lower level there was a plain very similar to that now surrounding
Callao, which being protected by a shingle beach, is raised but very
little above the level of the sea. On this plain, with its underlying
red-clay beds, I imagine that the Indians manufactured their earthen
vessels; and that, during some violent earthquake, the sea broke over
the beach, and converted the plain into a temporary lake, as happened
round Callao in 1713 and 1746. The water would then have deposited
mud, containing fragments of pottery from the kilns, more abundant at
some spots than at others, and shells from the sea. This bed, with
fossil earthenware, stands at about the same height with the shells on
the lower terrace of San Lorenzo, in which the cotton-thread and other
relics were embedded.
Hence we may safely conclude, that within the Indo-human period there
has been an elevation, as before alluded to, of more than eighty-five
feet; for some little elevation must have been lost by the coast having
subsided since the old maps were engraved. At Valparaiso, although in
the 220 years before our visit, the elevation cannot have exceeded
nineteen feet, yet subsequently to 1817, there has been a rise, partly
insensible and partly by a start during the shock of 1822, of ten or
eleven feet. The antiquity of the Indo-human race here, judging by the
eighty-five feet rise of the land since the relics were embedded, is
the more remarkable, as on the coast of Patagonia, when the land stood
about the same number of feet lower, the Macrauchenia was a living
beast; but as the Patagonian coast is some way distant from the
Cordillera, the rising there may have been slower than here. At Bahia
Blanca, the elevation has been only a few feet since the numerous
gigantic quadrupeds were there entombed; and, according to the
generally received opinion, when these extinct animals were living, man
did not exist. But the rising of that part of the coast of Patagonia,
is perhaps no way connected with the Cordillera, but rather with a line
of old volcanic rocks in Banda Oriental, so that it may have been
infinitely slower than on the shores of Peru. All these speculations,
however, must be vague; for who will pretend to say that there may not
have been several periods of subsidence, intercalated between the
movements of elevation; for we know that along the whole coast of
Patagonia, there have certainly been many and long pauses in the upward
action of the elevatory forces.
[1] Vol. iv. p. 11, and vol. ii. p. 217. For the remarks on Guayaquil,
349