Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.3)

582 ST. HELENA. July? 1836. from below, so that the confusion in structure from these dif- ferent causes is extreme. On the higher parts of the island considerable numbers of shells occur embedded in the soil, which have always been supposed to be of marine origin and the fact has been adduced as a proof of the retreat of the sea. The shell turns out to be a Bulimus, or terrestrial species. It is however very remarkable, that it is not now found in a living state : a circumstance which in all probability may be attributed to the entire destruction of the woods, and conse- quent loss of food and shelter, which occurred during the early part of the last century. The history of the changes, which the elevated plains of Longwood and Deadwood have undergone, as given in General Beatson's account of the island, is extremely curious. It is said the plain in former times was covered with wood, and was therefore called the Great Wood. So late as the year 17I6 there were many trees upon it, but in 1724 the old trees had mostly fallen ; and as goats and hogs were at that time suflFered to range about, all the young trees had been devoured. It appears also from the official records, that the trees were un- expectedly, some years afterwards, succeeded by indigenous wire grass, which now spreads over its whole extent.* He then adds, " These are curious facts, since they trace the changes which this remarkable spot of land has undergone, for now this formerly naked plain (after the trees had fallen) is covered with fine sward, and is become the finest piece of pasture on the island." The extent of surface, which was probably covered by wood at a former period is estimated at no less than two thousand acres ; at the present day scarcely a tree can be found there. It is said, that in 1709 there were quan- tities of dead wood in Sandy Bay: this place is now so utterly desert, that nothing but so well-attested an account could make me believe that trees had ever existed there. The fact, that the goats and hogs destroyed all the young trees as they sprung up, and that in the course of time * Beatson's St. Helena. Introductory diapter, p. iv.