> 2. Jeremy: California fossil -
> http://www.manandmollusc.net/Mystery_shell_pages/Jeremy-mystery.html
>
It's an oyster; there's a good chance that it has been called "Lopha"
but there are gryphaeid and ostreids, not to mention several different
genera in each family, that can look somewhat like that.  The oldest
oysters are Triassic.  If he can find out anything about the local
geology (try the California state geological survey), that would
greatly help in narrowing down the age.

Looking closely at the specimens with a hand lens, if broken surfaces
show a foam-like internal structure, it's a gryphaeid.

--
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"

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