CORRELATION OF FORMATIONS. 315

Cardium spillmani Conrad, are found at both horizons. Still others
found both in the Peedee and Black Creek in North Carolina are con-
fined to the Monmouth in the north, among them Pecten simplicius
Conrad and Lima pelagica (Morton). The fauna as a whole is, how-
ever, clearly that of the Monmouth and upper Ripley.

The Peedee in North Carolina is not followed by younger Oretaceous
deposits, as in New Jersey, where a decidedly younger fauna quite dis-
tinct from that in the lower beds is found.. The Peedee formation is
overlain only by Tertiary or post-Tertiary deposits, so that its upper
limits are everywhere sharply defined on both physical and paleontolog-
ical grounds.

As already stated, this fauna has been generally regarded as Senonian,
while the overlying Cretaceous fauna in New Jersey has been regarded
by the writer and others as probably Danian in age.

TABLE SHOWING CORRELATION OF UPPER CRETACEOUS FORMATIONS.

 

 

 

APPROXIMATE DELAWARE |
EUROPEAN | AND | VIRGINIA, Norra CAROLINA, ALABAMA.
EQuivaLENTs. MARYLAND. |
| {
Danian -.------- | Rancocas --.---- [slice . Drege |--4 ose 2- 2+ Se s+ + |-- ose te ++
‘ «| : |
Senonian - -- ----- | Monmouth--- --- eines aes b hae Peed66 wees - s+] Ripley, Selma.
| Eutaw.
| Matawan _------ | ;
Tironian. <>. 5-2 | In well borings... Black Creek -... Tuscaloosa.
Magothy .-.---- . i
Cenomanian - - --- Rehan on ees eee ee Yao pit OTE pee CORY ea

 

TRENT FORMATION.

The Trent formation lies unconformably on the underlying Creta-
ceous deposits. The lithologic materials are very unlike those of the
Eocene of adjacent States, consisting of a light-colored marl that is
either loose or locally consolidated. The strata were evidently depos-
ited after a long interval of erosion, but there is nothing in the position
or character of the beds that renders it possible to correlate them with
certainty with the Eocene of adjacent areas. In some particulars the
beds, both in position and character, suggest the Santee marl of South
Carolina, which has been regarded as belonging in the Claiborne group.
It is quite possible that they may belong to that horizon.

The fossils of the Trent horizon are largely casts of marine forms,
although in a few instances teeth and shells are preserved. The groups
best represented are the mollusca, bryozoa, and echinodermata. A
large oyster which has been identified as Ostrea georgiana Conrad, sev-