Page:A Treatise on Geology, volume 2.djvu/240

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A TREATISE ON GEOLOGY.
CHAP. IX.

Mount Albano, 12 miles from Rome, from which a current of lava is traced nearly to the city, as well as the volcanic tuff which alternates with other sediments below the soil of Rome, sufficiently prove the former activity of volcanic forces in this vicinity. Near Albano are four lakes, once probably craters. The Rocca Monfina, a mountain of great antiquity, on the road from Rome to Naples, surrounded with igneous volcanic deposits, carries on the line, of connection to the Phlegrean fields and Vesuvius.

In the Ponza Islands, Mount Vultur, the Lake Amsanctus, volcanic action, though long extinct, has left proofs of its former force and extent at points more or less connected with Vesuvius; while in the Val di Note, the early energies of Etna are manifested among tertiary strata.

Some of the Grecian islands and shores have exhibited volcanic fire, and great elevations of land in modern times, as Santorini; and extinct volcanic action is manifested in the Solfatara of Milo, and the convulsions of Methene and Trœzena, mentioned by Strabo and Ovid.

If we compare this brief notice of the situations where active and extinct volcanos have poured eruptions on the land and in the sea, with the extent of country included by Mr. Lyell in his "Volcanic Region from the Caspian to the Azores," it will immediately appear, that, with the exception of Iceland and Jan Mayen, all the points in Europe which have produced eruptions during the reach of history, are included in that region. The whole space between the Caspian and the Azores, a distance of 1000 miles, within the parallels of 35° and 45° north latitude, has been from time immemorial agitated by earthquakes; which also extend their effects farther to the north, so as perhaps to unite the Mediterranean band of volcanic energy with the distant fires of the Icelandic group. Near to and beyond the latitude of 45° are situated many of the most conspicuous of the older