‘289 
camp ; the effects are so like what must result if land werej^slowly rising 
that it is only after careful examination of all the conditions that one’s 
mind becomes disabused of this specious impression. There is no 
direct evidence that the land is rising and, as will be evident on con¬ 
sidering what has been said above, there is no necessity for supposing 
that it is. But though this is a very common type of bay, it is not 
the only type. On Great Coco, in some cases, and on Little Coco very 
generally a different stage may be observed. The shallow pools described 
as existing between the surf-built embankment at the margin of the 
fringing-reef and the beach, have in them many living corals that raise 
great rings which rise to almost the surface of the water in the pool 
at low-tide and, like huge lichens, grow peripherally till they meet and 
coalesce. The surf, too, breaks off pieces of greater or smaller size 
which are lodged in the pool behind, and by-and-bye become moi’e or 
less cemented together. In this way the whole of a pool becomes in time 
completely filled up with growing coral and cemented blocks, and there 
are many reefs, especially on Little Coco, that are completely uncovered 
at low-tide, while small patches of similar reef are here and there seen 
that ordinarily the high-tides do not cover. The uniformity that the 
surfaces of some of these exposed reefs display is very striking. They 
are almost as even as a paved floor and are as bare and destitute of 
marine vegetation as they are of living coral. The edge of such a reef, 
in place of being a fairly continuous embankment higher than the floor 
of the bay behind, is now broken into hundreds of jagged gulleys through 
which the wave-wash from the almost level platform tears its way back 
to the deep water beyond the fringing-reef. The main interest of this 
stage of the reef is less, however, from the present point of view, its 
actual physical condition than its effect on the vegetation of the shore. 
Behind a coral bay like one of those first described, and which charac¬ 
terises a less advanced stage of the history of the fringing-reef, has gone 
on a long and steady growth of land, with some shingle in it doubt¬ 
less, especially as one approaches the nearest ridge, but chiefly composed 
of coral sand with a thin coating of humus derived from the vegetation 
it has supported. The main force of the surf has for long been spent on 
the outer embankment, and the force of the waves that at high-water 
passed over its top has been so much diminished ere these reached 
the beach that there they did not act destructively. Wow all this is 
altered. At low-tide the force of the surf is still all expended on the 
edge of the reef, but as soon as the water has risen so high that the edge 
of the reef is covered, this force instead of being dissipated in the deeper 
water of a pool is accentuated as the breakers roll landward across a reef 
on which the water shallows slightly as the shore is approached; by the 
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