FLORA OP THE GALAPAGOS ISLANDS. 



253 



TABLE IV. — Pteridophttes and SpERjiAxorHTTEs Common to the 



Different Islands. 



Botanical Evidknce regarding the Oiugin of the 

 Galapagos Islands. 



Two views have been advanced regardiirjj: the origin of the Galapagos 

 Islands. According to the first they are pelagic i.slatids, built up from 

 the sea-floor by volcanic action, wliile accrording to the si-cond view they 

 are continental islands, tops of mountains, formerly a [lart of the main- 

 land, now separated from it by subsidence. The first view, namely, that the 

 Galapagos are islands of elevation, was hel4 until about 18"J0 with scarcely 



