438 W. F. BLAIR 



The climatic implications of the bog lemming {Synaptomys cooperi) 

 in the San Josecito cave fauna (Gushing, 1945) have been discussed 

 by Hibbard (1955a). The present southern limits of this species are 

 in northeastern Kansas, except for relictual populations in small 

 bogs in southwestern Kansas. 



The most complete picture of the southward shift of northern 

 faunas comes from the work of Hibbard in southwestern Kansas and 

 northwestern Oklahoma. Four cool faunas are recognized and ten- 

 tatively identified with the four major glaciations of the Pleistocene 

 (Hibbard, 1953). Two warm faunas are attributed to the Second 

 and Third Interglacials, and only the First Interglacial is unrepre- 

 sented. Mammalian components of several of these faunas are listed 

 by Hibbard (1949). The Cudahy fauna, regarded as representing the 

 closing phase of a Glacial age (Kansan), has the following small 

 mammals of northern afifinity: 



Sorex cinereus, present distribution (Fig. 2). 

 Sorex cudahyensis, extinct. 



Sorex (Neosorex) lacustris, extinct; most closely related species 

 today mostly in Ganada, south in Rocky Mountains to northern 

 New Mexico. 



Microsorex pratensis, extinct; most closely related species today 

 mostly in Ganada and Alaska, south to northern Iowa. 

 Synaptomys borealis, now north of Ganadian border. 

 Microtus paraoperarius, extinct ; related species operarius now in 

 northwestern Ganada and Alaska. 

 Microtus llanensis, extinct. 

 Pitymys meadensis, extinct. 



Phenacomys sp., genus now mostly in Ganada, but south in Rocky 

 Mountains to northern New Mexico. 



The assemblage contains a few cricetine rodents and a few species 

 of little climatic significance. The great preponderance of microtine 

 rodents and shrews, however, leaves no doubt that there was a shift 

 of a boreal fauna at least as far southward as southwestern Kansas. 

 There is no reason to assume that Hibbard 's work in this area was 

 done at the periphery of the range of this northern fauna, but the 

 evidence has yet to be accumulated to show how much farther south 

 it extended. 



The Jones fauna (Hibbard, 1949), regarded as late Wisconsin in 

 age, includes the northern species Sorex cinereus, Citellus richardsoni, 



