SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 131. NO. 6. PL. 10 



1 



^A. 



£-*:,«•- --• -P" 



Cf^r 



^ >r A 



I 1 jiT-^K^ Jmm\'>^ xK 



Wll^ini 



M 



.fs^. 



V m-' ^ 



:^^ 





Phenacodus? from the Bison Basin Paleocene 

 (see explanation at end of text.) 



