I found this fossil this week at Hornsea on the East Yorkshire coast. It's dimensions are 9cm x 7cm x 6 cm. It appears to be a fragment of a large ammonite. I have calculatred that the complete ammonite would have been between 1.5 and 2 feet in diameter. I am not aware of ammonites this size being found around here even though most fossils found are from glacial boulder clay so could have come from further north. Can you confirm from the photos that this is an ammonite fragment and if so what kind of ammonite it would have been?