OF THE UPPER MISSOURI. 
29 
CHAPTER VI. 
PROM BEAR BEAK TO FORT RANDALL ON THE MISSOURI RIVER. 
October 3d. Travelled eighteen miles in a southeasterly direction over Cretaceous beds 
Nos. 2 and 3. All the upland prairie surrounding the base of the Black hills is covered 
with a heavy deposit of drift. 
October 4th. Our route to-day led us over Cretaceous bed No. 4. Camped at night 
on the Sbyenne river opposite the mouth of Sage creek. Found vast quantities of finely 
preserved fossils, Ammonites, Baculites, Scapliites , Ostrea , and many unclescribed species. 
In the distance eastward the naked columns of the Bad Lands are seen quite conspicu¬ 
ously. 
October 5th. Ascending the valley of Sage creek we pass over a blending of Creta¬ 
ceous beds Nos. 4 and 5 for the first five miles, which contain an abundance of fossils 
similar to those found on the Sbyenne yesterday. We then meet with the lowest bed of 
the great Tertiary basin of White river, resting conformably upon the Cretaceous strata. 
We have first the dark clays of No. 4, then the yellowish brown arenaceous shale of No. 
5, with numerous ferruginous concretions; then, the Titanotherium bed, which sets regu¬ 
larly upon No. 5, and reaches its greatest development in the valleys of Sage and Bear- 
creeks. It is there composed first of a band of argillaceous grit, weathering to a pink 
color, tw r o feet in thickness, passing, up into an ash-colored plastic clay, with a greenish 
tinge, full of chalcedony and calcareous concretions ; third, a light-gray calcareous grit, 
upon which rests the turtle bed, the whole thickness being from 80 to 100 feet. A con¬ 
siderable deposit of water-worn boulders and fine sand is distributed over the surface of 
the Bad Lands to a greater or less extent. 
' October 6th. Passing up the valley of the Shyenne, we see only the Cretaceous beds 
Nos. 4 and 5, with many fossils, until we are beyond the mouth of Bear creek, when the 
Tertiary makes its appearance, crossing the Shyenne and stretching off toward the base of 
the Black hills in long ridges or isolated buttes. The drift material resting upon the 
Cretaceous rocks along the river sometimes attains a thickness of ten or fifteen feet. 
October 7th. The bed of Tertiary on the left side of the Shyenne river is about thirty 
miles in width. A section about fifteen miles above the mouth of Bear creek, on the left 
side of the Shyenne, presents the following strata: 
j, ri r 1. Light gray indurated clay. 6 feet, 
g ^ <2. Seam of gray sandstone. 18 inches. 
g -a 13. Ash-colored plastic clay with a greenish tinge, and a pinkish band of fine grit at the base. 30 feet. 
