SUBMARINE BANKS IN THE CENTRAL PACIFIC 529 



with their active volcanoes on the east;, the Ellice gronp of atolls on the 

 north, the Santa Cruz, Banks, and New Hebrides Islands with active 

 volcanoes on the west, and the Fiji archipelago on the south. Its mem- 

 bers vary from less than a mile to over 20 miles in diameter, and from 

 10 to 30 fathoms in central depth. It is difficult, if at all possible, to 

 explain these banks under the uniform conditions of the Glacial-control 

 theory; for if preglacial atolls and barrier reefs were cut down during 

 the Glacial period and have now been built up to the surface again in the 

 Ellice group on the north and in the Fiji group on the south, they should 

 have been similarly built up in the intermediate area; yet there they 

 remain below sealevel. It is, on the other hand, a simple matter to ex- 

 plain this extraordinary group of banks under the variable conditions of 

 Darwin's theory merely by postulating moderate inequalities in the rate 

 or amount of recent subsidence, the greater or more rapid subsidence 

 being in the region of the submarine banks, and tlie smaller or slower 

 subsidence being to the north in the Ellice group and to the south in the 

 Fiji group. 



But it is evidently desirable to find some independent confirmation for 

 the postulate of recent and rapid subsidence in the region of these banks, 

 such as neighboring high islands might furnish, similar to the confirma- 

 tion given by the submerged bank bordering the embayed and fringed 

 shore of Palawan for the recent and rapid subsidence of the banks in the 

 China Sea; for it is plain that if high islands occurred in or near the 

 region here under consideration, they should have been surrounded by 

 sealevel barrier reefs when the now submerged banks existed as sealevel 

 atolls, but that their barrier reefs should now be more or less submerged 

 as a result of the rapid subsidence by which the atolls were converted into 

 submarine banks; and inasmuch as submerged barrier reefs are rarely 

 found, the occurrence of one in this particular region would be significant. 



By good fortune, two high islands occur in association with this group 

 of submarine banks. Ilea or Wallis island is in the southeastern part of 

 the area; it is shown on Hydrographic Office chart 2019 to be 6 miles 

 long, about 200 feet high, and surrounded by a barrier reef about 2 miles 

 offshore : subsidence here must have been at a moderate rate. More im- 

 portant is Eotuma, near the center of the area; chart 1978 shows it to be 

 7 miles long, 690 feet high, and closely surrounded by a fringing reef; 

 but it rises eccentrically from a submarine bank, 3 miles wide on the 

 north and extending 6 miles to the west; the bank is for the most part 

 25 or 30 fathoms deep, but it has a rim about 15 fathoms deep ; hence it 

 is an excellent counterpart of a submerged ,barrier reef, such as the sub- 

 sidence theory suggests should occur here. Whale bank, a rimless shoal. 



