Beagle Expedition (1831-1836); Coral reefs and islands; Geology -- South America; Islands; Volcanoes
manuscripts not very ancient (“Comptes Rendus,” 1840, page 832), that
there are two active volcanoes on the eastern side of Formosa. In
Torres Straits, on Cap Island (9° 48′ S., 142° 39′ E.) a volcano was
seen burning with great violence in 1793 by Captain Bampton (see
Introduction to Flinders’ “Voyage,” page 41). Mr. M’Clelland (Report
of Committee for investigating Coal in India, page 39) has shown that
the volcanic band passing through Barren Island must be extended
northwards. It appears by an old chart, that Cheduba was once an
active volcano (see also “Silliman’s North American Journal”, volume
xxxviii., page 385). In Berghaus’ “Physical Atlas,” 1840, No. 7 of
Geological Part, a volcano on the coast of Pondicherry is said to have
burst forth in 1757. Ordinaire (“Hist. Nat. des Volcans,” page 218)
says that there is one at the mouth of the Persian Gulf, but I have
not coloured it, as he gives no particulars. A volcano in Amsterdam,
or St. Paul’s, in the southern part of the Indian Ocean, has been seen
(“Naut. Mag.” 1838, page 842) in action. Dr. J. Allan, of Forres,
informs me in a letter, that when he was at Joanna, he saw at night
flames apparently volcanic, issuing from the chief Comoro Island, and
that the Arabs assured him that they were volcanic, adding that the
volcano burned more during the wet season. I have marked this as a
volcano, though with some hesitation, on account of the possibility of
the flame arising from gaseous sources.
The _uncoloured coasts_ consist, first and chiefly, of those, where
there are no coral-reefs, or such small portions as to be quite
insignificant. Secondly, of those coasts where there are reefs, but
where the sea is very shallow, for in this case the reefs generally lie
far from the land, and become very irregular, in their forms: where
they have not become irregular, they have been coloured. thirdly, if I
had the means of ascertaining the fact, I should not colour a reef
merely coating the edges of a submarine crater, or of a level submerged
bank; for such superficial formations differ essentially, even when not
in external appearance, from reefs whose foundations as well as
superficies have been wholly formed by the growth of coral. Fourthly,
in the Red Sea, and within some parts of the East Indian Archipelago
(if the imperfect charts of the latter can be trusted), there are many
scattered reefs, of small size, represented in the chart by mere dots,
which rise out of deep water: these cannot be arranged under either of
the three classes: in the Red Sea, however, some of these little reefs,
from their position, seem once to have formed parts of a continuous
barrier. There exist, also, scattered in the open ocean, some linear
and irregularly formed strips of coral-reef, which, as shown in the
last chapter, are probably allied in their origin to atolls; but as
they do not belong to that class, they have not been coloured; they are
Public-domain text, read in full here on John Shaqi.
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