa- 
 Cott \strictor), Lacertilia [G/yptosaitrus, etc.); Birds numerous 
 (Odontopteryx), Waders (A/etomis), Cursores [Diattyma, Cope), 
 etc., extinct, but several modern types, as Eagle, Owl, Crane, 
 etc. Marsupials (few, small), first Cetaceans (Zeuglodon cetoides 
 abundant in Ala., S. C, Ga.), Manatee (in Europe, not yet in 
 Amer.), Perissodactyla — Coryphodon (5 toes, low-type brain), 
 Dinoceras and Uintatherium (both large, 5 toes, 4 to 6 horns, 
 extinct at close of Eocene), Eohippus, or first Horse (5 [one ru- 
 dimentary] front toes, 3 behind, size of fox), Orohippus (4 front 
 toes) first Tapir (many small sp.), Hyrachyus, Lophiodon 
 (Europe), first Rhinoceros (Amynodon), Palceosyops, Diplaco- 
 don, first Pigs (Eohyus, New Mex., etc., most with 4 toes), 
 Artiodactyla — -first Deer [Oromeryx, Up. Eocene), Tillo- 
 dontia — forms combining features of Bear, Rodents and Car- 
 nivores, Rodentia — Squirrels, small Insectivora, large Car- 
 nivora, many small Bats, low forms of Primates (Lemurs, 
 Marmosets, with even Carnivorous and Ungulate affinities). 
 C. Foreign, a. "London Basin," "Paris Basin," etc. b. 
 Life similar to America (in Europe), but with special forms; 
 Australian flora to-day similar to European Eocene flora, c. 
 Mammals largely Tapiroid (Palceotherium, Anoplotheriutn, Xi- 
 phodon, etc.) D. General Remarks, a. Fresh-water lakes 
 of Rocky Mts. Approach of modern conditions, b. Conti- 
 nental growth by elevation and deposition ; elevation in Plateau 
 area, depression of surrounding plains, deposition along coasts. 
 
 c. Elevation of Pyrenees, Carpathians, Appenines, Julian Alps, 
 etc. {Middle Eocene); W. Alps (Mt. Blanc, etc.), close of 
 Eocene, d. Climate sub-tropical over wide area. 
 
 2. Miocene Period (Yorktown). A. N. America. 
 I. White River Epoch {Brotitotherium Marsh); II. Wind 
 River Epoch (Oreodon); III. Oregon Epoch (Miohippus). 
 a. Martha's Vineyard, N. J., Md., Va. and southward along 
 
7 o GENERAL GEOLOGY. 
 
 coast; Rocky Mts., Nebr., Colo., Wyo., Mont.; Calif., Ore- 
 gon, b. 5000 ft., or more, clays, sands, etc., often but little 
 indurated; marine, east and west coasts; fresh-water lacus- 
 trine, Rocky Mts. B. Life. a. Diatoms in "infusorial 
 earths" of Richmond (Va.), Calif, and Europe; Australian 
 and American flora less differentiated from Eocene than Eu- 
 ropean, b. 30 percent, of shells now living (Europe); spe- 
 cial forms of Invertebrates; Insects very abundant in Eu- 
 rope, c. Vertebrates : Fishes in marine beds, but peculiarly 
 absent from fresh-water series of interior; Amphibian {Andrias 
 sciieucheri), Chelonia — Land Tortoises and Trio7iyx (in In- 
 terior), Colossochelys (Europe), some Crocodilia, Ophidia and 
 Lacertilia of modern types ; Birds of modern types ; first 
 Edentates in Amer., Cetaceans {Dolphin Earn., Sperm Whale, 
 etc.), few Sirenians, Ungulata — Mesohippus (size of sheep, 
 3 toes and rudiment, in front, 3 behind), Miohippus (near An- 
 chitherium of Europe), extension of Rhinoceros type, Bron- 
 totheridce, (Titatwtherium, Megacerops, etc.) introduced and ex- 
 panded to become extinct before next Period, Pigs (near Pec- 
 cary, abundant in Amer.), Llippopoiamus (not yet in Amer.), 
 Hyopotamus, Ofeodon, Camel tribe separated (Procamelus), 
 Deer continued (by Leptomeryx, Cosonyx, etc.) ; in Sewalik 
 Hills, India, first Proboscideans, Dinotheriutn (combining char- 
 acters of Elephant, Tapir, Hippopotamus and Dugong) Siva- 
 therium, first Mastodon (3 sp.), Elephant (7 sp.), Ox, Sheep, 
 etc.; Rodents (Hare, Squirrel, etc.), Edentates, Carnivores 
 (Machairodus, Wolf, Tiger, Hyaena), first true Monkeys in 
 Europe (in Amer. synthetic form Laopitheais). C. Foreign. 
 a. Not specially distinct from Eocene, b. Beds in Greenland 
 with plants. D. General Remarks, a. Lakes in interior 
 perhaps saline, as shown by absence of Fishes, and abundance 
 of land Mammals, b. Elevation of Coast Range and ejection 
 of some lavas through fissures, covering vast area in N. W. c. 
 Elevations general in other parts of U. S. and abroad, d. 
 Climate warw-temperate in U. S. e. Difference in climate 
 bet. N. and S. 
 
