igoy] Cobb — Geology of Core Bank. 27 
and Mr. R. C. Holton of Atlantic, the washing- up of sand 
from the sea and the southward movement of the dunes hav- 
ing nearly filled them. 
The Tertiary shell-rock was encountered in Core Sound 
between Core Bank and Cedar Island, and between Core 
Bank and the mainland. There is thus no longer any ques- 
tion as t to the origin of Core Bank or of Currituck Bank, for 
they are both essentially parts of the mainland. Currituck 
Sound was formerly a river that flowed into the Albemarle or 
Caroline River before the present Albemarle Sound was 
formed by the drowning of that valley; and Core Sound was 
for the greater part of its length a southern tributary of the 
large river made up of the Pamlico and the Neuse, and pass- 
ing to seaward through the present Ocracoke Inlet. The 
Albemarle River passed through the present fresh ponds just 
south of the Kill Devil Hills, and the margin of the conti- 
nent was some three score miles eastward of its present posi- 
tion. 
Then came the subsidence which drowned out the lower 
river valleys producing the estuaries and sounds already men- 
tioned, and this subsidence may still be in progress in the 
region to the north of Cape Hatteras. 
Since that subsidence, however, there has been an uplift of 
the land from Cape Hatteras southward, which, in all proba- 
bility is still going on. As the dunes advance towards the 
sound side they depress by their weight the swamp muck in 
which the trees of that side grow, and these are left exposed 
on the seaward side when the dunes have passed. This com- 
pression of the muck, which is common from Hatteras Island 
northward, may easily be mistaken for subsidence of the 
land. 
But on the land opposite Core Bank, successive strata of 
muck, filled with well-rounded wind-blown sands rise twenty 
feet above Core Sound at Atlantic. Kitchen middens, too, 
mark this line of elevated shore, the heaps being composed 
mainly of oyster shells with an occasional bit of broken 
