That is the work of ice!

Checking out a likely location for an earthcache - a type of geocache of geological interest - and found Agassiz Rock at the south east end of Blackford Quarry, close to the Hermitage of Braid.

This rock is andesite lava, undercut by a glacier, with striations on the rock where the ice has gouged lines in it. The photo shows the smoothed, polished under-surface, which contrasts with the blocks of natural andesite above.

Agassiz rock is of international geological importance as it was the first place where the action of ice was recognised in a place where there was then no ice. Such features had been observed in Switzerland where glaciers had retreated, but they had not been recognised anywhere else. It was Swiss geologist Louis Agassiz, visiting at the invitation of Professor Buckland, professor of geology at Oxford University, who uttered the words "That is the work of ice!", setting in motion the formulation of hypotheses leading to research into ice sheets and the Ice Age.

I had no idea of its importance, but it should make a most excellent earthcache!