SOUTH DAKOTA SCHOOL OF MINES 



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The shell body is often preserved with remarkable per- 

 fection but owing to the fact that weathering readily sep- 

 arates the bones, specimens exposed on the surface are 

 usually more or less disintegrated. The head and feet are 

 rarely found. Dr. Leidy, who first described the species 

 stated that he had seen hundreds of shells but no skull. 

 Even today there is record of only two skulls. One of these 

 in the Carnegie Museum of Pittsburg is accompanied by the 

 shell. The other is in the Princeton Museum but the body 

 to which it belonged was not found. The general absence 

 of the head is due perhaps to the fact that Stylemys was 

 a dry land tortoise and any freshet that might be able to 

 carry or roll the heavy decaying body into water where 

 deposition was taking place would wrench the head away. 

 This, separate from the body, would be inconspicuous and 

 hence fail of ready detection. 



Several fossil turtle eggs have been found in the Bad- 

 lands and they are regarded as belonging to the common 



Figure 73 — Head of the abundant Oligocene dryland tortoise, 

 Stylemys nebrascensis. Natural size, (a) view of right side; (b) 

 view from above; (c) view from below. Hay, 1906. 



species just described. Hay states that they are slightly 

 elongated but he indicates that this is perhaps due to de- 

 formation by pressure from an original globular form. They 



