Elementary Physical Geography

Front matter

ELEMENTARY PHYSICAL GEOGRAPHY Plate 1. — Frontispiece. Watkins Glen, N.Y. A post-glacial gorge in a shale rock. ELEMENTARY PHYSICAL GEOGRAPHY BY RALPH S. TARR B.S., F.G.S.A. ASSISTANT PROFESSOR OF DYNAMIC GEOLOGY AND PHYSICAL GEOGRAPHY AT CORNELL UNIVERSITY AUTHOR OF "ECONOMIC GEOLOGY OF THE UNITED STATES" MACMILLAN AND CO. AXD LONDON* 1896 All rig/its reserved Copyright, 1S95, By MACMILLAN" AND CO. Set up and electrotyped October, 1895. Reprinted March, 1896. Norfooorj 39rsss J. S. Cushing & Co. — Berwick & Smith Norwood .Mass. U.S.A.

Preface

. For some time there have been indications that new text books on physical geography are demanded ; and in the report of the Committee of Ten this finds definite expression. In the preparation of this book, which has been in hand for several years, there is an attempt to meet this apparent demand; but for reasons which are obvious to many, it has not seemed wise to attempt to follow the somewhat radical suggestions which were made by the majority of the geogra phy conference of the Committee of Ten. Therefore, while the physiographic side is given more prominence than is customary in works of this kind, this book attempts to only partly meet the Committee's suggestions. In the preparation of the book, effort has been made to introduce new material, particularly in the illustrations, which are a prominent part of the book.

Also, there has been an endeavor to make the book scientifically accurate, and to introduce the latest knowledge on the subjects treated. There are probably places in which this is not done, for the field is so large that much must be compilation ; and the compiler is liable to fall into error. I anticipate criticism of the order of presentation, of the relative amount of space allotted the various topics, of the

PREFACE.

. VIII omission of some subjects which are usually found in such books, and of the inclusion of some not usually discussed ; but these matters have been carefully considered, and the book is the result of a well-matured plan. In many respects it is experimental, but it is a deliberate attempt to supply a book which is certainly needed. It should not be inferred that the author is satisfied with the attempt, — he is keenly disappointed at the constant necessity of saving space and thereby weakening description and explanation. In many cases, explanations have been omitted ; in others, perhaps it would have been better to have done so. It is hoped that the more advanced teachers will find it possible to accompany the text-book work with laboratory and field study, along the line suggested in the appendix.

The discussion of method has been systematically eliminated from the text, and the sole effort has been to present facts and furnish information ; but if this alone is put before . the pupils, the value of the study will be very slight indeed. It furnishes the main story in a connected way, and supplies certain information ; but the laboratory and field will supply applications and extensions of the principles, at the same time giving value to the study as a means of mental disci pline. Merely to hear recitations from the book, will be the continuation of an all too prevalent habit, which in so many cases makes the science teaching in our secondaiy schools the weakest part of the curriculum. While the author has done much work in some of the subjects treated, particularly the ocean and the land, he would not wish to claim that much in the book is original. In reality, this book is based upon the manuscript of another and more advanced work, which is soon to be published as

PREFACE.

. IX a handbook for teachers and for reference. Both of these represent an attempt to gather from all available sources, the kind of matter which it seemed desirable to include in such books. While in the larger work direct reference is made to the sources of information, it has not seemed desirable to do so in this case ; for the acknowledgments take much space and distract the attention, without benefiting the pupil. I have had much generous assistance in the supply of illus trations, particularly of photographs ; and grateful general acknowledgment is made here, while special mention of the sources is made in a list in the succeeding pages. Although I have received aid from many sources, there are a few which I must mention especially. The writings of Geikie, Dutton, Powell, and Gilbert, particularly the latter, have not only given me bodies of fact, but also inspiration, as indeed they have to all who are working in physiographic geology.

To the writings and teachings of Professors Shaler and Davis of Harvard University, I owe more than I could possibly acknowledge ; and to the latter I am under an added obliga tion for his examination and kindly criticism of parts of my manuscript. While I acknowledge the debt which I owe these scientists, it must be understood that the mode of presentation is my own, and that I alone am responsible for any shortcomings which may appear. RALPH S. TARR. Ithaca, N.Y., August 30, 1895. CONTENTS. Part I. The Aik.