 3. Pliocene Period (Sumter). A. N.America, a. N.C., 
 S. C. ; Niobrara River, Loup Fork, Platte Riv. ; Rocky Mts., 
 South Pass (?), Wind River Valley (?), Stinking Water Riv. [all 
 in Wyo.] ; Oregon, b. Loams, sands, clays, etc., 500 ft. to 
 800 ft., or more. B. Life. a. Plants not advanced materi- 
 ally, b. Invertebrates of modern genera; majority of shells 
 are now living, c. Fishes largely Cyprinoid (Teliosts like 
 
HISTORICAL GEOLOGY. 71 
 
 Carp) ; one Crocodile and fragments of Ophidians ; Birds of 
 Miocene genera, with new sp. ; Edentates of great size {Mor- 
 opus, Mordtherium) in N. A. ; Horse Tribe represented by large 
 and more modern forms, as Protohippus (N. A.), Hipparion 
 (Eur.) [with 3 toes, but only one serviceable], Pliohippus (N. A.) 
 and Equus ; Rhinoceros continues in Amer. (becoming extinct 
 here) and in Eur., Tapir extinct in N. A., Pig not much ad- 
 vanced in N. A., Oreodon followed by Merychyus and allies 
 (here dying out in N. A.), Deer increasing, Bison introduced 
 in Amer. ; first Mastodons and Elephant in N. A. ; Rodents 
 of modern genera Castor, Hystrix, Lepus, etc. in N. A., Cavia 
 and others in S. A. and some in Europe; Moles; Cams, 
 Machairodus (S. A.), first Amer. Bears (Leptarctus.) C. For- 
 eign, a. Half of Sicily; marine and inland deposits in Gt. 
 Brit, and elsewhere. D. General Remarks, a. Continua- 
 tion of elevation, b. Reduction of temperature, etc. 
 
 4. Review of Tertiary Age. a. Relations of continents 
 and contained life during successive Periods. 
 
 B.—Q UA TERNAR Y A GE. 
 
 1. Glacial Period. A. N. America, a. N. E., from 
 present glacial line S. to Lat. 39 , W. to Long. 98 ; local in 
 Rocky Mts., N. and S. to Lat 35 ; Tenn., W. Va., etc. b. Ex- 
 tending to height of 6000 ft. above Atlantic in places (Mt. 
 Washington, etc.) ; scratchings, groovings, moraines. B. Life. 
 [Given below under 4]. C. Foreign, a. Deposits and phe- 
 nomena similar to American. D. General Remarks, a. 
 Effects and deposits quite similar to those of present glacier 
 regions [see ante, -p. 42]. b. Great Lakes, "parallel valleys" 
 of Cent. N. Y. lakes, Hudson River, etc., more or less modi- 
 fied, c. Remarks on local action in Rocky Mts. d. Eleva- 
 tion northward (southward in S. Hem.) e. Course of drift 
 material S. E. or S. W. (in general), as shown by groovings and 
 character of boulders, f. Agassiz's theory of Amazonian drift 
 refuted, g. Forced emigrations of plants and animals [Dr. 
 Gray,R. 13 (1857, xxiii, p. 62) ; A. R. Grote, R. 78 (B, p. 222) ; 
 and others], h. Fjords, i. Iceberg action along coasts, j. 
 Note : 
 
 These subjects are fully discussed in text-books and in special works re- 
 ferred to below [Ref., p. 76]. 
 
