Fossils fuel a shop

EVER fancied owning your own dinosaur tooth? Well, now you can.

Not some piffling, peg-shaped fossil smaller than a sixpence from a chicken-sized vegetarian dinosaur, either. The dinosaur teeth on sale at York's newest fossil shop come from a meat-eating monster that stomped the warm Cretaceous swamps of Northern Africa about 95 million years ago, looking for other dinosaurs to kill and eat.

At 50 feet long and weighing four tons or more, spinosaurus rivalled tyrannosaurus rex for size and savagery. What made this monster - one of the stars of Jurassic Park III - really stand out from the crowd, however, was the huge sail on its back. Supported by bony spines up to six feet long, the sail would probably have been a way of keeping cool in the swampy equatorial heat.

It must have been terrifying. If its teeth are anything to go by, it had quite a bite.

The fossilised spinosaurus tooth on display inside a glass case at Mr Wood's Fossils in Goodramgate is long and wickedly curved. And it can be yours for £16 - enough to make any boy's heart swell with pride and delight.

If a tooth isn't enough, how about a whole monster? In another display cabinet a few feet away, embedded in some ancient sedimentary rock, is the complete skeleton of a nothosaur. It, too, was a monster: a marine reptile a bit like a long-necked crocodile that lived more than 200 million years ago somewhere in what is now China, reached up to ten feet long and had a mouth full of needle-sharp teeth.

Admittedly, the nothosaur skeleton at Mr Wood's is a baby, just a few inches long. But it is beautifully preserved, its long neck elegantly curved, each bone clearly distinguishable. It's a little more expensive than the Spinosaurus tooth - £950 - but what a talking point.

For anyone who loves fossils, Mr Wood's is a treasure trove. Here, for prices ranging from 55p (for a piece of rose quartz) to £950 (that nothosaur), you can find everything from beautiful spiral ammonites and three-lobed trilobites to ancient carnivorous fish, teeth from giant, extinct sharks, ichthyosaur bones and even dinosaur droppings.

There are also ancient insects preserved for all time in golden amber and, for the botanists among you, fronds from tree ferns that flourished in the carboniferous period, 300 million years or so ago.

Mr Wood's should be good. The shop's owner, Stan Wood, is an international fossil collector who has discovered more than 30 'new' species of fossil animals. They include 'Lizzie' - at 336 million years the oldest reptile ever discovered, a kind of 'missing link' between reptiles and amphibians that forced us to revise our estimates of when vertebrates first colonised the land.

Mr Wood began by supplying museums - then, in 1988, opened his first shop in Edinburgh. York, opened in December, is his second shop.

Some people may be uneasy at the thought of fossils being bought and sold across a shop counter: but really, says shop manager Kay Mannifield, it is no different from buying a diamond. Both are rocks, after all, which have survived millions of years of the worst geology can do to them.

She does not encourage amateur fossil hunters to go prowling along North Yorkshire's dinosaur coast with their hammers hoping to make a fortune by digging out precious fossils. Mr Wood's gets its fossils from established suppliers, who can say exactly where and in what kind of rock fossils were found - vital to be able to properly age them, Kay says.

Kay herself has a PhD in palaeontology - so if you want to know more about any of the fossils in her shop, just ask. She doesn't know all the answers (she specialised in invertebrates, she stresses), but you're likely to pick up fascinating snippets of information.

Anyone who's at all interested in fossils, for example, will instantly recognise an ammonite - one of those beautiful spiral shapes often found in limestone that is perhaps the 'classic' fossil.

But do you know what an ammonite actually was? What is preserved is only the creature's shell. An ammonite was rather like a squid, Kay says - but a squid with its own buoyancy chamber that allowed it to rise or sink through the water like a submarine.

There are many beautiful ammonites at Mr Wood's, some just a few inches across, others up to two feet in diameter.

Most fascinating of all, however, are the ammonite cross sections - broken open fossils that show the inside of the ammonite's shell.

The spiral is full of separate chambers, each one slightly bigger than the last. The animal itself lived in the last chamber. As it grew, the spiral grew with it: and every now and then it would lay down a wall behind it, sealing off another chamber.

The clever part was that all the chambers apart from the one the ammonite lived in were full of gas. The animal could alter the gas pressure in these with a little tube - making it able to rise through the water if the gas pressure was increased, or sink down if it was decreased. Amazing.

Equally amazing was the trilobite, a marine creature that looked a bit like a woodlouse which lived up to 570 million years ago. It was an arthropod - a member of the family that includes insects and spiders - and like a woodlouse could curl itself up into a little ball if threatened.

Trilobites were hunters and scavengers that ranged in length from less than an inch to nearly a yard. They mainly lived near the seabed, swimming, walking along the sea floor, or even burrowing into it.

What made them really interesting, however, was their compound eyes.

These were mounted on the creature's back, and each consisted of hundreds of tiny lenses, giving excellent all-round vision.

Amazingly, the trilobite even had primitive 'visors' to protect its eyes from the bright sun coming from above, so it could search out its prey in the gloom of the sea bed without being blinded.

Wow. Not even spinosaurus had one of those.

Mr Wood's Fossils, at 42 Goodramgate, York, is open 10am to 5.30pm Monday to Saturday and 11am to 5pm Sunday.

Updated: 10:25 Saturday, March 27, 2004