I've worked out which is the right station for the Calderstones and looked out of the window at Allerton, and I'll eventually get there. When we were talking about paired things I'd forgotten that I've a stone with a paired carving. I've posted the picture - it's fuzzy and out of focus - the impression from the stone isn't that of nostrils but rather something visceral. The scratchy carvings seem like late graffiti on already old stuff.