OF THE MISSOURI RIVER. 133 
of which a fine lacustrine sediment collected, subsequent to the drift period ; 
entombing not only fresh-water species of mollusca, but a still greater number of 
terrestrial Helicide, which frequented its shores. These deposits were, at a later 
period, scooped out during the drainage of the country, which took place in propor- 
tion to the gradual rise of the land, and left conspicuous monuments of its existence 
in the form of abrupt bluffs, one hundred,and fifty to two hundred feet above the 
river bottom. Their appearance is shown by the illustration on the opposite page, 
sketched in the Missouri bottom, a few miles below Kanesville. 
Carboniferous Rocks of the Missouri River—The first locality where I had an 
opportunity of inspecting the carboniferous rocks, in place, on the Missouri, was 
above Bellevue, about twelve or fourteen miles above the mouth of Platte River. 
Ledges of light-coloured limestone are exposed here, ten feet above the water- 
level, on the right bank, containing Fusulina cylindrica, Productus punctatus, P. 
cora, P. costatus (?), P. Flemingii, P. Humboldtii (?), Spirifer fasciger (2), Orthis 
umbraculum, Terebratula plano-sulcata, and Bellerophon, allied to B. hiulcus. (See 
Section No. 40, M.) 
It is said that a seam of coal can be seen beneath these limestones, at extreme 
low water. Nothing of the kind, however, was visible when I was there, though 
the water was tolerably low. At the base of the bluff, on the opposite side of the 
river, limestone has been obtained, some slabs of which contain a few of the same 
species of Productus as at Bellevue. The bluffs rise here to the height of two hun- 
dred and thirty to three hundred feet above the water-level. 
The next good section is below the mouth of Platte River, and six miles above 
the mouth of Keg Creek, or Five-Barrel Island, of Nicollet. ; 
Towards the base of this Section (No. 39, M), I found limestone, containing 
Fusulina cylindrica, and above it marly limestones, affording Productus semireticu- 
latus, P. carbonarius (2), P. Flemingii (var. longi-spinus), Orthis umbraculum, Spirifer 
Jusciger (?), Chonetes semiovalis, Allorisma sulcata, a Cyathophyllum, intermediate in 
its structure between C. vermiculare and C. plicatus, and a small, undescribed species 
of Spirifer. ; 
A few miles lower down the river, the limestone with Fusulina cylindrica is at 
an elevation of sixty feet (Section 38, M), overlying black, red, and gray argilla- 
ceous shales. Hence, it is probable, that the coal reported to have been seen at 
extreme low water at Bellevue, is bituminous shale, with, perhaps, some imperfect 
coal; at least, no workable seam was observed at those sections, which present to 
view the strata inferior to the Productus and Fusulina bed of Bellevue. The bench 
of encrinital limestone, which lies about one hundred feet above the water-level, 
six miles above the mouth of Keg Creek, is only forty feet above the bed of the 
river, two or three miles lower down; showing that the principal axis of elevation, 
on this part of the Missouri, is near Keg Point. This is proved also by the northerly 
dip, at the head of the exposure, and the southerly dip, at the foot. 
As the strata again rise, on approaching Fort Kearney, the red, purple, and gray 
shales increase in thickness (Sections No. 34 and 35, M), and are overlaid by buff 
encrinital and marly limestones; one bed of the latter is charged with Productus 
