188 



PROCEEDINGS OF 



Patuxeiit, or tlie mouth of Town creek, the bank of the river presents a stratum of 

 Osirca virginiana, the shells not diftcring 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. Nealo, 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, 



C feet. 



2 feet. 



1 foot. 



10 

 feet. 



Sand without organic remains. 



Mixed sand and clay with oyster shells. 



Large gravel and sand without shells. 



Dove-colored clay with ferruginous seams, and full of small 

 crystals of selcnite. 



N. 



About five miles south of the estate of Dr. Robert Neale, at whoso mansion wc 

 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 : 



Chcsapcake.I N 



From observations made on the shores of the Chesapeake and Potomac, it is clear 

 that tho upper tertiary borders the lower part of tho 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 tlftse deposits of oyster shells, which arc sup- 



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