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
Williams believes that the
change has been quite gradual. Without the elevatory movement continues
at a quick rate, there can be no doubt that the sea will soon destroy
the talus of earth at the foot of the cliffs round the bay, and will
then reach its former lateral extension, but not of course its former
level: some of the inhabitants assured me that one such talus, with a
footpath on it, was even already sensibly decreasing in width.
I received several accounts of beds of shells, existing at considerable
heights in the inland parts of Chiloe; and to one of these, near
Catiman, I was guided by a countryman. Here, on the south side of the
peninsula of Lacuy, there was an immense bed of the Venus costellata
and of an oyster, lying on the summit-edge of a piece of tableland, 350
feet (by the barometer) above the level of the sea. The shells were
closely packed together, embedded in and covered by a very black, damp,
peaty mould, two or three feet in thickness, out of which a forest of
great trees was growing. Considering the nature and dampness of this
peaty soil, it is surprising that the fine ridges on the outside of the
Venus are perfectly preserved, though all the shells have a blackened
appearance. I did not doubt that the black soil, which when dry, cakes
hard, was entirely of terrestrial origin, but on examining it under the
microscope, I found many very minute rounded fragments of shells,
amongst which I could distinguish bits of Serpulae and mussels. The
Venus costellata, and the Ostrea (O. edulis, according to Captain King)
are now the commonest shells in the adjoining bays. In a bed of shells,
a few feet below the 350 feet bed, I found a horn of the little Cervus
humilis, which now inhabits Chiloe.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account