E. Desor on the Post-Pliocene of the Southern States. 53 
A glance at these two lists will be sufficient to show that the 
formations which contain these shells’ cannot but belong to the 
same epoch, however different they may be in structure and ma- 
terials. Moreover, the fossils of Point Shirley, like those of the 
Neuse and the Potomac, seem to indicate that the climate was by 
no means colder, but on the contrary rather warmer than at the 
present day. There indeed we find in considerable quantity the 
mercenaria, whereas at the present day it occurs but 
scantily in Massachusetts Bay. So likewise do we find Bucev- 
num plicosum among the fossils of Point Shirley, whereas its 
natural habitat now is south of Cape Cod. 
the other hand, we have shown elsewhere that the resem- 
blance is almost as close between the fossils of Nantucket and 
Point Shirley on one hand, and those of the valleys of Maine, 
Lake Champlain and the St. Lawrence on the other. ‘The lead- 
ing species in both regions are the same, except that a few of the 
Nantucket species, such as Venus mercenaria, Cumingia telli- 
noides and some of the Buccina have disappeared, or are re- 
placed on the St. Lawrence by species which do not occur south 
of Cape Cod, as for instance, Cyprina islandica, Mytilus edulis, 
Pecten islandicus, Saxicava rugosa. But on the whole the dif- 
ference is not greater than that which usually occurs between 
recent species from corresponding latitudes, for instance between 
a collection of shells from the coast of Maine and one from Long 
Island or Cape Cod. 
As far as palzeontological evidence goes, there seems to be suf- 
ficient reason to consider the Post-pliocene of the south as the 
equivalent of the Laurentian of the north. There is moreover 
evidence enough to warrant the conclusion that at the time of 
their deposition, the climate, far from being colder, was through- 
out warmer than at the present day. 
here are nevertheless some striking differences between the 
Post-pliocene of the south and the Laurentian of the north, which 
rve to be considered. : 
First, the Laurentian deposits of the north occur at much higher 
levels than the pliocene of the south. We have stated before on 
Mr. Tuomey’s authority, that on the whole coast of South Caro- 
lina the average height of the pliocene does not exceed eight 
feet ; and, according to Mr. Lyell, its elevation along the whole 
coast from Georgia to North Carolina is less than twenty feet. 
At Nantucket, on the contrary, the fossil oyster bank occurs at a 
eight of thirty feet; which is also the elevation at which the 
ehus mercenaria and other species are found at Point Shir- 
ley. At Brooklyn near New York, ~~ exceed 100 feet in height. 
eir elevation at usta on the ’ 
At Lake Ohamapisie they occur at 200 feet. At Moira on the ° 
Northern railroad they are found at 310 feet ; at the mouth of the 
