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Earth Features and Their Meaning / An Introduction to Geology for the Student and the General Reader

Chapter 4: ILLUSTRATIONS IN THE TEXT
By William Herbert Hobbs
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About This Book

The text provides an accessible introduction to geology, surveying the materials and structures of the lithosphere, the formation and classification of rocks, and the folding, faulting, and fracturing that shape strata. It treats earth form and surface features, seismic activity, and climatic influences on landscape—especially glaciation and desert processes—showing how to read historical records preserved in landforms. Emphasis falls on observational methods, field excursions, mapping, and illustrative diagrams to teach identification of minerals, rock textures, depositional environments, and the relation of processes to regional scenery. Appendices outline laboratory exercises and travel suggestions for applying the methods in the field.

ILLUSTRATIONS IN THE TEXT

FIG. PAGE
1. Diagram to show the measure of the earth’s surface irregularities 11
2. Map to show the reciprocal relation of areas of land and sea 11
3. The tetrahedral form toward which the earth is tending 12
4. A truncated tetrahedron to show the reciprocal relation of projection and depression upon the surface 13
5. Approximations to earlier and present figures of the earth 15
6. Diagrams for comparison of coasts upon an upright and upon an inverted tetrahedron 17
7. The continents, including submerged portions 18
8. Diagram to indicate the altitude of different parts of the lithosphere surface 18
9. Diagram to show how the terrestrial rocks grade into the meteorites 22
10. Comparison of a crystalline with an amorphous substance 24
11. “Light figure” seen upon etched surface of calcite 25
12. Battered sand grains which have developed crystal faces 26
13. Unassimilated grains of quartz within a garnet crystal 28
14. New minerals developed about the core of an augite crystal 28
15. A common rim of new mineral developed by reaction where earlier minerals come into contact 28
16. Laminated structure of a sedimentary rock 30
17. Characteristic textures of igneous rocks 33
18. Diagram to show the order of sediments laid down during a transgression of the sea 37
19. Fractures produced by compression of a block of molder’s wax 41
20. Apparatus to illustrate the folding of strata 41
21. Diagrams of fold types 42
22. Diagrams to illustrate crustal shortening 42
23. Anticlinal and synclinal folds 43
24. Diagrams to illustrate the shapes of rock folds 44
25. Secondary and tertiary flexures superimposed upon the primary ones 44
26. A bent stratum to illustrate tension and compression upon opposite sides 45
27. A geological section with truncated arches restored 47
28. Diagram to illustrate the nature of strike and dip 47
29. Diagram to show the use of T symbols for strike and dip observation 48
30. Diagram to show how the thickness of a formation is determined 49
31. A plunging anticline 50
32. A plunging syncline 50
33. An unconformity upon the coast of California 51
34. Series of diagrams to illustrate the episodes involved in the production of an angular unconformity 52
35. Types of deceptive or erosional unconformities 53
36. A set of master joints in shale 55
37. Diagram to show the manner of replacement of one set of joints by another 56
38. Diagram to show the different combinations of joint series 56
39. View of the shore in West Greenland 57
40. View in Iceland which shows joint intervals of more than one order 57
41. Faulted blocks of basalt near Woodbury, Connecticut 58
42. A fault in previously disturbed strata 59
43. Diagram to show the effect of erosion upon a fault 60
44. A fault plane exhibiting drag 60
45. Map to show how a fault may be indicated by abrupt changes in strike and dip 61
46. A series of parallel faults revealed by offsets 61
47. Field map prepared from the laboratory table 64
48. Areal geological map based upon the field map 64
49. A portion of the ruins of Messina 67
50. Ruins of the Carnegie Palace of Peace at Cartaga, Costa Rica 68
51. Overturned bowlders from Assam earthquake of 1897 69
52. Post sunk into ground during Charleston earthquake 69
53. Map showing localities where shocks have been reported at sea off Cape Mendocino, California 70
54. Effect of seismic water wave in Japan 70
