189o.] - Recent Literature. 937 
power in the lagoon of an atoll, and so little solvent power anywhere 
else. We find ourselves in very much the same state of mind. 
The distribution of coral formations in the Pacific accords exceed- 
ingly well with the Darwin-Dana theory. South and west of the 
Sandwich Islands there lies a large area nearly or quite destitute ot 
islands of any kind. Passing southward and westward from this area 
—the area of maximum subsidence, according to the theory—we tra- 
verse zones characterized respectively (though with much local irregu- 
larity, as might be expected) by the predominance of small atolls and 
lagoonless islands, of large atolls with broad and deep lagoons, and ot 
high islands encircled by barrier reefs, reaching at last an apparent 
limit to that area of subsidence in the fringing reefs of New Hebrides 
and the Solomon Islands. 
Dana has pointed out a very interesting evidence of subsidence in 
the dissected form of the coast-line of the high islands encircled by 
barrier reefs,—narrow ridges radiating outward in “ spider-leg ” fashion 
between deep bays. A deeply-dissected coast-line, on continent or is- 
land, is rightly regarded as evidence of subsidence, since valley-making 
is the characteristic work of rivers or glaciers. 
The limits of this article allow only a mention of the blocks of lime- 
stone on the submarine slope of Tahiti far below the reach of wave- 
action, and the discovery of coral rock hundreds of feet below the sea- 
level in the artesian borings at Honolulu, rightly regarded by Dana as 
evidences of subsidence. 
We are inclined to find a confirmation of the Darwin-Dana theory 
in a consideration which many will regard as too speculative to have 
any weight. Although there are some exceptions, Darwin's generaliza- 
tion appears, on the whole, to be well established, that areas of barrier 
reefs and atolls are destitute of active volcanoes, while active volcanoes 
are found in areas of fringing reefs. If we adopt the view that the 
interior of the earth, though solid, is mostly in a state which might be 
called potential liquidity, the relations of temperature and pressure 
everywhere, beneath a thin, cold crust, being such that the slightest local 
diminution of pressure will allow extensive liquefaction,—a theory which 
séems perhaps most satisfactorily to harmonize the apparently conflict- 
ing indications of geological and physical evidence bearing on the 
subject, —it seems probable that the fire-lakes from which volcanoes are 
fed may be developed generally in areas of local elevation and conse- 
quent local diminution of pressure. If, then, the presence of barriers 
and atolls may be accepted as a mark of regions undergoing subsi- 
dence, in distinction from regions stationary or undergoing elevation, 
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