272 G. T. BETTANY ON THE GENUS MEBYCOCHCERTTS. 



inches. 



Long diameter of orbit 1-J 



Depth of infraorbital arch 1 T 9 ^- 



Width of face 2| inches in front of orbit 2^ 



Height of face anteriorly 3f 



Length of last molar tooth 1^ 



Extreme length of lower jaw 10 



Appendix on the Geological Position of the Oreodontidce. 



It has been thought desirable to add to the foregoing paper a 

 view of the species of Oreodontidae already established, the loca- 

 lities from which they have been obtained, and the age of the 

 deposits, so far as they have been determined. There can be little 

 doubt that the number of species is less than is here indicated ; but 

 it would be futile at present to attempt such a revision as is required. 

 For similar reasons the name Merychyus is retained for the species 

 characterized by Prof. Leidy. 



Oreodon affinis ?, Leidy. Bed A, Mauvaises Terres, White E., Dakota. Miocene. 



hybridus ?, Leidy. „ „ „ 



bullatus?, Leidy. „ „ ,, 



Culbertsoni, Leidy. Beds B, C, and D, Mauvaises Terres, White R., 



Dakota. Miocene. 

 Culbertsoni, Cope. North Colorado, equivalent to White-river beds. 



Miocene. 



Culbertsoni, nobis. Bridge Creek, John Day's R., Oregon. Miocene. 



gracilis, Leidy. Beds B, C, and D, White R., Dakota. Miocene. 



gracilis, Cope. North Colorado. Miocene. 



major, Leidy. Bed D, White R., Dakota. Miocene. 



major, nobis. John Day's R., Oregon. Miocene. 



superbus, Leidy. „ ,, „ 



occidentalis ?, Marsh. ,, „ „ 



Merycochoerus proprius, Leidy. Bed D, Niobrara R., Nebraska. Miocene. 



temporalis, nobis. John Day's R., Oregon. Miocene. 



Leidyi, nobis. „ „ ,, 



rusticus, Leidy. Sweetwater R., Wyoming. Pliocene. 



Merychyus elegans, Cope. North Colorado. Miocene. 



elegans, Leidy. Niobrara R., Nebraska. Pliocene. 



medius, Leidy. ,, ,, ,, 



■ major, Cope. North Colorado. Miocene. 



major, Leidy. Niobrara R., Nebraska. Pliocene. 



The John-Day's-River deposits are indicated as Miocene in accord* 

 ance with Prof. Leidy's conclusion that the zoological character and 

 state of preservation of the fossils renders it probable that the for- 

 mation to which they belong is of contemporaneous age with those 

 of the White River, Nebraska. "With regard to the first-named 

 species in the list, Prof. Leidy says that certain facts "indicate 

 Oreodon affinis, hybridus, and bullatus to be species which preceded 

 the others in time, and were perhaps their ancestors, from one or 

 another of which they may have been derived." A further state- 

 ment of interest, borne out by the above Table, is that "Meryco- 

 choerus proprius appears not to have inhabited the same locality with 

 the Oreodons, at least contemporaneously." 