55. A fault of vertical displacement 71
56. Escarpment produced by an earthquake fault in India 72
57. A fault of lateral displacement 72
58. Fence parted and displaced by lateral displacement on fault during California earthquake 72
59. Fault with vertical and lateral displacements combined 72
60. Diagram to show how small faults may be masked at the earth’s surface 73
61. “Mole hill” effect above buried earthquake fault 73
62. Post-glacial earthquake faults 74
63. Earthquake cracks in Colorado desert 74
64. Railway tracks broken or buckled at time of earthquake 75
65. Railroad bridge in Japan damaged by earthquake 75
66. Diagrams to show contraction of earth’s crust during an earthquake 76
67. Map of the Chedrang fault of India 76
68. Displacements along earthquake fault in Alaska 77
69. Abrupt change in direction of throw upon an earthquake fault 77
70. Map of faults in the Owens Valley, California, formed during earthquake of 1872 78
71. Marquetry of the rock floor in the Tonopah district, Nevada 79
72. Map of Alaskan coast to show adjustments of level during an earthquake 79
73. An Alaskan shore elevated seventeen feet during the earthquake of 1899 80
74. Partially submerged forest from depression of shore in Alaska during earthquake 80
75. Effect of settlement of the shore at Port Royal during earthquake of 1907 80
76. Diagrams to illustrate the draining of lakes during earthquakes 83
77. Diagram to illustrate the derangements of water flow during an earthquake 84
78. Mud cones aligned upon an earthquake fissure in Servia 84
79. Craterlet formed near Charleston, South Carolina, during the earthquake of 1886 85
80. Cross section of a craterlet 85
81. Map of the island of Ischia to show the concentration of earthquake shocks 87
82. A line of earth fracture revealed in the plan of the relief 87
83. Seismotectonic lines of the West Indies 88
84. Device to illustrate the different effects of earthquakes in firm rock and in loose materials 88
85. House wrecked in San Francisco earthquake 90
86. Building wrecked in California earthquake by roof and upper floor battering down the upper walls 91
87. Breached volcanic cone in New Zealand showing the bending down of the strata near the vent 96
88. View of the new Camiguin volcano formed in 1871 in the Philippines 97
89. Map to show the belts of active volcanoes 98
90. A portion of the “fire girdle” of the Pacific 98
91. Volcanic cones formed in 1783 above the Skaptár fissure in Iceland 99
92. Diagrams to illustrate the location of volcanic vents upon fissure lines 100
93. Outline map showing the arrangement of volcanic vents upon the island of Java 100
94. Map showing the migration of volcanoes along a fissure 101
95. Basaltic plateau of the northwestern United States due to fissure eruptions of lava 102
96. Lava plains about the Snake River in Idaho 102
97. Characteristic profiles of lava volcanoes 103
98. A driblet cone 104
99. Leffingwell Crater, a cinder cone in the Owens Valley, California 104
100. Map of Hawaii and its lava volcanoes 106
101. Section through Mauna Loa and Kilauea 106
102. Schematic diagram to illustrate the moving platform in the crater of Kilauea 107
103. View of the open lava lake of Halemaumau 108
104. Map to show the manner of outflow of the lava from Kilauea in the eruption of 1840 109
105. Lava of Matavanu flowing down to the sea during the eruption of 1906 110
106. Lava stream discharging into the sea from a lava tunnel 111
107. Diagrammatic representation of the structure of lava volcanoes as a result of the draining of frozen lava streams 112
108. Diagram to show the formation of mesas by outflow of lava in valleys and subsequent erosion 112
109. Surface of lava of the Pahoehoe type 113
110. Three successive views to show the growth of the island of Savaii, from lava outflow in 1906 113
111. View of the volcano of Stromboli showing the excentric position of the crater 116
112. Diagrams to illustrate the eruptions within the crater of Stromboli 117
113. Map of Volcano in the Æolian Islands 118
114. “Bread-crust” lava projectile from the eruption of Volcano in 1888 119
115. “Cauliflower cloud” of steam and ash rising above the cinder cone of Volcano 120
116. Eruption of Taal volcano in 1911 seen from a distance of six miles 120
117. The thick mud veneer upon the island of Taal (after a photograph by Deniston) 121
118. A pear-shaped lava projectile 121
119. Artificial production of a cinder cone 122
