The Lee Creek Mine, aka Aurora, Texasgulf, or PCS Phosphate, has not let
fossil clubs in lately but has evidently given them hope for reopening.  I
have not tried recently myself (university connections sometimes help).
The fossils range from lower Miocene through Pleistocene in age, though the
most diverse mollusks are from the mid to upper Pliocene and possibly basal
Pleistocene (Chowan River Formation, James City Formation, etc.).  Older
mollusks generally do not have aragonite preserved, leaving molds or
nothing for most species.

Carcharodon is the genus for the modern great white shark.  If you believe,
as some do, that the large-toothed extinct species with a wide, triangular,
less polished region at the base of the enamel belong in a different genus,
Carcharocles and Procarcharodon have been used.  Carcharocles is preferred,
though I do not know the details.  C. megalodon is the last of this
lineage; the teeth are not uncommon in the lower Pliocene as well as
Miocene.

C. megalodon is distinguished from older species by the larger size and
lack of small teeth on the side of the main teeth.  However, the change is
gradational.    The Paleocene species of Otodus have little or no serration
on the sides of the teeth; later species assigned to Carcharodon or
Carcharocles have well-developed serration.  The modern great white has
smaller teeth than megalodon and lacks the triangular region at the base of
the enamel.

It is possible to collect nice teeth and shells out of a cliff by
undercutting it and coming back a while later, after the cliff collapses
and the water washes away most of the dirt.  However, this method is
inadvisable for two reasons.  The cliff may collapse earlier than you
expected, preventing your collecting anything ever again.  Also,
undermining the cliff gives the people living on top a legitimate reason to
be mad at you, resulting in possible legal action as well as throwing
rocks.  Either result could lead to the area being closed to collecting.

Megalodon is also a Paleozoic-Mesozoic genus of bivalves in the lineage of
the rudists.  Make sure you know what phylum you are referencing before
buying a specimen.



Dr. David Campbell

"Old Seashells"

Department of Geological Sciences
CB 3315 Mitchell Hall
University of North Carolina at Chapel Hill
Chapel Hill NC 27599-3315
USA

[log in to unmask]
919-962-0685
FAX 919-966-4519

"He had discovered an unknown bivalve, forming a new genus"-E. A. Poe, The
Gold Bug