206 FOUNDERS OF OCEANOGRAPHY 



growing part; the lagoon, according to Murray, is being 

 worn away or dissolved, and so the small atoll increases in 

 size, growing outwards like a *' fairy ring " on grass, and 

 supported upon a growing " talus " of its own broken frag- 

 ments (Fig. 11). On the same principle a fringing reef might 

 grow outwards to form in time a barrier reef on a stationary 

 or even a slowly rising area. 



The strong points of Murray's theory are (1) that it does 

 not require any great assumption, such as the subsidence of 

 a vast area of land in tropical seas ; and (2) that it depends 

 upon observed facts and known processes in the life and 

 growth of the coral animals. 



This theory was favourably received by many biologists, 

 especially by those who had themselves explored coral reefs. 

 Several more recent investigators, however, differ from 

 Murray's view that a lagoon may be formed or deepened by 

 solution of the dead coral, and regard the lagoon as an area 

 of deposition or sedimentation rather than of solution. 



An interesting corroboration of Murray's views was 

 furnished a few years later by Dr. H. B. Guppy, who found 

 in the Solomon Islands upraised coral reefs formed of a 

 relatively thin layer of coral upon limestones which were 

 evidently consolidated Pteropod and Globigerina ooze, and 

 the consolidated ooze was deposited upon a core of volcanic 

 rock, the whole structure being a remarkable verification 

 of what Murray had supposed would be the case. 



These two theories, Darwin's and Murray's, with various 

 modifications introduced by other investigators, such as 

 Wharton, A. Agassiz, Stanley Gardiner, Davis, and others, 

 now held the field, and opinion was very equally divided 

 as to which was the more correct interpretation. Darwin 

 himseK had long ago expressed the hope that someone would 

 some day make a boring through a Pacific atoll in order to 

 determine what its base was formed of, and whether, as he 

 supposed, coral which was living in situ went continuously 

 down to depths where no reef-building coral could live. 



