numerous. The lower plain stretches for some miles southward, and for an
unknown distance northward, but not far up the valley; its seaward face,
according to Meyen, is worn into caves above the level of the present
beach. The valley of Copiapo is much less steeply inclined and less direct
in its course than any other valley which I saw in Chile; and its bottom
does not generally consist of gravel: there are no step-formed terraces in
it, except at one spot near the mouth of the great lateral valley of the
Despoblado where there are only two, one above the other: lower down the
valley, in one place I observed that the solid rock had been cut into the
shape of a beach, and was smoothed over with shingle.

Northward of Copiapo, in latitude 26 degrees S., the old voyager Wafer
found immense numbers of sea-shells some miles from the coast. (Burnett's
"Collection of Voyages" volume 4 page 193.) At Cobija (latitude 22 degrees
34') M. d'Orbigny observed beds of gravel and broken shells, containing ten
species of recent shells; he also found, on projecting points of porphyry,
at a height of 300 feet, shells of Concholepas, Chiton, Calyptraea,
Fissurella, and Patella, still attached to the spots on which they had
lived. M. d'Orbigny argues from this fact, that the elevation must have
been great and sudden ("Voyage, Part Geolog." page 94. M. d'Orbigny (page
98), in summing up, says: "S'il est certain (as he believes) que tous les
terrains en pente, compris entre la mer et les montagnes sont l'ancien
rivage de la mer, on doit supposer, pour l'ensemble, un exhaussement que ce
ne serait pas moindre de deux cent metres; il faudrait supposer encore que
ce soulevement n'a point ete graduel;...mais qu'il resulterait d'une seule
et meme cause fortuite," etc. Now, on this view, when the sea was forming
the beach at the foot of the mountains, many shells of Concholepas, Chiton,
Calyptraea, Fissurella, and Patella (which are known to live close to the
beach), were attached to rocks at a depth of 300 feet, and at a depth of
600 feet several of these same shells were accumulating in great numbers in