CHAPTER II. 



OBSERVATIONS ON THE ROUTES TO AND FROM THE BLACK 



HILLS. 



Cheyenne to Fort Lakamik. — Fort Laramie to the Black Hills.— Rawhidk Butte and mono- 



CLINAL RIDGES ON KOAU TO ChEYENNK RiVER. — TERTIARY AND CRETACEOLS ON OlD WoMAN'S 



Foi!K. — Fort Union Groip on Cheyenne River. — Hog-backs or monoclinal ridges of 

 Cretaceous on west side of tiik Hills. — Route through the Hills. — Notes ox Geology 

 or eastern side of Hills. — Tertiary or White River Group. — Bad Lands, &c. 



The country between Cheyenne, at whicli place our party was organ- 

 ized, and Fort Laramie, 96 miles farther north, where the military escort 

 was added to it, has been so frequently examined and reported upon by 

 geologists and others, that little need be said concerning its features and 

 geological structure. Dr. Hayden has repeatedly passed over the route, 

 and his observations may be found recorded in the annual report of the 

 Geological Survey of the Territories for 1870. 



The government road between these two points runs in a northerly 

 direction, crossing the valleys of Lodge Pole, Bear, and Horse Creeks to 

 the Chugwater Valley, which it follows for some 15 miles, and then 

 strikes northwest to the valley of the Platte and Fort Laramie. It runs its 

 entire distance along the eastern base of the Laramie Mountains (Black 

 Hills of Wyoming), whose rugged and snow-capped summits lie some 15 

 to 18 miles to the west, while to the east spreads the broken, desolate, and 

 treeless region of the Plains. This great country of the Plains, which on 

 the Missouri River at Omaha has an elevation above the sea of 1,060 feet, 

 rises westward, until at Cheyenne, 51G miles distant, it has imperceptibly 

 reached an elevation of 6,075 feet. 



From Cheyenne to Fort Laramie the country is gently rolling, being 

 cut by the main drainage valleys from the mountains at the west into 



22 



