From: Bill Payne (firstname.lastname@example.org)
Date: Sun Mar 23 2003 - 23:22:36 EST
Thank you, David, for a rational reply. It had not occured to me that
since the bivalves burrow, they would not then be subject to mechanical
disarticulation in a depositional environment. George will be happy to
know that I have learned something new.
In the strata containing burrowing bivalves, do you also see bedding
structure, or is the bedding obliterated?
On Sat, 22 Mar 2003 15:50:55 -0500 "bivalve"
> The claim that bivalves invariably open and get disarticulated after
> death is a false statement. The forms most commonly found
> articulated are those that are deep burrowers or borers, e.g. the
> geoduck, Panopea. Their life position is deeply buried, and
> extensive disturbance is required to unearth them. Most bivalves
> normally live buried, so ordinary conditions are often adequate to
> bury them beyong the reach of normal bioturbation.
> Other species have extremely tightly attaching hinges, so that it
> takes breaking the shell to detach the valves. Also, there is
> variation in strength and decay-resistance of the ligament.
> Secondly, although the total number of articulated fossil bivalves
> is quite large, disarticulated specimens are much more common, and
> fragments commoner still. Very good specimens are exceptional,
> especially as one gets further back into the fossil record.
> Claiming that articulated specimens are the norm is false.
> Finally, the evidence of myriad separate events of rapid burial,
> interspersed with abundant evidence of slow deposition or even
> erosion, in no way supports a young earth.
> Dr. David Campbell
> Old Seashells
> University of Alabama
> Biodiversity & Systematics
> Dept. Biological Sciences
> Box 870345
> Tuscaloosa, AL 35487-0345 USA
> That is Uncle Joe, taken in the masonic regalia of a Grand Exalted
> Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at
> Droitgate Spa
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