The Evolution of the Sciences 



an oscillatory character, causing some regions 

 to emerge while others were gradually sinking. 

 No example of these long-period variations 

 is more widely known than that of the Pozzuoli 

 district. Three columns belonging to the ruined 

 temple of Serapis are standing there to-day with 

 their base immersed in the sea. These columns 

 have been pitted with holes by marine molluscs at 

 a height of ten feet above present sea level, and 

 thus bear witness to the successive changes in the 

 level of the sea in this region. As a matter of 

 fact the ground about Pozzuoli continued to 

 sink steadily from Roman times to the fifteenth 

 century. In 1538 an eruption of Monte Nuovo 

 caused a sudden upheaval, and since then the 

 ground has again been sinking gradually. 



Here a purely accidental fact compels our 

 attention to the progressive movements of the 

 ground, but the area affected around Pozzuoli 

 by these movements is too restricted for them 

 to be considered otherwise than purely local 

 manifestations of volcanic action. 



The study of the northern regions where the 

 earth first consolidated affords more typical 

 phenomena, owing to their freedom from 



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