Quantoxhead Ammonite


Mar 26, 2004

I'm new to this discussion board, but I'm hoping to direct some discussion trafic from my own fossil website 'Discovering Fossils'.

For those with an interest in Ammonites, we visited a location in North Somerset last weekend called Quantoxhead. The site is undergoing rapid erosion and conseuqntly the Jurassic cliffs are revealing a large volume of excellent fossils.

I'm attaching a picture of the best find of the day.

Later in the year we'll be returning to the site to film a BBC documentary, so watch this space, as we'll be asking for volunteers to accompany us on the day.

Wow! What a beauty! That's a great specimen.

Now I think, but am by no means certain, that the ammonite is an example of the unpronounceable Psilocertaceae, though I doubt it is Psiloceras itself (need to find a few more comparison pictures, Psiloceras seems to be generally smoother).

The Psilocertaceae were a very early group of the true ammonites (Ammonitina), appearing at the base of the Jurassic about 205 million years ago, becoming a successful flourishing group before disappearing about 190 mya. Psiloceras itself is used as a boundary fossil in UK stratigraphy in the early Jurassic.

These forms of ammonite often display differences in structure betwen the males and females, and well preserved examples sometimes have an enigmatic structure known as the anaptychus within the large body chamber. This is a semi-circular structure that has been variously interpreted as a form of door with which the ammonite could have closed off its living chamber, or possibly part of a jaw structure.

Thats a great location, Roy. That ammonite is twice as old as the stuff I find!



PS. Volunteer!!!!!!!

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