39 



DESCRIPTION OP THE EOCENE STRATA OF THE PAMUNKEY. 



Rising above the water-line at Northbury, the upper surface of the 

 deposite is seen ascending with a very gentle slope, as it extends- 

 higher up the river, until at Newcastle it attains an elevation of about 

 25 feet above medium tide. Beyond tins point, with slight undula- 

 tions in its outline, it continues with but little general deviation of 

 height from the water-line to near its termination at the junction of 

 the North and South Anna, where it dips or thins out until lost 

 immediately on the verge of the coarse sandstone, which there, for 

 the first time, makes its appearance in massy form. The deposite 

 appears on both sides of the river, wherever the flats do not inter- 

 vene, and at the base of the second level, corresponding in position 

 to its place in the river cliffs in the same vicinity. 



On the south side of the river, the deposite has been particularly 

 examined, at Northbury, Hampstead, Retreat, Washington Basset's, 

 Walker Tomlin's, Mrs. Ruffm's, Mr. Roane's and Mr. Wickham's, 

 where it terminates. Specimens have been collected from other 

 localities, either on the river or at the base of the second level : on 

 the north side, at Chericoke, captain Hill's, Mr. Nixon's, Piping 

 Tree, Newcastle, Dr. Braxton's and Mr. Fox's. Specimens also 

 from various other points on, and remote from the river, have been 

 procured, and thus a somewhat minute acquaintance with this por- 

 tion of the Eocene tract has been attained. Towards the southern 

 boundary of the deposite, the following arrangement of strata occurs, 

 commencing at the top. 



1st. A stratum of greenish yellow earth containing no shells, but 

 numerous traces or casts of them, plainly showing that shells were 

 ut one time embedded in the mass. Sulphate of lime or gypsum 

 occurs in crystals sometimes of considerable size, interspersed 

 throughout this stratum, which is principally made up of coarse 

 silicious sand, blended with granules of greensand or silicate of iron. 

 The thickness of this bed is variable ; at Chericoke and Hampstead 

 it is about two feet ; at Retreat from four to five. 



2d. Beneath this lies a layer of dark greenish blue or brown earth, 

 which when dried, generally falls to pieces, and is discovered to con- 

 sist mainly of coarse silicious sand, and greensand, together with 

 shells generally in a broken condition. The shelly matter is some- 

 times entirely wanting, though occasionally it composes a large por- 



