Madeira : its climate and scenery : a hand-book for invalid and other visitors / by Robert White.

  • White, Robert
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Madeira : its climate and scenery : a hand-book for invalid and other visitors / by Robert White. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    the same cause as that which produced the channel in S. Vicente. Another curious phenomenon which volcanic countries sometimes exhibit, is that of a stream of lava falling like a cascade over an ancient clifif. A good example of this was observed by Sir C. Lyell in Palma; and Captain Vidal records an instance near Porto Moniz in ]\Iadeira, which Mr. Hartung, a later observer, is able to confirm. In the recent eruption from Mauna Loa, a volcano in the island of Hawaii, a current of intensely bright lava was observed to pour over a height of 25 feet, at first in a broken stream, at length as a continuous tor- rent, striking on a ledge, and then sliding ofi into a deep pool below. Of the salient dikes which are strikingly dis- played in several valleys in the interior of the island, we have already spoken. Dikes may also be seen in section at many places on the coast. They are very numerous at C. Girao, where in addition to vertical dikes, there are oblique and horizontal dikes intruding between layers of volcanic materials previously accumulated above the level of the sea. There are a few in the neighbourhood of C. Garajao ; and the tufa forming the promontory is intersected by one which forms a conspicuous boss at the top. Between Machico and Canicjal ai-e several dikes varying from six P