THE MORRISON FORMATION OF COLORADO 



349 



which appear to be due to erosion of the shales previous to the 

 deposition of the Dakota. 



Vertebrate fossils were found in the shales near the mouth of 

 Plum Canyon in a number of places. No means were at hand 

 for digging deep enough to obtain good material, but many 

 fragments were found on and near the surface. Two of the best 

 preserved fragments — the centrum of a vertebra and the portion 



Fig. 4. 



of a femur — are shown in the photograph, Fig. 4, about one eighth 

 natural size. The dimensions of the vertebra are as follows: 



Length - 



Transverse diameter at ends 



Depth at ends 



Transverse diameter at center 



Depth at center - 



Depth of sockets, each 



8 inches 



7 

 8 



$% " 

 6/ 2 " 



The fragment of the femur is 13 inches long, 12 inches wide, 

 and 7 inches in diameter. This does not represent the thickness 

 of the complete bone, since one side is imperfect. These bones 

 are solid and coarse in texture. One hollow bone was also 

 found. The piece is about. 5 inches in diameter and 7 inches 

 lono-, with a hollow 2 inches in diameter. The material obtained 

 is not sufficient for generic determination, but in size, texture, 