 2. Champlain Period. A. N. America. I. Dihivian 
 Epoch [Erie clays). a. Wide-spread, but following largely 
 courses of old glaciers, with greater southward extension, b. 
 
7 2 GENERAL GEOLOGY. 
 
 Boulder clay, drift, largely stratified but also nntnodified, with 
 plant accumulations; clays abundant, with sands and gravels 
 [Orange sand, Lower Miss.; Saxicava sands, L. Champlain) 
 often irregularly disposed as in modern fluvial and lacustrine 
 deposits. II. Alhivian Epoch (Loess), a. Distribution same 
 as Diluvian. b. Deposits (loess, etc.) in more quiet waters, 
 along river, lake and sea borders. B. Life. [Given below 
 under 4]. C. Foreign, a. Very similar to American. D. 
 General Remarks, a. Melting of ice-sheet, due to depres- 
 sion, b. Flooding of land, obscuring and silting up river val- 
 leys, c. Formation of caverns, d. Greater height of deposits 
 northward above neighboring water-levels. e. Subsidence 
 greatest in interior, f. Seas, lakes and rivers. 
 
 (1) Champlain Sea extended over S. Me., up St. Lawrence nearly to 
 L. Ontario, including also L. Champlain area, as shown by marine fossils. 
 
 (2) Inland Lakes ; (a) over region of Gt. Lakes, possibly continuous 
 with (/>) immense body of water in Brit. Amer., outlined by G. M. Daw- 
 son [R. 65 (vol. xxxi, p. 620), 134 (chaps, ix, x)] ; both connecting with 
 Mississippi and Missouri drainage system. 
 
 (3) Hudson, Ohio, Mississippi and nearly all northern rivers (as about 
 Ithaca) much wider than now (Mississippi from 50-75 miles). 
 
 3. Recent Period. A. N.America. I. Reitideer (Sec- 
 ond Glacial) Epoch. II. Modern Epoch, a. Distribution 
 Continental, b. Terraces bordering sea, lakes and rivers, bone 
 breccias, etc., and deposits of modern character, travertine, 
 stalactites, etc. B. Life. [Included under 4, below]. C. 
 Foreign. More extensive and effective in some particulars. 
 D. General Remarks, a. Re-elevation of land still con- 
 tinuing, b. Increase of land along coasts, c. Separation of 
 Gt. Lakes and others by draining of Inland Lakes, d. Second 
 glacial epoch less evident in Amer. than in Eur., but probably 
 existent here. e. Amazonian diminution and terrace forma- 
 tions. 
 
 4- Life of Quaternary Age. a. Preserved in marshes, 
 peat-bogs, forest-beds, bone-caverns, and in ice. b. Plants 
 and Molluscs mainly of living species, mammals chiefly extinct. 
 c. Northward migrations of Plants and Molluscs since earlier 
 periods of Quaternary, d. Mammals extremely large; not 
 always easily referred to Epoch or Period : 
 
 (1) AT. America (promising field for investigation, in caves, etc.) Large 
 Hordes, Ox, Bison lalifrons, 2 sp. near Musk-Ox, gigantic Stag, Tapir, 
 Beaver (Casloroides), Elephas primigenius (northward), E. Americanus, 
 Mastodon Americanus, Whale {Beluga Vermontana), Megatherium, My- 
 lodon, Megalonyx, Bear, Lion, Raccoon, and others, with Birds (Turkey, 
 Crane, etc.) 
 
 (2) S. America. Very many and immense Edentates like N. Amer. 
 
PRE-HISTORIC AR CH^E QLOGY. 73 
 
 and others (as Glyptodon, Chlamydotherium, Pachy theriuni) \ also special 
 Mastodon and other peculiar forms. 
 
 (3) Europe and Asia. Immense Carnivora — Tiger, Wolf, Machairo- 
 dns, Cave Bear (Eur. Cont. ), Cave Hyaena (Gt. Brit.), allied to present 
 African forms ; Mammoth, and other Elephants, woolly-haired Rhinoceros 
 (A', tichorhinus), Grizzly Bear, Beaver ( Trogontherium), etc. ; fauna with 
 fades of present. 
 
