CORAL REEFS AND SUBMARINE BANKS 303 
size, if these calcareous rims originated on the platforms in post- 
glacial time” (219). As to the height of reefs we know little, 
because the depth of their base is undetermined. Nothing is 
gained by assuming their base to be 40 or 50 fathoms below present 
sea-level, for the resulting uniformity of height has no verification. 
However that may be, the visible differences in the height of reefs 
above their lagoon floors and the breadth of reefs at sea-level seem 
to me too great to support the above conclusion. Yap, in the west- 
ern part of the Caroline group, Western Pacific, and. Rodriguez, in 
the Southern Indian Ocean, have broad reef plains, a mile or more 
in width, attached to the central islands; that of Rodriguez is 4 
miles wide on the southwest side of the island. Borabora, in the 
Society Islands, has a barrier reef and reef flat half a mile or a 
mile wide, and a comparatively shallow lagoon; Mbengha, in 
Fiji, has a reef and reef flat of similar width around the southern 
side of its lagoon; the reef around Nairai, in central Fiji, is a half or 
a quarter of a mile wide; Budd reef, in northeastern Fiji, is narrow, 
generally less than a quarter-mile across, and its lagoon is 46 
fathoms deep; yet near by is the long and irregular Ringgold atoll, 
in which the reef is half a mile or a mile wide, though the lagoon is 
of similar depth to that of Budd reef; Tahiti has a narrower reef, 
often discontinuous; Fauro, in the Solomon Islands, is fringed with 
a narrow sea-level reef and surrounded by a submerged bank, 70 
fathoms deep in places, on which a very imperfect reef rim is found; 
Palawan, the southernmost member of the Philippines, is elab- 
orately embayed along its western coast, where the headlands are 
neither clift nor fringed with sea-level reefs, but are fronted by a 
broad submerged platform, varying in depth along its length with 
maximum of 60 fathoms. The Marquesas Islands, nearer the 
equator than the numerous Paumotu atolls, have no sea-level reeis; 
their headlands are strongly clift, and a submerged bank extends 
around them. Various submarine banks have well-defined reef 
rims that fail to reach the surface, or that rise very discontinuously 
to the surface, as will be specified below; and some submarine 
banks are flat and rimless. Differences of these kinds in reef 
volume are more consistent with the unlike conditions introduced 
by intermittent subsidence, varying as to rate, amount, place, and 
