38 



also is found retaining its carbonate of lime in undiminished quan- 

 tity. 



On the lower levels on the river banks, it appears seldom to have 

 escaped the dissolving and decomposing action of the sulphates, 

 while in the highlands it may usually be found containing its cal- 

 careous matter nearly as when first deposited. In King William, 

 Hanover, Prince George, &c, beds are found in the highlands, at 

 some distance from the rivers. The fossils they contain are identical 

 with those of the marl beds farther east, and the materials with 

 which they are intermixed present no peculiarity important to be re- 

 marked. Specimens of this Miocene from Hanover, King William 

 and Prince George, exhibit a good .per centage of the carbonate of 

 lime, and as might be expected, the strata from which they were 

 taken are usefully resorted to by the neighbouring farmers. 



As would be inferred from remarks previously made, the general 

 level at which this marl occurs, is higher than that of the Eocene, 

 and here the promise is held out that this latter, even in the high- 

 lands, would be exposed by excavations carried to some depth be- 

 neath the lower limits of the former. 



In examining the Eocene deposite on the Pamunkey and James 

 rivers, the interesting geological fact was observed of an actual su- 

 perposition of the Miocene upon it ; and on the Pamunkey, the pre- 

 cise point was determined at which the Eocene first makes its ap- 

 pearance above the water-line, being there overlaid by a heavy bed 

 of the more recent deposite. This occurs at Northbury, and directly 

 opposite at the plantation of doctor Charles Braxton. 



OF THE EOCENE OR LOWER TERTIARY MARL. 



The descriptions and facts which will be comprised under this 

 head, will principally refer to the localities on the Pamunkey and 

 James rivers, to which especial observation has been directed. At 

 the same time that their value, as applying to the Eocene district 

 generally, may be regarded as being sufficiently established by 

 general geological analogies, as well as such observations upon other 

 portions of the region, as the present early stage of the inquiries 

 has allowed me an opportunity of making. No region of eastern 

 Virginia holds out more certain promise of reward to future inves- 

 tigation, and none will roap from the research more lasting and im- 

 portant benefits. 



