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id help please

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rab7ies View Drop Down
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    Posted: 06 Jun 2011 at 7:52pm
this appears to be an echinoid but not one im familiar with...
down amongst the stones.
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Bill G View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill G Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:16pm
Nice find,  I think it's a sponge, Porosphaera globularis.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote hooken Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:18pm
Hi Rab,
 
Looks like a sponge from the pics- could be an Offaster echinoid but I can't tell. Can you see the ambulacra?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rab7ies Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:22pm
thanks bill..i thought it might be an echinoid as appears to have tubercles under eye glass,but maybe its just where its worn away a bit?(couldnt get closer pic)
down amongst the stones.
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rab7ies View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rab7ies Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:23pm
thanks hooken..no just what i thought was tubercles.
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Bill G View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill G Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:27pm
Tubercles or dimples? Here's a P. globularis close-up.
 
 
 
Cheers, Bill
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rab7ies View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rab7ies Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:30pm
thanks bill ,not dimples...looks quite worn but what seems to be a few tubercles
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Bill G View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill G Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:32pm
...and one that didn't clean up very well, with little bits that look like tubercles.
 
 
 
Cheers, Bill
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rab7ies View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rab7ies Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:37pm
thanks bill,it could well be..are these round? as i think you can see in photo one its flatish on one side and humped on the other.
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Bill G View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bill G Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:44pm
Porosphaera sp. vary quite considerably. See here
Cheers, Bill
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rab7ies View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rab7ies Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jun 2011 at 8:48pm
thanks bill,id just been on that site...i also just visited other sites and realised ive been throwing certain sponges down as thought they were nothing! lol.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary W Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jun 2011 at 10:04am
You sometimes do find round pebbles contained within a flint, one theory is thet they were gastroliths (stomach stones) of marine reptiles living in the cretaceous sea.  Below are two I have found  , the second being associated with fish scales (to the left) which gives support to this theory.
Gary
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rab7ies Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jun 2011 at 1:25pm
thanks gary..so thats what those are..as see these flint inclusions quite alot! thanks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary W Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jun 2011 at 1:39pm
As I said it is only one possible theory, they equally could be pebbles that existed in cretaceous times that simply became enclosed in flint...but the chalk was laid down in very deep water away from land.  So it is reasonable to attribute the pebbles to regurgitated gastroliths.  As I commented the one I found with closely associated fish scales gives support to this view.  What creature they came from is anyones guess.  I don't think fish use stomach stones so it was probably a reptile, perhaps a Mosasaur given the late age. 
Gary
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Post Options Post Options   Thanks (0) Thanks(0)   Quote rab7ies Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jun 2011 at 1:44pm
thanks gary..i shall pay more attention to em in the future as dont normally!
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