visited Etna in 1828, M. de Beaumont has published a most
valuable memoir on the structure and origin of that mountain, which he
examined in 1834;[575] and an excellent description of it has also
appeared in the posthumous work of Hoffmann.[576]

In M. de Beaumont's essay, in which he has explained his views with
uncommon perspicuity and talent, he maintains that all the alternating
stony and fragmentary beds, more than 3000 feet thick, which are exposed
in the Val del Bove, were formed originally on a surface so nearly flat
that the slope never exceeded three degrees. From this horizontal
position they were at length heaved up suddenly (d'un seul coup) into a
great mountain, to which no important additions have since been made.
Prior to this upthrow, a platform is supposed to have existed above the
level of the sea, in which various fissures opened; and from these
melted matter was poured forth again and again, which spread itself
around in thin sheets of uniform thickness. From the same rents issued
showers of scoriae and fragmentary matter, which were spread out so as to
form equally uniform and horizontal beds, intervening between the sheets
of lava. But although, by the continued repetition of these operations,
a vast pile of volcanic matter, 4000 feet or more in thickness, was
built up precisely in that region where Etna now rises, and to which
nothing similar was produced elsewhere in Sicily, still we are told that
Etna was not yet a mountain. No hypothetical diagram has been given to
help us to conceive how this great mass of materials of supramarine
origin could have been disposed of in horizontal beds, so as not to
constitute an eminence towering far above the rest of Sicily; but it is
assumed that a powerful force from below at length burst suddenly
through the horizontal formation, uplifted it to a considerable height,
and caused the beds to be, in many places, highly inclined. This
elevatory force was not all expended on a single central point as Von
Buch has imagined in the case of Palma, Teneriffe, or Somma, but rather
followed for a short distance a linear direction.[577]

Among other objections that may be advanced against the theory above
proposed, I may mention, first, that the increasing number of dikes as
we approach the head of the Val del Bove, or the middle of Etna, and the
great thickness of lava, scoriae, and conglomerates in that region, imply
that the great centre of eruption was always where