 (4) Australia. Immense Marsupials {Diprotodon, etc.) 
 
 e. In supposed earliest glacial deposits ("Cromer Forest 
 Bed"), Cave Bear, Megaceros, Trogontherium, Elephas (3 sp.). 
 Hippopotamus major, 2 sp. of Rhinoceros, Machairodus latidens. 
 [Several of preceding are Pliocene types, and last named is 
 even Miocene]. 
 
 Ref. 1 :— 1 (pp. 5 2 7-573), 2 (chap, xli), 3 (pp. 
 5 x 3-5 57). 9> IO > r 3i (many papers, for which 
 consult General Index), 22, 37, 46, 47, 55, 
 65 {Index), 67 (occasional papers), 73 [In- 
 dices), 78, 84, 87, 88, 104, 106, 112, 128 (es- 
 pecially vol. II, pp. 1-83), 130, 134, 135, 136, 
 137- 
 
 PART VII.-PRE-HISTORIC ARCHEOLOGY. 
 
 1. Scope, etc. a. Relations to Geology, b. Relations 
 to written History, c. Material for study, d. Nature of the 
 records. 
 
 DIVISION A.— ANTIQUITY OF MAN. 
 
 1. Estimates, a. Chronology of Usher and Petavius 
 (less than 6000 yrs.) quite generally regarded as far too short. 
 b. Baron Bunsen, from philological data, 20,000 yrs. c. Sir 
 Chas. Lyell, estimating growth of Somme Delta on basis of 
 Mississippi deposition, considers age of remains in former 
 100,000 yrs. d. Sir John Lubbock, basing calculations on ex- 
 cavation of valley of Somme, 100,000 yrs. to 240,000 yrs. e. 
 Estimates based on cosmical changes make period fully as 
 great, f. Other calculations. 
 
 2. Geological Age of Earliest Human Relics, a. 
 
 1 Local and fragmentary papers upon the deposits and phenomena of this AGE are 
 very numerous, but much scattered. Students who begin to study the subject will soon 
 find references from paper to paper, however, and similar references are made in most 
 ' general works upon the Drift Period. 
 
74 GENERAL GEOLOGY. 
 
 Undoubted remains in Quaternary; some think in Pliocene, a 
 few even Miocene, b. Difficulty of determining horizon of 
 deposits, c. Reports often founded on unreliable evidence. 
 
 3. Age of Man in North America, a. A. C. Koch 
 reports Mastodon from Missouri, stoned to death and burned. 
 b. Plain underlying New Orleans, alluvium 500 ft. thick, with 
 several cypress forests; human remains found at depth of 16 
 ft., at foot of tree of 4th forest below surface [see R. 46]. 
 
 Ref. :— 1, 2, 3, 7, 24, 46 (vol. i), 70, 89, 138 
 
 (chap, xii), 140. 
 
 DIVISION B.-CHRONOLOCJY. 
 
 1. Subdivisions, a. Based in part upon Lartet's system. 
 b. The grouping below shows geological relations of divisions 
 adopted. 
 
 I. Psychozoic [Caenozoic] Era. 
 
 Age A. — Pre-Historic. Period i. Stone. EpocJi L. Pa- 
 leolithic, or Mammoth (Dupont), equivalent of Champlain ; 
 rude stone implements ; extinct Elephant, Rhinoceros, Horse, 
 Hippopotamus, Cave-animals. Epoch II. Reindeer. Medium 
 stone implements, split marrow-bones and charcoal; extinct El- 
 ephant, Urus, Cave-Bear, Cave-Lion, Cave-Hyaena, etc. ; Horse, 
 Reindeer and other living northern species (Aurochs, Ibex, Elk, 
 etc.) Epoch III. Neolithic, equivalent to large part of Modern 
 Period. Polished 'stone implements, pottery, kjokkenmodding, 
 Pfahlbauten ; bones of dog and other living quadrupeds. 
 Period 2. Bronze, part of Modern Period. Bronze imple- 
 ments, earth-works, etc. ; living Mammals. Period 3. Iron, 
 close of Modern and beginning of Historical Period. Iron 
 implements, hieroglyphs, mounds, etc. 
 
 Age B. — Historic, within historical times. Written rec- 
 ords, traditions, etc. 
 
 N. B. — Stone Period continued to Historical Period in Amer., 
 and a somewhat restricted Copper Period is exemplified which must 
 have been synchronous with a portion of one of the Periods above, in 
 Europe. 
 
