QUATERNARY AGE. 259 



of silicified wood are found in this Old Forest Bed. Of fifty speci- 

 mens that I examined microscopically at different times, thirty-nine 

 were conifers. A few oaks, a willow, a cottonwood and some 

 other species that I could not determine also occurred among them. 

 If these specimens are any indication of dominant type, then a con- 

 iferous vegetation flourished here during those times. Here are 

 also found the remains of the elephant, mastodon, the Bison lati- 

 frons, a huge elk and deer, and the giant beaver {Castor Ohiaticus}. 

 Curiously enough, I found the molar of a horse in this same bed, 

 but too much injured to identify specifically. An abundant animal 

 life, a life remarkable for its gigantic character, ruled in these old 

 forests. It was probably colder than at present in the same lati- 

 tudes, but with conditions of moisture and temperature eminently 

 adapted to the production of vast and sombre forests, whose soli- 

 tudes were enlivened principally by huge herbivorous and carnivor- 

 ous mammals. That the Forest Bed period was a long one is clear 

 from the thickness of the bed that was formed, from its vast forests 

 and the remains of its abounding animal life. Black soils form 

 with excessive slowness, and as the Forest Bed is known, even in 

 Nebraska, to have a thickness in places of ten feet, the time involved 

 in its production is simply incalculable. 



Second Appearance of Glacial Drift. On top of the Old Forest 

 bed materials, and where these have been removed, on top of the 

 silicious clay floor of the Forest Bed, occur gravel, sands of various 

 degrees of fineness, boulders and boulder clay. In places the 

 boulders of various sizes constitute the principal portion of the over- 

 lying materials. Sometimes these boulders are marked with par- 

 allel striae, and beds and piles of them occur of enormous thickness. 

 One such exists on the banks of Oak Creek, six miles from Lin- 

 coln. Here I measured seventeen feet of vertical thickness of these 

 boulders of all sizes, from a grain of corn to a hundred pounds in 

 weight some rounded and some angular, with sand also intermin- 

 gled. In the upper portion of these beds there are signs, with 

 greater or less distinctness, of stratification. Often it bears in its 

 lower portions a striking resemblance to the drift materials below 

 the Forest Beds. Above the indistinctly stratified materials are 

 various beds in places where the stratification is undoubted. These 

 beds are mostly made up of variously colored gravels and sands, the 

 latter predominating. 



Kames. On the Logan, Elkhorn, on tributaries of the Republi- 

 can and Loup, and in other places occur long rows of sometimes 



