Chap. XII.^ MEANS OP DISPERSAL. 14,9 



bones, and the nest of a land-bird, it can hardly be 

 doubted that they must occasionally, as suggested by 

 Lyell, have transported seeds from one part to another 

 of the arctic and antarctic regions; and during the 

 Glacial period from one part of the now temperate 

 regions to another. In the Azores, from the large 

 number of plants common to Europe, in comparison 

 with the species on the other islands of the Atlantic, 

 which stand nearer to the mainland, and (as remarked 

 by Mr. H. C. Watson) from their somewhat northern 

 character in comparison with the latitude, I suspected 

 that these islands had been partly stocked by ice-borne 

 seeds, during the Glacial epoch. At my request Sir C. 

 Lyell wrote to M. Hartung to inquire whether he had 

 observed erratic boulders on these islands, and he 

 answered that he had found large fragments of granite 

 and other rocks, which do not occur in the archipelago. 

 Hence we may safely infer that icebergs formerly 

 landed their rocky burthens on the shores of these 

 mid-ocean islands, and it is at least possible that they 

 may have brought thither some few seeds of northern 

 plants. 



Considering that these several means of transport, 

 and that other means, which without doubt remain to 

 be discovered, have been in action year after year for 

 tens of thousands of years, it would, I think, be a mar- 

 vellous fact if many plants had not thus become widely 

 transported. These means of transport are sometimes 

 called accidental, but this is not strictly correct: the 

 currents of the sea are not accidental, nor is the direc- 

 tion of prevalent gales of wind. It should be observed 

 that scarcely any means of transport would carry seeds 

 for very great distances: for seeds do not retain their 



