THE OVEELAKD EOUTE COUN^CIL BLUFFS TO OGDEN. 



41 



Succession of the Tochformatwns exposed along the Union Pacific Railroad east and tvest 



of the Laramie Mountains. 



Period and 

 system. 



Tertiary, 



Tertiary (pos- 

 sibly in elud- 

 ing some 

 Cretaceous). 



Cretaceous 



Jurassic or Cre 

 taceous. 



Jurassic. 



Triassic or Per- 



mian . 



Carboniferoiis 



Archean . 



Epoch and series. 



Groups and formations. 



Pliocene. 



East of Laramie Mountains. 



Ogalalla formation 



Miocene. 



Arikaree formation. 



West of Laramie Mountains. 



Olierocene 



Gering formation. 



Not represented 





White Eiver group: 

 Brule clav. 



Chadron formation. 



Upper Creta- 

 ceous. 





Lower Creta- 

 ceous. 



Montana group: 



Fox Hills sand- 

 stone. 

 Pierre shale. 



Colorado group: 



Niobrara limestone. 



Benton shale, in- 

 cluding Mo wry 

 shale. 



''Upper Laramie" for- 

 mation. 



'* Lower Laramie " forma- 

 tion. 

 Montana group: 

 Lewis shale. 

 Mesaverde forma- 

 tion. 

 Steele shale. 

 Colorado ^roup: 



Niobrara limestone. 

 Benton shale, in- 

 cluding Mo wry 

 shale. 



Cloverly formation. 



Pennsylvanian. 



i[orrjson formation. 



Cloverly formation 



Morrison formation. 



Sundance formation 



Chugwater formation. 



Casper formation. 



Sundance formation. 



Chugwater formation 



Fnrelle limestone. 

 Satanka shale. 

 Casper formation. 



Granite (including Sher- 

 *man granite), gneiss, 

 and schist. 



Granite (including Sher- 

 man granite), gneiss, 

 and schist. 



