38 USIRAUBIE Cn IAI SSIBIE, 
Hayden,’ N. H. Winchell? and Henry Newton,3 and from these 
descriptions the following has been compiled. 
The butte rises 1200 feet above the surrounding plain and 
attains an elevation above the sea of 4570 feet. As seen from 
the north, it is a simple cone, but from the east and west summit 
appears as a ridge several hundred feet in length, with a trend 
about North 40° West. The strata which are exposed about its base 
and dip away from it in all directions, are composed of rocks of 
all ages from the Middle Cretaceous to the Potsdam, inclusive. 
A dense quartzite, probably of Potsdam age, occurs at the 
immediate base of the butte in vertical strata, but does not form 
a continuous circular outcrop. 
The rock of which the butte proper is composed is very sim- 
ilar if not identical with that forming Inyan Kara, Bear Lodge, 
etc. It is crossed by cleavage plains but is not columnar. When 
freshly broken it is gray in color but when weathered it appears 
nearly black. The débris in the immediate vicinity of the butte 
is so abundant that good exposure of the stratified rocks sur- 
rounding its base are seldom seen. The harder beds in these 
strata, however, influence the relief sufficiently to show the 
presence of an encircling rampart of the same character as the 
much more conspicuous one, about the base of Inyan Kara. 
Denudation has stripped the central plug of igneous rock of its 
enveloping stratified beds almost as completely as in the case of 
the great tower in the valley of the Belle Fourche. 
Crow Peak.—This peak is situated in the northern part of 
the Black Hills, about five miles west of the town of Spearfish, 
and rises to an elevation of approximately 1,500 feet above 
bottom of the Red Valley, which skirts its northern base. 
It is described by Newton,‘ as a pustular outbreak of igne- 
ous rock through Red Bed limestone. As seén from the west it 
appears as two peaks closely united; the southern one is the 
* Trans. Amer. Philo. Soc., Vol. XII., n. s., 1863, p. 28. 
? Reconnoissance in the Black Hills, pp. 55-56. 
3 Geology of the Black Hills, pp. 195-197. 
4 Geology of the Black Hills, pp. 194-195. 
