DOUCI.ASS : VKKTHIiRATHS FROM MONTANA 'I'KR'riARV. 



lof) 



Merycodiis nccatus Leidy. 



Af(-rycodus ? agi/is (Douglass). 



Palicomcryx amcricanus Douglass. 



Palceomcryx borealis (Cope). 



Mastodon. 



These beds overlie the ^^'hite River and occupy the top of the trian- 

 gular bench between the Madison anddallatin rivers from the vicinity 

 of Logan on the north, nearly to Elk Creek on the south ; also the 

 tops of the high bench west of the Madison River. 



Descriptions of New Genera and Species. 

 All the fossils described in this paper were collected by the writer, 

 unless otherwise stated. The drawings were made by Mr. S. Pren- 

 tice. The numbers given to the specimens are the Carnegie Museum 

 numbers. 



EOCENE? (Sage Creek Beds.^ 



PERISSODACTYLA. 



Heptodon ? 



No. 717. Fig. I. 



Part of a superior maxillary with the last premolar ai.^ tne three 

 molars on the left side. From the Sage Creek beds northeast of Lima. 



It is doubtful whether this should be 

 assigned to the genus Heptodon or to 

 Systemodon. Taking Dr. Wortman's 

 distinguishing characters of the teeth 

 it is intermediate between the two. 

 A comparison with the specimens in 

 the American Museum of Natural 

 History confirms this, but it seems 

 to be nearer to Heptodon than to 

 Systemodon, appearing to be some 

 more primitive form of that genus. 



The cross crests are low. The pos- 

 terior outer cusp in M^ is flat and 

 pushed far inward, making the meta- 

 loph very short, and the tooth nearly 

 an equilateral triangle in outline as 

 seen from above. In M- the posterior outer cone is a trifle convex 

 outwardly, though it is slightly concave near the posterior edge. In 



Fig. I. Heptodon? (717), Sage 

 Creek Beds. Natural size. a. Part 

 of left maxillary with last premolar 

 and three molars, b. Crown view of 

 teeth of same. 



