188 
PROCEEDINGS OF 
Patuxent, or the mouth of Town creek, the bank of the fiver presents a stratum of 
Ostrea virginiana , the shells not differing much in size and appearance from the 
recent oyster of the vicinity, and which might by some observers be referred to In- 
dian agency. But this is a bed of nearly uniform thickness, traceable several miles, 
and frequently five or six feet beneath the surface. Some miles south of Town 
creek, on the farm of Dr. Neale, this bed of oyster shells lies six feet below the 
summit of the bank; and I noticed many shells with connected valves, among those 
which are disunited, probably about the same proportion which obtains among the 
recent species of the more exposed estuaries and lagoons. The following section 
will convey some idea of the bank at this place: 
Patuxent. 
6 feet. 
Sand without organic remains. 
2 feet. 
Mixed sand and clay with oyster shells. 
1 foot. 
Large gravel and sand without shells. 
10 
feet. 
Dove-colored clay with ferruginous seams, and full of small 
crystals of selenite. 
N. 
About five miles south of the estate of Dr. Robert Neale, at whose mansion we 
were most kindly received, we visited a more interesting deposit of the same age, 
inasmuch as the oceanic shells make their appearance in the bank of the Chesa¬ 
peake, as represented in the following section: 
Chesapeake. 
4 feet. 
Whitish clay. No fossils. 
4 feet. 
Gravel. 
3 feet. 
Clay, without shells. 
4 feet. 
Clay, with marine shells, very chalky, among which are 
Mactra lateralis , Pholas costata , Area transversa. All the 
species here are yet in existence. 
7 feet. 
Clay, similar to that last described, with an occasional 
oyster shell, and a few small pebbles. 
N 
From observations made on the shores of the Chesapeake and Potomac, it is clear 
that the upper tertiary borders the lower part of the peninsula, from near the mouth 
of Town creek on the Patuxent, to a point on the Potomac about half way between 
St. Mary’s river and Brittain’s bay. But I am disposed to extend the limits of this 
formation, in order to include most of those deposits of oyster shells, which are sup. 
