The environmental sequence on this site, as deduced from the evidence of land snails, has already been published in detail (Evans, 1970. Essentially, there was an episode of deforestation which we can now say took place shortly before 2461 ± 79 bc. This was followed by a period of about 800 years during which the landscape remained open. By 1531 ± 54 be the site had once more become wooded. It is not certain whether deforestation was an entirely artificial process brought about by Neolithic man, or a natural one caused by the overwhelming action of wind-blown sand, but there can be no doubt that it was closely associated in time with man's presence on the island.