and 970 feet in height.

From Coy Inlet, where the high summit-plain trends inland, a plain
estimated at 350 feet in height, extends for forty miles to the river
Gallegos. From this point to the Strait of Magellan, and on each side of
that Strait, the country has been much denuded and is less level. It
consists chiefly of the boulder formation, which rises to a height of
between one hundred and fifty and two hundred and fifty feet, and is often
capped by beds of gravel. At N.S. Gracia, on the north side of the Inner
Narrows of the Strait of Magellan, I found on the summit of a cliff, 160
feet in height, shells of existing Patellae and Mytili, scattered on the
surface and partially embedded in earth. On the eastern coast, also, of
Tierra del Fuego, in latitude 53 degrees 20' south, I found many Mytili on
some level land, estimated at 200 feet in height. Anterior to the elevation
attested by these shells, it is evident by the present form of the land,
and by the distribution of the great erratic boulders on the surface, that
two sea-channels connected the Strait of Magellan both with Sebastian Bay
and with Otway Water. ("Geological Transactions" volume 6 page 419.)

CONCLUDING REMARKS ON THE RECENT ELEVATION OF THE SOUTH-EASTERN COASTS OF
AMERICA, AND ON THE ACTION OF THE SEA ON THE LAND.

Upraised shells of species, still existing as the commonest kinds in the
adjoining sea, occur, as we have seen, at heights of between a few feet and
410 feet, at intervals from latitude 33 degrees 40' to 53 degrees 20'
south. This is a distance of 1,180 geographical miles--about equal from
London to the North Cape of Sweden. As the boulder formation extends with
nearly the same height 150 miles south of 53 degrees 20', the most southern
point where I landed and found upraised shells; and as the level Pampas
ranges many hundred miles northward of the point, where M. d'Orbigny found