12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



Except for their intermediate positions, no particular additional 

 evidence is forthcoming from the ledge and west-end locality faunas, 

 other than that the ledge would seem almost certainly closer to the 

 saddle than to the Titanoides locality in age. 



SYSTEMATIC DESCRIPTION OF VERTEBRATE REMAINS 

 REPTILIA 



Sauria 



ANGUIDAE 



The only nonmammalian specimens encountered during the collect- 

 ing were four fragmentary dentaries, two portions of maxillae, and a 

 premaxilla of a lizard. These were examined by Dr. David H. Dun- 

 kle and recognized as belonging to a small anguid type. The genus 

 represented could not be determined from the material at hand, but 

 Pcltosaurtis has been recognized in horizons as early as Lance and 

 Fort Union. Nevertheless Glyptosaurus and Xesfops also include 

 diminutive species and these genera are known in the Eocene. All 

 but one of the specimens came from the saddle locality. A single 

 fragmentary dentary was found at the Titanoides locality. 



MAMMALIA 



MULTITUBERCULATA 



PTILODONTIDAE 



Although the multituberculates appear to be comparatively rare, to 

 judge by the frequency with which their remains are encountered, 

 nevertheless they must have been highly diversified, because each of 

 the four fragmentary specimens known evidently represents a different 

 form. The materials in each case are too incomplete to indicate with 

 certainty the genus represented but, of the forms tentatively identified, 

 two suggest Torre jonian and two Tiffanian, although three of the spec- 

 imens came from the small saddle locality discovered by Dr. R. W. 

 Brown. The fourth specimen, that compared with the Tiffanian 

 Ectypodus musculus, came from a short distance away but regarded 

 as the same stratigraphic horizon as the saddle. 



Cf. PTILODUS MONTANUS Douglass, 1908 

 Plate I, figure i 



A relatively large ptilodont multituberculate is represented by a 

 single incomplete left P4, U.S.N.M. No. 2o8yy. There is no certainty 



