Ch, X.] 
OUTLINE OF COUNTRY HOW CAUSED. 
127 
suited from the decomposition of felspathic lava which abounds 
in Ischia, the materials having been transported by rivers and 
marine currents, and spread over the bottom of the sea where 
testacea were living. We may observe generally of these sub- 
marine tuffs, lavas, and clays, of Campania, that they strictly 
resemble those around the base of Etna, and in parts of the Val 
di Noto before described. 
External configuration of the country how caused. — When 
once we have satisfied ourselves by inspection of the marine 
shells imbedded in tuffs at high elevations, that a mass of land 
like the island of Ischia has been raised from beneath the waters 
of the sea to its present height, we are prepared to find signs 
of the denuding action of the waves impressed upon the outward 
form of the island, especially if we conceive the upheaving force 
to have acted by successive movements. Let us suppose the 
low contiguous island of Procida to be raised by degrees until 
it attains the height of Ischia, we should in that case expect 
the steep cliffs which now face Misenum to be carried upwards 
and to become precipices near the summit of the central moun- 
tain. Such, perhaps, may have been the origin of those pre- 
cipices which appear on the north and south sides of the ridge 
which forms the summit of Epomeo in Ischia. The northern 
escarpment is about 1000 feet in height, rising from the hollow 
called the Cavo delle Neve above the village of Panella. The 
abrupt manner in which the horizontal tuffs are there cut off, 
in the face of the cliff, is such as the action of the sea, working 
on soft materials, might easily have produced, undermining 
and removing a great portion of the mass. A heap of shingle 
which lies at the base of a steep declivity on the flanks of 
Epomeo, between the Cavo delle Neve and Panella, may once, 
perhaps, have been a sea-beach, for it certainly could not have 
been brought to the spot by any existing torrents. 
There is no difficulty in conceiving that if a large tract of the 
bed of the sea near Ischia should now be gradually upheaved 
during the continuance of volcanic agency, this newly-raised land 
might present a counterpart to the Phlegrsean fields before ch> 
