"We speak of as if rock were the epitome of durability. It isn’t. Where rock meets water, it is water that wins in time, every time, and there are few places in England where this is more obviously true than the . Hollowness is ubiquitous here; a landscape riddled with caves and pots and channels. You can even watch them forming in many rivers and becks, where below most drops, you can find circular dishings in the rock, some shallow, some deep, some containing pebbles conscripted to the river’s work; swirling and scouring, day and night. ... It’s not necessarily the speed, volume or power of a river that wins, but its relentlessness. It needs no breath, no sleep, no pause to stretch or shake. And in time, without fuss or ceremony, it will take heat from flesh, life from limb, tree from bank, rock from channel, mountain from continent. It will hollow the land. And it demands total respect."