TERTIARY SYSTEM. 89 



the continuing erosion since Silurian times. The two lonely towers in the valley of 

 the south branch of Root River, in Fillmore County, known as "Eagle Rocks," 

 rise as high as the rocky walls of the valley, and evidence subaerial erosion, but are 

 inconsistent with the idea that any large body of ice ever passed down the valley 

 or across it. 



195. There is no drift in California, nor on the Pacific Coast as far north as 

 British Columbia and Alaska. There are no indications of it in the Rocky Mount- 

 ain regions, or upon the great plains of the West. There are no such exhibitions 

 of scratched and grooved rocks succeeded by fossiliferous marine clays and sands, 

 with bowlders, as occur in the New England States and St. Lawrence region, nor 

 of scratched rocks and ancient soils succeeded by clay, sand, and gravel, with bowl- 

 ders, as occur in the central part of the continent ; but, on the contrary, the whole 

 country west of the Mississippi Valley is absolutely driftless, except as to local drift 

 produced upon the shores of Tertiary lakes, and more or less distributed by the 

 rivers that, in the course of time, cut out the canons which drained them. On the 

 borders of the ancient lakes and rivers there are terraces, marking shore-lines at 

 various places from Mexico to Alaska, but they are standing monuments to disprove 

 the existence of a continental ice-sheet ; for no one can conceive of the movement 

 of a heavy body of ice across a valley without disturbing the graveled terraces 

 that border upon both sides at different elevations. The natural towers that stand 

 as evidence of erosion from the Wahsatch times to the present; from the Green 

 River Eocene to the present ; from the Bridger Eocene to the present ; from the 

 White River Miocene to the present; the columnar masses, irregular pyramids, 

 sandstone towers, and turreted outliers of the Bad Lands of Colorado, Wyoming, 

 Montana, Dakota, and British Columbia ; the monuments on Monument Creek ; the 

 Garden of the Gods; the buttes in all the mountain chains; the transverse ridges, 

 lone mountains, and exalted peaks ; and the whole array of canons from Texas and 

 Mexico to Alaska, all alike tell us, in language unmistakable, that no glacial sheet 

 ever moved south upon the western plains or mountain ranges. 



196. Indeed, there is no evidence a glacial sheet ever existed on any part of 

 the continent; none that gives any warrant to the hypothesis of a glacial period. 

 On account of the valleys, hills, and mountains, no glacial sheet could move; and 

 if one had ever existed, the waters flowing from it would have cut out channels of 

 such dimensions they could have been not only traced, but their dimensions would 

 have been such they could not be mistaken for any of the valleys now existing. 

 Had there been a glacial period, northern plants and shells would be found occupy- 

 ing their places as far south as Florida, Louisiana, and Texas. But, on the con- 

 trary, no such flora or fauna is found farther south than it now exists, while the 

 present flora and fauna occur in the same latitude throughout the Post-pliocene age, 

 and passing back through earlier ages, unmolested by any visible climatic changes. 

 The scratches and furrows so often cited as evidence of the glacial period do not 

 exist upon the mountains, but occur only in the valleys and lower lands that were 

 overflowed by water ; and in these valleys there are now standing lone rocks and 

 outliers that a glacier moving in the valleys would necessarily have swept away. 

 The scratches and furrows are readily accounted for without the hypothesis of a 

 glacial period ; and on account of their position on the northern side of the higher 

 elevations of land and not upon the southern, and their universal course up the 