Chapter I

The Earth as a Planet. PAGE Form of the Earth 3 The Solar System 5 The Sun 6 The Planets 8 Asteroids 11 The Earth 11 The Moon 13 Comets, Shooting Stars, and Meteors 15 The Stellar System 17 Symmetry of the Solar System 18 The Nebular Hypothesis ......... 19 Verification of the Nebular Hypothesis 20

Chapter II

The Atmosphere. General Statement 23 Light 25 Electricity and Magnetism 29 Heat 30 Moisture 35 Pressure ............. 39 Effect of Gravity 39 Effect of the Earth's Rotation 39

Chapter III

Distribution of Temperature. General Statement 43 Effect of Atmospheric Movements 44 CONTENTS. XII PAGE Influence of Oceans -*****1 Effect of Topography .......-•• *• Seasonal Temperature Range ....•••■ 48 Isothermal Charts .......•••• " Daily Temperature Curve ......•-• 60 Temperature Ranges .......••■ 62 Earth Temperatures 65

Chapter IV

General Circulation of the Atmosphere. General Statement 68 Classification of the Winds 70 Planetary or Permanent Winds ........ 71 Trade Winds .71 Doldrum Belt 74 Anti-trade Winds 74 Horse Latitude Winds 75 Prevailing Westerlies 75 Periodical Winds ........... 76 Seasonal Winds 76 Migrating Wind and Calm Belts 76 Monsoon Winds 77 Diurnal Winds 79 Sea and Land Breezes 79 Mountain and Valley Breezes 80 Eclipse and Tidal Breezes 82 Irregular Winds ........... 82 Accidental Winds .......... 82 The Nature of Winds 83

Chapter V

Storms. Cyclonic Storms 85 Hurricanes 86 Description 86 Effects 88 Path 90 Time of Occurrence 91 Cause ........... 9i CONTENTS. XIII PAGE Temperate Latitude Cyclones 93 Resemblance to Hurricanes 93 Differences from Hurricanes ....... 95 Effects 98 AVinds 98 Anticyclones 100 Cause 100 Secondary Storms 101 Thunderstorms 101 Tornadoes and Waterspouts 104

Chapter VI

The Moisture of the Atmosphere. Dew 107 Frost 108 Fog 109 Haze lio Mist Ill Clouds Ill Rain 114 Snow 115 Hail 110 Distribution of Rainfall in the World 117 Distribution of Rainfall in the United States 118 Distribution of Snowfall 121 Seasonal Distribution of Rainfall 122 Irregularities of Rainfall ......... 123

Chapter VII

Weather and Climate. Weather 124 Tropical and Arctic 124 Temperate Latitude Weather 125 Climate 129 Tropical Climate 130 Temperate Climate 130 Arctic Climate 132 Minor Variations 132 Changes in Climate CONTENTS.

Chapter VIII

Geographic Distribution of Animals and Plants. PAGE General Statement 135 The Ocean 135 Fresh Water 13" The Land 137 Effect of Temperature and Moisture 137 Plant and Animal Habits 141 Life Zones 143 The Spread of Life 145 Barriers to the Spread of Life 147 Effect of Man 147 Part II. The Ocean.

Chapter IX

Form and General Characteristics of the Ocean. Distribution of Land and Water 151 Composition of Ocean Water 151 Color and Phosphorescence ......... 152 Exploration of the Ocean Bottom 153 Methods used in Deep-sea Explorations 153 Sounding . . . . . . . . . . . .153 Dredging ............ 155 Topography of the Ocean Bottom 156 General . . . . . . . . . . . .156 The Atlantic Ocean 158 Other Oceans 160 Topography near the Coast ........ 160 Temperature of the Ocean Bottom ....... 162 Light on the Ocean Bottom 163 Materials composing the Ocean Floor . . . . . . .164 Mechanical Sediments ......... 161 Globigerina Ooze .......... 164 Red Clay 105 Life in the Ocean ........... 166 Pelagic or Surface Faunas ........ 106 Littoral or Shore Faunas ......... 107 Faunas of the Ocean Bottom ........ CONTENTS. XV

Chapter X

Ocean Waves and Currents. PAGE Wind Waves 174 Earthquake Waves 178 Storm Waves ........... 179 Ocean Surface Temperatures 179 Ocean Currents 182 Planetary Circulation 182 The System of Ocean Currents 183 Cause of Ocean Currents 185 The Gulf Stream 187 The Labrador Current 189 Effects of Ocean Currents 189

Chapter XI

Tides Nature of tbe Tidal Wave 192 Cause of Tides 192 Effect of the Land 193 Other Causes for Variation in Tidal Height 198 Effects of Tides 201 Part III. The Land.

