UPPER ORETACEOUS. 147

surface observations along Cape Fear River and upon data obtained
from the deep well borings at Wilmington and Fort Caswell, give re-
sults pointing to a dip of between 20 and 25 feet to the mile.

The greatest known thickness of the formation in North Carolina is
that presented by the section of the Fort Caswell well (p. 169). The
base of the Eocene is at 254 feet and the lowest occurrence of character-
istic Peedee fossils is at 1,140 feet, making a thickness of 886 feet of
undoubted Peedee beds. In the deep well at Wilmington the Peedee
beds were penetrated from the surface to a depth of 720 feet (p. 163).

That a comparable thickness of Peedee beds would probably be en-
countered in wells sunk near the coast elsewhere in North Carolina is
indicated by records of wells at Charleston, 8. C., and at Norfolk, Va.
At the former place marine Cretaceous strata were recognized from a
depth of about 600 feet to 1,980 feet, and at the latter from 715 to
1,320 feet. It is probable that in each case the greater part of the Cre-
taceous strata penetrated should be referred to the Peedée sand.

The formation is quite generally fossiliferous. Marine invertebrates -
constitute the bulk of the contained fossil remains. Among vertebrates,
however, sharks’ teeth are not uncommon, and fragments of bones occur
at rare intervals. The invertebrates occur either scattered irregularly
through the deposits or aggregated in layers. In places the shells have —
been preserved, but elsewhere the shell material has been dissolved
away, leaving casts. of impure lime, clay, sand, pyrite, or phosphate.
Collections were made at many. places, lists of which will be found i in

the detailed accounts of localities. ee

The table opposite shows the geographic distribution and range of the
invertebrate species of the Peedee formation in North Carolina.
Detailed Sections—The bluffs of Cape Fear River furnish the best
series of exposures of the Peedee formation in the State. These occur
_ from Donohue Creek Landing, 5014 miles above Wilmington, to near
" the mouth of Black River. At several places in this distance the Peedee _
beds are overlain by a few feet of Miocene or Pliocene sand or marl,
but for the greater part of the distance a surficial Pleistocene terrace |
covering rests directly upon the Cretaceous surface. — sketch ee
_ of Cape Fear River, Plate I, opposite p. 88.) sf

A detailed section of the exposure at Donohue Oreck Tanding is

given below. hee

SECTION AT DONOHUE CREEK LANDING, 504 MILES oe WILMINGTON.

_ Pleistocene: fie
Yellow loam, grading down into sand with icici: band at ~ 5: ee
foot Sn thicknesses osc eee see eee yee teehee rene

~ (Unconformity.)- Bie P