76 MOSTLY MAMMALS 



the presence of grassy plains alternating with the forest. 

 The same is probably indicated by the numerous species 

 allied to the guanaco, which flourished at the same time, 

 and some of which attained the dimensions of a camel, 

 while the various kinds of deer may also have inhabited 

 the same regions. The gigantic hoofed mammal known 

 as the Toxodon^ which had ever-growing teeth like those 

 of a rodent, was, however, probably an inhabitant of swamps 

 and marshes, while the still more extraordinary Macrau- 

 chenia, with its slender, camel-like neck and long, three- 

 toed Hmbs, probably stalked over the plains, cropping here 

 and there the foliage from some tree or copse. Rodents 

 nearly related to existing South American types were 

 likewise common, and there were also certain large carni- 

 vores, such as a species of sabre-toothed tiger and a huge 

 bear-like creature. With the exception of these carnivores, 

 together with the guanacos, horses, deer, and mastodons, 

 which are unknown in the older formations, and are there- 

 fore probably late immigrants from the north, all the animals 

 of the Pampean formation are peculiar to South America. 

 A further distinctive feature of this fauna is the large bodily 

 size attained by so many of its representatives, this being 

 especially the case with the glyptodons, mylodons, megalo- 

 theres, guanacos, mastodons, macrauchenias, and toxodons, 

 all of which would come under the designation of giant 

 animals. In this respect the Pampean fauna corresponds 

 with that of the Pleistocene period of Europe, with which 

 it also agrees approximately in age, seeing that there is 

 evidence of the contemporaneous existence of man with 

 several of the extinct mammals. 



In certain parts of the Pampean formation the remains 

 of these animals occur in extraordinary profusion, and 

 generally in a perfect state of preservation. At times they 



