210 THE BERMUDA ISLANDS. 



in those vast and permanent hollows of the earth which are 

 occupied by the waters of the ocean (loc. cit., p. 516). But in 

 what lies the evidence for these assertions ? It would proba- 

 bly be as difficult to prove a general elevation in volcanic 

 tracts as it would be difficult to furnish that evidence in favor 

 of subsidence in coral areas which the opponents to the Dar- 

 winian hypothesis demand. Indeed, it is well known that by 

 many geologists volcanic tracts are considered to be areas of 

 subsidence, rather than the reverse. This is the view now 

 held by the foremost Austrian geologists, like Suess and Neu- 

 mayr, who associate the great crustal fractures or depressions 

 the " sunken basins " with volcanic phenomena. While 

 subsidence may, and with little doubt does, initiate volcanic 

 outflows, it seems reasonable to suppose that any very great 

 extravasation of material from the earth's interior will produce 

 subsidence, except in so far as this subsidence may be locally 

 balanced by the material ejected. Dana, indeed informs us, 

 from a study of the deep-sea soundings of the " Tuscarora " and 

 "Challenger," that the region of the great island of Hawaii, 

 "although it is now actively volcanic and has little growing 

 coral about it," has seemingly " undergone more subsidence 

 than the coral reef end of the chain, and that its height and 

 steepness of submarine slopes are due to the fact that its out- 

 flows of lava have kept ahead of the subsidence, and also built 

 up nearly 14,000 feet above the sea" (A. J. Science, 3d ser., 

 XXX, p. 101). 



H. B. Guppy. "Notes on the Characters and Mode of Formation of the Coral-Reefs of 

 the Solomon Islands." Proc. Royal Soc. Edinburgh, 1885-86, pp. 857-904. 



This is one of the most comprehensive papers dealing with the 

 coral formations of any one single group of islands. The re- 

 gion of the Solomon Islands comprises, according to this in- 

 vestigator, all three forms of reefs atolls, fringing-reefs, and 

 barrier-reefs and thus presents special advantages for the 

 study of the coral-reef problem. The author's main conclusions 

 may be briefly summed up as follows: 



