noes are produced, with a cavity in the middle. There is no
difficulty in conceiving that the pumiceous mud, if so thrown out, may
have set into a kind of stone on drying, just as some cements, composed
of volcanic ashes, are known to consolidate with facility.

I am informed that Baron Von Buch discovered some marine shells of
existing species, such as occur fossil in the tuff of the neighborhood,
in beds exposed low down in the walls of the crater of Monte Nuovo.
These may have been ejected in the mud mixed with sea-water which was
cast out of the boiling gulf; or, as Signor Arcangelo Scacchi has
suggested,[508] they may have been derived from the older tuff, which
contains marine shells of recent species. The same observer remarks that
Porzio's account upon the whole corroborates the doctrine of the cone
having been formed by eruption, in proof of which he cites the
following passage:--"But what was truly astonishing, a hill of
pumice-stones and ashes was heaped up round the gulf to the height of a
mile in a single night."[509] Signor Scacchi also adds that the ancient
temple of Apollo, now at the foot of Monte Nuovo, and the walls of which
still retain their perfect perpendicularity, could not possibly have
maintained that position had the cone of Monte Nuovo really been the
result of upheaval.

Tripergola was much frequented as a watering-place, and contained a
hospital for those who resorted there for the benefit of the thermal
springs; and it appears that there were no fewer than three inns in the
principal street. Had Porzio stated that any of these buildings, or the
ruins of them, were seen by himself or others raised up above the plain,
a short time before the first eruption, so as to stand on the summit or
slope of a newly-raised hillock, we might have been compelled, by so
circumstantial a narrative, to adopt M. Dufranoy's interpretation.

But in the absence of such evidence, we must appeal to the crater
itself, where we behold a section of the whole mountain, without being
able to detect any original nucleus of upheaved rock distinct from the
rest; on the contrary, the whole mass is similar throughout in
composition, and the cone very symmetrical in form; nor are there any
clefts, such as might be looked for, as the effect of the sudden upthrow
of stony masses. M. C. Prevost has well remarked, that if beds of solid
and non-elastic materials had yielded to a violent pressure directed
from below upward, we