Re: test questions-old topic

From: Bill Payne (bpayne15@juno.com)
Date: Sun Mar 23 2003 - 23:22:36 EST

  • Next message: Bill Payne: "Re: test questions-old topic"

    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?

    Bill

    On Sat, 22 Mar 2003 15:50:55 -0500 "bivalve"
    <bivalve@mail.davidson.alumlink.com> writes:
    >
    > 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
    > bivalve@mail.davidson.alumlink.com
    >
    > 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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