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PHYSICAL GEOGRAPHY. 



speedily resumed. The thick clouds of dust which rose from the ruins and darkened the 

 air, had fallen to the ground. The shocks had ceased. Never was there a finer or a 

 quieter night. The rounded summits of the Silla mountain were illuminated by the 

 moon, nearly at the full, and the serenity of the heavens seemed to mock the disturbed 

 state of the earth, where under a heap of ruins lay nearly ten thousand of the inhabitants 

 of Caraccas. " In this city," says Humboldt, " was now repeated what had taken place 

 in the province of Quito, after the dreadful earthquake of the 4th of February 1797. 

 Marriages were contracted between persons who for many years had neglected to sanction 

 their union by the sacerdotal blessing. Children found parents in persons who had till 

 then disavowed them; restitution was promised by individuals who had never been 

 accused of theft ; and families who had long been at enmity, drew together from the 

 feeling of a common evil." Caraccas was at this period one of the foci of subterranean 

 commotions, which from the beginning of 1811 to 1813 operated on a vast extent of the 

 earth's surface, an area limited by the meridian of the Azores, the valley of the Ohio, and 

 the cordilleras of New Grenada. The shocks fatal to the city were sensibly felt at Honda 

 on the banks of the Magdalena, 620 miles distant. Large masses of earth fell in the 

 mountains, and enormous rocks were detached from the Silla. The lake of Maracaybo 

 underwent considerable diminution, but at Valecillo, the ground opened, and emitted so 

 great a mass of water, that a new torrent was formed, the same phenomenon taking place 

 near Porto Cabello. In all parts the disturbance was more violent in the cordilleras of 

 gneiss and mica-slate, or immediately at their base, than in the plains. 



A personal examination was made by Dolomieu and Sir William Hamilton of the 

 surface of the Calabrias after the earthquakes which continued from the beginning of 1783 

 to the close of 1786, and their survey illustrates the superficial changes produced by the 

 action of such events. Those provinces have been subject to such visitations since the 

 first Greek colonists landed upon their shores, but the most terrible instances in modern 

 times occurred in 1633 and 1783, in the latter of which Sicily largely participated. The 

 soil of the mainland is chiefly composed of modern marine strata, immensely thick, 

 generally of calcareous clay, of a very yielding nature, which was greatly disturbed, and 

 assumed a variety of new forms, under control of the irresistible force acting upon it. 



Fissures at Polistena. 



The earth exhibited a variety of motions, called in the Italian accounts vorticoso, orizon- 

 tale, and oscillatorio, whirling like a vortex, horizontal, or by pulsations or beatings from 