 DIVISION C— PRE-HISTORIC AGE. 
 
 I. Stone Period. I. Palceolithic Epoch, a. River-border 
 deposits, entombing bones of man associated with those of 
 extinct Mammals and living shells. 
 
 Mammoth and other Elephant, 2 sp. of Rhinoceros, 1 Bear, 1 Hysena, 
 I Tiger, 2 sp. of Ox {Bos), Musk Ox, 2 sp. (?) of Horse, 3 sp. of Deer, 
 1 Hippopotamus, I Hog, 1 Lemming; 5 2 Molluscs, of which 42 now live 
 in Sweden. 
 
PRE-HISTORIC AR CH.E OLOGY. 75 
 
 b. Cavern deposits (older), Bear caves on Eur. Cont., Hy- 
 czna caves in Brit. Is. ; some British and Belgian caverns prob- 
 ably o( this Epoch, c. Environment, including : (^Topogra- 
 phy, (2) Climate, (3) Enemies, (4) Food, (5) Clothing, (6) 
 Mental condition, (7) Morals, etc. d. Degree of civilization, 
 as shown by (1) Tools, (2) Weapons, (3) other manufactures 
 (as pottery, etc.) II. Reindeer Epoch, a. Cavern deposits 
 (newer) : stone implements better fashioned than Palaeolithic 
 Epoch, bone implements, bone-carvings, b. Reindeer abun- 
 dant, with extinct Cave Mammals, similar to Palaeolithic, c. 
 Cavern deposits of S. France, Sicily, etc., probably of this Epoch 
 d. Tall men, round-headed like Laplander, tibiae often flatten- 
 ed (platycnemic) [See H. Gillman, R. 13 (Jan'y, 1874), 78 
 (vol. xxiv, 1875, B, p. 316), 147 (6th Rep't)] and skulls some- 
 times perforated. III. Neolithic Epoch, a. Shell-heaps, or 
 kjokkenmodding ("kitchen-middens"). b. Lake-Dwellings, 
 or Pfahlbauten (Crannoges). c. Tumuli, etc. d. Difficulties 
 of determining synchronism; views of different authorities, e. 
 Pfahlbauten remains: 72 sp. (10 Fishes, 4 Reptiles, 26 Birds, 
 32 Mammals), 6 domesticated, viz. : Dog, Pig, Horse, Goat, 
 Sheep, Ox (2 var.) f. Special consideration of certain relics: 
 
 (1) Polished Stone Imple?nents. (a) Certainly 100,000 or more speci- 
 mens in collections. (<$) Comprise flint-flakes, spear-heads, arrow-heads, 
 axes, scrapers, awls, etc.; spindle-whorls, sinkers, etc. (c) Material 
 obsidian, quartzyte, green-stone (dioryte, etc.), porphyrine, etc. (d) Mode 
 of manufacture [Torquemada, Hernandez, Baines, etc. ; quoted in R. 138, 
 pp. 88-90, with illus.] 
 
 (2) Bone Implements comprise harpoons, knives, awls, chisels (?), 
 handles for tools and weapons, perforated teeth (used as charms). 
 
 (3) Tumuli and Monuments, (a) Dolmens, menhirs, cromlechs, stone- 
 circles, etc. (b) Chambered tumuli, (c) Used as dwellings or tombs or 
 both, (d) Many Druidical and other modern forms, but large number 
 undoubtedly Pre-historic, probably of Stone Period, and, perhaps, 
 mainly A'eolithic. 
 
 (4) Pottery, (a) Urns, incense-cups, food-vases, drinking-cups, etc. 
 (b) In ornamentation, etc., indicate progressive art. 
 
 (5) Other Relics, (a) Rude rock sculptures, (b) Coarse cloth (woven). 
 (<:) Articles of food, as grain, fruits, etc. (d) Remains of fire, etc. 
 
 2. Bronze Period, a. Bronze implements, with few 
 stone, all of higher type than before, b. Men more highly 
 civilized, c. Less to contend with from lower animals and 
 greater skill in the chase, d. More warlike, more and better 
 weapons. 
 
 3. Iron Period, a. Overlaps period of written history. 
 b. Beyond the scope of Geology, except in special cases. 
 
 4. Ancient Modes of Burial, a. Observations of Sir 
 R. C. Hoare and Mr. Bateman combined as below : 
 
7 6 
 
 GENERAL GEOLOGY. 
 
