‘ 40 F. D. Chester—Grawels of Southern Delaware. 
but in less abundance than over the northern area. As we 
continue southward, even to the utmost limits of the peninsula, 
the country becomes nearly flat, the red‘and brown sands change 
to a lighter color, until quite white, in which case the two 
members of the gravels merge into each other. At numerous 
localities within this region of white sands, however, the latter 
become distinctly red and brown with so large an admixture 
of gravel as to become identical with the red gravels of New 
Castle County, in which case there is always an overlying 
layer of white loam bearing upon its surface the characteristic 
bowlders. Often, again, we see one thick stratum of white 
sand, in which are streaks of red’ in varying quantity, while 
oftener still, the white sand assumes a slightly reddish tinge. 
Origin of the Southern Sand and Gravel.—From the above 
facts, there can be no doubt but that the white sands which 
cover over one-half of the area of the peninsula are contem- 
poraneous with the Delaware grave/s; but the two differ en- 
tirely as regards origin. While the Delaware gravels were a 
fluviatile deposit spread out over the upper portion of the estu- 
ary flour, the white sands were of marine origin, the deposition 
taking place at the broad mouth of the estuary and at a con- 
siderable distance out in the open sea. The probable truth of 
this statement is further shown by the finding of modern 
marine shells in the lower part of the white loam, near its junc: - 
tion with the tertiary blue clay, of which mention will be made 
shortly. 
To account for the intimate mingling of the red gravel with 
the white sands, we suppose that as the red gravel from the 
th 
This lower deposit of white sand and gravel we shall desig- 
nate the Hstuary sands. 
Professor J. C. Booth, in his Report upon Delaware (1841), 
attributed the white estuary sand to the destruction of ancient 
dunes which have gradually been blown far inland. The basis 
of that theory was the finding of dunes as far to the west as 
the town of Seaford, and the observation there and elsewhere 
of a similarity between these sands and those which formed the 
universal covering. This hypothesis is, I think, a mistaken 
on 
FT IS RS ies eee SET Ey Vo age ee Saeagt tal ana can ce eee ee EER a Nato eae 
