PLEISTOCENE OF EUROPE, NORTH AFRICA, AND NORTH AMERICA 453 



Thus it must be stated at once that portions of the Equus Zone fauna of 

 the Great Plains region are probably synchronous with the Megalonyx Zone 

 fauna of the forest and mountain region. 



Some of the chief localities where the early and mid-Pleistocene mammals 

 of these two epochs have been found together in large numbers are the 

 following, placed in ascending order: 



6. Kansas Pleistocene, several localities, early and late (Fig. 

 194, 19, 20, 21). 



5. Lake Lahontan (Nevada), Lake Bonneville (Utah) 'upper 

 terraces' (Fig. 214, L, B). 



4. Silver Lake, Lake County, Oregon, a more recent phase con- 

 taining plains and river, or fluviatile types (Fig. 194, 31). 



3. Rock Creek, Tule Canon, Llano Estacado, Texas, a fluviatile 

 formation containing Equus scotti (Fig. 194, 16). 



2. Hay Springs, western Nebraska, chiefly an open plains and 

 river border fauna (Fig. 194, 24). 



1. Peace Creek, southern Florida (see p. 367), a forest and plains 

 fauna of late Pliocene or early Pleistocene times, partly inter- 

 mingled with a more recent fauna (Fig. 194, 13). 



Relative age of the Equus and Megalonyx faunas. — The late Pleistocene 

 age of the Silver Lake fauna of the Equus Zone is supported by the geologic 

 and physiographic studies of Gilbert in the region of the great Pleistocene 

 lakes of Bonneville and Lahontan. Cope ^ believed (1895) that the fauna 

 of the Equus Zone, covering areas in Oregon, Nevada, California, Nebraska, 

 the Staked Plains, in southern Texas, Chihuahua, and the valley of Mexico, 

 was throughout contemporary with the Megalonyx fauna of the East, dif- 

 fering from it only in details. He regarded the Megalonyx fauna as pre- 

 Champlain. 



This conclusion was accepted by Williston in 1897, ^ who was, moreover, 

 disposed to relegate the Equus fauna to very late Pleistocene times. " Every 

 fact furnished from Kansas seems to substantiate Cope's conclusions that 

 the Megalonyx fauna of the East and the Equus fauna of the West were 

 contemporaneous, and that both occurred during the period of depression, 

 that is, during late Pleistocene time." It is certain that during the Cham- 

 plain period there was a depression in Kansas, though probably not a very 

 profound one. The Champlain is a period of fluviatile conditions and 

 ameliorated climate, of luxuriant forest growth, and more or less submer- 

 gence. From the presence everywhere, the same author continues, in the 



* Cope, E. D., The Antiquity of Man in North America. Amer. Natural., Vol. XXIX, 

 no. 342, June, 1895, pp. 593-599. 



2 Williston, S. W., The Pleistocene of Kansas. Univ. Geol. Surv. Kansas, Vol. II, 1897, 

 pp. 299-308. 



