[1874. 375 [Kneeland. 



April 15, 1874. 



The President in the chair. One hundred and twelve per- 

 sons present. 



Dr. Samuel Kneeland read a paper on the geology, geog- 

 raphy, and scenery of the Union Pacific Railroad, illustrated 

 by specimens of ores, fossils, and minerals found along the 

 route from Cheyenne to the Sierra Nevada, with lantern 

 illustrations of such of the scenery as best displayed the 

 geological features. 



After pointing out the geographical features of rivers, plains, lakes, 

 and mountains along the route, he drew attention to the fertility of 

 Eastern Nebraska, especially along the valley of the Platte River, 

 well adapted for cereal grains, fruits, and vegetables. In Western 

 Nebraska and Wyoming the alkali region begins, and is unfit for 

 agriculture ; but, when properly watered, one of the finest and largest 

 grazing countries in the world — the sterility not depending on the 

 alkali, but on the absence of water to carry it off; this extensive re- 

 gion is probably the residue of the evaporation of a large inland sea, 

 whose waters were charged with alkaline salts from the surrounding 

 mountains, in a basin without an outlet. 



From Omaha westward, for about one hundred and twenty miles, 

 there are the carboniferous and secondary limestones and cretaceous 

 strata; then the tertiary marls and clays to the mountains west of 

 Cheyenne, the mountains themselves here having a nucleus of red- 

 dish felspathic granite, probably of Laurentian age. 



The Laramie or Black Hills, with Sherman at their top, formed 

 the western shore-line of an immense fresh water lake on the eastern 

 slope of the mountains during the middle and upper tertiary, the 

 eastern shore of this lake extending to the vicinity of Grand Island; 

 this lake occupied an area, now almost waterless, of more than 

 one hundred thousand square miles. The nearly level character of 

 these plains shows that the upheaval of this plateau was gradual and 

 of long continuance, embracing the five hundred miles between the 

 Missouri and the mountains, the lofty ranges bursting through at a 

 comparatively recent period, draining off the waters with an immense 

 denudation, here and there great thicknesses of clays, marls, sand, 

 and sandstones being left high on their sides, and sometimes reach- 

 ing to the very crest; the effects of this denudation are now seen in 



