GeologyRocks

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What you actually have there is an ammonite fossil.

The rock as a whole is a concretion of some kind (sometime called a nodule). They often form around the decaying matter of a dead animal - in this case the ammonite. The "wibbly" line is what reamins of the outer whorl of the ammonite. On the third photo you can see the remains of an inner whorl which is presevered. The brown "stuff" sorrounding this is the organic remains of the outer whorls. You can even see the where this outer whorl would lie in this picture.

I don't suppose you know where this was collected from?

More ammonite pictures from this page:
/search/node/ammonite

Hope that helps!

Hi Jon,

 I can't find a location for that fossil, but there is a pice of paper that has fossils written on it and 3 place names. They are: Derbyshire, Cornwall and Lyme Regis. I don't know if this one came from one of these places or not??

The collection was labeld at one time but the lables have fallen off, there is also pices of paper that have names of rocks/minerals on them. I think they were stored on the paper...lol so I now have to link the stone/mineral with the names on the paper as it also has the place that they were collected.  I think they were all collected in the early 70's

 John

It has to be Mesozoic (the sutures are ammonitic), hence must be from Lyme Regis (the only Jurassic outcrops from the list you gave). It's a nice specimen that shows a lot of detail - an expert should be give you a species name for it (but I'm not expert )