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Mrs. Stockhill

Recently we went out onto Bridlington Beach to collect a few bags of rocks to take back to the flat, when Barry suddenly exclaimed "Blimey- what's this ? " I peered into his hand and said " You know what you've found , Barry听 - it's an Ammonite! Quick, pop it into the bag before anybody sees it. We've made a bit of a discovery here."

Nigel: Hard to say for certain but my guess, as they're very common, is that it's a Dactyloceras commune which means the " Common finger ammonite ". They lived in the lower Jurassic era about 180 million years ago.

How did it end up on the beach in Bridlington?

Nigel: The Ammonites lived and died in the Jurassic or Cretaceous seas. When they died they became entombed in mud which later turned into rock. The rock was later lifted up by earth movements.

Bridlington Beach

The fossils were then ripped from the rock by glaciers during the last great Ice Age and dumped in a jumbled mass in the boulder clay of Holderness as the glaciers retreated 15 000 thousand years ago. As the coast of Holderness is eroded by the North Sea, the fossils fall onto the beach where you can find them today.

Are there any ammonites alive today?

Nigel: They all died out in the mass extinction that saw the end of the dinosaurs 65 million years ago. But some of their distant relatives are still found in our modern seas. The Pearly Nautilus, Octopus and the Cuttlefish. Ammonites were probably intelligent and active hunters of small fish.

Where is the best place to find ammonite fossils?

Mrs. Stockhill carrying rocks

Nigel: Ammonites turn up all along the Holderness Coast, but probably the best place to find them is further north around Whitby, Port Mulgrave and the Peak, south of Robin Hood's bay. One attraction of looking for them on the Holderness beaches is that it's better for conservation as anything not collected will end up being destroyed by erosion anyway and you don鈥檛 need to hammer away at the cliffs to find the fossils.

Were there lots of different sorts of ammonites?

Nigel: Ammonites evolved rapidly and any given species may only have existed for a few million years, so you you can use them to tell how old a piece of rock is. You'll find lots of different sorts if you look for them. By the way, Ammonites feature in the coat of arms of Whitby and in ancient times people believed they were serpents, turned to stone.

Fancy that! Thank you Nigel.