THE CRUST OF THE EARTH. 



of the river became deeper at several places, and different parts of 

 its bed, formerly fordable, ceased to be so. 



115. In the records of all ages and countries, effects of the 

 ;?ame kind are recorded. Large crevices in the earth have 

 been formed, deep gulfs opened, into which cities, and even 

 whole countries, have sometimes been swallowed up. From these 

 openings, mephitic vapouts, water in enormous quantities, some- 

 limes cold, sometimes warm, have been ejected, and, occasionally, 

 even flame has issued. Plains have been suddenly transformed 

 into mountains, shoals produced in the deepest seas, mountains 

 cracked and overturned, and mountainous tracts, many hundred 

 miles in extent, suddenly levelled or replaced by deep lakes ; 

 rivers, turned from their beds, have discharged their waters into 

 cavities thus formed ; lakes, breaking through their banks, have 

 been emptied, and their bottoms left dry, or have been turned 

 through subterraneous openings suddenly formed beneath them. 

 On the contrary, in some cases numerous springs, natural artesian 

 wells, have been formed, supplying waters which suddenly issued 

 i'rom crevices of the rock or from tunnels. Thermal springs have 

 been suddenly rendered cold, or altogether dried up, while others, 

 on the contrary, have been produced where none existed. 



All these, and many other phenomena, indicate the existence of 

 internal convulsions, by which the matter subjacent to the crust of 

 the earth is driven upwards through its crevices. 



116. Independently of the phenomena of this class which are 

 authentically recorded in history, many others are subjects of 

 tradition. Thus, Pliny relates a tradition that Sicily had been 

 separated from Italy, Cyprus from Syria, and Euboea from Boeotia, 

 by earthquakes. According to another classical tradition, a great 

 island called Atlantis existed in ancient times west of the Straits 

 of Gibraltar, having a numerous population. Its princes invaded 

 Africa and Europe, but were defeated by the Athenians and their 

 allies. Its inhabitants afterwards became wicked and impious, 

 and the island was visited with the vengeance of the Gods, and 

 swallowed up by the ocean in a single day and night. This 

 legend is given by Plato, and is said to have been related to 

 Solon by the Egyptian priests. According to all the analogies 

 supplied by the phenomena described above, there is nothing 

 impossible, or even improbable, in that part of this legend which 

 refers to an island being engulfed by the ocean. 



117. The cases in which the dry land has been invaded by the 

 sea, or the bed of the sea left dry by the retirement of the waters, 

 has been popularly, and even by the scientific of former days, 

 ascribed to the change in the level of the waters of the ocean, 

 their elevation producing inundations, and their fall leaving 



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