Bennettites dacotensis Macbride. — Calvin. 83 
pie limestone and gypsiferous red clays of the Red Beds. 
Battle mountain, east of the town of Hot Springs, has an 
elevation of about a thousand feet above the valley. The 
upper part of the mountain is composed of Dakota sandstone, 
and away up at the summit is the quartzite seen on the 
higher eminences around Minnekahta. Fall river, formerly 
known as Minnekahta creek, Hows off toward the southeast 
to join the south fork of the Cheyenne river. About four 
miles from Hot Springs the stream emerges from the sand- 
stone hills in a series of cascades which constitute the falls 
of Fall river. At the falls, as previous^ observed by New- 
ton, the sandstone is inclined at a high angle and passes be- 
neath the dark colored shales of the Fort Benton group. 
Crossing the nearly level plain that separates the last of the 
sandstone hills from a high escarpment that curves 
around nearly parallel to the margin of the uplift, we find 
ourselves on calcareous beds of the Niobrara group. These 
beds are charged with Inoceramus problematicus Schlot., 
with occasional colonies of Ostrea c<ni<i<'st<t, the whole aspect 
of the formation resembling closely the Inoceramus-bearina; 
beds near Sioux City, Iowa, and Ponca, Nebraska. The sim- 
ilarity of the Sioux City deposits to Niobrara beds on French 
creek, a locality probably thirty miles northeast of the point 
just noted was remarked by Prof. N. H. Wincheil in 1S74. 
Over on the Cheyenne river, about six miles east of Fall 
river falls, is an exposure of Niobrara that reminds one of the 
massive chalk beds at St. Helena, Nebraska. The resemblance 
is not complete, for at St. Helena the beds are for the most 
part white, only occasionally portions are bluish in color, ow- 
ing to the presence of organic matter. On the Cheyenne the 
beds are all bluish. They give out a strong foetid odor when 
struck with the hammer. There are indications of the pres- 
ence of organic matter in unusual amount. But the massive 
bedding of the soft, calcareous material, the manner in which 
the layers break down, the greal angular blocks of talus, the 
occasional small colonies of Ostrea congesta, the vertebrae and 
scales of fishes, are each and all perfectly duplicated at the 
two points mentioned — namely, on the Missouri at St. Helena 
and on the south fork of the Cheyenne southeast of Not 
Springs. 