Chapter XII

The Crust of the Earth. Interior Condition 205 Movements of the Crust 206 Disturbance of the Rocks 207 Volcanic Action ........... 211 Rocks of the Earth's Crust 212 Igneous Rocks ........... 213 Metamorphic Rocks 214 Sedimentary Rocks .......... 214 Deposition of Sedimentary Rocks 215 Consolidation of Sedimentary Rocks 217 Geological Chronology 218 Age of the Earth CONTENTS. XVI

Chapter XIII

Denudation of the Land. PAGE Underground Water 224 The Formation of Caverns 226 Springs and Artesian Wells ......... 228 Durability of Rocks 231 Weathering 233 Agents of Erosion ........... 238 Wind Erosion 238 Rain Erosion 239 Percolating Water 240 River Erosion ........... 241 Ocean Erosion ........... 244 Glacial Erosion 245 Denudation ............ 246

Chapter XIV

Topographic Features of the Earth's Surface. Continents and Ocean Basins 249 Physical Geography of the United States ...... 253 Atlantic Coast Area ......... 254 The Eastern Mountains ......... 254 The Canadian Highlands 256 The Central Plains 256 The Cordilleran Area ......... 257 The Drainage of the Country ........ 259 The Shore Line 261

Chapter XV

River Valleys. General Description 262 Development of River Valleys ........ 265 Adjustment of Streams .......... 272 The River Divide 273 Accidents to Streams ••••...... 275 Land Movements 276 Climatic Accidents *......... 279 Other Accidents CONTENTS. XVII

Chapter XVI

Deltas, Floodplains, Waterfalls, and Lakes. PAGE Deltas 285 Floodplains 288 Waterfalls 294 Lakes 298 Swamps 303

Chapter XVII

Glaciers. Cause of Glaciers 306 Alpine or Valley Glacier 307 Continental Glaciers .......... 313 Icebergs 315 Glacial Period 316 Area covered by Ice 316 Terminal Moraine 319 Formation of Soil 321 Formation of Lakes ......... 323 Formation of Waterfalls 325

Chapter XVIII

The Coast Line. General Statement 328 Effect of Elevation 329 Effect of Depression 329 Effect of Sediment 330 Effect of Waves and Currents 332 Effect of Plants 337 Effect of Animals 340 Changes in Coast Form 343 Islands ............. 344 Promontories ............ 346 Lake Shores 347 Fossil Shore Lines 348

Chapter XXIII

Economic Products of the Earth. Soil 420 Building Stones 420 Economic Deposits of Sedimentary Origin 422 Miscellaneous Substances CONTENTS. XIX PAGE Coal 423 Natural Gas and Petroleum 425 Ore Deposits 426 Distribution of Ore Deposits 428 Mineral Wealth of the United States 429

Appendix

I. Meteorological Instruments, Apparatus, and Methods. Thermometric Records .......... 431 Barometric Records 432 Measurement of Wind Direction and Force 433 Measurement of Evaporation ......... 434 Measurement of Moisture in the Air 434 Study of Clouds and Sunshine 434 Measurement of Rainfall . . 435 Meteorological Methods and Results 435

APPENDIX.

II. Topographic Maps 437

APPENDIX.

III. Suggestions to Teachers 440

APPENDIX.

IV. Questions upon the Text ILLUSTRATIONS. DIAGRAMS AND PHOTOGRAPHS **I«. PAGE 1. Sphere and oblate spheroid 3 2. Land and water hemispheres 4 3. The solar system 5 4. Relative size of sun and large planets 7 5. Sun spots, 1872 8 6. Relative distances of planets from the sun 8 7. Relative size of smaller planets 9 8. Illustration of the cause of seasons 12 9. Relative size of earth and moon 14 10. Lunar craters 14 11. Comet of Donati, 1858 15 12. Orbit of comet of 1862 10 13. Andromeda nebula 17 14. Thickness of the atmosphere 23 15. Decrease in density of the atmosphere 24 16. Passage of sun's rays through the atmosphere .... 26 17. Inclination of the sun's rays 34 18. Daily change in relative humidity 37 19. Increase in temperature of descending air 38 20. Deflection of air currents 40 21.

