VI PKEFACE TO 



can affect the whole circumference of a large island 

 is not clear. Nor does this fact, if fully established, 

 falsify my generalisation that volcanos in a state of 

 action are not found within the areas of subsidence, 

 whilst they are often present within those of elevation ; 

 for I have not been influenced in my judgment by the 

 absence or presence of coral-reefs round active volcanos ; 

 I have judged only by finding upraised marine remains 

 within the areas of elevation, and by the vicinity of 

 atolls and barrier-reefs with reference to the areas 

 of subsidence. Professor Dana apparently supposes 

 (p. 320) that I look at fringing-reefs as a proof of 

 the recent elevation of the land ; but I have ex- 

 pressly stated that such reefs, as a general rule, 

 indicate that the land has either long remained at the 

 same level or has been recently elevated. Neverthe- 

 less, from upraised recent remains having been found 

 in a large number of cases on coasts which are fringed 

 by coral-reefs, it appears that of these two alternatives 

 recent elevation has been much more frequent than a 

 stationary condition. Professor Dana further believes 

 that many of the lagoon-islands in the Paumotu 

 or Low Archipelago and elsewhere have recently 

 been elevated to a height of a few feet, although 

 originally formed during a period of subsidence ; but I 

 shall endeavour to show in the sixth chapter of the 

 present edition that lagoon-islands which have long 