120. Diagram to show the contrast between a lava dome and a cinder cone 123
121. Mayon volcano on the island of Luzon, Philippine Islands 123
122. A series of breached cinder cones due to migration of the eruption along a fissure 124
123. The mouth upon the inner cone of Mount Vesuvius from which flowed the lava of 1872 124
124. A row of parasitic cones raised above a fissure opened on the flanks of Etna in 1892 125
125. View of Etna, showing the parasitic cones upon its flanks 125
126. Sketch map of Etna to show the areas covered by lava and tuff respectively 126
127. Panum crater showing the caldera 126
128. View of Mount Vesuvius before the eruption of 1906 127
129. Sketches of the summit of the Vesuvian cone to bring out the changes in its outline 128
130. Night view of Vesuvius from Naples before the outbreak of 1906, showing a small lava stream descending the central cone 129
131. Scoriaceous lava encroaching upon the tracks of the Vesuvian railway 130
132. Map of Vesuvius, showing the position of the lava mouths opened upon its flanks during the eruption of 1906 131
133. The ash curtain over Vesuvius lifting and disclosing the outlines of the mountain 132
134. The central cone of Vesuvius as it appeared after the eruption of 1906 132
135. A sunken road upon Vesuvius filled with indrifted ash 133
136. View of Vesuvius from the southwest during the waning stages of the eruption 133
137. The main lava stream advancing upon Boscotrecase 133
138. A pine snapped off by the lava and carried forward upon its surface 133
139. Lava front pushing over and running around a wall in its path 134
140. One of the ruined villas in Boscotrecase 134
141. Three diagrams to illustrate the sequence of events during the cone-building and crater-producing periods 135
142. The spine of Pelé rising above the chimney of the volcano after the eruption of 1902 136
143. Successive outlines of the Pelé spine 137
144. Corrugated surface of the Vesuvian cone due to the mud flows which followed the eruption of 1906 138
145. View of the Kammerbühl near Eger in Bohemia 139
146. Volcanic plug exposed by natural dissection of a volcanic cone in Colorado 140
147. A dike cutting beds of tuff in a partly dissected volcano of southwestern Colorado 140
148. Map and general view of St. Paul’s rocks, a volcanic cone dissected by waves 141
149. Dissection by explosion of Little Bandai-san in 1888 141
150. The half-submerged volcano of Krakatoa before and after the eruption of 1883 142
151. The cicatrice of the Banat 142
152. Diagram to illustrate a probable cause of formation of lava reservoirs and the connection with volcanoes upon the surface 143
153. Effect of relief of load upon rocks by arching of a competent formation 144
154. Character profiles connected with volcanoes 146
155. Diagrams to show the effect of decomposition in producing spheroidal bowlders 150
156. Spheroidal weathering of an igneous rock 151
157. Dome structure in granite mass 152
158. Talus slope beneath a cliff 153
159. Striped ground from soil flow 154
160. Pavement of horizontal surface due to soil flow 154
161. Tree roots prying rock apart on fissure 154
162. Bowlder split by a growing tree 155
163. Rock mantle beneath soil and vegetable mat 155
164. Diagram to show the varying thickness of mantle rock upon the different portions of a hill surface 156
165. Gullies from earliest stage of a river’s life 160
166. Partially dissected upland 160
167. Longitudinal sections of upper portion of a river valley 161
168. Map and sections of a stream meander 163
169. Tree undermined on the outer bank of a meander 164
170. Diagrams to show the successive positions of stream meanders 164
171. An ox-bow lake in the flood plain of a river 165
172. Schematic representation of a series of river terraces 165
173. “Bird-foot” delta of the Mississippi River 167
174. Diagrams to show the nature of delta deposits as exhibited in sections 168
175. Gorge of the River Rhine near St. Goars 169
176. Valley with rounded shoulders characteristic of the stage of adolescence 170
177. View of a maturely dissected upland 170
178. Hogarth’s line of beauty 171
179. View of the oldland of New England, with Mount Monadnock rising in the distance 171
180. Comparison of the cross sections of river valleys of different stages 172
181. The Beavertail Bend of the Yakima River 173
182. A rejuvenated river valley 174
183. Plan of a river narrows 174
