THE GEOLOGICAL SUCCESSION '389 



Catholicon Springs hotel. It is in a small draw which heads in the 

 sandstone ridge lying east of the Red Bed valley. The succession here 

 is as follows : 



Unkpapa sandstone. 



Green shales with belemnites, etc 80 fee't thick. 



Red sandy shales 80 " " 



Greenish shales and thin sandstones 8 " " 



Buff, slabby, ripple-marked sandstone 15 " " 



Limestone filled with ostreas 10 " " 



Green shales, very sandy . : 21 " " 



Soft, thin-bedded sandstone, fish-bearing layer 4 " " 



Buff sand 2 " " 



Eed beds. 



The buff sand lies on a slightly eroded surface of the Red beds. To 

 the north and to the south it thickens and becomes a conspicuous bed 

 of red to buff sandstone. The limestone with Ostrea is a local lense not 

 found elsewhere. The fish appear to occur only on the surface of one 

 of the sandstone layers about ten inches above the top of the buff sand. 

 Although extensive excavations were made, only a small lot of material 

 was found. A fairly extended scanning of the same horizon in the 

 vicinity revealed only an occasional fish scale. 



Hot Springs vicinity. — Near Hot Springs there is considerable strati- 

 graphic variation in the Sundance formation. The general average sec- 

 tion is as follows : 



Unkpapa sandstone. 



Green shales, belemnites 90 feet thick. 



Red sandy shales and sandstones 80 " " 



Green shales 8 " " 



Buff slabby sandstones, ripple-marked 30 " " 



Dark shales .9 " " 



Red massive sandstone 25 " " 



Red beds. 



The fossils are very abundant, both in the calcareous layers in the 

 upper green shales and in the buff, ripple-marked sandstones. They 

 occur in some of the other beds, but in much less number. 



Buffalo Gap vicinity. — At Buffalo gap, where there are extensive ex- 

 posures, the following beds are seen : 



Unkpapa sandstone. 



Green shales with thin fossiliferous limestone beds. . . 100 feet thick. 



Red, sandy shales and soft sandstones 65 " " 



Greenish buff, sandy shales and thin sandstones 15 " " 



