Geological Observations on South AmericaDarwin, Charles
Science
Geological Observations on South America
Darwin, Charles
Beagle Expedition (1831-1836); Geology -- South America; Mollusks, Fossil -- South America; Paleontology
Now it is a most significant circumstance that, no sooner did the
officers of the Geological Survey commence the careful and detailed
study of the Scottish Highlands than they found themselves compelled to
make a formal retraction of the views which had been put forward by
Murchison and Geikie in opposition to the conclusions of Darwin. The
officers of the Geological Survey have completely abandoned the view
that the foliation of the Highland rocks has been determined by their
original stratification, and admit that the structure is the result of
the profound movements to which the rocks have been subjected. The same
conclusions have recently been supported by observations made in many
different districts—among which we may especially refer to those of Dr.
H. Reusch in Norway, and those of Dr. J. Lehmann in Saxony. At the
present time the arguments so clearly stated by Darwin in the work
before us, have, after enduring opposition or neglect for a whole
generation, begun to “triumph all along the line,” and we may look
forward confidently to the near future, when his claim to be regarded
as one of the greatest of geological discoverers shall be fully
vindicated.
JOHN W. JUDD.
CHAPTER I.
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.
In the following Volume, which treats of the geology of South America,
and almost exclusively of the parts southward of the Tropic of
Capricorn, I have arranged the chapters according to the age of the
deposits, occasionally departing from this order, for the sake of
geographical simplicity.
The elevation of the land within the recent period, and the
modifications of its surface through the action of the sea (to which
subjects I paid particular attention) will be first discussed; I will
then pass on to the tertiary deposits, and afterwards to the older
rocks. Only those districts and sections will be described in detail
which appear to me to deserve some particular attention; and I will, at
the end of each chapter, give a summary of the results. We will
commence with the proofs of the upheaval of the eastern coast of the
continent, from the Rio Plata southward; and, in the Second Chapter,
follow up the same subject along the shores of Chile and Peru.
Public-domain text, read in full here on John Shaqi.
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