1903.] Matthew, Fauna of Titanotherium Beds of Montana. 1 99 



both localities the lithologic distinctions are confirmed by the 

 fossils found. 



The Titanotherium Beds are soft, easily weathering, banded 

 clays, often sandy, crumbling to the usual weathered-clay 

 surface, varying in color from dark reddish brown through 

 buff to an almost greenish white. Cross-bedding is seen in 

 the sandier layers. They are not unlike the Titanotherium 

 Beds in South Dakota, but run to deeper and more contrasted 

 coloring. At Pipestone Springs they dip quite steeply toward 

 the north, lying up against the ancient crystalline rocks on 

 the south side of the creek. We found in them the following 

 fauna : 



Marsupialia. 



Peratherium titanelix, sp. nov. Allied to Peratheria of Middle Eo- 



cene and Oligocene. 



Insectivora. 



Aptemodus medisevus, g. et sp.nov. Allied to ? Centracodon of Middle 



Eocene. 

 Microptemodus borealis, " " Allied to ? Centetodon of Middle 



Eocene. 

 Ictops acutidens Douglas ) More primitive than any Middle 



thomsoni, sp. nov. ) Oligocene Leptictid. 



Creodonta. 



Pseudopterodon minutus {Douglas) C Intermediate between the Oligo- 

 ? Hysnodon sp. •< cene Hycenodon and Middle 



( Eocene Sinopa. 



Carnivora Fissipedia. 



Bunselurus infelix, sp nov. 



Cynodictis paterculus, sp. nov. Somewhat more primitive than 



Middle Oligocene species. 



Rodentia. 



Ischyromys veterior, sp. nov. Somewhat more primitive than 



Middle Oligocene species. 

 Cylindrodon fontis Douglas. 

 Sciurus vetustus, sp. nov. 

 Gymnoptychus minor {Douglas) . 

 " minimus, sp. nov. 



