Perhaps the most reasonable approach would be to investigate the tolerance or in tolerance of the various environments to human use in general and to some particular uses. The first zone is the beach and, fortunately for us all, it is astonishingly tolerant. It is cleaned by the tides twice a day of the debris that men leave, and even the most vulgar residues achieve a beauty when handled by the sea. The creatures that live in this area do so mostly in the sand and thus escape destruction from humans. So the beach is tolerant to all the happiest of uses—swimming and picnicking, the making of sand castles, fishing and sunbathing.