Volume 2

Principles of geology : being an inquiry how far the former changes of the earth's surface are referable to causes now in operation. / By Charles Lyell ...

  • Lyell, Charles, Sir, 1797-1875.
Date:
1834
Catalogue details

Licence: Public Domain Mark

Credit: Principles of geology : being an inquiry how far the former changes of the earth's surface are referable to causes now in operation. / By Charles Lyell ... Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    5* Egypt, which lies six or seven degrees south of the volcanic line already traced, has been almost always exempt from earthquakes; but the north-western por- tion, especially Fez and Morocco, which fall within the line, suffer greatly from time to time. The south- ern part of Spain, also, and Portugal, have generally been exposed to the same scourge simultaneously with Northern Africa. The provinces of Malaga, Murcia, and Granada, and in Portugal, the country round Lisbon, are recorded at several periods to have been devastated by great earthquakes. It will be seen, from Michell’s account of the great Lisbon shock in 1755, that the first movement proceeded from the bed of the ocean ten or fif teen leagues from the coast. So late as February 2. 1816, when Lisbon was vehemently shaken, two ships felt a shock in the ocean west from Lisbon ; one of them at the distance of 120, and the other 262 French leagues from the coast*:—a fact which is the more interesting, because a line drawn through the Grecian archipelago, the volcanic region of Southern Italy, Sicily, Southern Spain, and Portu- gal, will, if prolonged westward through the ocean, strike the volcanic group of the Azores, which has, therefore, in all probability, a submarine connexion with the European line. How far the isles of Madeira and the Canaries, in the former of which violent earth- quakes occur, and in the latter great eruptions, may communicate beneath the waters with the same regions, must for the present be mere matter of con- jecture. Besides the continuous spaces of subterranean dis- turbance, of which we have merely sketched the out- * Verneur, Journal des Voyages, vol. iv. p. 111. Von Hoff, vol. ii. p. 275.