he waste of the island,
presses down the bed of the ocean, the continent being on the other hand
relieved of pressure; "this brings about a state of strain in the crust
which will crack in its weakest spot, the heavy side going down, and the
light side rising." In discussing this view Lyell writes ("Principles,"
Volume II. Edition X., page 229), "This hypothesis appears to me of
very partial application, for active volcanoes, even such as are on the
borders of continents, are rarely situated where great deltas have been
forming, whether in Pliocene or post-Tertiary times. The number, also,
of active volcanoes in oceanic islands is very great, not only in
the Pacific, but equally in the Atlantic, where no load of coral
matter...can cause a partial weighting and pressing down of a supposed
flexible crust.") Would not the Atlantic and Antarctic volcanoes be the
best examples for you, as there then can be no coral mud to depress
the bottom? In my "Volcanic Islands," page 126, I just suggest that
volcanoes may occur so frequently in the oceanic areas as the surface
would be most likely to crack when first being elevated. I find one
remark, page 128 (493/4. "Volcanic Islands," page 128: "The islands,
moreover, of some of the small volcanic groups, which thus border
continents, are placed in lines related to those along which the
adjoining shores of the continents trend" [see Figure 5].), which seems
to me worth consideration--viz. the parallelism of the lines of eruption
in volcanic archipelagoes with the coast lines of the nearest continent,
for this seems to indicate a mechanical rather than a chemical
connection in both cases, i.e. the lines of disturbance and cracking. In
my "South American Geology," page 185 (493/5. "Geological Observations
on South America," London, 1846, page 185.), I allude to the remarkable
absence at present of active volcanoes on the east side of the
Cordillera in relation to the absence of the sea on this side. Yet I
must own I have long felt a little sceptical on the proximity of water
being the exciting cause. The one volcano in the interior of Asia is
said, I think, to be near great lakes; but if lakes are so important,
why are there not many other volcanoes within other continents? I have
always felt rather inclined to look at the position of volcanoes on the
borders of continents, as resulting from coast lines being the lines of
separation between areas of elevation and subsidence. But it is us