44 LAKAMIE BASIN, WYOMING. 
A well bored in the NE. J NW. J sec. 27, T. 19 N., K. 77 W., on 
Dutton Creek, passed through Tertiary deposits into the underlying 
Montana. The Tertiary was reached beneath 43 feet of loose sand 
and gravel, and is reported to consist of 332 feet of "soapstone," 
sand, and gravel, ranging from 10 to 25 feet in thickness, the whole 
resting upon 60 feet of sandstone, which carries two thin veins of 
coal and belongs to the upper part of the Montana. 
SHEEP MOUNTAIN-RED MOUNTAIN REGION. 
On the high slopes at the south end of the Centennial Valley and 
also south and west of Ring and Red mountains there are deposits 
of supposed Tertiary age. The altitudes range from 8,000 to 9,000 
feet and the underlying formations range from the pre-Cambrian 
crystalline rocks to the Niobrara, most of the deposits at the south 
end of the Centennial Valley lying upon the pre-Cambrian. The 
material is an incoherent mixture of sand and gravel, mostly derived 
from the crystalline rocks and ranging in size from small pebbles up to 
large bowlders. In places, especially near the bottom, the material is 
cemented into a rather firm arkose or conglomerate with a matrix 
mostly of lime. The topography is very characteristic, consisting of 
low rounded hills in the midst of rough ridges of granite and sedimen- 
tary rocks. The beds lie nearly level but on an uneven surface, and 
the maximum thickness is apparently between 200 and 250 feet. No 
evidence was obtained as to the age of the beds and they may be as 
old as Wasatch or much younger. 
LITTLE MEDICINE BOW VALLEY. 
A large portion of the valley of Little Medicine Bow Creek and the 
mountain slopes to the north are occupied by sands and sandy clays 
of the Chadron formation of the White River group and possibly by 
some of later Tertiary age. These deposits lie unconformably across 
various older formations, from granite to the upper beds of the 
Montana, and west of Little Medicine post-office reach a thickness of 
several hundred feet. They begin at an altitude of about 7,000 feet 
and extend up the mountain slopes and up some of the valleys to and 
across divides at altitudes of more than 7,500 feet. On the north- 
west side of Little Medicine Bow Valley they rise in a steep badland 
escarpment facing southeastward which extends far to the west. The 
summit of this feature is a high plateau which, rising gently to the 
northeast, extends to the summit of the range on the divide at the 
head of Boxelder Creek. 
One broad deposit caps the divide in the Laramie Plains west of 
Garrett. It also extends northward up the valley of North Laramie 
River and through a gap at its head which crosses the main Laramie 
Mountains to the head of the valley of Labonte Creek. (See PL VII, A.) 
