A large Voluta is abundant in
southern Tierra del Fuego and the Falkland Islands. At Bahia
Blanca, in latitude 39 degrees south, the most abundant shells were
three species of Oliva (one of large size), one or two Volutas, and
a Terebra. Now these are amongst the best characterised tropical
forms. It is doubtful whether even one small species of Oliva
exists on the southern shores of Europe, and there are no species
of the two other genera. If a geologist were to find in latitude 39
degrees on the coast of Portugal a bed containing numerous shells
belonging to three species of Oliva, to a Voluta, and Terebra, he
would probably assert that the climate at the period of their
existence must have been tropical; but, judging from South America,
such an inference might be erroneous.
The equable, humid, and windy climate of Tierra del Fuego extends,
with only a small increase of heat, for many degrees along the west
coast of the continent. The forests for 600 miles northward of Cape
Horn, have a very similar aspect. As a proof of the equable
climate, even for 300 or 400 miles still farther northward, I may
mention that in Chiloe (corresponding in latitude with the northern
parts of Spain) the peach seldom produces fruit, whilst
strawberries and apples thrive to perfection.
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