>  >   Here in Cincinnati, all our Brachiopods and Trilobites, Horn
>Corals, etc. are fossils. They range about 400 million years.
>Ordivician. The only sub-fossils we have serve on city council and
>the various judicial benches.<

You sure those are SUBfossils?

>Along with some of your Ordovician bivalves, those fossils are
>generally preserving the original calcite mineral layers.

A lot of those, especially in the limestones, will have been replaced
by silica. This is common, and if the replacement is complete enough
can be taken advantage of by dissolving the matrix with acids.

>You may also have some fossil to subfossil land and freshwater
>shells nearby, along with mammoth bones and other traces of the ice
>ages, when the politicians were younger.
>
>>    But, seriously, is the term "sub-fossil" really relevant?

Sure it is. If it's old but still too young to be a fossil...

>Don't we have enough trouble with sub-species, form of, cf.,
>"interesting variety", etc.?

I cringe whenever I hear or see "subspecies". Most workers,
fortunately, no longer use them.

>  >   When does a shell jump from just plain dead to
>sub-fossilization? Is there a percentage of replacement that must be
>met? It's all very confusing. I think I'll collect match-book covers.
>
>There's no absolute cutoff between dead and subfossil.  Still smelly
>is probably not a subfossil.  Subfossil is more or less equivalent
>to long dead but not yet fossil.  It tends to imply that the
>material is not very good for telling about modern faunas.  Thus, a
>pile of unionid shells on the bank just left by a muskrat and still
>having periostracum and maybe some meat would not be subfossils, but
>a pile of unionid shells buried in the river bank, with all the
>periostracum gone, would probably qualify as subfossil.

A fair definition. But beware... the chitinous parts of shells CAN be
fossilized. I find ligaments of middle Eocene (40my) Latiarca,
Oligocene Limopsis and venerids, byssus of Oligocene Anomia... and am
expecting to eventually spot a corneous operculum (or at least a
ghost of one, possibly carbonized). In theory tough corneous
periostracum should also be preserved at least rarely... and in fact
articulated but distorted late Cretaceous unionids are common here
with periostracum still in place!
--
Andrew Grebneff
Dunedin, New Zealand
64 (3) 473-8863
<[log in to unmask]>
Fossil preparator
Seashell, Macintosh & VW/Toyota van nut
I want your sinistral gastropods!
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Q: Because it reverses the logical flow of conversation.
A: Why is top posting frowned upon?