184. Successive diagrams to illustrate the origin of “trellis drainage” 175
185. Sketch maps to show the earlier and present drainage near Harper’s Ferry 176
186. Section to illustrate the history of Snickers Gap 177
187. Character profiles of landscapes shaped by stream erosion in humid climates 177
188. Diagram to show the seasonal range in the position of the water table 180
189. Diagram to show the effect of an impervious layer upon the descending water 181
190. Sketch map to illustrate corrosion of limestone along two series of vertical joints 181
191. Diagram to show the relation of limestone caverns to the river system of the district 182
192. Plan of a portion of Mammoth Cave, Kentucky 183
193. Trees and shrubs growing upon the bottoms of limestone sinks 183
194. Diagrams to show the manner of formation of stalactites and stalagmites 185
195. Sinter formations in the Luray caverns 186
196. Map of the dolines of the Karst region 187
197. Cross section of a doline formed by inbreak 187
198. Sharp Karren of the Ifenplatte 188
199. The Zirknitz seasonal lake 189
200. Fissure springs arranged at intersections of rock fractures 190
201. Schematic diagrams to illustrate the different types of artesian wells 191
202. Cross section of Geysir, Iceland 192
203. Apparatus for simulating geyser action 193
204. Cone of siliceous sinter about the Lone Star Geyser 194
205. Former shore lines in the Great Basin 198
206. Map of the former Lake Bonneville 199
207. Borax deposits in Death Valley, California 201
208. Hollowed forms of weathered granite in a desert of Central Asia 201
209. Hollow hewn blocks in a wall in the Wadi Guerraui 202
210. Smooth granite domes shaped by exfoliation 203
211. Granite blocks rent by diffission 204
212. “Mushroom Rock” from a desert in Wyoming 205
213. Windkanten shaped by sand blast in the desert 205
214. The “stone lattice” of the desert 206
215. Shadow erosion in the desert 206
216. Cliffs in loess with characteristic vertical jointing 207
217. A cañon in loess worn by traffic and wind 207
218. Diagrams to illustrate the effects of obstructions in arresting wind-driven sand 209
219. Sand accumulating on either side of a firm and impenetrable obstruction 210
220. Successive diagrams to illustrate the history of the town of Kunzen upon the Kurische Nehrung 210
221. View of desert barchans 211
222. Diagrams to show the relationships of dunes to sand supply and wind direction 211
223. Ideal section showing the rising mountain wall about a desert and the neighboring slope 212
224. Dry delta at the foot of a range upon the borders of a desert 213
225. Map of distributaries of streams which issue at the western base of the Sierra Nevadas 213
226. A group of “demoiselles” in the “bad lands” 214
227. Amphitheater at the head of the Wadi Beni Sur 215
228. Mesa and outlier in the Leucite Hills of Wyoming 216
229. Flat-bottomed basin separating dunes 216
230. Billowy surface of the salt crust on the central sink of the desert of Lop 217
231. Schematic diagram to show the zones of deposition in their order from the margin to the center of a desert 217
232. Mounds upon the site of the buried city of Nippur 218
233. Exhumed structures in the buried city of Nippur 218
234. Section across the High Plains 219
235. Section across the lenticular threads of alluvial deposits of the High Plains 220
236. Distributaries of the foot hills superimposed upon an earlier series 220
237. Character profiles in the landscapes of arid lands 220
238. Rain sculpturing under control by joints 224
239. Sagging of limestone above joints 224
240. Map of the joint-controlled Abisko Cañon in Northern Lapland 225
241. Map of the gorge of the Zambesi River below Victoria Falls 225
242. Controlled drainage network of the Shepaug River in Connecticut 226
243. A river network of repeating rectangular pattern 226
244. Squared mountain masses which reveal a distribution of joints in block patterns of different orders 228
245. Island groups of the Lofoten Archipelago 229
246. Diagrams to illustrate the composite profiles of the islands on the Norwegian coast 229
247. Diagram to show the nature of the motions within a free water wave 231
248. Diagram to illustrate the transformation of a free wave into a breaker 232
249. Notched rock cliff and fallen blocks 233
250. A wave-cut chasm under control by joints 233
251. Grand Arch upon one of the Apostle Islands in Lake Superior 234
