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buried in the entrails of the Earth; but if the narrow circle, in which all certain traditions are confined, do
not present any of those general revolutions, which have heaved up the Cordilleras, and buried myriads of
pelagian animals, Nature, acting under our eyes, does not less exhibit tumultuous though partial changes,
the study of which may throw light on the most remote epochs. Those mysterious powers reside in the
interior of the Earth, the effects of which are manifested at the surface by the production of vapours, of
incandescent slags, of new volcanic rocks and thermal springs, by the appearance of new islands and
mountains, by commotions propagated with the rapidity of an electric shock, finally by those subterranean
thunders*, which are heard during whole
*Those which alarmed the inhabitants of the town of Guanaxuato, in Mexico, lasted from the 9th of
January till the 12th of February, 1784. This phenomenon, almost without example among those
accurately observed, will be described in the sequel of this Narrative. It is sufficient here to observe,
that the town is situate forty leagues North of the volcano of Jorullo, and sixty leagues North-West
of the volcano of Popocatepetl. In places nearer these two volcanoes, three leagues distant from
Guanaxuato, the subterraneous thunders were not heard. The noise was circumscribed within a
very narrow space, in the region of a primitive schist, which approaches a transition schist,
containing the richest silver mines of the known world, and on which rest trap porphyries, slates,
and diabasis (gruenstein).