 Implements. 
 
 CORPSE. 
 
 Total. 
 
 Contracted. 
 
 Burnt. 
 
 Extended. 
 
 Position 
 Uncertain. 
 
 None, 
 Stone, 
 Bronze, 
 Iron, 
 Total, 
 
 36 
 
 55 
 19 
 
 2 
 
 223 
 53 
 59 
 
 3 
 
 6 
 3 
 
 7 
 21 
 
 19 
 
 3 2 
 15 
 11 
 
 284 
 
 143 
 IOO 
 
 37 
 
 112 
 
 338 
 
 37 
 
 77 
 
 564 
 
 Ref. : — 1, 2, 3, 24, 46. 51, 77 (Index), 78 (vari- 
 ous papers), 88 (ditto), 89, 138, 139, 140, 143, 
 147. 
 
 DIVISION ».- 
 
 -NORTH AMERICAN ARCHE- 
 OLOGY. 
 
 1. Earthworks. I. Defensive Inclosures; II. Sacrificial 
 Mounds; III. Sepulchral Mounds ; IV. Temple Mounds ; V. 
 Animal Mounds; VI. Miscellaneous Mounds : VII. C/z^ 1 " 
 Dwellings. 
 
 2. Stone and Bronze Periods not Synchronous 
 with European, a. Even N. Amer. Indians relics of Stone 
 Period, having no knowledge of use of iron at date of first 
 settlements. b. Possible Palaeolithic implements in various 
 parts of U. S. c. Numerous Neolithic implements, many of 
 recent date, and some forms still in use by Shoshones and other 
 tribes, d. Bronze Period may be wholly or in part represented 
 by 
 
 3. Copper Period, a. Copper implements, especially in 
 L. Superior region (Isle Royal, Keewenaw Penin., etc.) b. 
 Copper mined and hammered into useful forms, by stone im- 
 plements, from lumps of native metal. 
 
 4. Pottery, a. Often highly ornamented, b. American 
 forms frequently related to Peruvian, etc. c. Pipes, many in 
 shape of animals, and even S. A. Manatee represented. 
 
 5. Ornaments, a. Shells (often marine farmland), beads, 
 bracelets, necklaces, etc. b. Carvings, etc. 
 
 6. Pre-Historic Agriculture, a. " Garden beds," very 
 ancient in many cases, b. Now covered by second forest. 
 
 Ref. :— 1, 2, 3, 46, 50, 51, 55, 70; various pa- 
 pers in 73, 77, 78 and 88; 89, 91, 104, 132, 
 138, 144, 145-148. 
 
CONCLUSION. 77 
 
 PART VIII -PHILOSOPHICAL GEOLOGY. 
 
 Devoted to the amplification, in Review, of a few such im- 
 portant topics as are given below : 
 i. Length of Geologic Time. 
 
 2. Growth of Continents. 
 
 3. Evolution of Life upon the Globe. 
 
 4. Catastrophism versus Secular Movement. 
 
 5. Cosmical Influences, including 
 
 6. Cause of Cold of Glacial Periods. 
 
 7. Legitimate Use of Imagination in Geology. 
 
 PART IX.-CONCLUSION. 
 
 1. Importance of Care in Observation. 
 
 2. Temporary Value of Theories. 
 
 3. Parting Hints : 
 
 " Hold fast to that which is good." 
 
 " If truth do anywhere manifest itself, seek not to smother it 
 with glossing and vain delusions, but acknowledge the greatness 
 thereof and consider it thy greatest victory when the same doth 
 prevail over thee." 
 
 " The greatest friend of Truth is Time ; her greatest enemy is 
 Prejudice, and her constant companion is Humility." 
 
LIST OF REFERENCES. 
 
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 11. Young. Physical Geography. [Putnam's Advanced Series]. Use 
 
 with great caution ; contains a few serious errors. 
 
 12. Owen, R. Key to Geology of Globe. 
 
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 14. Wallace, A. R. Malay Archipelago. 
 
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 16. Wallace, A. R. Distribution of Animals. 
 
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 18. Flammarion. The Atmosphere. 
 
 19. Blodgett, Lorin. Climatology of United States. 
 
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 28. Thomson, Wyville. The Challenger Expedition. 
 
