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..This is the highest mountain in Mexico, and is continually burning. The two others lie on the western side of Mexico, and are

called Jorullo and Colima, the latter being 9000 feet in height. We shall have occasion to speak of Jorullo and its eruptions hereafter. It is somewhat remarkable that these five volcanoes now active, are connected by a chain of intermediate ones, which undoubtedly have been so at some remote period, and that if the line of volcanic vents be prolonged in a westerly direction, it will -pass through a group of volcanic islands, called the isles of Revillagigedo. Proceeding north of Mexico, another chain of mountains running parallel with the Rocky Mountain chain, commencing in the peninsula of California, runs as far north as the 50th deg. of north latitude, where it ends near the Rocky Mountains. In the peninsula of California there are three, or according to some accounts, five active volcanoes. In the Rocky Mountain chain from Mexico north, no active volcano occurs, but the whole country, says Mr. Parker, “from the Rocky Mountains on the east and Pacific Ocean, on the west, and from Queen Charlotte's Island on the north to California on the south, presents one vast scene of igneous or volcanic action. Internal fires appear to have reduced almost all the regular rock formations to a state of fusion, and then, through fissures and chasms of the earth, to have forced the substances which constitute the present wolcanic form. Such has been the intensity aud extent of this

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Rocky MoUNTAINs. 241

agency, that meuntains of amygdaloid and basalt have been thrown up; and the same substance is spread over the neighboring plains, to what depth is not known; but from observations made upon channels of rivers and the precipices of ravines, it is evidently very deep. The tops of some mountains are spread out into horizontal plains, some are rounded like domes, and others terminate in conical peaks and abrupt eminences of various magnitudes, which are numerous, presenting themselves in forms resembling pillars, pyramids, and castles. There are several regularly formed craters; but these, presenting themselves in depressions or in cones, are rendered obscure by the lapse of time.” Mr. Parker also states that nearly all the rocks of this region are amygdaloid, i.e. a trap rock in which agates and mineral substances are scattered about like almonds in a cake; basalt, lava, and volcanic glass, or obsidian. The Rocky Mountain chain extends north to the Arctic ocean, skirts along its coast, and is probably connected subterraneously, with the volcanic band which we shall presently describe, extending from the Aleutian Isles, or extremity of the peninsula of Alaska, in Russian America, to the Molucca Isles. The whole shore of western America, from the peninsula just mentioned to Vancouver's Islands, presents a bold and awful aspect, being bordered with mountainous steeps, covered with primeval forests, and containing two of the most elevated peaks in the northern part of America, Mount St. Elias, 18,000 feet, and Mount Fairweather, 14,913 feet above the ocean. Passing from the peninsula of Alaska, we find the volcanic chain extending through the Aleutian or Fox Islands, which are a long and numerous group extending nearly to Kamschatka. From almost every island, steep and lofty peaks arise, and from many, volcanic fire is discharged. In 1795 an island was thrown up and added to this group, by an eruption from beneath the sea, and continued to increase, till in 1807 it measured twenty miles in circuit. Throughout this whole tract, earthquakes of the most terrific description occur. The line of volcanic craters continues through the southern extremity of Kamschatka, where are seven active volcanoes, which in some eruptions have scattered ashes to immense distances. The chain is prolonged through the Kurile islands, where a train of volcanic mountains exists, nine of which are known to have been in eruption; and elevations of the bed of the sea from earthquakes have occurred several times since the middle of the last century. The line is next continued through the Japanese group, which contains a number of active volcanoes and is continually liable to earthquakes. Proceeding southward, the chain is continued through the islands of the East Indian Archipelago. Mountain ranges of a volcanic character traverse almost all these, some rising upwards of 12,000 feet in height. In Sumatra, four volcanoes occur, and also several in Java. The largest of the Mollucca group, Celebes, contains a number of volcanoes in a state of activity, and one of the most terrible eruptions ever recorded happened on the island of Sumbawa another of this group. Here the chain branches off eastward and westward, passing to the west through New Guinea, New Britain the Solomon group,and the New Hebrides, thence through the Friendly and Society lslands nearly east. Indeed the Pacific Ocean in the equatorial regions seems to have been one vast theatre of igneous action, its innumerable archipelagos being composed of volcanic rocks, or coralline limestones with active vents here and there. To the westward, the chain passes through Borneo, and Sumatra, to Barren Island in the Bay of Bengal. From Java southward, the chain may be traced along the coast of New Holland and Van Diemens land, and thence probably is a submarine connection with Freeman’s Peak, in the Ballerny Isles, on the Antarctic continent. Still farther south we have the chain extending along Victoria land, between 80° and 70° of south latitude, connecting with Mounts Erebus and Terror before mentioned. Another great chain of mountains runs nearly east and west from the shores of the Caspian sea to the Atlantic, passing through Turkey, Austria, Italy, Switzerland, France, and Spain. The whole region along this chain, which sends off many lateral branches, is subject to earthquakes and other volcanic phenomena; the well known volcanoes Etna, and Vesuvius, are a part of this chain. In addition to the volcanic chains we have named, there are some cases of isolated volcanic action, such as Mount Hecla in Iceland, and the volcanoes of Madagascar.

