"So there I lie on the plateau, under me the central core of fire from which was thrust this grumbling grinding mass of plutonic rock, over me blue air, and between me the fire of the rock and the fire of the sun, scree, soil and water, moss, grass, flower and tree, insect, bird and beast, wind, rain and snow - the total mountain."
Those words - from Nan Shepherd's recently resurrected gem The Living Mountain (Canongate) - perfectly evoke the intimate relationship between the flora and fauna of upland Britain and its ancient volcanic past.
In this case, the reverence is for the rounded granite bulk of the Cairngorm mountains in north-east Scotland, but across Britain and Ireland rocks born molten many millions of years ago still fashion the familiar natural world around us.
The Cairngorms themselves are the roots of mountains that formed about 420 million years ago when a great seaway separating the rocks of Scotland and Northern Ireland from those of England and Wales crumpled shut.
During the final death throes of that ancient Iapetus Ocean, a chain of explosive volcanic islands had lined the leading edge of the approaching southern landmass of Avalonia - today the jagged highlands of Snowdonia and the Lake District are the ice-sculpted remains of that once fiery frontier.
When Avalonia finally collided with the Celtic fringes of the northern landmass (Laurentia), a mountain range of Himalayan stature was thrown up.