at the bed of the
sea was uplifted at once to the height of twenty-four feet, during the
single earthquake of 1751, because other movements may have occurred
subsequently; but it is said, that ever since the shock of 1751, no
vessels have been able to approach within a mile and a half of the
ancient port of Penco. (See Map, p. 455.) In proof of the former
elevation of the coast near Penco our surveyors found above high-water
mark an enormous bed of shells of the same species as those now living
in the bay, filled with micaceous sand like that which the Biobio now
conveys to the bay. These shells, as well as others, which cover the
adjoining hills of mica-schist to the height of several hundred feet,
have lately been examined by experienced conchologists in London, and
identified with those taken at the same time in a living state from the
bay and its neighborhood.[693]

Ulloa, therefore, was perfectly correct in his statement that, at
various heights above the sea between Talcahuano and Conception, "mines
were found of various sorts of shells used for lime of the very same
kinds as those found in the adjoining sea." Among them he mentions the
great mussel called Choros, and two others which he describes. Some of
these, he says, are entire, and others broken; they occur at the bottom
of the sea, in four, six, ten, or twelve fathom water, where they adhere
to a sea-plant called Cochayuyo. They are taken in dredges, and have no
resemblance to those found on the shore or in shallow water; yet beds of
them occur at various heights on the hills. "I was the more pleased with
the sight," he adds, "as it appeared to me a convincing proof of the
universality of the deluge, although I am not ignorant that some have
attributed their position to other causes."[694] It has, however, been
ascertained that the foundation of the Castle of Penco was so low in
1835, or at so inconsiderable an elevation above the highest spring
tides, as to discountenance the idea of any permanent upheaval in modern
times, on the site of that ancient port; but no exact measurements or
levellings appear as yet to have been made to determine this point,
which is the more worthy of investigation, because it may throw some
light on an opinion often promulgated of late years, that there is a
tendency in the Chilian coast, after each upheaval, to sink gradually
and return towards its former position.

_Peru_, 1746.--Peru was visited, on the 28th of October, 174