776 THE AMERICAN NATURALIST [Vol. XL 



Certainly the most direct instance of a great extinction of quad- 

 rupeds contemporaneous with a secular change of climate is that 

 of the Glacial Period in the entire northern hemisphere. The 

 close of the Pliocene or beginning of the Pleistocene found North 

 America peopled with the following kinds of great quadrupeds, 

 all of which disappeared during the Ice Age. 



Artiodactyla Camelidaj 



Camels 



Llamas 



Perissodactyla Ec}uidtTe 



Horses 



Tapiridie 





Proboscidea Mastodontinie 



Mastodons 



Elephantinse 



Elephants 



Edentata Gravigrada 



Giant Sloths 





jNIegalonyx 





iVlegatherium 





Parainvlodon 





(ilyptotherinm 



X)imrri('al Dhiiinnt'um of Camclidcr. 



— The Glacial Period was 





ers and cold waves. The 





<'al diminution of the Gamelidjc. 





"Around the lake lay piled the skulls and bones of dead game, 



guanaco (Lama huanachus) and a fewh 



uemnles (Furcifrr chilnh'iitt). 





the lower ground and near 



unfrozen water during the cold season, and there, wlien the weather 



is particularly severe, they die in crow( 



Is. We saw their skeletons, 



in one or two places literally heaped oni 



eupon the other" {Through 



ihc Ifrarf nf Pafof/nnia, m)2, p. VV2). 



"Again we came upon a 



se<-(.na drafh-phuv of guanaco, which 



made a scene strange and 





been less than five hundred 



lying du'iv in |H..itinn. forced an<l nn 



gaiiily as the most ill-taken 



outirrctclull. Ihr vLr nf t!ir \svmUvv 







upon tlirir dc<-aNin- hides. 



and their l.nn.-j<Mnt^ -!i>UMUiig tlm.u. 



■li llu' uouikI. nu'l<> l.v the 



i,eaks „r carrion-l.inK. 'Hwy lia.l d 



ie<l <hn-ing the seN<'rities of 



the previous winter, and lay literall^ 



' ]>iled one upon another" 





of this r gatliered from 



Mr. Ernest Cattie. lie told me that 



in the winter of 1899 enor- 



