now lives in parts never uncovered by the tides. At considerable heights,
Mr. Kent found only a few shells; but from the summit of one hill, 625 feet
high, he brought me specimens of the Concholepas, Mytilus Chiloensis, and a
Turbo. These shells were softer and more brittle than those from the height
of 164 feet; and these latter had obviously a much more ancient appearance
than the same species from the height of only twenty feet.

COAST NORTH OF CONCEPCION.

The first point examined was at the mouth of the Rapel (160 miles north of
Concepcion and sixty miles south of Valparaiso), where I observed a few
shells at the height of 100 feet, and some barnacles adhering to the rocks
three or four feet above the highest tides: M. Gay found here recent shells
at the distance of two leagues from the shore. ("Annales des Scienc. Nat."
Avril 1833.) Inland there are some wide, gravel-capped plains, intersected
by many broad, flat-bottomed valleys (now carrying insignificant
streamlets), with their sides cut into successive wall-like escarpments,
rising one above another, and in many places, according to M. Gay, worn
into caves. The one cave (C. del Obispo) which I examined, resembled those
formed on many sea-coasts, with its bottom filled with shingle. These
inland plains, instead of sloping towards the coast, are inclined in an
opposite direction towards the Cordillera, like the successively rising
terraces on the inland or eastern side of Chiloe: some points of granite,
which project through the plains near the coast, no doubt once formed a
chain of outlying islands, on the inland shores of which the plains were
accumulated. At Bucalemu, a few miles northward of the Rapel, I observed at
the foot, and on the summit-edge of a plain, ten miles from the coast, many
recent shells, mostly comminuted, but some perfect. There were, also, many
at the bottom of the great valley of the Maypu. At San Antonio, shells are
said to be collected and burnt for lime. At the bottom of a great ravine