TO YELLOWSTONE NATIONAL PARK. Lie 
march of seven miles took us to Camp Baker; the road passing along by bluffs of Miocene Tertiary, 
to be described later. 
CAMP BAKER. 
At Camp Baker, where we made a short stay, we were the recipients of most kind hospitalities 
from the officer at that time in command there, from whom also we received valuable informa- 
tion in regard to the surrounding country. During the time spent at this point, we were enabled to 
make an imperfect reconnaissance of the immediate vicinity. The descriptions given below may be 
better understood by reference to the following cut (fig. 9): 
Fig. 9. 
i Miocene, 
Pea) (eee (Fellow slates.) 
Miocene. 
Camp Baker lies in a broad plain, which is surrounded on all sides by mountains, of which the 
Big Belt to the south are the most conspicuous and highest. We are here on the eastern border 
of the mountain-region, which extends far to the westward. The valleys of Deep Creek and its 
tributaries are filled with deposits of Miocene Tertiary. These consist for the most part of homo- 
geneous cream-colored clays, so hard as to be with difficulty cut with a knife. The lower layers 
are generally more loose and homogeneous, while the upper beds are harder, firmer, and sometimes 
quite calcareous. Some of the upper beds are remarkable for the large number of white clay con. 
cretions which are found in them. 
The beds are horizontal, and rest unconformably on the somewhat upturned yellow and red 
slates below; the clays of which they are formed resemble closely those of the Miocene beds 
at Scott’s Bluffs near the North Platte River in Wyoming. The deposits at Camp Baker have 
been extensively denuded, and nowhere reach any very great thickness. At a point about three 
miles southeast of the post, some bluffs were noticed where the Miocene beds attained a thickness 
of 200 feet, and these were capped by 50 feet of Pliocene clays, both beds containing characteristic 
fossils. 
We saw the first exposures of these beds a few miles west of the Sulphur Springs, just after 
crossing the high ridge of trachyte before referred to, through which Deep Creek flows. From 
here, the lake bed was traced continuously along Deep Creek for a distance of fifteen miles. Beds 
of the same character, containing fossils, were found on Spring Creek to the east, on White-tailed 
Deer Creek, about seven miles to the north of Camp Baker, as well as on Camas Creek to the south- 
west. On Camas Creek, the beds are exposed for a mile or more in bluffs ranging from 20 to 25 
feet in height. The exposures on White-tailed Deer Creek are much more extensive than those last 