Decrease in diameter on different latitudes 40 22. Daily temperature curves 44 23. Irregularities of seasonal curve 45 24. Seasonal temperature ranges 49 25. Seasonal temperature range (New York) 51 26. Isotherms for February (northern hemisphere) .... 52 27. Daily temperature curve (summer and winter) .... 60 28. Daily temperature range for several days 61 29. Daily temperature record for several days 61 ILLUSTRATIONS. XXII FIG. PiGEI 30. Temperature ranges, United States, 1892 62 31. Minimum temperatures, United States, 1892 63 32. Maximum temperatures, United States, 1892 64 33. Daily temperature range near and above the ground ... 66 34. General circulation of the globe 69 35. Summer monsoons, India 77 36. Winter monsoons, India 77 37. The sea breeze 78 38. The land breeze 79 39. Effect of sea breeze on air temperature 80 40.

Valley breeze 81 41. Ideal diagram of a storm 85 42. Barometric record during passage of a hurricane .... 86 43. Diagram of hurricane winds 87 44. Map of a hurricane 88 45. Tracks of August hurricanes 89 46. Map of temperate latitude cyclone 94 47. Paths of low-pressure areas 95 48. Average storm tracks, 1878-1887 (Northern hemisphere) . 96 49. Tracks of low-pressure areas 97 60. Photograph of thunderstorm 102 51. Path of thunderstorm 103 52. View of a tornado 104 53. Effect of tornado at Lawrence, Mass 105 54. Distribution of tornadoes (1794-1881) 106 55. Valley fog in the Himalayas 110 56. The banner cloud Ill 57. Photographs of clouds 112 58. Photographs of snowflakes 115 59. Damp snowfall 116 60. Evaporation in United States 120 61. Monthly rainfall in the West 121 62. Variation in annual rainfall in the West 122 63.

A cold wave 127 64. Temperature descent during cold wave 128 65. Climatic zones 129 66. Near the timber line 138 67. Above the snow line, Mount St. Elias, Alaska .... 139 68. Effect of sunlight on mountain vegetation 140 69. Arid land vegetation 141 70. Arid land vegetation, Rio Grande valley ILLUSTRATIONS. XXIII no. PAGE 71. The tropical forest 143 72. Life zones of United States 144 73. Deep-sea sounding machine 154 74. Deep-sea trawl 155 75. Contrast between land and ocean bottom topography . . . 156 76. Cross-section of Atlantic Ocean 158 77. Temperature of the Mediterranean 163 78. Globigerina ooze 165 79. Coral reef on Australian coast 168 80. Ocean waves 174 81. Breakers on the coast 175 82. Effect of storm waves on the coast 177 83. Normal vertical descent of ocean temperatures .... 180 84.

Tides near Hell Gate, N.Y 196 85. Time and height of tides at Hell Gate 196 86. The tides at Eastport, Me., September, 1893 199 87. Height of high tide, Eastport, Me., 1893 and 1894 . . .200 88. Tidal mud flat in Bay of Fundy 202 89. Tidal rise and fall, Cape Ann, Mass 203 90. Horizontal rocks in Kansas 208 91. A monoclinal fold 208 92. Anticline 208 93. Syncline 209 94. Photograph of anticline, Hancock, W.Va 209 95. Photograph of anticline near Quebec, Canada .... 209 96. Photograph of a fault in Arizona 210 97. Photograph of a fault in glacial clay, Massachusetts . . . 210 98. A dike crossing granite 212 99. Contorted limestone 214 100. Stratified shale, near Ithaca, N.Y 215 101. Section of alternating strata 210 102. Unconformity in horizontal rocks 217 103. Unconformity in inclined rocks 217 104.

