HUNTING FOSSIL ANIMALS IN NEBRASKA, WYOMING, 



AND SOUTH DAKOTA 



By CHARLES W. GILMORE 

 Curator, Division of Vertebrate Paleontology, U. S. National Museum 



Our efforts of previous years have been directed toward an ade- 

 quate representation in the National Museum collections of all im- 

 portant Tertiary faunas. In continuation of this program, explora- 

 tion of the Oligocene was planned for 1932. 



Harrison, Nebr., the county seat of Sioux County, adjacent to ex- 

 tensive badland areas of both Oligocene and Miocene, has for years 

 been the base for fossil-hunting expeditions, and here I met my field 

 party with camp equipment and truck. Fair success attended our 

 efforts in the two weeks spent in this field, although the workable ter- 

 ritory was much restricted owing to the presence of other collecting 

 parties in adjacent areas. It is of interest to note that 46 men repre- 

 senting 13 institutions were collecting vertebrate fossils in or near 

 the fields covered by us during the summer. In more than 30 years' 

 field experience, never before in a single season have I encountered so 

 many " bug hunters " as we are commonly designated by the local 

 ranchers. 



In the vicinity of Harrison, near the summit of the Lower Harrison 

 formation occur the Daemonclix beds, named from the giant spirals of 

 hard rock which resist erosion and at many points stand out promi- 

 nently against the bluffs along the upper reaches of the Niobrara 

 River (fig. 5). These spirals, popularly called "devil's corkscrews," 

 were originally thought to represent the spiral roots of some gigantic 

 plant, but later authorities have regarded them as the burrows of the 

 extinct rodent Stcncofibcr, remains of which were found inside the 

 spiral. Be that as it may, knowing the National Museum did not pos- 

 sess a specimen of Daemonclix, we grasped the opportunity to collect 

 a representative specimen of this interesting fossil. 



While I was visiting the Colorado Museum of Natural History at 

 Denver, on my way to the field, the director, J. D. Figgins, voluntarily 

 granted permission for my party to work in their rhinoceros quarry 

 near Torrington, Wyo. (fig. 6), and it was decided to take advantage 

 of this generous offer. A few days' work there resulted in the recovery 

 of a large slab of rock containing a skull and several jaws of Cacnopus, 

 an Oligocene rhinoceros. 



