It's a hot June morning on Yaverland Beach, Isle of Wight, and 52 Year 6 pupils from St Joseph's Catholic Primary School, Upminster, focus their gaze on the exposed Cretaceous strata of the cliffs and the rocks around their feet. Their thoughts, thanks to the tutoring of Trevor Price, education officer at the Dinosaur Isle museum, are on what was going on here 122 million years ago, when all around was arid plain, dotted with water pools, tree ferns and a meandering river where gigantic iguanodons came to drink.
Wave action, Trevor demonstrates, is exposing the muddy shallow bank of this ancient river, criss-crossed by recognisable dinosaur tracks. While these crumble and vanish with each tide, the tridactyl (three-toed) "foot casts" littering the beach are far more enduring. The original tracks, he explains, were made with each stride of a 2.5-tonne iguanodon, baked firm and then filled with sand. Over millennia the sand hardened to create today's rock-solid impressions, now dropping from the retreating cliffs.
"This is a site of special scientific interest," says Trevor. "This means there are no coastal defences here, which is great for children, enabling them to collect anything they find on the beach for school displays. It's either that or the sea takes it. If this was an inland quarry site, it would be a different matter."
Dinosaur Isle retains first refusal in case anything rare crops up. "Last year, a boy found part of the vertebrae of a small dinosaur called a Coelurosaur - it was hollow, indicating it came from a predator," says Trevor. "We have more than 10,000 schoolchildren through here each year, so there's always a chance someone will come up with something that adds to our collection."
A steady stream of St Joseph's pupils bring their discoveries to Trevor and his colleague, curator Lorna Steel, for identification. "Nothing's 'just a rock'," says Trevor. He breaks one specimen open and invites those around him, so long as they don't have asthma, to have a sniff. "It smells of sulphur - the residue of a fossilised bacteria colony," he explains.
One of the day's most spectacular finds is a perfectly preserved mussel.
"This was a fresh-water bivalve - a reminder of the river that once crossed the landscape here."
The tides have dictated that St Joseph's field work is done before their visit to the exhibition in Dinosaur Isle's seafront home - its front arrangement of struts and steel plates designed to resemble a gigantic pterosaur (flying reptile). "The beach activities usually fire pupils'
enthusiasm, making them more receptive for a talk or for a museum tour,"
The group get a mini course in geology, learning about the main rock types and the kinds of fossils that all but igneous rocks can contain. Then it's time for the spectacular displays and interactive thrills of the main gallery. This year marks the 100th anniversary of the naming of Tyrannosaurus rex and the museum has just put on display a life-sized model of one of that creature's ancestors, an eotyrannus, remains of which have been found locally.
There are plenty of other excitements on offer; from activating a Dilophosaurus display to feeling a lump of coprolite (dinosaur dung). For 11-year-old Joe, the biggest wonder is standing next to an iguanodon skeleton. "I had no idea they were so big," he says.
For Bethany, also 11, the trip confirms her desire to be a palaeontologist:
"The displays here tell you so much - it has made me even more enthusiastic."
* St Joseph's arranged their trip with Isle of Wight Experience Tel: 01983 404279 www.isleofwightexperience.co.uk
On the map
Dinosaur Isle Culver Parade, Sandown, Isle of Wight PO36 8QA Email: email@example.com
Tel: 01983 404344 www.dinosaurisle.com