Fabien,
If they are fossils they probably are from strata equivalent to the late
Pleistocene Fort Thompson Formation, roughly 100,000 to 300,000 years
before the present.  It underlies the nearby Fort Lauderdale area, and
may not be deeply buried offshore.  There are a few species of Conus
named from this formation that can be found in Ed Petuch's 1994 Atlas of
Florida Fossil Shells.  Most would be varieties or subspecies of Recent
forms.
Allen
On Wed, 20 Nov 2002 14:41:09 +0100 =?iso-8859-1?q?Ringwald=20Fabien?=
<[log in to unmask]> writes:
> Hi!
>
> Florida is an ancient immerged platform. Florida
> underground is very rich in marine fossil molluscs of
> the latter Tertiary. They can be very well-preserved
> (even some cowries of the siphocypraea subgenus have
> kept their glossy aspect and original colours),
> especially cones.
> My opinion is that those cones are FOSSILS and that's
> certainly why they're very hard to identify!
> Do you agree?
> Perhaps it's untrue but it's the idea that came first
> to my mind.
> Sincerely,
>
> Fabien Goutal
>
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