LIFE OF TERTIARY PERIOD 237 



of which 5 feet consisted of the massive armoured tail, which 

 latter is believed to have borne a number of movable horns. 

 The earlier fossil species were of much smaller size, and, 

 though far more abundant in the south, a few of them have 

 been found in the Pliocene deposits of Texas. 



The extinct ground-sloths are even more remarkable, 

 since they were intermediate in structure between the living 

 sloths and the ant-eaters, but adapted for a different mode of 

 life. Almost all are of large, and many of gigantic size. 

 The Megatherium, which was discovered more than a century 

 ago, was one of the largest, the skeleton (represented by a 

 cast in the British Museum) being 18 feet long. Their 

 massive bones show enormous strength, and they no doubt 

 were able to uproot trees, by standing erect on the huge 

 spreading hind feet and grasping the stem with their power- 

 ful arms, in order to feed upon the foliage, as shown in the 

 illustration (Fig. 89). The jaw-bones are lengthened out, 

 indicating extended lips and probably a prehensile tongue 

 with which they could strip off the leaves. An allied genus, 

 Mylodon, which is somewhat smaller, has been found also in 

 Kentucky in beds of the same age, the Pleistocene. 



What renders these creatures so interesting is, that they 

 survived till a very recent period and that they were contem- 

 porary with man. Both human bones and stone implements 

 have been found in such close association with the bones or 

 skeletons of these extinct sloths that they have been long 

 held to have lived together. But a more complete proof of 

 this was obtained in 1897. In a cavern in Patagonia, in a 

 dry powdery deposit on the floor, many broken bones of a 

 species of Mylodon were found ; and also several pieces of 

 skin of the same animal showing marks of tools. Bones of 

 many other extinct animals were found there, as well as 

 implements of stone and bone, remains of fires, and bones of 

 man himself. Among the other animal remains were those 

 of an extinct ancestral horse, and on some of the bones there 

 were found shrivelled remains of sinews and flesh. 



Allied forms are found in older deposits, as far back as 

 the Miocene, but these are all of smaller size. They prob- 

 ably ranged all over South America, and the two genera 

 Megatherium and Mylodon occur also in the most recent 



