GEOGNOSY AND GEOLOGY. 215 
a 
which vomited forth flame, smoke, dust, and pumice, which, in the course 
of two days, heaped up a mountain of about 8000 feet in circumference, and of 
considerable height, with a crater on the summit. Shortly afterwards, this 
outbreak ceased, and the whole became quiet. Subsequently followed other 
powerful eruptions, but at the present time, Monte-Nuovo belongs to extinct 
voleanoes, overgrown with the most luxuriant vegetation, and whose crater 
exhibits only traces of its original condition. 
The elevation of Jorullo in Mexico, as described by Alexander von Hum- 
boldt, must have been an awfully sublime spectacle. The locality of this 
stupendous exhibition was a highly cultivated plan, elevated about 2000 
feet above the level of the sea, with loosely scattered blocks of basalt upon 
the surface. In June of 1759, a terrible bellowing was heard, with ominous 
earthquake shocks. This lasted sixty days, until, towards the end of Septem- 
ber, all danger appeared to have vanished. But suddenly, in the night of the 
18th and 19th of this month, the sounds recommenced, and an extent of land 
of nearly four square miles was covered with scoria and lava, by means of 
eruptions, which did not cease until February, 1760. Six volcanic cones 
were formed, the central one, or Jorullo, attaining an elevation of 1600 
feet above the level of the plain. Thousands of small cones, called hornitos, 
are dotted over the region, produced by the heaping up of dome-shaped 
masses of lava by the disengagement of gaseous matters. Some have 
supposed that part, at least, of the general elevation has been produced by 
the actual elevation of the plain, as on the surface of a gigantic bubble; this 
hypothesis, however, hardly appears to be substantiated by the physical 
features of the region. The six cones above referred to, were arranged along 
an immense fissure, extending from north-east to south-west. From this 
central fissure, with its subsequent ridge and six elevations, the volcanic 
masses siope at a general angle of 6° to the circumference of the tract. It is 
not probable that any material accession to the volcanic matter was experienced 
after the year 1760; at the present day, the greater portion of the plain is 
covered with a rich or Sei 
The elevation sia disappearance of the island of Puriand™ in thé 
channel between Sicily and Africa, was a highly interesting phenomenon: 
The water of the sea was thrown into great waves, gigantic columns of smoke 
escaped, the neighboring coasts experienced earthquake shocks, and ari 
island rose suddenly from the troubled sea. It was on the 28th of June; 
1831, that earthquakes were experienced in Sciacca, on the southern coast 
of Sicily, accompanied by a thundering noise. A British vessel in thé 
vicinity experienced shocks, and vesicular dust was carried by the winds 
and deposited on the Sicilian coast. At break of day, on the 13th of July, 
up to which ‘time the indications of volcanic phenomena were continued, the 
new voleano was first observed from Sciacca, emitting immense volumes of 
sulphurous acid, which annoyed the whole neighboring region. A few days 
after, an immense expanding column was observed to rise out of the mouth 
of the volcano, consisting of various ejecta, the more solid portions of which 
fell into the water with a hissing sound. Lightnings, accompanied by heavy 
thunder, illuminated the dark scene, whose horrors were heightened by 
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