MEANS OF DISPERSAL. I3I 



" In a memoir lately published, a naval officer relates 

 that, as he returned from China by the eastern passage, 

 he fell in^ among the Moluccas, with several small 

 floating islands of this kind, covered with mangrove 

 trees interwoven with underwood. The trees and 

 shrubs retained their verdure, receiving nourishment 

 from a stratum of soil which formed a white beach 

 round the margin of each raft, where it was exposed to 

 the washing of the waves and the rays of the sun. The 

 occurrence of soil in such situations may easily be 

 explained ; for all the natural bridges of timber which 

 occasionally connect the islands of the Ganges, Mis- 

 sissippi, and other rivers, with their banks, are exposed 

 to floods of water, densely charged with sediment. 



"Captain W. H. Smyth informs me, that, when cruis- 

 ing in the Cornwallis amidst the Philippine Islands, he 

 has more than once seen, after those dreadful hurricanes 

 called typhoons, floating masses of wood, with trees 

 growing upon them ; and ships have sometimes been in 

 imminent peril, as often as these islands were mistaken 

 for terra firma, when, in fact, they were in rapid 

 motion. 



'* It is highly interesting to trace, in imagination, the 

 effects of the passage of these rafts from the mouth of a 

 large river to some archipelago, such as those in the 

 South Pacific, raised from the deep, in comparatively 

 modern times, by the operations of the volcano and 

 the earthquake, and the joint labours of coral-animals 

 and testacea. If a storm arise, and the frail vessel be 

 wrecked, still many a bird and insect may succeed in 



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