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 30. Dana, J. D. Manual of Mineralogy [Last Edition], 
 
 31. Dana, E. S. and J. D. Text Book of Mineralogy. 
 
 32. Comstock, Theo. B. Classification of Rocks. 
 
 33. Comstock, Theo. B. Descriptive Classification of Rocks. Used in 
 
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 79 
 
80 REFERENCES. 
 
 34. Collins, J. H. First Book of Mineralogy. [Putnam's Element Ser. ] 
 
 35. Geikie, Arch. Scenery of Scotland. 
 
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 38. Brush, G. J. Determinative Mineralogy. 
 
 39. Soc. Pub. Philosophical Transactions. Edinburgh. 
 
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 41. Humboldt, Alex. Von. Cosmos. 
 
 42. Soc. Pub. Transactions Royal Society. Edinburgh. 
 
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 47. Lyell, Sir Chas. Elements of Geology. 
 
 48. Soc. Pub. Transactions Geological Society. London. 
 
 49. Daubeny, Chas. Volcanoes, Thermal Springs, etc. 
 
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 58. Scrope, G. P. Volcanoes of Central France. 
 
 59. Miller, Wm. A. Chemical Physics. 
 
 60. Palmieri. Vesuvius. 
 
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 63. Periodical. Archives des Sciences Physique et Naturelle (Supple- 
 
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 64. Haughton. Manual of Geology. 
 
 65. Soc. Pub. Quarterly Journal Geological Society. London. 
 
 66. Soc. Pub. Proceedings Geological Society. London. 
 
 67. Soc. Pub. Proceedings Boston Society Natural History. 
 
 68. Reclus, Elis£e. The Ocean, Atmosphere and Life. 
 
 69. Thomson, Wyville. Depths of the Sea. 
 
 70. Prichard, J. C. Natural History of Man. 
 
 71. Hochstetter, Ferd. Von. New Zealand; its Physical Geography, 
 
 Geology and Natural History. 
 
 72. Bischof, Gustav. Researches into Internal Heat of Globe. 
 
 73. Hayden, F. V. and Assistants. Annual Reports U. S. Geological 
 
 Survey of Territories. 
 
 74. Comstock, Theo. B. Unexplained Phenomena in Geyser Basins of 
 
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 75. Comstock, Theo. B. "Two-Ocean Water," etc. [Reprint from 
 
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 76. Comstock, Theo. B. Scientific Value of Yellowstone Park. [Re- 
 
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 77. Periodical (Monthly). American Naturalist. 
 
 . 78. Soc. Pub. Proceedings Am. Assoc'n for Advancement of Science. 
 79. Johnston, Keith. Physical Atlas. 
 
REFERENCES. 81 
 
 80. Von Hoff. Veranderungen der Erdoberflache. 
 
 81. Griesbach, C. L. Erdbeben in den Jahren 1867 und 1868 [From 
 
 Geographical Society, Vienna]. 
 •82. Scrope. Volcanoes [2nd Ed. , 1872]. 
 
 83. Reports (Annual). U. S. Coast Survey. 
 
 84. Darwin, C. Naturalises Voyage. 
 
 85. Mallet. Report on Neapolitan Earthquakes, 1862 (2 Vols.) [Ab- 
 
 stract in R. 26, i860]. 
 
 86. Poggendorf s Annalen der Physik und Chemie. 
 ■87. De la Beche. Geological Observer. 
 
 .88. Reports (Annual). British Association. 
 
 89. Lyell, Sir Chas. Atitiqtiity of Man. 
 
 90. Periodical (Weekly). Comptes Rendus. 
 
 91. Reports (Annual). Smithsonian Institution. 
 
 92. Tyndall, John. Glaciers of the Alps. 
 
 .93. Ives and Newberry. Explor. Colorado River of the West, 1861. 
 
 .94. Powell, J. W. Exploration of Colorado River of the West, 1869-72. 
 
 95. Playfair. Illustrations of Huttonian Theory. 
 
 .96. Kane. Arctic Explorations (2 Vols.) 
 
 97. Hayes, Isaac. Open Polar Sea. 
 
 98. Richardson, Sir J. Polar Voyages. 
 
 99. Agassiz, Louis. Nouvelles Etudes stir les Glaciers. 
 
 100. Agassiz. L. Atlas of Plates accompanying preceding. 
 
 101. Forbes, J. Travels in the Alps, 1843. 
 
 102. Forbes, James. Norway and its Glaciers. 
 
 103. Tyndall, John. Forms of Water [International Scientific Series]. 
 
 104. Wheeler, Geo. M., and Assistants. Annual Reports, U. S. Geo- 
 
 graphical Survey West of 100th Meridian. 
 
