Terra Mobilis

"Through the spectacles of geology, terra firms becomes terra mobilis, and we are forced to reconsider our beliefs of what is solid and what is not. Although we attribute to stone great power to hold back time, to refuse its claims (cairns, stone tablets, monuments, statuary), this is true only in relation to our own mutability. Looked at in the context of the bigger geological picture, rock is as vulnerable to change as any other substance.

Above all, geology makes explicit challenges to our understanding of time. It giddies the sense of here-and-now. The imaginative experience of what the writer John McPhee memorably called 'deep time' - the sense of time whose units are not days, hours, minutes or seconds but millions of years or tens of millions of years - crushes the human instant; flattens it to a wafer. Contemplating the immensities of deep time, you face, in a way that is both exquisite and horrifying, the total collapse of your present, compacted to nothingness by the pressures of pasts and futures too extensive to envisage. And it is a physical as well as a cerebral horror, for to acknowledge that the hard rock of a mountain is vulnerable to the attrition of time is of necessity to reflect on the appalling transience of the human body."

- Robert Macfarlane (1976 - )

Mountains of the Mind: A History of a Fascination