Erratic boulder

 

Erratic granite boulder, Galloway Hills. The rounded, grey boulder has been carried by a glacier from the Mullwarchar granite outcrop just to the north, to rest on a quite different sort of stone. That underlying bedrock is hornfels, a grey sandstone that has itself been altered by the heat of that nearby granite as it arrived as molten magma 400 million years ago.

 

Current page: 6