ysical structure and contour bear
so striking a resemblance (as already observed) to those of Vesuvius and
Rocca Monfina that we are much tempted to infer that it had a somewhat
similar origin. Now we know that Vesuvius was built up by means of
successive eruptions taking place under the air; and the question arises
whether it could be possible that Santorin had a similar origin owing to
the waters of the Mediterranean having been temporally lowered at a
later Tertiary epoch. It has been stated by M. Fouque that the age of
the more ancient volcanic beds of Santorin belong, as shown by the
included fossils, to the newer Pliocene epoch. These are of course the
unsubmerged, and therefore more recent strata, and may have been
recently upheaved during one or more of the outbursts of volcanic
energy. But it seems an impossibility that the Gulf of Santorin, with
its precipitous walls and deep circular interior channel, as shown by
the Ideal Section (Fig. 13), could have been formed otherwise than under
the air. We are led, therefore, to inquire whether there was a time in
the history of the Mediterranean, since the Eocene period, when the
waters were lower than at present. That this was the case we have clear
evidence. The remains of elephants, hippopotami, and other animals,
which have been discovered in great numbers in the Maltese caves, show
that this island was united to Sicily, and this again to Europe, during
the later Pliocene epoch, so as to have become the abode of an
Europasian fauna. According to Dr. Wallace, a causeway of dry land
existed, stretching from Italy to Tunis in North Africa through the
Maltese Islands--an inference involving the lowering of the waters of
the Mediterranean by several hundred feet.[2] There is every reason for
supposing that the old volcano of Santorin was in active eruption at
this period; and its history may be considered to be similar to that of
Vesuvius until, at the rising of the waters during the Pluvial (or
Post-Pliocene) epoch, during which they rose higher than at present,
Santorin was converted into a group of islands, slightly differing in
form from those of the present day. This view seems to meet the
difficulties regarding the origin of this group, difficulties which
Lyell had long since clearly recognised.

(_c._) _Limit of the Mediterranean Volcanic Region._--With the Santorin
group we conclude our account of the active European volcanoes. It may
be observed, however, that