I had this fossil brought to me recently.
It was found on the surface at the Middleton Lakes nature reserve, south of Tamworth, Staffs, a former aggregate quarry. It appears to be a mollusc shell, having a mother-of-pearl lustre over its surface, It could be out of situ and not from the underlying strata, which isn't very helpful, I know.
I would be grateful for even a general identification. It has me baffled.
I suspect oyster, such as Ostrea.
The shape can be quite variable, as the specimens in this photo demonstrate
The Middleton Lakes expose the Mercia Mudstone Group (Triassic).
I wonder if your specimen might be a Ostrea liassica, perhaps from the overlying Lower Jurassic.
I'd look in a local geology reference but I don't have any for the area.
- Mercia Mudstone Group - http://en.wikipedia.org/wiki/Mercia_Mudstone_Group
Many thanks for your reply. I think you are correct in identifying it as an oyster from the Jurassic.. I was initially puzzled by the fact that mother of pearl was on both surfaces, but I think this would be explained by the 'lower' valve of the shell being bent over.