EXPLANATION OF PLATE VII. 



All the figures are of the natural size, except Fig. 10, which is reduced to one-half the diam- 

 eter of the original. 



Figs. 1-5. Merycochcerus eusticus. From specimens obtained on Sweetwater River,. Wyoming, by 

 Professor Hayden's party in 1870. 



Fig. 1. Series of. upper molars of the right side, viewed on their trituratiDg surfaces. The 

 last tooth had not entirely protruded, and iu the first one the median enamel-pits are 

 nearly obliterated. 



Fig. 2. Upper last premolar and molar of the left side, of the temporary series. 



Fig. 3. Upper second and third premolars of the left side, of the permanent series. The trit- 

 urating surfaces but slightly worn. 



Fig. 4. Outer view of the same teeth, in a small jaw-fragment. 



Fig. 5. Symphysis of the lower jaw, with the four incisors on each side. 



Fig. 6. Merycochcerus proprius. First and second upper molars of the right side. From a specimen 

 obtained on the Niobrara River, by Professor Hayden, in 1857. 



Figs. 7-11. Oreodon supehbus. From specimeus discovered iu Oregou by the Rev. Thomas Condon. 

 Fig. 7. Last lower molar of the right side, viewed on the triturating surface. 

 Fig. 8. First and part of the second molars, from the same jaw-fragment as tho preceding 



figure. 

 Fig. 9. The three lower premolars of the right side, viewed on their triturating surf his. 



From the same specimen as Fig. 16, Plate II. 

 Fig. 10. Upper view of the intermediate portion of tho face, one-half the natural size. 

 Fig. 11. Yiew of the inner surface of a lower canine, from the left side of a specimen of a 



jaw, which lies with its outer face imbedded in a hard mass of rock. 



Fig. 12. Oreodon Culbertsoni. A series of upper true molars of the left side. Specimen discovered 



by Mr. Condon on John Day's River, Oregon. 

 Figs. 13, 14. Dicotyles pristinus. Specimens in the Condon collection of Oregou fossils. 



Fig. 13. Triturating surface of a lower penultimate molar. 



Fig, 14. Outer view and view of tho triturating surface of a lower last molar. 

 Fig. 15. Anchitherium Bairdi. An upper right molar. From the Coudou collection. 



Figs. 16, 17. Anchitherium agreste. From a specimen found on Red Rock Creek, one of the head 

 streams of the Jefferson Fork of the Missouri. Obtained by Professor Hayden in 1871. 



Fig. 16. Lower last rjremolar and first molar of tho left side. • Triturating surface much 

 worn. 



Fig. 17. Last molar, from the same specimen of tho jaw as the former. 



Figs. 18, 19. Felis Augustus. Specimens discovered by Professor Hayden on the Loup Fork of the 

 Niobrara River, Nebraska. 

 Fig. 18. Portion of the right premaxillary, containing the second incisor, viewed in front. 

 Fig. 19. Upper sectorial molar of the left side, viowed externally. 



Fig. 20. Patriofelis ultTv (?) A premolar, probably of the upper jaw. Specimen found by Dr. Carter in 

 the vicinity of Fort Bridger, Wyoming. 



Figs. 21-23. Teeth of a carnivore, undetermined. Obtained by Professor Hayden's party on Henry's 

 Fork of Green River, Wyoming. 

 Fig. 21. Outer view of the crown of an anterior premolar. Fig. 22. Upper view of the same. 

 Fig. 23. Outer view of tho crown of a canine tooth. 



