378 TJie Americaji Geologist. June, is99 
was elevated in time to permit the almost complete erosion 
of whatever Eocene once existed there. 
The evidence as to the conditions in the region during the 
Miocene is more explicit. Basal and early Miocene deposits 
with their characteristic fauna are well known to occur as sur- 
face formations from New Jersey southward to Richmond and 
Petersburg, but disappear farther southward. They are 
reached in the borings at Fort Monroe, where their base rests 
about 580 feet below the surface. Across the portion of Xorth 
Carolina under discussion and in the adjacent portion of South 
Carolina the few feet of Miocene that are found bear not an 
early h\\\ a late Miocene fauna, and where the writer has seen 
them are of rather coarse texture, consisting of sands rather 
than of clays. The evidence then leads to the conclusion that 
this Carolina region was a land area in early Miocene time, 
while north of it there existed a great Miocene embayment 
extending westward as far as Richmond and northward 
through New Jersey, in which the diatomaceous and other 
older Miocene deposits of that region were being laid down 
several hundred feet thick. 
During this early and perhaps middle Miocene time the 
Cretaceous and Eocene land surface of this region must have 
been well reduced and a mid-Miocene peneplain well devel- 
oped, on which the late Miocene deposits rest. These late 
Miocene deposits tell of a subsidence of the land and a marked 
westward transgression of the sea across it as a necesssary 
antecedent condition of their formation. The thinness of these 
deposits together with their lithological and faunal characteris- 
tics indicate that the submergence was not very great and was 
perhaps not of very long duration. 
During the several oscillations of the coastal plain since the 
beginning of Lafayette time there has been, as ^^IcGee has 
shown*, minimum movement in the region of the Hatteras 
axis, and he describes it as "an axis of interruption or change 
in epeirogenic movement during every geologic period since 
the Cretaceous." f * 
By the term axis, the present writer — as doubtless, also, 
*The Lafayettee Formation, 12th Ann. Rept.. U. S. Geol. Sur., pp. 
486, 514, etc., i8qi. 
tibid, p. 403. 
