VI POST-PLEIOCENE FOSSILS. 



The color or texture of a fossil, therefore, does not always absolutely determine its rela- 

 tive age ; as Professor Leidy has himself remarked in a foot-note to his letter alluded to 

 above, viz; 



" Fossilization, petrification, or lapidification, is no positive indication of the relative age 

 of organic remains. 



"The Cabinet of the Academy of Natural Sciences, of Philadelphia, contains bones of 

 the megalonyx, and of the extinct peccary, that are entirely unchanged ; not a particle of 

 gelatin has been lost, nor a particle of mineral matter added, and, indeed, some of the bones 

 of the former even have portions of articular cartilage and' tendinous attachments, well pre- 

 served." 



Fig. 8, Plate XXIV, is the tooth of a sperm whale found in the Ashley beds. This 

 specimen, when submitted some years ago to Prof. Leidy, was instantly recognized as a 

 true fossil, similar in color and general character to those of the Ashley beds; specimens 

 from these beds being more fossilized or petrified than those found in the peat-bogs and 

 shell-beds of other localities. Fig. 9, of the same Plate, repiesents another tooth of the 

 same species, from the Charleston shell-beds, and is as recent and fresh in appearance, as 

 though just taken from the living whale. 



From the foregoing it would appear that of the ancient fauna of America, which inclu- 

 ded representatives of many of our present domestic animals, some species have undoubt- 

 edly become extinct; but I confess I am not yet prepared to admit from any evidence yet 

 adduced, or from my own examinations, that all of the living species are distinct from 

 those found fossil in the Post-Pleiocene. The teeth and bones of the rabbit, raccoon, opos- 

 sum, deer, elk, hog, dog, sheep, ox and horse are often found in these beds, and though 

 associated with those known to be extinct, such as mastodon, megatherium, hipparion, etc., 

 need not necessarily be referred to extinct races also, since their remains cannot be distin- 

 tinguished from the bones and teeth of the living species. 



Of the mollusca from the same beds about ninety -five per cent, are to my mind identi- 

 cally the same with species now living on the coast of South-Carolina. Two species of 

 these shells though extinct or not in existince here, are now living in numbers on the coast 

 of Florida and the northern shores of the Gulf of Mexico;* and two have no living repre- 

 sentatives that we can discover. f 



The question therefore naturally suggests itself— are the living horses, dogs, hogs, rac- 

 coons, opossums, deer, elk, tapirs, beavers, etc., and the one hundred and fifty living shells 

 of the coast, the descendants of the animals whose remains we find fossil in the above- 

 named beds? 



It has been just remarked that about ninety-five per cent., or nearly all of the one hun- 

 dred and fifty shells of molluscous animals from these beds, are specifically identical with 



* Strombiis pugilis; Gnatliudon cuneatum. 

 f Cavolina. Tellina. 



