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1896 Views 7 Replies Last post: Nov 16, 2011 11:39 PM by Spud RSS
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Oct 20, 2011 5:48 PM

Answered afap - What are these? I am finding dozens of them.

I keep finding these in commercial gravel on the border between Lincolshire and Norfolk.

Notice they are right and left handed. The reverse is smooth and curved.

There are also huge numbers of belemnites and gryphaea, if that helps.

 

I'd like to know what the whole organism looked like. Many thanks.

IMG_3594.jpg

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    Sep 29, 2011 10:51 AM (in response to Spud)
    Re: What are these? I am finding dozens of them.

    The outer part is reminiscent of these:

    ...but these are microfossils and much smaller than what you have. These are Citharina sp. Not sure they are related but I thought it was worth mentioning! Also considering you have found lots of these, at this size and with a larger attachment I doubt this is related, but its something to think about.

     

    Best wishes,

     

    Louise

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    Sep 29, 2011 3:18 PM (in response to Spud)
    Re: What are these? I am finding dozens of them.

    Hmm - are the gryphaea all broken up into gravel sized chunks? I wondered if these are actually marks from the extraction process.

     

    Regards,

     

    Ryan

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      Oct 15, 2011 8:31 PM (in response to Spud)
      Re: What are these? I am finding dozens of them.

      I would say you are almost definately correct- they are the broken remains of the front ends ('beaks') of Bivalve mollusc shells, probably all that remains of the shells after they were rolled and eroded by Jurassic seas. The layers are layers of shell put down by the mollusc as it grew - this structure is fairly distinctive. The grooves are what remains of the hinge teeth which articulated the mollusc's two shells. They could be bits of 'Bakevellia' or 'Parallelodon', but as they are very worn and eroded it's unlikely you can put an exact name to them.

       

      Hope this is helpful,

       

      Theo.

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    Oct 20, 2011 5:48 PM (in response to Spud)
    Re: What are these? I am finding dozens of them.
    I agree they look like the broken points (umbo) of bivalves - something like Trigonia sp, where two types of striation meet sharply on the shell. And it would be the umbo you generally find because it is the thickest and strongest part of the shell.
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  • On this page (http://bg-fossils.com/Bivalvia_center_2.htm - the caption says "fossil bivalves", but some look more like brachiopods, well, never mind...) there are four things that reminds of yours. There are also five that seem to be viewed from the outside - well don't they look like oysters? I thought so - but are there oysters with this peculiar striation? Well - yes there obviously are! - becuse I found this: http://paleobiology.si.edu/geotime/main/htmlversion/evidence/oli_08.html. Now I at least had a genus - Hippochaeta! Well, Hippochaeta seems to be included in Isognomon - which led me to: http://www.bioone.org/doi/pdf/10.4202/app.2009.0062- and check image 15. That is pretty close - isn't it?
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