252. Stack near the shore of Lake Superior 234
253. The Marble Islands, stacks in a lake of the southern Andes 235
254. Squared stacks revealing the position of the joint planes on which they were carved 235
255. Ideal section cut by waves upon a steep rocky shore 236
256. Map showing the outlines of the island of Heligoland at different stages in its history 236
257. Ideal section carved by waves upon a steep shore of loose materials 237
258. Sloping cliff and boulder pavement at Scituate, Massachusetts 237
259. Map to show the nature of the shore current and the forms which are molded by it 238
260. Crescent-shaped beach in the lee of a headland 239
261. Cross section of a beach pebble 239
262. A storm beach on the northeast shore of Green Bay 240
263. Spit of shingle on Au Train Island, Lake Superior 240
264. Barrier beach in front of a lagoon 241
265. Cross section of a barrier beach with lagoon in its rear 242
266. Cross section of a series of barriers and an outer bar 242
267. A barrier series and an outer bar on Lake Mendota at Madison, Wisconsin 242
268. Series of barriers at the western end of Lake Superior 243
269. Character profiles resulting from wave action upon shores 243
270. The even shore line of a raised coast 246
271. The ragged coast line produced by subsidence 246
272. Portion of the Atlantic coastal plain at the base of the oldland 246
273. Ideal form of cuestas and intermediate lowlands carved from a coastal plain 247
274. Uplifted sea cave on the coast of California 248
275. Double-notched cliff near Cape Tiro, Celebes 248
276. Uplifted stacks on the coast of California 249
277. Uplifted shingle beach across the entrance to a former bay upon the coast of California 250
278. Raised beach terraces near Elie, Fife, Scotland 250
279. Uplifted sea cliffs and terraces on the Alaskan coast 250
280. Diagrams to show how excessive sinking upon the sea floor will cause the shore to migrate landward 251
281. A drowned river mouth or estuary upon a coastal plain 251
282. Archipelago of steep rocky islets due to submergence 252
283. The submerged Hudsonian channel which continues the Hudson River across the continental shelf 252
284. Marine clay deposits near the mouths of the Maine rivers which preserve a record of earlier subsidence and later elevation 253
285. View of the three standing columns of the Temple of Jupiter Serapis, at Pozzuoli 254
286. Three successive views to set forth the recent oscillations of level on the northern shore of the Bay of Naples 255
287. Relief map of San Clemente Island, California 256
288. Relief map of Santa Catalina Island, California 257
289. Cross section of the Blue Grotto, on the island of Capri 258
290. Character profiles of coast elevation and subsidence 259
291. Map showing the distribution of existing glaciers and the two important wind poles of the earth 263
292. An Alaskan glacier spreading out at the foot of the range which nourishes it 264
293. Surface of a glacier whose upper layers spread with but slight restraint from retaining walls 265
294. Section through a mountain glacier 267
295. Profile across the largest of the Icelandic ice caps 267
296. Ideal section across a continental glacier 267
297. View of the Eyriks Jökull, an ice cap of Iceland 268
298. The zones of the lower atmosphere as revealed by recent kite and balloon exploration 269
299. Map of Greenland, showing the area of inland ice and the routes of explorers 271
300. Profile in natural proportions across the southern end of the continental glacier of Greenland 272
301. Map of a glacier tongue with dimple above 273
302. Edge of the Greenland inland ice, showing the nunataks diminishing in size toward the interior 274
303. Moat surrounding a nunatak in Victoria Land 274
304. A glacier pavement of Permo-Carboniferous age in South Africa 276
305. Diagrams to illustrate the manner of formation of scape colks 277
306. Marginal moraine now forming at the edge of the continental glacier of Greenland 279
307. Small lake between the ice front and a moraine which it has recently built 279
308. View of a drained lake bottom between the ice front and an abandoned moraine 280
309. Diagrams to show the manner of formation and the structure of an outwash plain and fosse 280
310. Map of the ice masses of Victoria Land, Antarctica 282
311. Sections across the inland ice and the shelf ice of Antarctica 283
