DAKOTA AND NEBRASKA. 



13 



General Section of the Tertiary Eocks of Nebraska. 



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White and light drab clajs, with 

 some beds of sandstone, and local 

 layers of limestone. Fossils : Oreo- 

 don, Titanotherium, Hi/ojjotamus, 

 RJmwceros, Anchitherium, Hyceno- 

 don, Machairodus, Trionyx, Testudo, 

 Helix, Planorbis, Limncea, petrified 

 wood, &c., — all extinct. No brack- 

 ish water or marine remains. 



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Bad Lands of White River, 

 under the Loup River beds on 

 the Niobrara, and across the 

 country to the Platte. 



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Light and ash colored sandstones, 

 with more or less argillaceous lay- 

 ers ; fossils ; fragments of Trionyx, 

 Testudo with large Helix vivipara, 

 petrified wood, &c. No marine or 

 brackish water types. 



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Wind River Valley ; also 

 west of Wind River Mountains. 



Beds of clay and sand, with 

 round ferruginous concretions, and 

 numerous beds, seams, and local 

 deposits of lignite ; great numbers 

 of dicotyledonous leaves, stems, 

 &c., of the genera Platanus, Acer, 

 TJlmus, Popidus, &c., with very 

 large leaves of true fan palms; 

 also Helix, Melania, Vivipara, Cor- 

 hicula, Unio, Ostrea, Potamomya, 

 and scales of Lepidotus, with bones 

 of Trionyx, Emys, Compsemys, Cro- 

 codilus, &c. 



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Occupies the whole country 

 around Fort Union. Extend- 

 ing north into the British pos- 

 sessions to unknown distances, 

 also southward to Fort Clark. 

 Seen under the White River 

 group, on the North Platte 

 River above Fort Laramie, 

 also on Avest side of Wind 

 River Mountains. 



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