The cave engravings emerged first, then shadowy bas-reliefs. Steve Farrar reports
The finest collection of Ice Age bas-relief sculpture found on a cave ceiling is as elusive as it is beautiful. Indeed, the experts who will soon officially announce the discovery overlooked its existence during a preliminary survey.
A search of Church Hole, a cave in Creswell Crags, near Worksop, Nottinghamshire, last year first revealed engraved - as opposed to bas-relief - images of horses, bison, red deer and possibly a wolf that are probably more than 13,000 years old.
Until then, the Ice Age residents of Britain were widely considered impoverished cousins of continental Europeans who produced rich cave paintings and carvings.
But even as that image crumbles, the team admits that the most astonishing achievements of the Creswellian artists initially evaded detection.
"We'd seen no bas-relief before," says Paul Bahn, an independent scholar and leading Ice Age art expert. "When we first saw the horse's head, we thought it was a trick of the light."
The oversight is forgivable. At first glance, only the natural cracks and bumps of the limestone are evident in the cave. But with expert guidance, a menagerie of animals can be espied in the gloom.
Chaotically aligned, overlapping figures peer out from every corner. First come the engraved outlines, which reveal a sophisticated understanding of the animals' physiology. Then comes the bas-relief, formed by chipping away rock to leave images proud of their background.
Many combine natural features suggestive of an animal with sculpted elements such as an eye, ear or muzzle. Among them is a large brown bear and the horse - a haunting image with a bas-relief mane - whose mouth is formed by a white chip of mineral in the rock.
Paul Pettitt, lecturer in human origins at Sheffield University, who organised the search for UK cave art with Dr Bahn 18 months ago, notes how a minimum of elaboration was often enough to complete the picture.
"They bring out the ghost of these animals' form," he says.
When the experts began the work, they dared not imagine they would enjoy such success. Dr Pettitt and Dr Bahn were joined by Sergio Ripoll, a leading Ice Age art specialist at the Spanish Open University, who is renowned for having "the eyes" to detect previously unrecognised cave art.
They started at Creswell Crags, where traces of Ice Age people had been found. Twenty minutes after entering Church Hole something caught Dr Ripoll's eye.
"I saw a line and suddenly a head was there. I then said a very big bad word in Spanish - it was so exciting," Dr Ripoll says. He had found the outline of what later turned out to be a red deer stag.
Since then, up to 81 possible pictures have come to light, most emerging since international experts descended on Creswell in April to discuss the discoveries.
The artists are thought to have been the first hunter-gatherers to return to Britain after the last Ice Age.
Dr Pettitt says the artwork suggests strong cultural links between the people of Creswell Crags and their counterparts elsewhere on the great plain that once linked Britain to Germany.
The experts admit they can only guess what the pictures meant to the artists, though their sheer number suggests they were intensely personal.
Dr Pettitt interprets boomerang-shaped figures found deep in the cave as highly stylised depictions of dancing women similar to those found on the continent. His colleagues are not convinced.
"We still argue for hours and bounce ideas about," Dr Bahn says.
The evidence is still coming in. It seems likely that Church Hole was completely covered in pictures, while the handful of images identified in other Creswell caves makes it possible that the entire gorge was decorated.
The pictures might even have been brightly painted - a possibility that infra-red imaging could soon confirm.
With more discoveries possible elsewhere in Britain, it seems the original exponents of Brit Art are finally getting recognition.