Photograph of fossiliferous rock 219 105. Mammoth Hot Springs, Yellowstone Park 225 106. Diagram illustrating formation of caverns 226 107. A sink hole in limestone region 227 108. Stalactites in Luray Cave 227 109. The Natural Bridge, Va 228 110. A spring on a fault plane 228 111. Hillside spring ILLUSTRATIONS. XXIV FIG. TAG* 112. Photograph of an artesian well 229 113. Artesian well in monoclinal strata 230 114. Artesian well in syncline 230 115. Rock pillars in Garden of Gods, Col 231 1 16. The weathering of granite 233 117. Effect of roots in breaking up rocks 235 118. Talus in Rio Grande valley, N.M 236 119. The formation of residual soil 237 120. Sand dunes, Cape Ann, Mass 238 121. Moqui pueblo, New Mexico 239 122. Talus furnishing load to river ........ 240 123. Yellowstone valley, broadening by weathering .... 242 124.

Boulder bed of Westfield River, Mass 243 125. Sea cliffs on volcanic island 244 126. Granite hill rounded by glacial action 245 127. Relief map of Eurasia 250 128. Section across the Atlantic and United States .... 251 129. Relief map of North America 252 130. A deep mountain valley 262 131. Stream issuing from a limestone cave 263 132. Brink of Niagara Falls 264 133. Gorge near Ithaca, N.Y 205 134. Royal Gorge, Col 265 135. Oxbow cut-off in Connecticut valley 266 136. Development of the caiion 267 137. Development of the canon profile 267 138. Development of old valley 267 139. The Yellowstone, broadening by weathering 268 140. A bit of Illinois drainage 269 141. A bit of West Virginia drainage 269 142. Canon of the Colorado 270 143. A broad Alpine valley 271 144. Mountain gorge in the Alps 272 145.

Diagram illustrating change in divide 273 146. Diagram illustrating change in divide 274 147. Diagram illustrating monoclinal shifting 274 148. Diagram illustrating sudden change in divide .... 275 149. Effect of elevation on Colorado canon 276 150. The drainage of an arid region 280 151. The Great Basin 281 152. Effect of glaciation on stream courses ILLUSTRATIONS. XXV FIG. PAGE 153. Delta of the Mississippi 286 154. Mode of formation of a delta 288 155. An alluvial fan 288 156. Floodplain among mountains .... 289 157. Floodplain of a great river 290 158. Meandering of the Mississippi 291 159. Meandering of the Mississippi _ 292 160. Meandering of the Mississippi .... 292 161. Falls of the Yellowstone 293 162. Taughannock Falls, N.Y .294 163. American Falls, Niagara 295 164. Yosemite Falls 296 165.

Falls in a gorge near Ithaca, N.Y 297 166. Diagram illustrating origin of Niagara 298 167. River valley transformed to a lake (Adirondacks) . . . 299 168. Glacial lakes in the Adirondacks 300 169. Bird's-eye view of Niagara River 301 170. Shore lines of extinct Lake Bonneville 302 171. A Florida swamp 303 172. Ray Brook, Adirondacks 304 173. An Alpine snow field 306 174. Whitney Glacier, Mount Shasta 307 175. The Rhone glacier 308 176. Crevasse in a glacier 309 177. Glacier, Mount Dana, Cal 310 178. Section of a glacier 312 179. Ice cave at terminus of a glacier 312 180. Forest at foot of Malaspina Glacier, Alaska 313 181. A Nunatak in Greenland 314 182. Icebergs in the Antarctic 315 183. An iceberg in water 316 184. Glacial lakes and moraine in a mountain valley .... 317 185. Extent of the continental ice sheet in America .... 318 186.

Boulder in moraine, Cape Ann, Mass 320 187. Bear-den moraine, Cape Ann, Mass 321 188. Boulder-strewn till soil in Maine 321 189. Glacial scratches on a pebble 322 190. Glacial lakes in Massachusetts 324 191. Watkins Glen, N.Y 326 192. Sea cliff, Cape Cod, Mass 328 193. Submerged valley on the coast of Mount Desert, Me. . . . ILLUSTRATIONS. XXVI FIG.' page 194. Ocean bar on the Texas coast 331 195. Destruction of Heligoland by the ocean 332 196. Lake Spit . 333 197. Hook, Lake Michigan 333 198. Sea cave in granite rock, Cape Ann, Mass 334 199. Effect of dike on form of coast, Cape Ann, Mass. . . . 335 200. Pond formed by beach barrier, Cape Ann, Mass. . . . 335 201. Crescent-shaped beach, Cape Ann, Mass 336 202. Boulders worn from headland by waves 336 203. Rocky beach on exposed coast, Cape Ann, Mass. . . . 337 204.

