Man and the Glacial Period 4
Appendix on the Tertiary Man 365-374
Index 375-385
LIST OF ILLUSTRATIONS.
FIG. PAGE
1. Zermatt Glacier 2
2. Formation of veined structure 3
3, 4. Formation of marginal fissures and veins 4
5. Fissures and seracs 4
6. Section across glacial valley, showing old lateral moraines 5
7. Mont Blanc glacier region 10
8. Svartisen Glacier 13
9. Floating berg 18
10. Iceberg in the Antarctic Ocean 20
11. Map of southeastern Alaska 22
12. Map of Glacier Bay, Alaska 25
13. Front of Muir Glacier 26
14. Map of glaciers in the St. Elias Alps 31
15. Map of Greenland 33
16. Diagram showing the character of glacial motion 43
17. Line of most rapid glacial motion 45
18. Diagram showing retardation of the bottom of a glacier 46
19. Bed-rock scored with glacial marks 52
20. Scratched stone from the till of Boston 54
21. Typical section of till in Seattle, Wash. 55
22. Ideal section showing how the till overlies the stratified
rocks 56
23. Vessel Rock, a glacial boulder 56
24. Map of Rhône Glacier 58
25. Conglomerate boulder found in Boone County, Ky. 63
26. Mohegan Rock 72
27. Drumlins in Goffstown, N. H. 73
28. Map of drumlins in the vicinity of Boston 75
29. Section of kame 77
30. Map of kames in Andover, Mass. 78
31. Longitudinal kames near Hingham, Mass. 79
32. Map showing the kames of Maine and southeastern New Hampshire 81
33. Western face of the Kettle Moraine near Eagle, Wis. 99
34. Section of the east-and-west glacial furrows on Kelly's
Island 103
35. Same as the preceding 105
36. Section of till near Germantown, Ohio 108
37. Moraines of Grape Creek, Col. 123
38. Map of North America in the Ice period 127
39. Quartzite boulder on Mont Lachat 128
40. Map showing glaciated areas in North America and Europe 130
41. Maps showing lines of _débris_ extending from the Alps into
the plains of the Po 134
42. Section of the Cefn Cave 148
43. Map showing moraine between Speeton and Flamborough 156
44. Diagram-section near Cromer 166
45. Section through the westerly chalk bluff at Trimingham,
Norfolk 162
46. Section across Wales 172
47. Section of cliff at Flamborough Head 176
48. Enlarged section of the shelly sand and surrounding clay
at _B_ in preceding figure 177
49. Map showing the glaciated area of Europe 184
50. Map showing old channel and mouth of the Hudson 195
51. New York Harbor in preglacial times 197
52. Section across the valley of the Cuyahoga River 200
53. Map of Mississippi River from Fort Snelling to Minneapolis 209
54. Map showing the effect of the glacial dam at Cincinnati 213
55. Map of Lake Erie-Ontario 219
56. Map of Cuyahoga Lake 221
57. Section of the lake ridges near Sandusky, Ohio 223
58. Map showing stages of recession of the ice in Minnesota 225
59. Glacial terrace on Raccoon Creek, in Ohio 227
60. Ideal section across a river-bed in drift region 229
61. Map of Lakes Bonneville and Lahontan 234
62. Parallel roads of Glen Roy 239
63. Map showing glacial terraces on the Delaware and
Schuylkill Rivers 243
64. Palæolith found by Abbott in New Jersey 244
65. Section across the Delaware River at Trenton, N. J. 245
66. Section of the Trenton gravel 246
67. Face view of argillite implement found by Dr. C. C. Abbott
in 1876. 247
68. Argillite implement found by Dr. C. C. Abbott, March, 1879 248
69. Chipped pebble of black chert found by Dr. C. L. Metz,
October, 1885 249
70. Map showing glaciated area in Ohio 250
71. Palæoliths from Newcomerstown and Amiens (face view) 252
72. Edge view of the preceding 253
73. Section across the Mississippi Valley at Little Falls, Minn. 254
74. Quartz implement found by Miss F. E. Babbitt, 1878, at Little
Falls, Minn 255
75. Argillite implement found by H. T. Cresson, 1887 259
76. General view of Baltimore and Ohio Railroad cut,
Claymont, Del. 260
77. Section across valley of the Somme 262
78. Mouth of Kent's Hole 268
79. Engis skull (reduced) 274
80. Comparison of forms of skulls 276
81. Skull of the Man of Spy 277
82. Tooth of Machairodus neogæus 281
