PROSSER. | The Upper Permian. 87 
light gray to whitish gypsum, where it has a thickness of 29 feet. 
At the bottom of the quarry is a reddish to greenish very hard 
stratum termed the “iron rock” by the quarrymen. The base of the 
gypsum is darker in color than the upper part and is somewhat 
impure. Next is the hard marble like kind called the Terra alba, 
and above, reaching to the surface is the softer white gypsum said to 
be of the best quality. On the eastern slope of the Gypsum Hills in 
the numerous ravines and small canyons which mark their sides 
are fine exainples of erosion. The sloping sides are partly covered 
with talus and marked here and there by projecting ledges formed 
by harder strata. From the summit of the Gypsum Hills is a mag- 
nificent view displaying a bewildering number of isolated buttes 
and mounds, separated by small valleys to the west and north, and 
on the east and south the valley of the Medicine Lodge river limited 
by the red bluffs to the east. All of this region affords an excellent 
illustration of the effects of erosion on soft rocks that may well be 
compared to the Tertiary Bad Lands of Dakota. 
To the west of the Gypsum Hills, eight miles southwest of Med- 
icine Lodge is the prominent mound known as the Flower Pot 
mound. It forms the end of the divide between east and west Cedar 
creeks and is the type locality of the shales below the Medicine 
Lodge gypsum which Professor Cragin has called the Flower. Pot 
shales. 
Plate XIV gives a view of Flower Pot Mound, as seen from the 
south. The cedar trees on top of the mound are shown and the 
heavy stratum forming the top of the steep part stands out quite 
clearly. Below are two terraces before reaching the base in the 
eroded. valley. An idea of the sparse vegetation covering the 
slopes of the mound is also given. The upper part is a greenish-gray 
massive stratum above which on the ridge to the west is the heavy 
gypsum. The mound consists largely of reddish shales but these 
have a mottled appearance due to the presence of greenish, bluish 
and other colored shales, together with immense numbers of small 
pieces and thin layers of various kinds of gypsum, especially selenite. 
The steep part of the mound is about 120 feet in hight, the base 
of which is about 100 feet above the level of East Cedar creek. On 
account of the gently rolling country over which the lower part of 
