gical research, not to history,
that we are principally indebted for the information. I shall now
proceed to lay before the reader some of the results of modern
investigations in the Bay of Baiae and the adjoining coast.

PROOFS OF ELEVATION AND SUBSIDENCE IN THE BAY OF BAIAE.

[Illustration: Fig. 86.

Ground plan of the coast of the Bay of Baiae, in the environs of
Puzzuoli.]

_Temple of Jupiter Serapis._--This celebrated monument of antiquity, a
representation of which is given in the frontispiece,[711] affords in
itself alone, unequivocal evidence that the relative level of land and
sea has changed twice at Puzzuoli since the Christian era; and each
movement, both of elevation and subsidence, has exceeded twenty feet.
Before examining these proofs, I may observe, that a geological
examination of the coast of Baiae, both on the north and south of
Puzzuoli, establishes, in the most satisfactory manner, an elevation, at
no remote period, of more than twenty feet, and, at one point, of more
than thirty feet; and the evidence of this change would have been
complete, if even the temple had, to this day, remained undiscovered.

_Coast south of Puzzuoli._--If we coast along the shore from Naples to
Puzzuoli, we find, on approaching the latter place, that the lofty and
precipitous cliffs of indurated tuff, resembling that of which Naples is
built, retire slightly from the sea; and that a low level tract of
fertile land, of a very different aspect, intervenes between the present
sea-beach and what was evidently the ancient line of coast.

The inland cliff may be seen opposite the small island of Nisida, about
two miles and a half southeast of Puzzuoli (see Map, fig. 40, p. 361),
where, at the height of thirty-two feet above the level of the sea, Mr.
Babbage observed an ancient mark, such as might have been worn by the
waves; and, upon farther examination, discovered that, along that line,
the face of the perpendicular rock, consisting of very hard tuff, was
covered with barnacles (_Balanus sulcatus_, Lamk.), and drilled by
boring testacea. Some of the hollows of the lithodomi contained the
shells; while others were filled with the valves of a species of
Area.[712] Nearer to Puzzuoli, the inland cliff is eighty feet high, and
as perpendicular as if it was still undermined by the waves. At its
base, a new deposit, constituting the fertile tract above alluded to,
attains a height of about twenty feet above the sea; and, s