Mat of seaweed between tides, Cape Ann, Mass. . . . 338 205. A mangrove swamp ......... 338 206. Salt marsh, Cape Ann, Mass 339 207. Coral reef on the Australian coast 341 208. Keys on the Florida coast ........ 341 209. An atoll in the Pacific 342 210. Diagram illustrating origin of atolls 343 211. The coast of Casco Bay, Me 345 212. Cliff on the shore of Lake Michigan 347 213. Lagoon enclosed behind lake beach ...... 348 214. Plain in Pecos Valley, N.M 350 215. Plain in valley of Red River of the North 350 216. Taos Mountains, N.M 351 217. Plateau near Colorado River 352 218. Butte in New Mexico 353 219. Talus slope in the Elk Mountains, Col 354 220. Matterhorn, Switzerland 355 221. A mountain park (Baker's) 357 222. Mountain gorge in the Peruvian Andes 358 223. Mount of the Holy Cross, Col 359 224.

Trail on Long's Peak, Col 360 225. Mountain ridge on the Canadian Pacific 361 226. Section across a mountain ridge 364 227. A bit of mountain drainage 365 228. Map of mountain drainage ........ 366 229. Diagram illustrating the development of a mountain . . . 367 230. A mountain ridge in Colorado ....... 368 231. Vesuvius in eruption, 1872 ........ 372 232. Surface of a recent lava flow 373 233. Lake formed by a lava dam ....... 374 234. Volcano in the Lipari Islands ILLUSTRATIONS. XXVII fig. page 235. Disruption of Krakatoa 375 236. Vesuvius, from Pompeii ........ 376 237. Mount Hood — an apparently extinct volcano .... 378 238. Muir's Butte, Cal., — a recent volcano 379 239. Fusiyama, a Japanese volcano 380 240. Angle of slope of volcanic cones ....... 380 241. Mounts Shasta and Shastina 382 242.

Mato Tepee, Wyo., — a volcanic neck . . . . . . 383 243. Diagram illustrating the earthquake wave ..... 384 244. Waves of Charleston earthquake 384 245. Earthquake shock in Japan ........ 385 246. Effect of earthquake in Japan, 1891 386 247. Fault line associated with Japanese earthquake of 1891 . . 387 248. Crater of Oblong Geyser, Yellowstone Park .... 388 249. Old Faithful Geyser, Yellowstone Park 389 250. Etching of hard layer by denudation, Brazil .... 396 251. A cliff in the Yosemite 398 252. Cliffs in the loess of China . . 399 253. A wave-worn chasm, Gloucester, Mass 400 254. A rugged granite coast, Cape Ann, Mass 401 255. A sloping granite coast, Cape Ann, Mass 401 256. Effect of hard layers on topography 402 257. Signal Butte, Tex 402 258. Effect of tilted layers on topography 403 259.

Form of seacoast in inclined strata ...... 403 260. Form of seacoast in inclined strata ...... 403 261. Ridge of hard rock, etched by denudation 404 262. Topography in region of folded rocks 405 263. A part of the Adirondack forest 409 264. Deforesting of the Adirondacks 410 265. Bare rock exposed by removal of forest 411 266. Model of Cumberland Valley, Penn 437 267. Hachure map ILLUSTRATIONS. PLATES AND CHARTS. PLATE PAGE 1. Watkins Glen, New York Frontispiece 2. Isotherms for the year (world) faeing 50 3. Isotherms for the year 1892 (United States) 54 4. Isothermal chart for July (world) ..... facing 55 5. Isothermal chart for January (world) .... facing 56 6. Isothermal chart for July (United States) ..... 57 7. Isothermal chart for January (United States) .... 58 8. Isothermal chart of New York (year) ...... 59 9.

