XIV INTRODUCTION. 



time; become perfect polypes. That the Sargassum 

 should continue to exist in this manner^ is not so 

 surprising when we bear in mind that; excepting in 

 the parasitical sea-weeds, the root does not appear 

 to serve the purpose of nourishing the plant so much 

 as of affording it a secure holdfast in its appropri- 

 ate habitat; against the violence of the winds and 

 waves. It iS; however, surprising that only one 

 species of algae should be found amongst the inass : 

 and this fact would seem to afford conclusive evi- 

 dence against the supposition that there is any land 

 now existing in its vicinity, or other species besides 

 this particular kind would vegetate thereon. But 

 according to the views of Professor Forbes, this 

 Sargassum indicates land existing, or which did ex- 

 ist before some great geological change -, and Hugh 

 Miller, in speaking of these changes, says, — " It is 

 not at all impossible that the long trails of sea-weed 

 that undulate in mid-ocean to the influence of the 

 Gulf-stream, and darken the water over an area of 

 hundreds of miles in extent, are anchored beneath 

 to what once formed the Rocky Mountains of this 



