High above the residential northern shores of the Clyde is a strip of sandstone geology outcropping all the way to Craigmaddie Muir in the east. It lies hidden under a mossy understorey mostly, and varies in consistency and quality, but was once the attention of neolithic archaeologists, until they had to bury what is one of Scotland's greatest rock-art sites.The 'Cochno Stone' was uncovered by the Rev James Harvey in 1887 on open land near what is now the Faifley housing estate. It is covered with dozens of cup and ring marks, grooved spirals, along with a ringed cross and a pair of four-toed feet. It was briefly a chalked-in tourist attraction until it was buried to prevent vandalism in 1964. Rock-art these days is a kinaesthetic thing, recorded as bouldering on photo-video networks, rather than pecked out on rock plinths. I've always like the connection between the vibrant, fluid circles and lines inscribed on the rock and the modern tracery of bouldering; ther