Although a few of the
vermilion spots occur within no great distance of single circles
tinted blue, yet not one single active volcano is situated within
several hundred miles of an archipelago, or even small group of
atolls. It is, therefore, a striking fact that in the Friendly
Archipelago, which consists of a group of atolls upheaved and since
partially worn down, two volcanos, and perhaps more, are
historically known to have been in action. On the other hand,
although most of the islands in the Pacific which are encircled by
barrier-reefs are of volcanic origin, often with the remnants of
craters still distinguishable, not one of them is known to have
ever been in eruption. Hence in these cases it would appear that
volcanos burst forth into action and become extinguished on the
same spots, accordingly as elevatory or subsiding movements prevail
there. Numberless facts could be adduced to prove that upraised
organic remains are common wherever there are active volcanos; but
until it could be shown that in areas of subsidence volcanos were
either absent or inactive, the inference, however probable in
itself, that their distribution depended on the rising or falling
of the earth's surface, would have been hazardous.
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