rminate. There are many ledges of rock on
the face of that precipice where eruptions have occurred.

The circular form of the Val del Bove is well shown in this view. (Pl.
IV.) To the right and left are the lofty precipices which form the
southern and northern sides of the great valley, and which are
intersected by dikes projecting in the manner afterwards to be
described. In the distance appears the "fertile region" of Etna,
extending like a great plain along the sea-coast.

The spots particularly referred to in the plate are the following:--

_a_, Cape Spartivento, in Italy, of which the outline is seen
in the distance.

_b_, The promontory of Taormino, on the Sicilian coast.

_c_, The river Alcantra.

_d_, The small village of Riposto.

_f_, The town of Aci Reale.

_g_, Cyclopian islands, or "Faraglioni," in the Bay of Trezza.

_h_, The great harbor of Syracuse.

_k_, The Lake of Lentini.

_i_, The city of Catania, near which is marked the course of
the lava which flowed from the Monti Rossi in 1669,
and destroyed part of the city.

_l_, To the left of the view is the crater of 1811, which is
also shown at No. 7 in Plate III.

_m_, Rock of Musara, also seen at No. 9 in Plate III.

_e_, Valley of Calanna.

The Val del Bove is of truly magnificent dimensions, a vast amphitheatre
four or five miles in diameter, surrounded by nearly vertical
precipices, varying from 1000 to above 3000 feet in height, the loftiest
being at the upper end, and the height gradually diminishing on both
sides. The feature which first strikes the geologist as distinguishing
the boundary cliffs of this valley, is the prodigious multitude of
verticle dikes which are seen in all directions traversing the volcanic
beds. The circular form of this great chasm, and the occurrence of these
countless dikes, amounting perhaps to several thousands in number, so
forcibly recalled to my mind the phenomena of the Atrio del Cavallo, on
Vesuvius, that I at first imagined that I had entered a vast crater, on
a scale as far exceeding that of Somma, as Etna surpasses Vesuvius in
magnitude.

But I was soon undeceived when I had attentively explored the different
sides of the great amphitheatre, in order to satisfy myself whether the
semicircular wall of the Val del Bove had ever formed the boundary of a
crater, and whether the beds had the same quaqua-versal dip which is so
beauti