Winds and isobars for January (world) . . . facing 70 10. General circulation of the Atlantic, July ..... 72 11. General circulation of the Atlantic, January 73 12. Rainfall chart of the world facing 117 13. Rainfall chart of the United States 119 14. Depths of the ocean 161 15. Ocean surface temperature, Atlantic 181 16. Oceanic circulation ....... facing 183 17. Gulf Stream 188 18. Co-tidal lines ......... facing 194 19. English Channel tides 195 20. Earth columns, New Mexico 232 21. The Bad Lands of South Dakota 247 22. Relief map of the United States facing 253 23. Drainage areas of the United States 260 24. Delaware and Chesapeake bays ....... 277 25. Drainage in glaciated region, Wisconsin ..... 283 20. White Glacier, Alaska 311 27. Distribution of volcanoes and ocean surface temperatures (world) facing 370 28.

Marble Canon, Colorado River 391 29. Navajo church, Arizona ......... 397 3. ILLUSTRATIONS. XXIX ACKNOWLEDGMENT OF ILLUSTRATIONS. The following illustrations are from the sources indicated. In some cases they have been exactly reproduced, but in others they have been made more diagrammatic to suit the needs of this book. Some of the illustrations not acknowledged are from photographs or lantern slides, the source of which could not be ascertained.1 Abbe, U. S. S. S., Annual Report for 1890, Fig. 56. Agassiz, Three Cruises of the Blake, Plate 15. Branner, Journal of Geology, Vol. 1, Fig. 250. Brown, C. D. (dealer in photographs, Gloucester, Mass.), Figs. 81, 89, 203, 204, and 254. Buchan, Atmospheric Circulation, Challenger Reports, Plates 2, 4, 5, and 9. Calvin, Prof. S., State Geologist of Iowa, Des Moines, — Photograph by the Survey, Fig. 131.

Canadian Geological Survey, Photograph, Fig. 99. Challeuger Reports, Narrative, Figs. 78, 125, and 182. Chamberlin, Third Annual Report, U. S. G. S., Fig. 185. Diller, Bulletin 79, U. S. G. S.,2 Figs. 232, 233. Dunwoody, Summary of International Meteorological Observations, Figs. 26 and 48 ; same, Professional Paper IX., U. S. S. S., Plate 13. Dutton, Second Annual Report, U. S. G. S.,Figs. 137 and 149; same, Sixth Annual, Plate 29 ; same, Ninth Annual, Fig. 244 ; same, Monograph II. , U. S. G. S., Fig. 136. Ferrel, Popular Treatise on the Winds, Fig. 34. Finley, U. S. S. S., Professional Paper VIL, Fig. 54. Gannett, Thirteenth Annual Report U. S. G. S., Plate 22. Gardner, J. L., 2d, Boston, Mass. (Photographs by), Figs. 98, 116, 3 117, 3 120, 126,3 186,3 187, 198,3 199,3 200, 201, 202,3 206, and 255.3 Gilbert, Monograph I., U. S. G. S., Figs. 151, 154, 155, 170, 197, and 213 ; same, Fifth Annual Report U. S. G. S., Figs. 212 and 217 ; same, Annual Report Smithsonian Institution, 1890, Figs. 166 and 169 ; same, Geology of the Henry Mountains, Fig. 147. 1 U. 8.

C. 8., refers to the United States Coast Survey ; U. S. G. 8., to the United States Geological Survey ; and U. 8. 3. 8., to the United States Signal Service. 2 Some of these which are referred to the Geological Survey publication were made from photographs obtained from the Survey. 3 Also published by Shaler in Ninth Annual Report, U. S. G. S. ILLUSTRATIONS. XXX Greely, U. S. S. S., Professional Paper II., Plates 6 and 7. Griswold, L. S., Dorchester, Mass. (Photograph by), Fig. 97. Guyot, Physical Geography, Fig. 2. Hann, Berghaus, Atlas der Meteorologie, Plate 12. Hann, Hochstetter, and Pokorny, Allgemeine Erdkunde, Fig. 77. Harvard College Astronomical Observatory Engravings, Figs. 5, 11, and 13. Harvard College Geological Department, Figs. 215 and 231 (former, photograph from South Dakota World's Fair Commissioner ; latter, photograph by Sommer) .

