126 
THEORY OF THE ^FORMATION 
Ch. V. 
miles in length and of considerable breadth, with 
broad summits attaining the same height, from within 
120 to 180 feet ? Even if it be assumed without any 
evidence that the reef-building corals can flourish at a 
depth of 100 fathoms, yet the weight of the above argu- 
ment is but little diminished ; for it is almost equally im- 
probable, that as many submarine mountains, as there 
are low islands in the several great and widely-separated 
areas above-specified, should all rise within 600 feet of 
the surface of the sea and not one above it, as that they 
should be of the same height within the smaller limit 
of one or two hundred feet. So highly improbable is 
this supposition, that we are compelled to believe, that 
the rocky foundations of the many atolls did never at 
any one period all lie submerged within the depth of a 
few fathoms beneath the surface, but that they were 
brought into the requisite position or level, some at one 
period and some at another, through movements in the 
earth’s crust. But this could not have been effected 
by elevation ; for the belief that points so numerous and 
so widely-separated were successively uplifted to a cer- 
tain level, but that not one point was raised above that 
level, is quite as improbable as the former supposition, 
and indeed differs little from it. It will probably occur 
to those who have read Ehrenberg’s account of the reefs 
of the Bed Sea, that many points in these great areas 
may have been elevated, but that as soon as raised, the 
protuberant parts were cut off by the destroying action 
of the waves : a moment’s reflection, however, on the 
basin-like form of the atolls, will show that this is 
