S T . r n S L E N A .
which, in the coarse of future events, became the prison of one of __
Europe’s greatest monarchs.
Repeated outpourings of lava would in time raise the era ter-edge
above the surface of the water, and the flow of .lava inclining from
it would eventually bring up the land to the same elevation. At an
early period the crater would doubtless have its edge intact, and would
necessarily contain water, which, during the interval between
volcanic action, would mix with bits of broken rock, débris, and
dust rolling down into it from the disintegration of its sides, and
produce volcanic mud. A renewal of volcanie activity would first
of all discharge from the crater this mud, accompanied with steam
and water ; the rubble, or small fragments of rock, which, being
heaviest, would sinlpto the bottom, would next be shot forth, and
finally the molten lava would follow, thrown up high into the air
amidst smoke, dust, and keary clouds, ju st as in the'present day we
witness it at Vesuvius ; sometime* r high that detached fragments
of lava, rendered spherical bjn their'passage A"-- ’-A -would
descend in the form of bomb« weighing halt a Um or The
lava would, for the most part, however, descend in huge sheets of
liquid matter. A period of quiescence, or rest from volcanic discharge,
extending over a century or two,* would O ' , O * then intervene,
when another similar outpour would follow: first mud, then
rubble, followed by the pure lava, and this would, with intervals
of rest, he repeated through hundreds of centuries until
the edge of the great crater was built up to thousands of feet in
height, with the land on its outer sides, excepting th a t towards
which the prevailing wind blows, sloping outwards at such angles
as the flow of lava naturally takes, probably 5° or 7°. ’ Now this is
precisely what we. find on examining that part of St. Helena
which is outside of the erater-walls. The whole of this portion of the
Island is thus built up of numerous layers of mud, rubble, and lava ;
occasionally the former two are ihissing in the regular order,- and
beds of lava overlie beds of lava, but such is the exception ; arid
although it is difficult now, in consequence of disintegration and
surfacè-soil overlying them, to trace the distinct strata, it is easy to
count, on the northern face of the Island, at least forty or fifty
* G. Smith states, with reference to Teneriffe, that voice w t oeeur once in
j .
Plate 14:
'VOLCANIC BOMBS . ROAD SIDE, SWAMPY GUT. p. 52.
‘J.C.Mdliss,
BELL STONE. A MASS OE PHONOLITE NEAR SHIPWAYS .
■WHICH ‘WHEN STRUCK EMITS A SOUND -RESEMBLING- A DEEP TONED BELL. .
L .Reeve &C? London.