Now The Volcano Of Cotopaxi Is A Cone, More Than One Thousand Eight Hundred Toises Above The Basin Of Honda, And It Rises From A Table-Land, The Elevation Of Which Is More Than One Thousand Five Hundred Toises Above The Valley Of The Magdalena.

In all the colossal mountains of Quito, of the province of los Pastos, and of Popayan, crevices and valleys without number intervene.

It cannot be admitted, under these circumstances, that the noise was transmitted through the air, or over the surface of the globe, and that it came from the point at which the cone and crater of Cotapaxi are situated. It appears probable, that the more elevated part of the kingdom of Quito and the neighbouring Cordilleras, far from being a group of distinct volcanoes, constitute a single swollen mass, an enormous volcanic wall, stretching from south to north, and the crest of which presents a superficies of more than six hundred square leagues. Cotopaxi, Tunguragua, Antisana, and Pichincha, are on this same raised ground. They have different names, but they are merely separate summits of the same volcanic mass. The fire issues sometimes from one, sometimes from another of these summits. The obstructed craters appear to be extinguished volcanoes; but we may presume, that, while Cotopaxi or Tunguragua have only one or two eruptions in the course of a century, the fire is not less continually active under the town of Quito, under Pichincha and Imbabura.

Advancing northward we find, between the volcano of Cotopaxi and the town of Honda, two other systems of volcanic mountains, those of los Pastos and of Popayan. The connection between these systems was manifested in the Andes by a phenomenon which I have already had occasion to notice, in speaking of the last destruction of Cumana. In the month of November 1796 a thick column of smoke began to issue from the volcano of Pasto, west of the town of that name, and near the valley of Rio Guaytara. The mouths of the volcano are lateral, and situated on its western declivity, yet during three successive months the column of smoke rose so much higher than the ridge of the mountain that it was constantly visible to the inhabitants of the town of Pasto. They described to us their astonishment when, on the 4th of February, 1797, they observed the smoke disappear in an instant, whilst no shock whatever was felt. At that very moment, sixty-five leagues southward, between Chimborazo, Tunguragua, and the Altar (Capac-Urcu), the town of Riobamba was overthrown by the most terrible earthquake on record. Is it possible to doubt, from this coincidence of phenomena, that the vapours issuing from the small apertures or ventanillas of the volcano of Pasto had an influence on the pressure of those elastic fluids which convulsed the earth in the kingdom of Quito, and destroyed in a few minutes thirty or forty thousand inhabitants?

To explain these great effects of volcanic reactions, and to prove that the group or system of the volcanoes of the West India Islands may sometimes shake the continent, I have cited the Cordillera of the Andes. Geological reasoning can be supported only by the analogy of facts which are recent, and consequently well authenticated: and in what other region of the globe could we find greater and more varied volcanic phenomena than in that double chain of mountains heaved up by fire? in that land where nature has covered every mountain and every valley with her marvels? If we consider a burning crater only as an isolated phenomenon, if we be satisfied with merely examining the mass of stony substances which it has thrown up, the volcanic action at the surface of the globe will appear neither very powerful nor very extensive. But the image of this action becomes enlarged in the mind when we study the relations which link together volcanoes of the same group; for instance, those of Naples and Sicily, of the Canary Islands,* of the Azores, of the Caribbee islands of Mexico, of Guatimala, and of the table-land of Quito; when we examine either the reactions of these different systems of volcanoes on one another, or the distance at which, by subterranean communication, they simultaneously convulse the earth. (I have already observed (Chapter 1.2) that the whole group of the Canary Islands rises, as we may say, above one and the same submarine volcano. Since the sixteenth century, the fire of this volcano has burst forth alternately in Palma, Teneriffe, and Lancerote. Auvergne presents a whole system of volcanoes, the action of which has now ceased; but in the middle of a system of active volcanoes, for instance, in that of Quito, we must not consider as an extinguished volcano a mountain, the crater of which is obstructed, and through which the subterraneous fire has not issued for ages. Etna, the Aeolian Isles, Vesuvius, and Epomeo; the peak of Teyde, Palma, and Lancerote; St. Michael, La Caldiera of Fayal, and Pico; St. Vincent, St. Lucia, and Guadaloupe; Orizava, Popocatepetl, Jorullo, and La Colima; Bombacho, the volcano of Grenada, Telica, Momotombo, Isalco, and the volcano of Guatimala; Cotopaxi, Tunguragua, Pichincha, Antisana, and Sangai, belong to the same system of burning volcanoes; they are generally ranged in rows, as if they had issued from a crevice, or vein not filled up; and, it is very remarkable, that their position is in some parts in the general direction of the Cordilleras, and in others in a contrary direction.)

The study of volcanoes may be divided into two distinct branches; one, simply mineralogical, is directed to the examination of the stony strata, altered or produced by the action of fire; from the formation of the trachytes or trap-porphyries, of basalts, phonolites, and dolerites, to the most recent lavas: the other branch, less accessible and more neglected, comprehends the physical relations which link volcanoes together, the influence of one volcanic system on another, the connection existing between the action of burning mountains and the commotions which agitate the earth at great distances, and during long intervals, in the same direction.

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