16.

Some of these plains become lakes, by rivers spreading over or falling into them and then flowing off. Some are dried up, and being very fertile, are cultivated in every possible way. But as the ground underneath is full of caverns and fissures, it has frequently happened, that violent earthquakes have obstructed some passages, and formed others under-ground, or on the surface, the water being carried off, either by subterranean channels, or by the formation of lakes and rivers on the surface. If the deep subterranean passages are stopped up, the waters of the lakes increase, so as to inundate and cover cities and whole districts, which become uncovered, if the same or other passages are again opened. The same regions are thus traversed in boats or on foot, according [Pg 100]
[CAS. 406] to circumstances; and the same cities are, occasionally, on the borders of, or at a distance from, a lake.