i 
GRIMSLEY. | Gypsum Mines and Mills. 71 
but the gypsum is continuous 
over the greater portion of 
western Barber and eastern 
Comanche counties. The rock 
usually lies near the 1800-foot 
contour line, as shown in 
Plate IV. 
In the eastern part of Co- 
manche county, on Cave creek, 
a second gypsum layer 15 feet 
thick is found, 15 feet above the 
Medicine Lodge layer. This 
upper layer was called the 
‘‘Shimer gypsum ”’ by Cragin.” 
It appears to be a local de- 
posit. 
GEOLOGICAL RELATIONS. 
Looking west from the town 
of Medicine Lodge one can see 
in the distance a range of hills 
of erosion with sloping sides 
and level tops. These hills 
extend in a north and south 
direction and are called the 
Gypsum Hills. The sides are 
composed of the red clays and 
shales of the Red Beds, the age 
Be ed Se Coe OLWAnLe Dy ish still somenw hat jum: 
yest of Medicine Lodge. certain, but they probably be- 
long to the Permian. The cap 
rock is a ledge of solid gypsum, which has protected to a con- 
siderable extent the underlying soft strata. 
The base of the hills, Plate VII, is a massive red sandstone. 
A second red sandstone is found 125 feet higher, and 100 feet 
above this comes the ledge of gypsum forming the top of the 
hills. This gypsum layer varies from 3 to 20 feet in thickness, 
34. Loc. cit. 
