Siphocypraea occurs in the lower to upper Pliocene as far north as Virginia
(L. Campbell, 1993, Pliocene Molluscs from the Yorktown and Chowan River
Formations in Virginia, Virginia Division of Mineral Resources Pub. 127).
S. problematica is the only species in the Calosahatchee.  Siphocypraea is
very variable in the lower to middle Pliocene, but the presence of
intermediate forms makes almost all of Petuch's genera and species of
doubtful merit.

>During the summer I spent a couple of hours digging out fossils in Leon
>County, Texas, particularly looking for cones and cowries.  I found one of
>each.
>Various people suggested that the fossils there were likely
>Upper Cretaceous,

Various people need to check a geologic map.  You're right-apart from a
small spot of Cretaceous on the Navasota River on the county line, Leon
County is mostly Paleocene and Eocene.  Conus sauridens is unquestionably
Eocene.

Cypraeaorbis is the genus to which the Eocene cypraeids in the southeastern
U.S. have mostly been assigned.  They are rather rare in most deposits,
though not uncommon here in the Carolinas as molds in limestone.  Bulletins
of American Paleontology is the journal you need to locate, though the
relevant volumes are out of print.  I think Krause Reprint Company will
still reprint them for you if you pay them enough.  Palmer 1937 (v. 7) and
Harris and Palmer 1946 (v. 30) figure a couple of "species", though I am
not certain how to distinguish them.  Cypraeorbis ventripotens is one
species name I remember; I believe the other was nuculoides but am less
certain.  Palmer and Brann (1965-1966, v. 48, which might still be
available from the Paleontological Research Institute) attempted to list
all species known from the Paleocene and Eocene of the eastern U.S., thus
providing a good source of information on where to look next.  David
Dockery, at the Mississippi Geological Survey, is probably the person most
actively working on describing the Paleogene faunas of the Gulf Coast, so
there are some more recent bulletins of the Mississippi Geological Survey
and articles in Mississippi Geology that discuss ovulids.  I do not
remember anything more recent on true cypraeids.

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

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