THE TERTIARY FORMATIONS OF YIRGINIA. 363 



variety of the Ostrea Virginiea,^ of which a similar deposit exists on 

 the opposite side of the Rappahannock. It is distinguished by the 

 length and depth of the channel of the hinge in the valve, and the 

 large angular pivot-like protuberance in the other, as well as by the 

 general elongated form of the shell. 



Bank of the Rappahannock from near Cherry Point to Musqueto Faint, Lancaster County. 



At about one mile above Cherry Point, at Mr Palmer's, the bank 

 consists of the following strata : 



1. Forming the base of the cliff, and extending up about three feet 

 is a blue clay marl, containing a great many shells. This layer reaches 

 to some depth below, and extends out beneath the sand of the beach. 



2. A bed of chocolate coloured clay, imbedding a vast number of 

 the variety of Ostrea Virginica, previously described. This is three 

 feet in thickness. 



3. A bed of partially decomposed Serputa, containing few other 

 fossils, one foot thick. 



4. A layer of ferruginous sandstone, in bands, alternating with thin 

 seams of sand. Three feet thick. 



5. Ten feet of diluvium. 



The above strata, in the order just described, continue down the 

 river for the distance of half a mile, appearing to dip gently towards 

 the bay. The marl is then lost for about two and a half miles, after 

 which it reappears, at intervals, as far down as Musqueto Point. Here 

 the country becomes a sandy flat, and so continues to the bay shore. 

 In the interval of two and a half miles, where no marl is seen, the 

 cliflfs, which are from twenty to thirty feet in height, consist at the 

 base of blue clay, containing impressions of shells; above this of ferru- 



* The variety here referred to has not been found at any other points in the meiocene 

 district but those above enumerated, a circumstance which, together with its close resem- 

 blance to the edible Ostrea Virginica of the coast, and its place of deposit being so near the 

 extremity of the peninsula, would favour the idea of its belonging either to the modern period, 

 or to a more recent tertiary epoch than the meiocene. This view, however, can scarcely be 

 reconciled with the fact that the shell in question occurs beneath, and associated with, the 

 usual fossils of the meiocene, and that the latter have been found in several places beneath the 

 surface of the flats, still nearer to the bay shore. 



VI. — 4 q 



