These five terraces are formed of shingle and sand; three of them, as
marked by Captain B. Hall (namely, B, C, and F), are much more conspicuous
than the others. From the marine remains copiously strewed at the mouth of
the valley on the lower terraces, and southward of the town on the upper
one, they are, as before remarked, undoubtedly of marine origin; but within
the valley, and this fact well deserves notice, at a distance of from only
a mile and a half to three or four miles from the sea, I could not find
even a fragment of a shell.

ON THE INCLINATION OF THE TERRACES OF COQUIMBO, AND ON THE UPPER AND BASAL
EDGES OF THEIR ESCARPMENTS NOT BEING HORIZONTAL.

The surfaces of these terraces slope in a slight degree, as shown by the
sections in Figures 9 and 10 taken conjointly, both towards the centre of
the valley, and seawards towards its mouth. This double or diagonal
inclination, which is not the same in the several terraces, is, as we shall
immediately see, of simple explanation. There are, however, some other
points which at first appear by no means obvious,--namely, first, that each
terrace, taken in its whole breadth from the summit-edge of one escarpment
to the base of that above it, and followed up the valley, is not
horizontal; nor have the several terraces, when followed up the valley, all
the same inclination; thus I found the terraces C, E, and F, measured at a
point about two miles from the mouth of the valley, stood severally between
fifty-six to seventy-seven feet higher than at the mouth. Again, if we look
to any one line of cliff or escarpment, neither its summit-edge nor its
base is horizontal. On the theory of the terraces having been formed during
a slow and equable rise of the land, with as many intervals of rest as
there are escarpments, it appears at first very surprising that horizontal
lines of some kind should not have been left on the land.