172 DISTRIBUTION OF CORAL-REEFS. Ch. VI. 



Evidence that many coasts fringed with coral-reefs 

 and coloured red on the map, have been recently 

 elevated,— As the areas which have slowly subsided with- 

 in the period of existing corals are many and large, 

 we might have expected that such movements would 

 have been counterbalanced by the recent elevation of 

 other equally large areas ; and this, as we shall see, 

 apparently holds good. Corals attached to a rising 

 coast would necessarily form a fringing-reef ; and this 

 reef would be upraised at each successive elevation, with 

 a new one formed on the coast at a lower level. Such 

 reefs would differ only by their smaller breadth from 

 those attached to a shore which had long remained 

 stationary ; for they would not have had sufficient time 

 to form a foundation of their own detritus and grow far 

 outwards. Fringing-reefs indicate as a general rule 

 that the land to which they are attached has not re- 

 cently subsided. But they do not tell us whether 

 the land is rising or stationary. Nevertheless, the 

 crust of the earth seems liable to such incessant changes 

 of level that a long-continued stationary condition ap- 

 parently is rare. We may infer that this is so from 

 the number of cases, within the limits of our map, in 

 which upraised corals or other organic remains have 

 been found on the shores which are fringed with reefs, 

 and are, therefore, coloured red. It may be mentioned 

 as bearing on this subject, that I was much surprised 

 on first reading a memoir on coral formations by 



