84 R. S. Lull — New Tertiary Artio dactyls. 



INTRODUCTORY. 



In 1914 a Yale expedition under the guidance of the 

 writer was working its way westward along the Niobrara 

 River, following, in so far as possible, although in a re- 

 verse direction, the route of the very successful Marsh 

 expedition of 1873. While camped near the mouth of 

 Antelope Creek, a tributary of the Niobrara, one of our 

 number, Mr. W. S. Benton, had the good fortune to find 

 on one side of a small tributary canyon, a talus slope 

 literally strewn with bones, many entire, others the more 

 resistant articular ends of limb bones or the centra of 

 vertebrae, jaws and teeth, which, while varying in size, 

 apparently all belonged to the same species of small 

 ruminant, which for want of better identification was 

 called " Blast ornery x." Several days were spent by vari- 

 ous members of the party in collecting all of the surface 

 material on the talus slope, and then, the bone-bearing 

 layer being identified, it was excavated for a considerable 

 area, with still more astonishing results, for no fewer 

 than nineteen skulls were obtained in varying degree of 

 perfection. 



The locality lies in the northwestern portion of Cherry 

 County, Nebraska, and it is our purpose to reopen the 

 quarry in the near future, as it gives promise of further 

 results. The quarry, " Quarry F" as it is called on our 

 records, lay in a 6-foot bed of hard, light gray sandstone 

 at a level of 106 feet above the surface of the Niobrara 

 River, and 25 feet above the canyon floor. A section pre- 

 pared by Doctor Malcolm R. Thorpe, another member of 

 the party, is here reproduced. 



Talus, fragments of white sandstone 25' 



Fine-grained, grayish, shaly sandstone 15' 



Massive white sandstone. Soft, more or less jointed. 



Turtle and other (mammal) small bones 19' 6" 



Hard, light gray sandstone, jointed. Alet ornery x bones. 0' 6" 



Talus. Aletomeryx bones 25' 



Associated Material. 



Besides the specimens of the species to be described 

 in this paper, "Quarry F" also yielded the remains of 

 several other forms, some of which pertain to the actual 

 6-foot layer in which the ruminant was entombed, others 

 were found either in the talus or on the slope above. Yet 



