460 



N. H. DARTOX PALEOZOIC AND MESOZOIC OF WYOMING 



bed lies next above the heavy sandstone members in the Rock Creek re- 

 gion, but there are also higher beds farther south. These coal deposits 

 have recently been described by Mr Siebenthal." 



A typical section of the Montana formation was measured by Mr Sie- 

 benthal, as follows : 



Section of Montana Formation Southeast of Rock Creel: Station, Wyoming 



Upper division . . 



Lower division. 



r Sbale 



Brown sandstone, partly concretionary (Inocera- 



7)1 us, etcetera, Upper fossil liorizon) 



Soft, gray sandstone witli hard concretions 



BufC shale 



Concretionary sandstone (gasteropods, baculites, 



etcetera ) 



Gray sandstone 



Buff shale 



Massive, disintegrated, gray sandstone ; no fossils . 



Shale '. 



Massive, buff and brown, concretionary sandstone 



(baculites) 



Black shale with beds of coal 



Shaly sandstone and shale ("Pine ridge" coal) .... 

 Massive white to gray sandstone ; some shale in 



lenses (Scandstone of "Pine ridge") 



Feet 

 140 



10 

 200 



5 



12 



150 



20 

 125 



15 



560 



30 



60 



Shale 



Bro-mi sandstone, round concretions (very few fos- 

 sils) 



Shale 



Sandstone nodules (probably contain fossils) 



Shale 



Concretionary sandstone (main collection of fos- 

 sils) 



Shale 



Brown sandstone, with oval concretions (few fos- 

 sils) 



Shale 



Gray sandstone (plants, baculites ?) 



Shale 



Sliale and claystone lenses (baculites) 



Shale 



Sandstone, with round concretions 



Black shale, with thin beds of nodular sandstone. . 



1,332 



300 



5 

 225 



2 

 240 



15 



300 



3 



115 



5 



425 



10 



150 



5 



2,350 



Niobrara. 



4,1B0 



"U. S. Geological Survey, Bulletin no. 316, pp. 261-263. 



