ous and arenaceous rocks, of which the mountains
surrounding Etna are composed, and which appear capped with lava near
Bronte and elsewhere. 3. Basaltic rocks, which are met with near Motta
S. Anastasia, Paterno, Licodia, and Aderno, and in the Isole de'Ciclopi.
4. Rolled pebbles, which form a range of slightly rising ground between
the first slopes of Etna on the southern side and the plain of Catania.
(Lyell speaks of this rising ground as consisting of "argillaceous and
sandy beds with marine shells, nearly all of living Mediterranean
species, and with associated and contemporaneous volcanic rocks.") 5.
Ancient lavas forming the escarpments around the Val del Bove; and 6th,
Modern lavas. He considers that the fissures which abound on Etna are
shifts or faults produced by dislocation, and that the minor cones are
points along such fissures from which ashes and lava have been ejected.
He admits the existence of two cones. The geological map of Etna
prepared by M. Elie de Beaumont to accompany his memoir can scarcely be
regarded as a great addition to our knowledge of the mountain. For
although in the main points it is correct, so many details have been
omitted that the map must be considered to have now been quite
superseded by those of Von Waltershausen and Friedrich Hoffmann.

[20] "Recherches sur la structure et sur l'origine du Mont Etna." 1836.

The most convenient geological map of the mountain is without doubt that
of Hoffmann, given in the _Vulkanen Atlas_ of Dr. Von Leonhard; and here
reproduced. Von Waltershausen's geological map has been the foundation
of all others which have subsequently appeared. It is a marvel of
accurate work, and patient industry. The form however is inconvenient,
as it nowhere appears as a whole, but in separate portions, which are
scattered through the folio sheets of the very expensive _Atlas des
Aetna_. It is accurate, and at the same time very clear and
intelligible. By reference to the map it will be seen that from Capo di
Schiso westward, to near Paterno, Etna is surrounded by sandstone hills;
at the south we have recent clays, and, at intervals, chalk. A large
triangular space having the two angles at its base, respectively near
Maletto and Aderno, and its apex at the great crater, is covered with
new lava; while around Nicolosi there is volcanic sand. At the Isole
de'Ciclopi, Motta S. Anastasia, and a few other places, basalt is seen;
on each side of the Val del Bove, dolerite