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

July, 1836. CHANGES IN VEGETATION. 583 the old ones, which were safe from their attacks, perished from age, seems clearly made out. Goats were introduced in the year 1502 ; eighty-six years afterwards, in the time of Cavendish, it is known they were exceedingly numerous. More than a century afterwards, in 1731, when the evil was completed and found irretrievable, an order was issued that all stray animals should be destroyed. When at Valparaiso, I heard it positively affirmed, that the Sandal-wood tree had been found on the island of Juan Fernandez in considerable numbers, but that all without ex- ception were standing dead. At the time, I thought it was some mysterious case of the natural death of a species ; but when it is remembered, that goats for very many years have abounded on that island, it seems most probable that the young trees were prevented growing, and that the old ones perished from age. It is a very interesting fact, to observe that the arrival of animals at St. Helena in 1501 did not change the whole aspect of the island, until a period of two hundred and twenty years had elapsed : for they were intro- duced in 1502, and in 1724 it is said "the old trees had mostly fallen." There can be no doubt, this change affected not only the Bulimus and probably some other land shells (of which I obtained specimens from the same bed), but hkewise a multitude of insects. St. Helena, situated so remote from any continent, in the midst of a great ocean, and possessing a unique Flora, — this little world within itself, — excites our curiosity. Birds and insects,* as might have been expected, are very few in number * Among these few insects, I was surprised to find a small Aphodiiis (nov. spec.) and an Oryctes,both extremely common under dung. When the island was discovered it certainly possessed no quadruped, excepting perhaps a mouse : it becomes, therefore, a difficult point to ascertain, whether these stercovorous insects have since been imported by accident, or if aborigines, on what food they formerly subsisted. On the banks of the Plata, where, from the vast number of cattle and horses, the fine plains of turf are richly manured, it is vain to seek the many kinds of dung-feeding beetles, which occur so abundantly in Europe. I observed only an Oryctes (the insects of this genus in Europe generally feed