Excerpt from Earth by Richard Fortey, plus links to reviews, author biography & more

The massive limestones continue westwards on to the island of Capri, which is a twenty-minute ferry ride from Sorrento and bounds the southern edge of the Bay of Naples. The island rises sheer from the sea, circumscribed by steep limestone cliffs, and your first thought is how could it support the smallest village, let alone a town. The town of Capri lies at the top of a vertiginous funicular railway running from the harbour. The buildings are ancient and quaint, and, naturally enough, built of the local stone. The blocks themselves are often concealed under stucco. There is a fine medieval charterhouse where the pale limestone is put to good effect in columns supporting cloisters. Almost everything else is fabricated of limestone—walls, floors, piazzas. In the bright Mediterranean light there is an overwhelming sense of whiteness; some of the villas glimpsed on the hillside have the appearance of frosted cakes tucked under umbrella pines. Only dark basalt must have been imported from Vesuvius to make the surfaces of the streets: this volcanic rock is less liable to shatter than limestone. It is not difficult to imagine the racket that iron-rimmed wheels made as they clattered over these roughly matched, large blocks. On the inner side of the island there are truly astonishing vertical limestone cliffs dropping hundreds of metres to the sea. The Roman Emperor Tiberius spent his declining years in a palace on the island, the ruins of which endure. According to the prurient accounts of his chronicler Suetonius, he indulged every kind of sexual perversion in a life of epicene self-gratification. Small boys were favoured. Those who displeased him were liable to be thrown off the monstrous cliffs. There is a subtle undercurrent in the Caprese atmosphere that hints at such darker things. Just offshore there are two enormous and forbidding sea-stacks—masses of limestone isolated from the main cliff by the relentless erosion of the sea. According to Norman Douglas, this was the abode of the Sirens, whose alluring and fatal song Odysseus was able to resist only by being strapped to the mast of his vessel, while his muffled crew rowed onwards to safety. Capri makes you wonder whether an idyllic hilltop haven might eventually also deprave and destroy. One of the grandest villas (now a hotel) overlooking the fearsome cliffs was built by the Krupps dynasty, once the armourers of German ambitions. Unexpectedly, the builder apparently immersed himself in studying the growth of lampreys, a primitive and parasitic fish. On this island there is a seamless continuity with the past—with Hellenic myth and Roman decadence and medieval devotion. The island gardens have seen the ages come and go, perched high upon the hardened sediments of a sea far more ancient than human frailty.

There is something different about the cliffs behind the harbour in the middle of Sorrento. From afar they have a greyish cast, a dull uniformity, lacking all the brilliance of limestone. The streets career downwards towards the sea below the central piazza, following a steep-sided valley. Now you can see the rock in the valley sides. It is brownish, like spiced cake, and displays little obvious structure. Look closely and you see that embedded within it, like dates in a home-bake, there are darker patches. Some are little more than wisps, others are larger—angular pieces of another rock, here nearly black, there umber brown, some including little bubbles. Then you notice that the same rock has been recruited by the local builders to construct the high walls that line the steeply sloping path, comprising blocks a few tens of centimetres across, neatly cut and used like bricks. Clearly, this rock is softer than the rough limestones that bolster the hilly vineyards and terraces. Then you notice that the same stone has been used to construct the older buildings. Down by the port there are shops and cafés painted jolly ochre and sienna, but where the stucco has peeled— or where warehouses have simply been left undecorated—the same rock is revealed as having been used for their construction. Much of the town has grown from the identical rock that forms the steep cliffs backing the harbour.

Excerpted from Earth by Richard Fortey Copyright © 2005 by Richard Fortey. Excerpted by permission of Knopf, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.