FORMATIONS OF THE NACIMIENTO GROUP 733 



No. I. Chriacus plevidens (Cope), last right lower molar, crown view. Acces- 

 sion No. 5713. 



No. 2. Same as No. i (side view). 



No. 3. Periptychus carnidens, left lower molar, ma, crown view. Accession 

 No. 5707. 



No. 4. Periptychus carnidens, right lower premolar, ? pg, crown view. Same 

 individual as No. 3. 



No. 5. Euprotogonia puercensis, last right upper molar, crown view. Acces- 

 sion No. 5710. 



No. 6. Insectivor, new genus and species, right lower molar, ? mj, side view. 

 Accession No. 5715. 



No. 7. Same as No. 6, crown view. 



No. 8. Olbodotes ? copei, second upper molar of left side, crown view. Acces- 

 sion No. 57 14. 



No. 9. Oxyclaenus sp., second upper molar of left side crown view. Four 

 times natural size. 



No. 10. Tricentes subtrigonus, second upper molar of right side in fragment 

 of jaw, crown view. Accession No. 5709. 



No. II. Miacidae, genus and species new, second upper molar of right side, 

 crown view. Accession No. 5712. 



CORRELATIONS 



With the exception of a small area in Montana where Torrejon 

 fossils have been found, neither of the faunas of the Nacimiento 

 group is known in North America outside of the one limited region 

 in the San Juan Basin of northwestern New Mexico. 



The beds in Montana which contain the Torrejon fossils were 

 discovered by Mr. Earl Douglass in igoi.s^ The first fossils were 

 found near Fish Creek in Sweetgrass County, T. 6 N,, R. 16 E., 

 in beds of Fort Union age. A collection of leaves from a sandstone 

 overlying the shale containing Torrejon vertebrates was sent to Dr. 

 F. H. Knowlton who pronounced the species all Fort Union beyond 

 a doubt. In 1908 and 1909 collections for the U.S. National Museum 

 were made in this region by Messrs. A. C. Silberhng and J. W. 

 Gidley. All who have worked in the district agree that the fossils 

 are in the Fort Union and all who have studied the fauna, including 

 Scott, Matthew, Gidley, Farr, and Douglass, agree that the fossils 

 are Torrejon. In that region beneath the Fort Union, containing 

 the fossil mammals, is the Lance formation or "Ceratops beds." 

 This formation contains dinosaurs and is Cretaceous in age, unless 

 perchance dinosaurs lived into Tertiary time as the flora seems to 



