At Valecillo, A Few Leagues From Valencia, The Yawning Earth Threw Out Such An Immense Quantity Of Water, That It

Formed a new torrent. The same phenomenon took place near Porto-Cabello.* (* It is asserted that, in the mountains of

Aroa, the ground, immediately after the great shocks, was found covered with a very fine and white earth, which appeared to have been projected through crevices.) On the other hand, the lake of Maracaybo diminished sensibly. At Coro no commotion was felt, though the town is situated on the coast, between other towns which suffered from the earthquake. Fishermen, who had passed the day of the 26th of March in the island of Orchila, thirty leagues north-east of La Guayra, felt no shock. These differences in the direction and propagation of the shock, are probably owing to the peculiar position of the stony strata.

Having thus traced the effects of the earthquake to the west of Caracas, as far as the snowy mountains of Santa Martha, and the table-land of Santa Fe de Bogota, we will proceed to consider their action on the country eastward of the capital. The commotions were very violent beyond Caurimare, in the valley of Capaya, where they extended as far as the meridian of Cape Codera: but it is extremely remarkable that they were very feeble on the coasts of Nueva Barcelona, Cumana, and Paria; though these coasts are the continuation of the shore of La Guayra, and were formerly known to have been often agitated by subterranean commotions. Admitting that the destruction of the four towns of Caracas, La Guayra, San Felipe, and Merida, may be attributed to a volcanic focus situated under or near the island of St. Vincent, we may conceive that the motion might have been propagated from north-east to south-west in a line passing through the islands of Los Hermanos, near Blanquilla, without touching the coasts of Araya, Cumana, and Nueva Barcelona. This propagation of the shock might even have taken place without any commotion having been felt at the intermediate points on the surface of the globe (the Hermanos Islands for instance). This phenomenon is frequently remarked at Peru and Mexico, in earthquakes which have followed during ages a fixed direction. The inhabitants of the Andes say, speaking of an intermediary tract of ground, not affected by the general commotion, "that it forms a bridge" (que hace puente): as if they mean to indicate by this expression that the undulations are propagated at an immense depth under an inert rock.

At Caracas, fifteen or eighteen hours after the great catastrophe, the earth was tranquil. The night, as has already been observed, was fine and calm; and the commotions did not recommence till after the 27th. They were then attended by a very loud and long continued subterranean noise (bramido). The inhabitants of the destroyed city wandered into the country; but the villages and farms having suffered as much as the town, they could find no shelter till they were beyond the mountains of los Teques, in the valleys of Aragua, and in the llanos or savannahs. No less than fifteen oscillations were felt in one day. On the 5th of April there was almost as violent an earthquake as that which overthrew the capital. During several hours the ground was in a state of perpetual undulation. Large heaps of earth fell in the mountains; and enormous masses of rock were detached from the Silla of Caracas. It was even asserted, and this opinion prevails still in the country, that the two domes of the Silla sunk fifty or sixty toises; but this statement is not founded on any measurement. I am informed that, in like manner, in the province of Quito, the people, at every period of great commotions, imagine that the volcano of Tunguragua diminishes in height. It has been affirmed, in many published accounts of the destruction of Caracas, that the mountain of the Silla is an extinguished volcano; that a great quantity of volcanic substances are found on the road from La Guayra to Caracas; that the rocks do not present any regular stratification; and that everything bears the stamp of the action of fire. It has even been stated that twelve years prior to the great catastrophe, M. Bonpland and myself had, from our own observations, considered the Silla as a very dangerous neighbour to the city of Caracas, because the mountain contained a great quantity of sulphur, and the commotions must come from the north-east. It is seldom that observers of nature have to justify themselves for an accomplished prediction; but I think it my duty to oppose ideas which are too easily adopted on the LOCAL CAUSES of earthquakes.

In all places where the soil has been incessantly agitated for whole months, as at Jamaica in 1693, Lisbon in 1755, Cumana in 1766, and Piedmont in 1808, a volcano is expected to open. People forget that we must seek the focus or centre of action, far from the surface of the earth; that, according to undeniable evidence, the undulations are propagated almost at the same instant across seas of immense depth, at the distance of a thousand leagues; and that the greatest commotions take place not at the foot of active volcanoes, but in chains of mountains composed of the most heterogeneous rocks. In our geognostical observation of the country round Caracas we found gneiss, and mica-slate containing beds of primitive limestone. The strata are scarcely more fractured or irregularly inclined than near Freyburg in Saxony, or wherever mountains of primitive formation rise abruptly to great heights. I found at Caracas neither basalt nor dorolite, nor even trachytes or trap-porphyries; nor in general any trace of an extinguished volcano, unless we choose to regard the diabases of primitive grunstein, contained in gneiss, as masses of lava, which have filled up fissures. These diabases are the same as those of Bohemia, Saxony, and Franconia;* (* These grunsteins are found in Bohemia, near Pilsen, in granite; in Saxony, in the mica-slates of Scheenberg; in Franconia, between Steeben and Lauenstein, in transition-slates.) and whatever opinion may be entertained respecting the ancient causes of the oxidation of the globe at its surface, all those primitive mountains, which contain a mixture of hornblende and feldspar, either in veins or in balls with concentric layers, will not, I presume, be called volcanic formations.

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