GEOLOGICAL SURVEY OF THE TERRITORIES. 345 



American mastodon, both in the eastern and western portions of the 

 continent. 



Bison latifrons. — The great extinct bison of America was originally 

 indicated by a portion of a skull discovered on a tributary of the Ohio 

 River about a dozen miles from the famous deposit of bones, Big-Bone 

 Lick, Kentucky. Bemains bave also been found in the latter locality, on 

 the Brazos Biver, Texas, and elsewhere. The cranial portion of a skull, 

 apparently of the same species, was discovered in California, by Walter 

 Brown, of San Francisco, and was presented to the Academy of Natural 

 Sciences of Philadelphia. The species was about as large as the living 

 buffalo or arnee of India and Java. 



OREODONTID^E. 



The above name is given to an extinct family of animals, the remains 

 of which, discovered in the Western Territories of the United States, 

 indicate that during the tertiary period it embraced many genera and 

 species. The members of the family in anatomical character exhibit 

 strong suilline affinities, while the structure of their grinding teeth 

 indicate them to have chewed the cud like our ruminating animals. 

 Their feet were constructed nearly as in the hog, and, as in this animal, 

 were provided with four toes. 



The skull of the oreodonts approaches in form that of the peccaries. 

 The cranial portion resembles that of the camel, and, as in this, is horn- 

 less. The temporal fossae are large and separated by a median sagit- 

 tal crest, as in the camel. The orbits are closed behind by an arch, as 

 in the latter, and other living ruminants. Large and comparatively 

 deep depressions occupy a position just in advance of the orbits, as in 

 the living deer family, but no unossifled spaces occupy any part of the 

 face. The teeth in both jaws form nearly unbroken arches, a condition 

 in which we find none of the allied living families, and but few of any 

 other living mammalia. Well-developed incisors occupy both jaws, such 

 as exist alone in the lower jaw of living ruminating animals. The 

 canine teeth approach in character most nearly those of suilline ani- 

 mals. The grinders are constructed like those of the living ruminants, 

 resembling most nearly those of the deer family. 



OREODON. 



The remains of this genus are of all other fossils the most abundant 

 of those which have been discovered in the miocene tertiary deposits of 

 the mauvaises terres of White Biver, Dakota. Two species especially, 

 judging from the great quantity of their remains which have been col- 

 lected, appear to have formerly existed in immense numbers. They 

 were most likely gregarious, in the manner of the existing peccaries, and, 

 like the modern bison, roamed together in great herds over the exten- 

 sive prairies of the West. Compared with the latter animal they were 

 insignificant in size, and in this respect approached the former. 



Oreodon Culbertsoni. — This species, the remains of which have been dis- 

 covered in the greatest abundance, was first brought to our notice by 

 Messrs Alexander and Thaddeus Culbertson. These gentlemen, brothers, 

 engaged in the fur trade, were the first to collect fossils from the mauvaises 

 terres, and place them in the hands of naturalists. Oreodon Culbertsoni, 

 named in their honor, was intermediate in size and appearance to the do- 

 mestic sheep and the collared peccary. Skulls, fragments of jaws with 

 teeth, and other bones of the skeleton of upwards of a thousand individu- 

 als of this species have come under the inspection of the writer. In the 



