MIKE BAGSHAW, travel and countryside writer, goes on the trail of a few fossils.

Ice ages apart, Ryedale has pretty much always been blessed with a rich and varied selection of wildlife. 10,000 years ago, the Vale of Pickering held the country’s largest lake, teeming with fish, waterfowl and beavers and 60,000 years before that, hippos, elephants and lions roamed wild where the streets of Kirkbymoorside now stand. How do we know all this? From fossils of course.

The very specific reference to Kirkbymoorside should actually read Kirkdale, because it was in this nearby valley that Victorian quarry-workers uncovered a cave chamber full of old animal bones and teeth. Local geologists collected as many as they could and some were passed to William Buckland, professor of geology at Oxford University.

He realised that what the quarrymen had chanced upon was an extinct cave hyena family’s lair and the bones were the remains of their prey – 21 types of tropical animal in total. Many of the fossils found in Kirkdale are on display in the Yorkshire Museum, in York.

The rocks that make up the walls and roof of Kirkdale cave tell an even older story. They consist of limestone that was formed about 150 million years ago during the Jurassic Period, when Ryedale lay at the bottom of a tropical sea near the equator.

The rock itself is actually a fossil coral reef punctuated by the remains of the shells of the millions of creatures that lived on that reef. For an excellent illustrated explanation of the whole affair visit the old quarries behind Pickering Castle, where the North East Yorkshire Geological Trust has erected some interpretive panels and produced a trail guide to follow.

All the rocks of the North York Moors are Jurassic in origin, and many contain fossils from the period. Probably the best places to find them are on the coast, preferably when the tide is out.

I was down at Sandsend last month on the day of the eclipse, when the tide happened to be of the equinoxial spring variety – in other words it went out a very long way. I was able to walk down onto the shale scar much further than normal and find the imprinted remains of long-dead marine creatures in the bare wave-cut rock.

The most numerous were oysters, virtually identical to those alive around the UK coast today, but there were also some fossils of creatures long extinct. Some were spiraled and snail-like (ammonites) and some distinctly bullet-shaped (belemnites) – both members of the squid family, but with different shaped shells.

Our medieval forebears had no idea what these strange shapes in the rock could be, so invented plausible(ish) explanations. Belemnites became “thunderstones” where lightening had struck the shore and the coiled ammonites were snakes miraculously turned into stone by St Hilda, the Abbess of Whitby.

Ask any child what Jurassic means to them and they will no doubt reply, “Dinosaurs”. They may not be as common or easy to find as ammonites, but there are dinosaur fossils to be found in our neck of the woods. North Yorkshire sandstones were once Jurassic beaches which dinosaurs walked over and their footprints can still be seen at various sites such as Saltwick Bay, Scalby Mills and river-side rocks near Goathland. Lucky searchers have even occasionally found plesiosaur vertebrae among the beach pebbles.

If you don’t have the patience to go searching for your own prehistoric reptiles, then visit either the Rotunda Museum in Scarborough or Whitby Museum where you can admire not just footprints but whole skeletons.