Interesting - I'd been on another board where someone spoke of smooth circles on Ilkley Moor. I wasn't sure what they were talking about - but I just found the following article on the New Scientist site. It would be fascinating if there was a completely new archaeology out there waiting to be classified: http://www.newscientist.com/news/news.jsp?id=ns99994256 Weird rock carvings puzzle archaeologists Mysterious rock carvings engraved into strange shapes are baffling UK archaeologists. One resembles a heart, another a human footprint. Aron Mazel and Stan Beckensall, who stumbled across the unusual carvings close to England's border with Scotland, believe they are the first such designs to have been discovered in the UK. "We have absolutely no idea what they are," says Mazel, an archaeologist at the University of Newcastle. "They are nothing like anything we, or anybody else we have talked to, have seen before." He believes the carvings were not created recently - in the last 15 to 20 years - and could be as ancient as 3000 years old. The researchers were alerted to the etchings on an isolated boulder by a farm worker, while they were investigating the well-known "cup and ring" rock art in Northumberland. These prehistoric etchings have been found across the UK, and are particularly abundant in the county. Stone pick axes "The carvings we have found before - cup and ring - dated back to the Neolithic Bronze Age and were probably done by early farmers," Mazel told New Scientist. They were hacked into rock faces using stone pick axes. But the new-found carvings are "very different", he says. "They are sharper on one hand, but also quite smooth." Metal tools are likely to have been required to make them. "Also, the imagery reflected in the carvings are very different," Mazel says. "They are elliptical shapes, and something which looks like a footprint, and a heart." Mazel and Beckensall are puzzled by their discovery and have consulted experts in the field such as English Heritage, but no one has been able to shed any light. "We are keen to draw people's attention to them - seeing the pictures of the markings may prompt somebody to come forward with new information, perhaps relating to similar rock art samples they have viewed elsewhere," says Beckensall.