1897.] THE FOSSIL SLOTH AT ]5IG BONE CAVE, TENN. 69 



as, rising upon their hind legs or climbing to the forks of heavy 

 trunks, they tear their fodder to the ground. 



If they despised water, like the Ai and Unau, they licked salt, as 

 their fossil bones bedded in the Petit Anse salt pit in Louisiana 

 and the mire of Big Bone Lick testify. As terrestrial animals 

 continually on the defensive against the foes of the forest, probably 

 little less active than bears, the great sloths would hardly have 

 rolled helplessly upon their backs when attacked like the Unau, or 

 yielded up their dinner with a melancholy drone. On the contrary, 

 though we must imagine them inoffensive and by no means agres- 

 sive enemies of animals or man, the thrust of the powerful arm, and 

 scratch with the claws that brought down saplings, might well have 

 defended them against powerful and active foes. 



A categorical demonstration that this individual animal was a 

 contemporary of the geologically recent Indian in Tennessee must 

 be abandoned. But the reasonable inference of such association 

 remains. Though the human handiwork, in the form of charcoal and 

 torch refuse (except the rat-hole specimens), lay really on the surface 

 (Layer i), from six inches to one foot above any sloth bone found ; 

 we may justly be satisfied with the recent significance, broadly 

 regarded, of the whole record, and with the absence of plants and 

 smaller animals of any extinct or positively ancient form. 



Gradually a thin sprinkling of rat excrement upon the clay floor 

 had thickened into a dry dense mass. Before the deposit had 

 reached a depth of two feet, the sloth had appeared and perished, 

 and while the duration of this manure-making process, which 

 finally, rising round the bones, covered them to a depth of one foot 

 or eighteen inches, cannot be safely guessed at in terms of centuries, 

 there can be no doubt that it is geologically recent, and that its 

 construction which preceded and followed the deposition of the 

 sloth bones is continued by the visits of existing cave rats at the 

 present day. The manure formed, the leaves, nuts, grass and seeds 

 found their way in, without the interruption of any important in- 

 terval of time or geological event changing the topography of the 

 cavern. The roof holes had probably remained open continuously. 

 The subterranean temperature of fifty-five degrees Fahrenheit, with 

 an extreme dryness, had probably persisted. The same flora had con- 

 tinued to flourish upon the mountain. The same visiting animals 

 had continued to find the same plant food, while the same bat 

 species had sailed in from the open entrance. 



PROC. AMER. PHILOS. SOC. XXXVI. 154. F. PRINTED APRIL 2G, 1897. 



