Section IV., 1905 [ 43 ] Trans. R. S. C 



IV. — Fossil horses of the Oligocène of the' Cypress hills, Assiïiiboia. 



By Lawrence M. Lambe, F.G.S., Vertebrate Palaeontologist to the 

 Geological Survey of Canada. 



(Read May 25, 1905.) 



Among the fossil vertebrate remains obtained by the writer during 

 an expedition to the Cypress hills on behalf of the Geological Survey 

 in 1904 are a number of horse teeth that are of special interest. These 

 teeth are from the Oligocène deposits, at the eastern end of the hills, in 

 Bone coulée, where the greater part of the collection of last year was 

 made. They form the subject of the present paper, and are described 

 in detail, as the majority of the species represented, of which there are 

 a number, appear to be new. It is surprising to find in them so 

 marked a variation, coming as they do from a rather restricted area. 



The deposits capping the Cypress hills, from which the collection 

 ■^i^-i and the previous collections of 1883-84 (also from Bone coulée) 

 were obtained, are referred to as of Miocene age by ]\IcConnell in his 

 report of 1885.^ Cope, from a study of the 1883-84 collections, con- 

 cl.idcd that these beds are of Oligocène or Lower Miocene age.^ ]\Iat- 

 thew has assigned them to a more definite horizon at the -bottom of the 

 Oligocène, expressing the opinion that they are probably of approxi- 

 mately the same age as the Titanotherium beds at Pipestone springs, 

 Montana.^ Judging from a study of the vertebrate remains included 

 in the 1904 and previous collections from the Cypress hills, the "writer 

 believes that the deposits in question include, besides beds of the horizon 

 of the Titanotherium beds of Montana and Dakota, the equivalents of 

 the Oreodon beds of a slightly higher horizon, and of probably the still 

 later Upper Oligocène beds, in part at least. This conclusion regard- 

 ing the precise age of these deposits is reached more particularly from 

 a study of the fossil remains described in this paper. limongst these 



^ Report on the Cypress hills. Wood mountain and adjacent country, &c., 

 by R. G. McConnell. Part C, Annual Report, 1S85. Geological and Natural 

 History Survey of Canada. 



' The Species from the Oligocène or Lower Miocene beds of the Cypress 

 hills, by E. D. Cope. Contributions to Canadian Palaeontology, Vol. Ill 

 (quarto). Part 1, 1891. Geological Survey of Canada. 



^ The fauna of the Titanotherium beds at Pipestone Springs, Montana, 

 by W. D. Matthew. Bull, of the American Museum of Natural History, Vol. 

 XIX., Article VI., 1903. 