Haynes, F. Jay, St. Paul, Minn. (Photographer), Figs. 105, 123, 139, 161, 248, 249. Hellmann, Schneekrystalle, Fig. 58. Hill, First Annual Report, Texas Geological Survey, Fig. 257. Hope, J. D., Photographer, Watkins, N.Y., Plate 1 and Fig. 191. Jackson Photograph Co., Denver, Col., Figs. 134, 221, 224, 237, 238, and 251. James, C. H., Photographer, Philadelphia, Pa., Fig. 108. Jukes-Browne, Handbook of Physical Geology, Fig. 195. Kent, Great Barrier Reef, Figs. 79 and 207. Kobayashi, Earthquake Observations in Japan, Fig. 245. Koppen, Segelhandbuch stir den Atlantischen Ozean (reproduced by Davis, American Meteorological Journal, Vol. IX.), Plates 10 and 11. Lesley, Coal and its Topography, Figs. 256 and 262. Levy and Co., Paris (Dealers in Photographs), Figs. 143, 144, 175, and 220. Merriam, North American Fauna, Bulletin No. 3, U. S. Dept. of Agriculture, Fig. 68 ; same, National Geographic Magazine, Vol. VI., 1894, Fig. 72.

Mills, H. F., Annals, Harvard College Astronomical Observatory, Vol. 31, Fig. 53. Mills, H. R., Realm of Nature, Plates 16 and 27. Mississippi River Commission (Maps), Figs. 158, 159, and 160. Mitchell, U. S. C. S., Annual Report for 1886, Fig. 85. Murray and Renard, Challenger Reports — Deep Sea Deposits, Plate 14. Nasmyth and Carpenter, The Moon, Fig. 10. Newcomb, Popular Astronomy, Fig. 12. Newell, Eleventh Census Report on Irrigation, Figs. 61 and 62. Newton & Co., London, England (Dealers in Lantern Slides), Figs. 52, 55, 71, 106, 181, 205, 209, 234, and 339. New York State Weather Bureau, Fifth Annual Report, Plate 8 and Fig. 25 ; Figures based on the records of this bureau : 18, 28, 29, 33, 42, and 64. Notman (Photographer), Montreal, Canada, Fig. 225. Pach (Photographer), New York, N.Y., Fig. 82.

Peschels (Leipoldt), Physische Erdkunde, Plates 18 and 19. Pillsbury, Annual Report, U. S. C. S. for 1890, Plate 17. ILLUSTRATIONS. XXXI Proctor Bros. (Dealers in Photographs), Gloucester, Mass., Fig. 80. Reid, National Geographic Magazine, Vol. IV., Plate 26. Richthofen, China, Fig. 252. Riggenbach (Photographs), Figs. 50 and 57 (latter from several sources). Ritchie, J., Jr., Boston, Mass. (Photographs by), Figs. 124 and 188. Russell, Fifth Annual Report, U. S. G. S., Fig. 177 ; same, Eighth Annual, Fig. 184 ; same, Thirteenth Annual, Figs. 67 and 180. Sella (Photographs; Chas. Pollock, Boston, Agent), Figs. 176 and 179. Shaler, Twelfth Annual Report, U. S. G. S., Figs. 107, 157, and 171. Sigsbee, U. S. C. S., Deep Sea Sounding and Dredging, Figs. 73 and 74. Smith, W. M. (Dealer in Photographs, Provincetown, Mass.), Fig. 192.

Stoddard, S. R. (Photographer), Glens Falls, N.Y., Figs. 88, 167, 168, 172, 193, 263, 264, and 265. Symons, Eruption of Krakatoa, Fig. 235. Todd, Bulletin I. , South Dakota Geological Survey, Fig. 112. Trotter, Lessons in the New Geography, Figs. 127 and 129. United States Coast Survey Charts, Figs. 153, 194, 208, 211, 267, and Plate 24. United States Geological Survey Photographs, Figs. 66, 94, 95, 96, 119, 122, 132, 142, 163, 174, 196, 230, 241, 242, 261, and Plate 28 ; same, Topographic Maps, Figs. 150, 190, 228, and Plate 25. United States Geological Survey of the Territories (Hayden), Photographs, Figs. 69, 115, 121, 130, 156, 164, 219, 223. United States Hydrographic Bureau (Coast Pilot), Figs. 43, 44, 45. United States Signal Service and Weather Bureau, Figs. 30, 31, 32, 46, 47, 49, 60, 63, and Plate 3.