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“But, even then, the ground
Heaved 'neath their tread — the giant turrets rocked,
And fell: and instantly black night rushed down,
And from its bosom burst a thunderous crash
Stunning and terrible.” Wm. Howitt.

THE mumber of active volcanoes, and solfatares or vents, from which sulphureous and acid vapors and gases are given off, is about 305; of these, 196 are in islands, and the other 109, are on continents. It is however, a remarkable fact that a majority of them are located near the ocean, or large bodies of water; and even submarino volcanoes are not of unfrequent occurrence. Besides the volcanoes now in action, there are many undisputable extinct volcanoes, i. e., volcanoes which at some period of the earth’s existence, but before the historic era, have been in the state of active eruption. In no country is there better evidence of this than in France. There are in the districts of Auvergne, Vivarais, and Cervennes, more than a hundred comical mountains, composed of lava, scoriae, and volcanic ashes heaped up, many of them still retaining their ancient craters, and in some cases currents of lava may be traced to great distances. The evidences of volcanic action in the Rocky Mountains we have already alluded to.

How long a period of repose may be necessary to constitute an extinct volcano, is of course undetermined. We include as such, those which show indúbitable evidence of former activity, but which have not had eruptions within the historic era. It is by no means necessary that volcanoes, to be considered active, should incessantly emit flames, they may remain for ages choked up,

and again suddenly resume all their former character. Thus Vesuvius, which had been extinct from time immemorial, although its crater was clearly formed by some ancient volcanic action; suddenly rekindled in the reign of Titus, and buried the cities of Herculaneum, Pompeii, and Stabia, under its ashes. After this effort it again slumbered, the memory of its former power faded away; trees and grass grew on its summit, when suddenly in 1630, it renewed its action. At this time, the crater, according to the account of Bracini, who visited Vesuvius not long before the eruption of that year, “was five miles in circumference, and about a thousand paces deep; its sides were covered with brushwood, and at the bottom there was a plain on which cattle grazed. In the woody parts wild boars frequently harbored. In one part of the plain, covered with ashes, were three small pools, one filled with hot and bitter water, another salter than the sea, and a third hot but tasteless.” Suddenly, in December 1630, these forests and grassy plains were blown into the air, and their ashes scattered to the winds; seven streams of lava poured at the same time from the crater, and overflowed several villages at the foot, and on the side of the mountain; since that time there has been a constant series of eruptions. Etna after slumbering for ages, burst forth and destroyed the city of Catania; the accounts of its previous eruptions having been considered by the inhabitants as fables. Subterranean noises, and the appearance, or increase ofsmoke, are the first symptoms of approaching volcanic action. This is soon accompanied by a trembling of the earth, and louder noises; the air darkens, and the smoke, thick with fine ashes, increases. . The stream of smoke rises like an immense black shaft, high up into the air, and arriving at a point where its density is the same as the atmosphere, spreads out like a vast umbrella, overshadowing the whole country with its dark gloom. Such was the appearance as described by Pliny, the Elder, who witnessed the eruption of Vesuvius which overwhelmed Pompeii, in A. D. 79. Occasionally, lightning flashes illuminate the dark cloud, and streams of red hot sand, like flames, shoot up into the sky, attended with loud explosions. The shocks, and tremblings of the

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