CH. VI MABINE FAUNA OF TALIS SE 8H0BFS 151 



that the corals themselves provide the substance which is 

 analogous in function to the chlorophyl of plants, this 

 anomaly receives its explanation. 



A discussion of the vexed question of the origin of 

 barrier reefs and atolls would hardly be in place in this 

 volume, for the coasts of N. Celebes and the neighbouring 

 islands present but few examples of those characteristic 

 forms upon which the most important theories are based. 

 I have already stated the views I hold upon the subject in 

 a paper I read before the British Association in 1888, and 

 in the opinions I have expressed in the preceding pages it 

 is evident that I am not a believer in what is known as the 

 ' general subsidence theory ' (12). Mr. Murray's view (52) 

 that coral reefs can, under favourable circumstances, grow 

 out into deep sea-water upon the talus of their own debris 

 seems to me to be supported by sufficient evidence, and is 

 fully confirmed by the phenomena of the reefs I visited in 

 this region. 



I searched for evidences of recent elevation or subsi- 

 dence of the land, but could find none anywhere, save in 

 the Talaut and Nanusa islands, where there has been a 

 recent slight elevation. In fact, the presence of consider- 

 able shore platforms in many regions on the coast indicates 

 that for a considerable number of years the land has been 

 stationary. There can be but little doubt, I think, that 

 coral reefs are constantly altering their shape, in some 

 places growing out seaward, in others dissolving and 

 retreating shoreward, and that these processes may go on 

 without any movement of the rocks on which they stand. 

 But a discussion of this wide and far-reaching subject 

 would take me beyond the limits of this book. 



