Rocks of Eastern Kansas and Nebraska. 17? 
it will be remembered that, so far as he relied at all upon pa- 
leontological evidence, he identifies the rocks at Bellevue, with 
a particular formation in New Mexico, and both with the Moun- 
tain Limestone of Europe, almost solely upon the testimony of 
certain Brachiopoda. 
After completing his researches in the region of Bellevue, 
Mr. Marcou continued his progress up the Missouri to examine 
a sandstone formation extending along-that stream for some dis- 
tance below Sioux City, located at the mouth of Sioux River, 
In regard to the age of this formation, the readers of this Journal 
will remember that Mr. Marcou and some géologists in this coun- 
try have differed widely. In 1853, the writer and Dr. Hayden ex- 
amined it while returning from an expedition to the Bad Lands for 
Prof. Hall. ‘They found but a few badly preserved fossils in it, but 
left the locality under the impression that it was probably Cre- 
taceous, as it was immediately overlaid by rock undoubtedly of 
that age; which opinion was adopted in a paper published by 
Prof. Hall and the writer in Mem. Am. Acad. Arts and Sci., 1856. 
In his Geological Map, however, of N. America, published in 
1855, (Ann. des Mines, [2], vii), Mr. Mareou had colored this. 
tock here on the east side of the Missouri, Mountain Lime- 
lying upon the Carboniferous rocks; is of the age of the New 
ndstone.”’ 
_ Butin a paper published in the Archives des Sci. Bibliothéque Uni- 
__ -verselle, June, 1858, 
(Sur later description, to the Jurassic. Being perfectly satisfied 
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Must be Cretaceous. The modern affinities of the leaves 
: showed it could not be older, and its position beneath unques- 
* 
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