322 GEOLOGY AND MINERALOGY. 



Proceeding northward from the last mentioned localities, we find on reaching 

 the Loup fork of Platte river, near the eastern limits of the Pawnee reservation, 

 outcrops of the light colored Inoceramus beds already mentioned, (No. 3, Nebraska 

 section,) near the water's edge ; and at the mouth of Loup fork, on the Platte, the 

 red sandstone No. 1, so often referred to, crops out near the river margin, while 

 the Inoceramus beds are seen in the bluffs above it. Going down the Platte in a 

 direction nearly contrary to the dip of the strata, we find this sandstone rising up 

 so as to form near the mouth of Elk Horn river, bluffs some sixty feet in height. 

 Here it seems to rest directly upon upper Carboniferous rocks. Continuing on 

 down the Platte, we find this red and yellow sandstone rising higher and higher in 

 the hills until we come within five or six miles of the Missouri, where it is seen 

 with its base elevated near sixty feet above the Platte ; and there are probably 

 outliers of it between that point and the Missouri at greater elevations. So that 

 we here find the same formation which at Smoky Hill river is elevated about twelve 

 hundred feet above the level of the Missouri at Fort Leavenworth, and seven 

 hundred feet above the same horizon near Little Blue river, has by the gradual 

 north-westward dip of the strata, sunk to within about one hundred feet of the 

 Missouri at the mouth of the Platte.* 



Ascending the Missouri from the localities just mentioned, we see occasional 

 exposures of the upper Carboniferous rocks, which gradually sink lower and lower 

 until they pass beneath the river near Florence, to be succeeded by the reddish 

 and yellow sandstones, &c., of No. 1, — (Nebraska section.) Above this, occasion- 

 al exposures of this formation are seen with its characteristic fossil leaves, along 

 the river ; and at several loeahties, some thirty miles below the mouth of Big 

 Sioux river, it forms perpendicular escarpments of yellowish sandstone, rising 

 from ths water's edge to an elevation of about eighty feet ; while at a higher 

 point, back on the summits of the Hills, the same calcareous beds are seen contain- 

 ing Inoceramus problematicus. Here at a quarry in the sandstone (formation No. 

 1,) some twenty feet above the level of the river, one of us (Dr. H.) collected a 

 large number fossil leaves, some of which are identical with species found by us 

 in this rock at the Smoky Hill locality already mentioned. The sketches of leaves 

 sent by us to Professor Heer were mostly drawn from specimens collected at this 

 locality. 



At the mouth of Big Sioux river a low bluff of this formation, not more than 

 fifteen or twenty feet in height, is seen, and on the hills back a little from the river 

 at a higher elevation the same Inoceramus bed crops out at several places, and is 

 used for making lime. At another locality, about eight er ten miles up Big Sioux 

 river, which comes in from the north west, one of us (Dr. H.) saw No. 1, contain- 

 ing its characteristic fossil leaves, directly beneath No. 2, of the Nebraska section. 



• The gradual descent of the Missouri river makes its surface at Fort Leavenworth, about 

 three hundred feet lower than at the mouth of the Platte, hence the exposures of No. 1, seen 

 at the latter locality, one hundred feet above the Missouri, are some four hundred feet above 

 the level of the Missovu-i at Fort Leavenworth, and of course about three hundred feet lower 

 than the Little Blue river outcrops. The dip, however, is greater than this would indicate, 

 for the strata incline towards the north toest, vi'hile the mouth of Platte river, is north east 

 of the Blue river localities. 



