and the obscure traces of stratification seem to indicate that the loam was
deposited under water; on the other hand, the presence of sea-shells, their
broken state, the pebbles of various sizes, and the artificial floor of
round stones, almost prove that it must have originated in a rush of water
from the sea over the land. The height of the plain, namely, 120 feet,
renders it improbable that an earthquake-wave, vast as some have here been,
could have broken over the surface at its present level; but when the land
stood eighty-five feet lower, at the period when the shells were thrown up
on the ledge at S. Lorenzo, and when as we know man inhabited this
district, such an event might well have occurred; and if we may further
suppose, that the plain was at that time converted into a temporary lake,
as actually occurred, during the earthquakes of 1713 and 1746, in the case
of the low land round Callao owing to its being encircled by a high
shingle-beach, all the appearances above described will be perfectly
explained. I must add, that at a lower level near the point where the
present low land round Callao joins the higher plain, there are appearances
of two distinct deposits both apparently formed by debacles: in the upper
one, a horse's tooth and a dog's jaw were embedded; so that both must have
been formed after the settlement of the Spaniards: according to Acosta, the
earthquake-wave of 1586 rose eighty-four feet.

The inhabitants of Callao do not believe, as far as I could ascertain, that
any change in level is now in progress. The great fragments of brickwork,
which it is asserted can be seen at the bottom of the sea, and which have
been adduced as a proof of a late subsidence, are, as I am informed by Mr.
Gill, a resident engineer, loose fragments; this is probable, for I found
on the beach, and not near the remains of any building, masses of
brickwork, three and four feet square, which had been washed into their
present places, and smoothed over with shingle during the earthquake of
1746. The spit of land, on which the ruins of OLD Callao stand, is so