38 Observations by T. A. Conrad 
searcely modified by these new researches, and it is not cae 
that it will be by future explorers. 
The first point at which I commenced my observations, was 
at Savannah, the site of which, was once an arm of the sea or 
bay, flowing over the land which now constitutes the extensive — 
rice plantations bordering the river. This submergence was in 
the Post-pliocene period and the evidence is derived from shells, 
of recent species, some of which have been thrown out of the 
sandy bed of the canal near its junction with the river. These 
consist of estuary shells, common in all the brackish waters of 
the southern states, and which are indicated in the fallonging list : 
Litiorina irrorata, Say; Solecurtus caribeus, Lam: ; Cyrena 
carolinensis, Bosc; and Ostrea virginiana, Gmel. ‘A bed: of 
the latter with the Cyrena intermixed occurs a few feet above the — 
level of high tide,. The water at Savannah is fresh and none of 
the foregoing species live therein. Several species of Unios oc- 
cur in the river and canal; the most common are U. Blandin- 
gianus, Lea, which is probably a variety of U. carolinensis, Bose j 
U. subinflatus, Con. ; and U. Shepherdianus, Lea. 
In ascending St. Fobne river, Florida, we passed a bluff on the 
right bank, about twenty feet high, in which appeared, a thin, 
very much undulated bed of abelliy which proved to be astratum 
of Ostrea virginiana, as I t hasty visit 
to the spot. It was at an elevation of ten or fifteen feet above 
high tide. .'This Post-pliocene deposit, taken in connexion with 
those of similar age on Tampa Bay, prove a considerable eleva- 
tion of the whole Florida peninsula in the Post-pliocene period, a 
movement which clearly has raised all the Florida Keys above 
The steamer having been beached to repair damages re- 
ceived on St. Johns bar, I had ample time to collect the shells 
near the village of Hasard a short distance above the sea. There 
is here a gently sloping sandy beach not rich in shells, which are 
few in number both of specimen and species. 'The most -abun- 
dant shell is Mactra lateralis, Say, which inhabits the whole 
coast from this point to Massachusetts, and is also common on the 
Keys at Tampa bay: It is also very numerous in the Post-plio- 
cene of Maryland and North Carolina, and occurs more rarely in 
the Miocene of Virginia. The age near the veieeeetee St. 
Johns river are pontine ee 
