A Remarkable Ground Sloth 5 



tion gives one the feeling that it cannot be more than a few hundreds of years old. The 

 half billion years that the mid-Pleistocene implies seems almost unthinkable. 



Again, the topography of the region cannot materially have altered since the 

 sloth was trapped, otherwise it is doubtful if he would have been. But the climate is 

 dry, the rock extremely obdurate, and erosion proportionately slow. There is abso- 

 lutely no way of determining the geologic age other than by correlation of the fauna 

 with that of the Rancho la Brea, for instance, and, while we have but a single speci- 

 men, there is always the possibility of individual survival. Perhaps the contents of 

 the sloth's coprolite, to be described later and including determinable plant remains, 

 may throw additional light upon the question of age. The contained vegetation is typi- 

 cal of today — sagebrush and other herbaceous plants but no cacti. The absence of the 

 last may, however, imply merely discrimination on the sloth's part. Otherwise the 

 botanical evidence again points to little or no climatic change. 



CONDITIONS OF PRESERVAL 



The specimen was complete, the bones being held in articulation by their original 

 ligaments and tendons. There are also present some of the periosteum, patches of skin, 

 and the mucous membrane lining the hard palate, as well as some muscle fibers. Ap- 

 parently, as we have seen, a greater part of the hide was devoured by fellow victims, 

 as the marks of rodent-like teeth are visible, including certain scorings of the skull 

 itself. The claws are also preserved. The left ribs and scapula and the left side of the 

 skull are somewhat decayed. This side, as I understand it, was downward as the 

 creature lay in the guano. Apparently the moisture of the body which accumulated in 

 the lower side of the animal as it lay is responsible for this disintegration, as it did not 

 affect the remaining portion of the left limbs. That the guano was the means of preser- 

 vation seems obvious, together with the general dryness of the cavern. To what extent 

 the sloth was buried in the guano and how much was covered by later accumulation 

 as it lay is not clear. A few protruding ribs gave evidence of its presence. 



ASSOCIATED MATERIAL 



At this writing nothing has come to light that was actually contemporaneous with 

 the sloth, the bobcat and coyotes being obviously later, probably much later, as they 

 are recent geologically. The only other associated object was the coprolite, or food 

 ball, mentioned above, which lay either in the rectum or was extruded with the re- 

 laxation of the animal at death. 



EXTENT OF MATERIAL 



The specimen is exceptionally perfect, the only missing parts being the corroded 

 portions, rib ends, and so forth, the tip of the tail, the left patella, several sternebrae 



