ORIGIN OF THE GROUP. 283 
This order is that shown by the extent of degradation on the 
surface. Each successive year since the finishing of the mountain 
has carried on this work of degradation; and the amount of it is 
therefore a mark of time, and affords evidence of the most decisive 
character. On this point we shall dwell more at length when speak- 
ing of the formation of valleys in the Pacific islands. 
We are thus sustained in our deductions, not only with regard to 
the general group, but particular parts of the group. The facts find 
a ready explanation in the view presented that the islands have pro- 
ceeded from a series of ruptures of the earth’s crust, each of which was 
largest at its southeast extremity, and the largest of the whole, the 
southeasternmost of the series. 
After the above explanations, the map of the group here annexed 
will not be deemed hypothetical. The origin of the islands from one, 
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two, or three vents, and their consisting of as many distinct volcanic 
mountains, though now much altered by degradation, fully accord 
his concluding remarks he says, “ The foregoing observations are applied to the course of 
volcanic action at the islands taken separately, with a view to show that it has been suc- 
cessive in each, from the western to the southeastern extremity of the group, and the 
possibility that they were also forced up in regular succession by the subterranean fire. 
The phenomena they present seem to point to such an origin, unless we adopt the 
hypothesis that they were formed in a cantinuous chain, which has been shattered by 
some great convulsion, and partially submerged, leaving them in their present relative 
position, 
