Pillars and columns

I took this photo the other day -- it's the best example I could find of pillars / columns in situ in the Carn Meini area. This outcrop is in one of the western tors of the group, some way away from the "enclosure" described by Darvill and Wainwright. The pillars look good at first sight -- ideal for plucking out of the bedrock and hauling off to Stonehenge, you might think......

But look again. The pillars of spotted dolerite are criss-crossed with weaknesses -- fractures and veins of quartz. When pillars like this are broken down by block collapse, or freeze-thaw, or even glacial action, the chances of the pillars surviving intact are very slim indeed. What you normally end up with is a collection of roughly rectangular blocks that are not much good for local gateposts, let alone heroic transport expeditions from here to Stonehenge.