Masters of rock

PD Smith on Ted Nield's Supercontinent, a book that shows us a world in which 250 million years is but the blink of an eye.

From The Guardian:

Charles Dodgson (aka Lewis Carroll) grew up in Ripon, a part of Yorkshire blessed with a unique but rather alarming geology. Deep vertical pits are liable to appear without warning in the ground, swallowing up homes and gardens in seconds. It is quite possible that the memory of these holes inspired Alice's fictional fall "down, down, down" the seemingly bottomless rabbit hole. After all, as Ted Nield points out, Carroll's fantasy was originally titled Alice's Adventures Under Ground. But Nield's real interest lies in geology, not literature. Why, he asks, are the rocks of Ripon so prone to sudden collapse? To answer this, you have to drive out of Ripon and head west to the Pennines, the backbone of England. Gradually the fertile fields with their oak trees and hedgerows give way to moorland from where you can look down across the lowlands to Ripon. If you take a walk up the heathery slopes and stand on a rough lump of millstone grit, says Nield, "you are climbing the exhumed topography of Pangaea".

Pangaea was the supercontinent that existed 250 million years ago. Our present continents are all that is left of this landmass: "the world we see today is no more than Pangaea's smashed remains, the fragments of the dinner plate that dropped on the floor." If you had stood on that same piece of millstone grit 250 million years ago, behind you would lie not the Pennines but 2,500 miles of mountain and desert that one day will be North America.

More here.