DAKOTA AND NEBRASKA. 



15 



to make any important changes in it in my subsequent explorations. It is probably 

 very nearly correct : 



Vertical Section, showing the order of superposition of the different heds of the Tertiary 



hasin of White and Niobrara Rivers . 







SUBDIVISIONS. 



LOCALITIES. 



S to 







Yellow siliceous marl, similar in 



Most fully developed along 









its character to the loess of the 



the Missouri River from the 









Rhine, passing down into varie- 



mouth of the Niobrara to St. 







fe 



gated indurated clays and brown 



Joseph. Also in the Platte 



o 



o 





t3 



and yellow fine grits. Contains 



Valley and on the Loup Fork. 



3 





remains of extinct mammals. 





o 

 o 



<5 





mingled with those identical with 

 recent ones ; also a few mollusca, 

 mostly identical with recent spe- 

 cies so far as determined. 





CO 



