222 MEMOIRS OP THE UNIVERSITY OF CALIFORNIA. 



associated with a fauna which falls well within the limits of the Pleistocene, 

 A discussion of the definite stage of the Pleistocene represented is deferred to 

 a later chapter, in which the evidence from various sources will be assembled. 



The material from the Upper Mississippi region is held to be Pleistocene, 

 and the Sheridan formation in which the Kansas specimen was found is gener- 

 ally considered to represent an early phase of the Pleistocene. 



The material described from Mexico by Freudenberg seems to have been 

 derived from the same horizon as the great lion, Felis atrox, as is the case at 

 Rancho La Brea, and presumably represents a horizon near that of the Pleis- 

 tocene of Rancho La Brea. 



The known occurrences of Canis dims show that this animal certainly roamed 

 over a large part of the Mississippi Valley ; its range extended south into Mexico, 

 and west into middle and southern California. Until we have a more exact 

 determination of the time relations of the beds in which this species is found, 

 it is not possible to be certain as to contemporaneity of the occurrence in 

 all of these regions, but such evidence as is before us indicates that the forma- 

 tions concerned do not differ greatly in age. It is probable that the species was 

 at one time present in all of the regions mentioned, though the earliest and 

 latest occurrences may have differed much in the several regions. 



That the range of Canis dims extended considerably beyond the territory 

 marked out by known occurrences is probable, but it is by no means certain 

 that it covered a region as large as that now occupied by wolves of the C. occi- 

 dentalis group. Until we are better acquainted with the correlation problem of 

 the American Pleistocene, it is perhaps unsafe to attach much significance to 

 the possible absence of C. dims from the Pleistocene of Silver Lake, Conard 

 Fissure, Samwel Cave, and Port Kennedy Fissure, and its absence or rarity in 

 Potter Creek Cave. Absence from some of these faunas may be due to differ- 

 ence in age of the beds, but the deposits included in this list represent a wide 

 range of the Pleistocene, and it is not probable that all are so far removed in 

 time from the beds containing C. dims as to have missed completely the life 

 range of that species. Some of the localities, particularly the cave regions, 

 evidently constituted a habitat very different from that of the known occur- 

 rences of C. dims, and to this difference in environment the presence or absence 

 of the great wolf may be due in some measure. The faunas of Potter Creek 

 Cave and Samwel Cave in California lived in a hilly or mountainous country 

 covered to a large extent with forest, whereas the Rancho La Brea fauna 

 represents the life of a plain bordering the hills. In view of what is known, 

 the great wolf may be presumed to represent a fauna which ranged mainly 

 over the great plains of an area corresponding approximately to what is now 

 the Sonoran region. What we know of the structure and probable habits of 

 C. dims would be in agreement with such a range, as the animal seems par- 

 ticularly suited for preying upon some of the larger plains mammals. 



