PLEISTOCENE FOSSILS 



135 



The mastodons and mammoths are the largest of our Pleistocene mammals. Their long 

 bones, ribs, and vertebrae look very much alike but if the skull or even just the teeth are 

 found, they can be identified. They have large teeth, some nearly a foot long, which set them 

 apart from anything else. In the mastodons the teeth (fig. 411) have two rows of large cone- 

 shaped bumps, called cusps; in 

 the mammoths (fig.- 412) the teeth 

 have a series of transverse ridges 

 instead. For a recent find of a 

 mastodon skeleton in Madison 

 County, see papers by Goldthwait, 

 LaRocque, Sears and Clisby, 

 Thomas and Wood, all (1952). 



Giant beaver skulls are easily Fig. 411 Fig. 412 



recognizable because of their size 



and the long, chisel-shaped front teeth, called incisors; smaller skulls, with the same kind 

 of teeth, may belong to a variety of mammals, such as beaver, muskrat, woodchuck, squirrels, 

 chipmunks, rats, and mice. 



Antlers of moose and deer turn up occasionally in Pleistocene deposits as well as horn- 

 cores of bison and musk-ox. Their skulls can easily be mistaken for cow skulls and vice 

 versa. Bear skeletons have also been found, but rarely. 



Ground sloths (fig. 413) ranged into Ohio during the warmer intervals of the Pleistocene. 

 One complete skeleton from Holmes County is mounted in the Geological Museum of the Ohio 

 State University in Columbus (Claypole, 1891). The ground sloths were much like the South 

 American tree sloths of the present day but they were much larger and lived on the ground, 

 rather than in trees. They 

 were slow-moving animals, 

 almost without teeth, feeding 

 on ground plants and the 

 leaves of trees and bushes. 

 They were clumsy looking 

 animals, walking on the sides 

 of their feet. The skull is 

 large, recognizable by the 

 near absence of teeth. The 

 foot bones may also be re- 

 cognized by their peculiar c\ /? // 2 -j >s Wr^ JT — C*. 

 shape and long claws. 



Peccaries are pig-like 

 animals, more like wild pigs 

 than the domestic animals, 

 and about the same size. 

 Skulls are easily recognizable 

 by the short tusks but the 

 remainder of the skeleton, 

 except for the hooves, would be hard to identify 



Fig. 413 



Horse skulls are easy enough to recognize, but identification as true Pleistocene horses 

 is another matter. One of the difficulties is that horses of the same species as the present- 

 day horse lived in Ohio during the Pleistocene, along with other species now extinct. Radio- 

 carbon dating helps to determine the age of a particular skeleton but many "fossil" finds turn 

 out to be very modern and as such of no particular scientific interest. 