83. Perfect tooth of an Elephas 281
84. Skull of Hyena spelæa 282
85. Celebrated skeleton of mammoth in St. Petersburg Museum 283
86. Molar tooth of mammoth 284
87. Tooth of Mastodon Americanus 284
88. Skeleton of Mastodon Americanus 286
89. Skeleton of Rhinoceros tichorhinus 287
90. Skull of cave-bear 287
91. Skeleton of the Irish elk 288
92. Musk-sheep 289
93. Reindeer 290
94. Section across Table Mountain, Tuolumne County, Cal. 294
95. Calaveras skull 295
96. Three views of Nampa image, drawn to scale 298
97. Map showing Pocatello, Nampa, and the valley of Snake River 299
98. Section across the channel of the Stanislaus River 300
99. Diagram showing effect of precession 308
100. Map showing course of currents in the Atlantic Ocean 314
101. Map showing how the land clusters about the north pole 319
102. Diagram showing oscillations of land-surface and ice-surface
during the Glacial epoch 323
103. Diagram of eccentricity and precession 333
104. Map of the Niagara River below the Falls 334
105. Section of strata along the Niagara Gorge 336
106. Map showing the recession of the Horseshoe Falls since 1842 338
107. Section of kettle-hole near Pomp's Pond, Andover, Mass. 345
108. Flint-flakes collected by Abbé Bourgeois 368
MAPS.
TO FACE PAGE
Contour and glacial map of the British Isles _Frontispiece._
Map showing the glacial geology of the United States 66
Map of glacial movements in France and Switzerland 132
MAN AND THE GLACIAL PERIOD.
CHAPTER I.
INTRODUCTORY.
That glaciers now exist in the Alps, in the Scandinavian range, in
Iceland, in the Himalayas, in New Zealand, in Patagonia, and in the
mountains of Washington, British Columbia, and southeastern Alaska, and
that a vast ice-sheet envelops Greenland and the Antarctic Continent,
are statements which can be verified by any one who will take the
trouble to visit those regions. That, at a comparatively recent date,
these glaciers extended far beyond their present limits, and that others
existed upon the highlands of Scotland and British America, and at one
time covered a large part of the British Isles, the whole of British
America, and a considerable area in the northern part of the United
States, are inferences drawn from phenomena which are open to every one's
observations. That man was in existence and occupied both Europe and
America during this great expansion of the northern glaciers is proved
by evidence which is now beyond dispute. It is the object of the present
volume to make a concise presentation of the facts which have been
rapidly accumulating during the past few years relating to the Glacial
period and to its connection with human history.
Before speaking of the number and present extent of existing glaciers,
it will be profitable, however, to devote a little attention to the
definition of terms.
[Illustration: Fig. 1.--Zermatt Glacier (Agassiz).]
A _glacier_ is a mass of ice so situated and of such size as to have
motion in itself. The conditions determining the character and rate
of this motion will come up for statement and discussion later. It is
sufficient here to say that ice has a capacity of movement similar to
that possessed by such plastic substances as cold molasses, wax, tar, or
cooling lava.
The limit of a glacier's _motion_ is determined by the forces which fix
the point at which its final melting takes place. This will therefore
depend upon both the warmth of the weather and upon the amount of ice.
If the ice is abundant, it will move farther into the region of warm
temperature than it will if it is limited in supply.
Upon ascending a glacier far enough, one reaches a comparatively
motionless part corresponding to the lake out of which a river often
flows. Technically this is called the _névé_.
_Glacial ice_ is formed from snow where the annual fall is in excess
of the melting power of the sun at that point. Through the influence
of pressure, such as a boy applies to a snow-ball (but which in the
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