PLEISTOCENE OF EUROPE, NORTH AFRICA, AND NORTH AMERICA 457 



Paramylodon is described ^ as in some features more, in others less 

 specialized than Mylodon and retaining features of the older, more prim- 

 itive sloths. It differs from Mylodon in having but four upper teeth, the 

 hindermost of which is tri-lobed instead of bi-lobed. The limbs are more 

 slender and the ankles more flexible than in Mylodon. A second specimen 

 has recently been found - near Walsenburg, Colorado, which contains five 

 upper teeth, and while exhibiting the elongate skull and inflated muzzle of 

 the type of Paramylodon, it indicates that the generic distinction between 

 these two forms may be insecurely founded. A fine specimen of a Mylodon, 



Fig. 198. — Quarry in which six skeletons of the Lower Pleistocene horse fi'guj/s scolli were 

 found. Head of Rock Creek, Te.xas. Lower Pleistocene or Equus Zone. Photograph by 

 American Museum, 1900. 



not distinguishable from the Walsenburg specimen, comprising most of the 

 skeleton, was found in 1880 by Mr. S. Garman of a Harvard University 

 expedition at Hay Springs. A description of this specimen, now preserved 

 in the Museum of Comparative Zoology, has not been published. 



Prairie wolves (C latrans) have been found, but few if any true felids. 

 The peccaries (Platygonus) are much more swift-footed and advanced in 

 dentition than the modern peccary, and may be supposed to have lived 

 more in the open. The prairie dogs (Cynomys), gophers (Thomomys), and 

 field mice (Microtus) are even now characteristic of the plains of this same 

 Nebraska region, while muskrats (Fiber zibethicus) occurred then as now 

 along the streams. Remains of a small species of Castor aides are occasional. 

 This fauna is, on the whole, similar to that of Silver Lake, which differs 



' Brown, Barnum, A New Genus of Ground Sloth from the Pleistocene of Nebraska. 

 Bull. Amer. Mus. Nat. Hist., Vol. XIX, Art. xxii, Oct. 28, 1903, pp. 569-583. 



^ Cockerell, T. D. A., A Fossil Ground-Sloth in Colorado. Univ. Col. Studies, Vol. VI, no. 

 4, Boulder, Col., June, 1909, pp. 309-312. 



