probable, by such starts conjointly with a gradual upward movement, or by
great and sudden upheavals, I have no direct evidence. But as on the
eastern coast, I was led to think, from the analogy of the last hundred
feet of elevation in La Plata, and from the nearly equal size of the
pebbles over the entire width of the terraces, and from the upraised shells
being all littoral species, that the elevation had been gradual; so do I on
this western coast, from the analogy of the movements now in progress, and
from the vast numbers of shells now living exclusively on or close to the
beach, which are strewed over the whole surface of the land up to very
considerable heights, conclude, that the movement here also has been slow
and gradual, aided probably by small occasional starts. We know at least
that at Coquimbo, where five escarpments occur in a height of 364 feet, the
successive elevations, if they have been sudden, cannot have been very
great. It has, I think, been shown that the occasional preservation of
shells, unrolled and unbroken, is not improbable even during a quite
gradual rising of the land; and their preservation, if the movement has
been aided by small starts, is quite conformable with what actually takes
place during recent earthquakes.

Judging from the present action of the sea, along the shores of the
Pacific, on the deposits of its own accumulation, the present time seems in
most places to be one of comparative rest in the elevatory movement, and of
denudation of the land. Undoubtedly this is the case along the whole great
length of Patagonia. At Chiloe, however, we have seen that a narrow sloping
fringe, covered with vegetation, separates the present sea-beach from a
line of low cliffs, which the waves lately reached; here, then, the land is
gaining in breadth and height, and the present period is not one of rest in
the elevation and of contingent denudation; but if the rising be not
prolonged at a quick rate, there is every probability that the sea will
soon regain its former horizontal limits. I observed similar low sloping