FORT UNION OF CRAZY MOUNTAIN FIELD, MONT. 271 



width All, 11.2; length M2, 14.8; width M2, 12.1; length P2 (referred) 

 11.8; width P2 (referred), 6.8. (The widths may have been a Uttle 

 greater before the teeth were corroded.) 



PANTOLAMBDA or allied genera, species nndetennined 



U.S.N.M. no. 6155 is an isolated M^ from "K mile N. of Fish Creek 

 Creek 200 ft. E. of Melville and Harlowton Road", in Fort Union 

 No. 3. This almost certainly means Loc. 28; it is about a half mile 

 from Fish Creek, but no other mammal locality more nearly corre- 

 sponds with the indication. This horizon is 400 feet above the base 

 of No. 3 and about 550 feet above the Gidley Quarry. This tooth 

 resembles the smaller Torrejon specimens referred to P. cavirictus 

 but has the cingula, external and internal, better developed. 



No. 9858, from Loc. 18, well up in Fort Union No. 3, is a frag- 

 ment of an upper molar probably of the same species as no. 6155. 



No. 9694, from Loc. 54, the same level as the Gidley Quarry, is a 

 symphysis and isolated Mo, which also approach small P. cavirictus in 

 size and is perhaps of this same species, although possibly still smaller. 

 It is nearer P. cavirictus than P. intermedius in size. 



No. 10048, from the Gidley Quarry, closely resembles a lower 

 posterior premolar of Pantolambda bathmodon in form but is smaller, 

 7.3 mm long and 5.9 wide. 



All these specimens are inadequate for determination, but they 

 show that pantolambdids were not uncommon in this general area 

 and that they were varied, despite the fact that conditions did not 

 lead to the good preservation of their remains. 



There are also isolated bones, without associated teeth, from the 

 horizon of the Gidley Quarry and in one unimportant case, the base of 

 No. 3, which probably belong to Pantolambda. AU are as large as the 

 corresponding parts of Torrejon P. cavirictus and differ only in insig- 

 nificant details. Since the probabilities suggest that some of these 

 belong to P. intermedius, it may be that the latter was a small-headed 

 form, with body equal to P. cavirictus in size but jaws and teeth con- 

 siderably smaller. In the absence of associated material, however, 

 this is obviously hypothetical. 