312. Diagram to show the nature of the fixed glacial anticyclone above continental glaciers 284
313. Snow deltas about the margins of a glacier tongue in Greenland 285
314. View of the sea ice of the Arctic region 286
315. Map of the north polar regions, showing the area of drift ice and the tracks of the Jeannette and the Fram 288
316. The shelf ice of Coats Land with surrounding pack ice 290
317. Tidewater cliff on a glacier tongue from which icebergs are born 290
318. A Greenlandic iceberg after a long journey in warm latitudes 291
319. Diagram showing one way in which northern icebergs are born from the glacier tongue 291
320. A northern iceberg surrounded by sea ice 292
321. Tabular Antarctic iceberg separating from the shelf ice 293
322. Map of the globe, showing the areas covered by continental glaciers during the “ice age” 297
323. Glaciated granite bowlder weathered out of a moraine of Permo-Carboniferous age, South Australia 298
324. Map to show the glaciated and nonglaciated regions of North America 298
325. Map of the glaciated and nonglaciated areas of northern Europe 299
326. An unstable erosion remnant characteristic of the “driftless area” 300
327. Diagram showing the manner in which a continental glacier obliterates existing valleys 301
328. Lake and marsh district in northern Wisconsin 302
329. Cross section in natural proportion of the latest North American continental glacier 303
330. Diagram showing the earlier and the later glacier records together upon the same limestone surface 304
331. Map to show the outcroppings of peculiar rock types in the region of the Great Lakes, and some localities where “drift copper” has been collected 305
332. Map of the “bowlder train” from Iron Hill, Rhode Island 306
333. Shapes and approximate natural sizes of some of the diamonds from the Great Lakes region 307
334. Glacial map of a portion of the Great Lakes region 308
335. Section in coarse till 310
336. Sketch map of portions of Michigan, Ohio, and Indiana, showing the distribution of moraines 312
337. Map of the vicinity of Devil’s Lake, Wisconsin, partly covered by the continental glacier 313
338. Moraine with outwash apron in front 313
339. Fosse between an outwash plain and a moraine 314
340. View along an esker in southern Maine 315
341. Outline map of moraines and eskers in Finland 315
342. Sketch maps showing the relationships of drumlins and eskers 316
343. View of a drumlin, showing an opening in the till 317
344. Outline map of the front of the Green Bay lobe to show the relationships of drumlins, moraines, outwash plains, and ground moraine 317
345. Character profiles referable to continental glacier 318
346. View of the flood plain of the ancient Illinois River near Peoria 320
347. Broadly terraced valleys which mark the floods that once issued from the continental glacier of North America 321
348. Border drainage about the retreating ice front south of Lake Erie 321
349. The “parallel roads” of Glen Roy in the Scottish Highlands 322
350. Map of Glen Roy and neighboring valleys of the Scottish Highlands 322
351. Three successive diagrams to set forth the late glacial lake history of the Scottish glens 324
352. Harvesting time on the fertile floor of the glacial Lake Agassiz 325
353. Map of Lake Agassiz 325
354. Map showing some of the beaches of Lake Agassiz and its outlet 326
355. Narrows of the Warren River where it passed between jaws of granite and gneiss 327
356. Map of the valley of the Warren River near Minneapolis 327
357. Portion of the Herman beach on the shore of the former Lake Agassiz 328
358. Map of the continental glacier of North America when it covered the entire St. Lawrence basin 329
359. Outline map of the early Lake Maumee 330
360. Map to show the first stages of the ice-dammed lakes within the St. Lawrence basin 330
361. Outline map of the later Lake Maumee and its outlet 332
362. Outline map of lakes Whittlesey and Saginaw 333
363. Map of the glacial Lake Warren 333
364. Map of the glacial Lake Algonquin 334
365. Outline map of the Nipissing Great Lakes 335
366. Probable preglacial drainage of the upper Ohio region 337
367. Diagrams to illustrate the episodes in the recent history of a Connecticut river 338
368. The notched rock headland of Boyer Bluff on Lake Michigan 341
369. View of Mackinac Island from the direction of St. Ignace 342
370. The “Sugar Loaf”, a stack of Lake Algonquin upon Mackinac Island 342
