58 £#. Desor on the Post-Pliocene of the Southern States. 
The absence of boulders constitutes, however, not the only 
difference between the Post-pliocene of the South and the Lau- 
rentian of the North. Whilst the latter is an exclusively marine 
formation, the Post-pliocene is said to contain besides remains of 
land and freshwater animals. M.'Tuomey mentions iy the Post- 
pliocene of South Carolina some bones {in a bed of mud on — 
Edding’s island ) which he is inclined to refer to the Megatherium. 
. Conrad, speaking of the deposits on the Neuse of North Caro- 
lina, says that they are ‘“‘of more than common interest in con- 
sequence of the quantity of bones of land animals which are 
ingled with the shells.”* According to Sir Ch. Lyell, the 
Post-pliocene of Georgia contains, besides the marine shells, some 
beds filled with freshwater shells which are said to be identical 
with species living actually in the neighborhood. It is farther 
stated that the same freshwater beds contain remains of many land 
animals, among them, bones of Mastodon,+ Elephas, Mylodon, 
Megatherium, horse, ox and Harlanus, a peculiar genus allied to 
Lophiodon. It is moreover stated by Sir Ch. Lyell that the bones, 
especially those of Megatherium, are by no means injured and 
their position is such as to convey the idea that whole skeletons 
must have been floated by a river to the place where they are 
found buried. On the strength of these statements it has been 
taken for granted that the above named quadrupeds must have — 
lived during the Post-pliocene period. 
ow if it be true, as we have endeavored to prove, that the 
Post-pliocene and Laurentian are parallel formations, it would — 
follow that the mastodon and its kindred existed on this continent 
at the time of deposition of the Laurentian of the North.. Suc 
an inference, however, would conflict with our knowledge of the 
position of mastodon remains throughout the northern states, 
where they have never been found in the Laurentian, but occur 
a: a in deposits of a more recent date, such as river terraces, 
Before taking it for granted that the deposits containing bones 
of mastodons and elephants in Georgia are really Post-pliocene, iy 
it might be well to inquire whether they may not belong toa 
later epoch, as the very suggestion of Lyell, “that the skeletons 
must have been floated by rivers,” seems to imply. We might, 
in like manner, point out various localities at the north where 
mastodons were said to occur in the drift, but which, after closer 
en were found to belong invariably to. a more recent 
The remarks of M. Tuomey respecting the bones mentioned 
y him among the Post-pliocene fossils of South Carolina, “ that Ef 
Det ee ee 
* Proceedings of the National Institution, 1842, p. 191. 
t M. Twomey mentions also the same elephant in the pliocene of South Carolina. 
. 
ee: 