 105. Ehrenberg. Passat-Staub und Blut-Regen. 
 .106. Geikie, James. Great Ice Age. 
 
 107. Maury, M. F. Physical Geography of the Sea. [Journal Geograph- 
 
 ical Society London]. 
 
 108. Humboldt, Alex. Von. Aspects of Nature. 
 .109. Dana, J. D. Corals and Coral Islands. 
 
 no. Dayman, Capt. Deep-Sea Dredgings. 1858. 
 
 III. Darwin, Chas. Structure and Distribution of Coral Reefs. 
 
 -112. Hartt, Ch. Fred. Geology and Physical Geography of BraziL 
 
 113. Jukes, J. B. Voyage of H. M. S. Fly. 
 
 . 1 14. Jones, T. Rymer. General Structure of Animal Kingdom. 
 
 115. Nicholson, H. A. Manual [or Text £ook~\ of Zoology. 
 
 116. Nicholson, H. A. Manual of Palaeontology. 
 
 117. Nicholson, H. A. Ancient Life-History of the Earth. 
 
 118. De Saussure. Voyage dans les Alpes, (4 Vols.) 1803. 
 
 119. Hooker. Himalayan Journals. 
 
 120. Agassiz, L. Corals and Coral Reefs. 
 
 121. Periodical. Quarterly Journal of Microscopical Science. 
 .122. Periodical. Quarterly Journal of Science. 
 
 123. Pictet. Traite" de Paleontologie. 
 
 .124. Brooks, Julien, Rominger, etc. Geol. Surv. of Mich. 1869-73. 
 .125. Huxley, T. H. Introduction to Classification of Animals. 
 .126. Dawson, J. W. Acadian Geology. 
 .127. Murchison, Sir R. I. Siluria. 
 
 128. Newberry, J. S. and Assistants. Reports, Geolog. Surv. of Ohio. 
 
 129. Safford. Reports, Geology of Tennesee. 
 
 6 
 
82 REFERENCES. 
 
 130. Whitney, J. D. Geological Survey of California. 
 
 131. King, Clarence. U. S. Geological Survey of 40th Parallel. 
 
 132. Bulletins. U. S. Geol. Survey of Territories (Hayden). 
 
 133. Marsh, O. C. Introduction and Succession of Vertebrate Life in 
 
 America [Vice President's Address before American Association 
 for Advancement of Science, 1877. Published separately], 
 
 134. Dawson, Geo. M. Report on Geology, etc., along 49th Parallel. 
 
 135. Foote, Chas. W. Notes on Physical Geology of Cayuga Lake, 
 
 N. Y., etc. [Thesis for Degree of Ph. D., Cornell, 1877]. 
 
 136. Hitchcock. Surface Geology. [Smithson. Contrib., Vol. IX]. 
 
 137. Southall, J. C. Recent Origin of Man. 
 
 138. Lubbock, Sir John. Pre-Historic Times. 
 
 139. Dawkins, Boyd. Cave-Hunting. 
 
 140. Vogt, Carl. Lectures on Man. 
 
 141. Tylor, E. B. Early History of Mankind. Primitive Culture. 
 
 142. Huxley, T. H. Man's Place in Nature. 
 
 143. Evans. Ancient Stone Implements of Great Britain. 
 
 144. Wilson, Daniel. Pre-Historic Man. 
 
 145. Squier and Davis. Ancient Monuments of Mississippi Valley. 
 
 146. Squier, E. G. Aboriginal Monuments of State of N. Y. 
 
 147. Reports (Annual). Peabody Museum of Archaeol. and Ethnol. 
 
 148. Lapham, I. A. Antiquities of Wis. [Smithson. Cont., Vol. VII]. 
 
 For other references consult Royal Society [London] Catalogue of Sci- 
 entific Papers, classified by authors. Most of the writers in the foregoing 
 list, and many others, have published numerous papers bearing upon the 
 subjects here treated. 
 
 N. B. — Of the references included in the above List, the following are 
 accessible to students in the Library of the 
 
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