THE 0\^ELAXD EOUTE COUNCIL BLUFFS TO OGDEX. 



75 



Eocene beds of the Bridger Basin. It was during tlie Eocene epoch 

 that the great development of mammalian life took place. The small 



F 



designated by other names than those 

 used for beds of essentially the same age 



that lie farther east. The following table 

 shows the relations of these formations: 



Succession of the roch formations exposed along the Union Pacific Railroad in ivestern 



Wyoming and eastern Utah, 



Period 



Tertiary. 



Epoch. 



Group and formation. 



Cretaceous or Ter- 

 tiary. 



Cretaceous. 



Jurassic . 



Jurassic or Triassic 



Triassic. 



Carboniferous. 



Devonian 



Silurian • 



Ordovician . 



Cambrian, 



Algonkian . 



Archean. 



Eocene. 



Bridger formation. 

 Green River formation 

 "Wasatch group: 



Kniiirht formation. 



Fowkes formation. 



Almy formation. 



(?) 



Evanston formation 





Upper Cretaceous 



Adaville formation. 

 Hilliard formation. 

 Frontier formation. 

 Aspen formation. 

 Bear River formation 



Lower Triassic. 



Permian (?) 



Beckwith formation (possibly including 



some Cretaceous). 

 Twin Creek limestone. 



Nu^rsret sandstone. 



Ankareh shale. 

 Thaynes limestone. 

 Woodside formation 



Park City formation 



Peunsylvaniau. 



ilississippian 



Weber quartzite. 

 Morgan formation 



Limestones. 



Granite, etc 