371. Beach ridges in series on Mackinac Island 343
372. Notched stack of the Nipissing Great Lakes at St. Ignace 343
373. Series of diagrams to illustrate the evolution of ideas concerning the uplift of the lake region since the Ice Age 344
374. Map of the Great Lakes region to show the isobases and hinge lines of uptilt 345
375. Series of diagrams to indicate the nature of the recovery of the crust by uplift when unloaded of an ice mantle 346
376. Portion of the Inner Sandusky Bay, for comparison of the shore line of 1820 with that of to-day 350
377. Ideal cross section of the Niagara Gorge to show the marginal terrace 353
378. View of the bed of the Niagara River above the cataract where water has been drained off 353
379. View of the Falls of St. Anthony in 1851 354
380. Ideal section to show the nature of the drilling process beneath the cataract 355
381. Plan and section of the gorge, showing how the depth is proportional to the width 355
382. Comparative views of the Canadian Falls in 1827 and 1895 356
383. Map to show the recession of the Canadian Fall 357
384. Comparison of the present with the future falls 358
385. Bird’s-eye view of the captured Canadian Fall at Wintergreen Flats 358
386. Map of the Whirlpool Basin 360
387. Map of the cuestas which have played so important a part in fixing the boundaries of the lake basins 361
388. Bird’s-eye view of the cuestas south of Lakes Ontario and Erie 362
389. Sketch map of the greater portion of the Niagara Gorge to illustrate Niagara history 363
390. Snowdrift hollowing its bed by nivation 368
391. Amphitheater formed upon a drift site in northern Lapland 369
392. The marginal crevasse on the highest margin of a glacier 370
393. Niches and cirques in the Bighorn Mountains of Wyoming 371
394. Subordinate cirques in the amphitheater on the west face of the Wannehorn 371
395. “Biscuit cutting” effect of glacial sculpture in the Uinta Mountains of Wyoming 372
396. Diagram to show the cause of the hyperbolic curve of cols 372
397. A col in the Selkirks 373
398. Diagrams to illustrate the formation of comb ridges, cols, and horns 374
399. The U-shaped Kern Valley in the Sierra Nevadas of California 375
400. Glaciated valley wall, showing the sharp line which separates the abraded from the undermined rock surface 375
401. View of the Vale of Chamonix from the séracs of the Glacier des Bossons 376
402. Map of an area near the continental divide in Colorado 377
403. Gorge of the Albula River in the Engadine cut through a rock bar 378
404. Idealistic sketch, showing glaciated and nonglaciated side valleys 378
405. Character profiles sculptured by mountain glaciers 379
406. Flat dome shaped under the margin of a Norwegian ice cap 379
407. Two views which illustrate successive stages in the shaping of tinds 380
408. Schematic diagram to bring out the relationships of the various types of mountain glaciers 383
409. Map of the Malaspina Glacier of Alaska 384
410. Map of the Baltoro Glacier of the Himalayas 385
411. View of the Triest Glacier, a hanging glacieret 385
412. Map of the Harriman Fjord Glacier of Alaska 386
413. Map of the Rotmoos Glacier, a radiating glacier of Switzerland 386
414. Outline map of the Asulkan Glacier in the Selkirks, a horseshoe glacier 387
415. Outline map of the Illecillewaet Glacier of the Selkirks, an inherited-basin glacier 388
416. Diagram to illustrate the surface flow of glaciers 390
417. Diagram to show the transformation of crevasses into séracs 391
418. View of the Glacier des Bossons, showing the position of accidents to Alpinists 392
419. Lines of flow upon the surface of the Hintereisferner Glacier in the Alps 393
420. Lateral and medial moraines of the Mer de Glace and its tributaries 393
421. Ideal cross section of a mountain glacier 394
422. Diagrams to illustrate the melting effects upon glacier ice of rock fragments of different sizes 394
423. Small glacier table upon the Great Aletsch Glacier 395
424. Effects of differential melting and subsequent refreezing upon a glacier surface 396
425. Dirt cone with its casing in part removed 396
426. Schematic diagram to show the manner of formation of glacier cornices 397
427. Superglacial stream upon the Great Aletsch Glacier 398
428. Ideal form of the surface left on the site of a piedmont glacier apron 399
429. Map of the site of the earlier piedmont glacier of the Upper Rhine 399
430. Diagram and map to bring out the characteristics of newland lakes 402
