CHAPTER I.. On the Elevation of the Eastern Coast of South America.

ON THE ELEVATION OF THE EASTERN COAST OF SOUTH AMERICA. Upraised shells of La Plata.—Bahia Blanca, Sand-dunes and Pumice-pebbles.—Step-formed plains of Patagonia, with upraised shells.—Terrace-bounded valley of Santa Cruz, formerly a sea-strait.—Upraised shells of Tierra del Fuego.—Length and breadth of the elevated area.—Equability of the movements, as shown by the similar heights of the plains.—Slowness of the elevatory process.—Mode of formation of the step-formed plains.—Summary.- -Great shingle formation of Patagonia; its extent, origin, and distribution.—Formation of sea-cliffs.