OF THE MISSOURI RIVE R. 



of which a line lacustrine sediment collected, subsequent to the drift period ; 

 entombing not only fresh-water species of mollusca, but a still greater number of 

 terrestrial Helicidce, 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 (?), Orthis 

 umbracidum, Terebratida plano-sulcata, and Bellerophon, allied to B. hiidcus. (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 beloAv 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 (?), P. Flemingii (var. longispinus) , Orthis umbraculum, Spirifer 

 fasciger (?), Ghonetes semiovalis, Allorisma sidcata, a Cyatliophyllum, intermediate in 

 its structure between G. vermiculare and G. plicatus, and a small, undescribed species 

 of Spirifer. 



A few miles lower down the river, the limestone with Fusidina 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 