431. View of the Warner Lakes, Oregon 402
432. Schematic diagram to illustrate the characteristics of basin-range lakes 403
433. Schematic diagram of rift-valley lakes and the valley of the Jordan 403
434. Map of the rift-valley lakes of East Central Africa 404
435. Earthquake lakes formed in 1811 in the flood plain of the Lower Mississippi 404
436. View of a crater lake in Costa Rica 405
437. Diagrams to illustrate the characteristics of crater lakes 406
438. View of Snag Lake, a coulée lake in California 406
439. Diagrams to illustrate the characteristics of morainal lakes 407
440. Diagram to show the manner of formation of pit lakes 408
441. Diagrams to illustrate the characteristics of pit lakes 408
442. Diagram to show the manner of formation of glint lakes 409
443. Map of a series of glint lakes on the boundary of Sweden and Norway 409
444. Map of ice-dam lakes near the Norwegian boundary of Sweden 410
445. Wave-cut terrace of a former ice-dam lake in Sweden 410
446. View of the Márjelen Lake from the summit of the Eggishorn 411
447. Diagrams to illustrate the arrangement and the characters of rock-basin lakes 412
448. Convict Lake, a valley-moraine lake of California 413
449. Lake basins produced by successive slides from the steep walls of a glaciated mountain valley 414
450. Lake Garda, a border lake upon the site of a piedmont apron 414
451. Diagrams to bring out the characteristics of ox-bow lakes 415
452. Diagrammatic section to illustrate the formation of saucer-like basins between the levees of streams on a flood plain 415
453. Saucer lakes upon the bed of the former river Warren 416
454. Levee lakes developed in series within meanders in a delta plain 417
455. Raft lakes along the banks of the Red River in Arkansas and Louisiana 418
456. Map of the Swiss lakes Thun and Brienz 419
457. Delta lakes formed at the mouth of the Mississippi 419
458. Delta lakes at the margin of the Nile delta 420
459. Diagrams to illustrate the characteristics of barrier lakes 420
460. Dune lakes on the coast of France 421
461. Sink lakes in Florida, with a schematic diagram to illustrate the manner of their formation 421
462. Map of the Arve and the Upper Rhone 426
463. View of the Arve and the Rhone at their junction 427
464. A village in Switzerland built upon a strath at the head of Lake Poschiavo 428
465. View of the floating bog and surrounding zones of vegetation in a small glacial lake 429
466. Diagram to show how small lakes are transformed into peat bogs 430
467. Map to show the anomalous position of the delta in Lake St. Clair 431
468. A bowlder wall upon the shore of a small lake 432
469. Diagrams to show the effect of ice shove in producing ice ramparts upon the shores of lakes 433
470. Various forms of ice ramparts 433
471. Map of Lake Mendota, showing the position of the ridge which forms from ice expansion and the ice ramparts upon the shores 434
472. The great multiple mountain arc of Sewestan, British India 436
473. Diagrams to illustrate the theories of origin of mountain arcs 437
474. Festoons of mountain arcs about the borders of the Pacific Ocean 438
475. The interrupted Armorican Mountains common to western Europe and eastern North America 438
476. A zone of diverse displacement in the western United States 439
477. Section of an East African block mountain 439
478. Tilted crust blocks in the Queantoweap valley 440
479. View of the laccolite of the Carriso Mountain 441
480. Map of laccolitic mountains 441
481. Ideal sections of laccolite and bysmalite 442
482. The gabled façade largely developed in desert landscapes 443
483. Balloon view of the Mythen in Switzerland 444
484. The battlement type of erosion mountain 445
485. Symmetrically formed low islands repeated in ranks upon Temagami Lake, Ontario 445
486. Forms of crystals of a number of minerals 454
487. Forms of crystals of a number of minerals 457
488. A student’s contour map 469
489. Models to represent outcrops of rock 472
490. Special laboratory table set with a problem in geological mapping which is solved in Figs. 47 and 48 472
491. Three field maps to be used as suggestions in arranging laboratory table for problems in the preparation of areal geological maps 473
492. Sketch map of Western Scotland and the Inner Hebrides to show location of some points of special geological interest 481
493. Outline map of a geological pilgrimage across the continent of Europe 483