The many fans of Richard Fortey's Dry Store Room No.1, about the outlandish denizens of the Natural History Museum, should try this rather more sober but engaging ramble round Britain's geological marvels. They would learn that the division between north and south was once more marked than it is today.
Around 500 million years ago, the Iapetus Ocean divided the British Isles by a gulf wider than the Atlantic. If you have ever pondered the whereabouts of England's coldest water, Berkshire residents maintain it is the River Lambourn. Fortey agrees. He introduces us to fossilised "armoured sharks" in Orkney and the preserved leaves of gingko trees in Jurassic rocks near Whitby. He even advises not to go for a pint in the Forest of Dean ("There is a certain spookiness about the place").