Echinoid ?

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Kenleyboy
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Back to normal duties today so off to brave the chilling boxing day breeze and get my Whippets out and about .
Once again scanning the edge of the flint strewn fields and yet another fossil .
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I like the way the shard of flint has been embedded into the fossil .
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DaveP
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Definitely an echinoid - shout if you want me (well others) to try and identify the species (will need location). The odd piece of flint under the Aristotle's lantern could be the cast of a sponge or just an odd bit of flint.

Did you pick up the lighter coloured piece of flint bottom left of picture 2? Just curious.
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Kenleyboy
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DaveP wrote: Sat Dec 26, 2020 2:29 pm Definitely an echinoid - shout if you want me (well others) to try and identify the species (will need location). The odd piece of flint under the Aristotle's lantern could be the cast of a sponge or just an odd bit of flint.

Did you pick up the lighter coloured piece of flint bottom left of picture 2? Just curious.
DaveP , thanks again for your help . Will pm you :thumbsup:

I am afraid I didnt pick up the lighter piece of flint but I should be able to locate it .
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DaveP
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Paul,

courtesy of a fossil forum:

Your echinoid is Echinocorys scutata. The conditions that encouraged the conversion of chalk to silica (flint) were sometimes better developed within the enclosed volume of the dead sea urchin, and in your case, the only two apertures (peristome and periproct) in the echinoid test allowed the flint replacement to spread out of the sea urchin test, hence the bottle-shaped extrusion joining these two holes. It has not long been eroded out of the chalk, as the original calcite test is still adhering over a large area.

Every day's a school day!
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Kenleyboy
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DaveP wrote: Sat Dec 26, 2020 7:25 pm Paul,

courtesy of a fossil forum:

Your echinoid is Echinocorys scutata. The conditions that encouraged the conversion of chalk to silica (flint) were sometimes better developed within the enclosed volume of the dead sea urchin, and in your case, the only two apertures (peristome and periproct) in the echinoid test allowed the flint replacement to spread out of the sea urchin test, hence the bottle-shaped extrusion joining these two holes. It has not long been eroded out of the chalk, as the original calcite test is still adhering over a large area.

Every day's a school day!
Thanks DaveP , that is brilliant , everyday certainly is a school day . Thankyou very much :thumbsup:
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