Identical ammonites to this specimen, called Asteroceras obtusum, are found in Robin Hood’s Bay in Yorkshire. This tells us that the rocks at Charmouth are exactly the same age as the rocks in Robin Hood’s Bay, over 300 miles away.
The collector, Barney Hansford, lived in Charmouth. Between the 1950s and the 1970s, he built up a large collection of local fossils and displayed them in Barney’s Fossil Exhibition in Charmouth. After his death in the late 1980s, the collection was broken up, but some specimens found their way to Bridport Museum’s collection.
Find out more about ammonites on the molluscs pages.