1906.] 



SEE— THE CAUSE OF EARTHQUAKES. 327 



rine fossils of past geological ages, could, I think, be explained by 

 tendencies developed under the crust, according to which the fluid 

 substratum is alternately thickened and thinned, owing to the con- 

 currence or non-concurrence of the subterranean forces. When 

 they work towards a point the result is elevation, and when they tend 

 to diverge from a point the result is depression, and the elevation 

 is transferred to neighboring areas. This is a modern view of the 

 periodic movement of the earth's crust so clearly foreseen by Strabo 

 nearly 2,000 years ago. 



According to this view the sea bottoms may oscillate, but on the 

 whole tend to subside, not on account of the shrinkage of the globe, 

 but by virtue of the gradual working out of the underlying fluid 

 substratum, which in the long run pushes up the land. 



In his " Principles of Geology," 12th edition, Vol. II, page 155, 

 Lyell discusses with characteristic fairness the historical cases of 

 elevation of coasts noticed in different parts of the world. We shall 

 content ourselves with citing a very few cases of this type : 



1. Islands in the sea innumerable, both volcanic and non-volcanic 

 (apparently, though all are raised by volcanic forces). 



2. The southwestern end of the Island of Crete, which even 

 Professor Suess admits to have experienced undeniable secular 

 elevation within the historical period. 



3. The region about Pozzuoli and the Bay of Naples. This is 

 shown by the famous temple of Jupiter Serapis, and by the eleva- 

 tibn of the coast actually witnessed at the time of the eruption of 

 Monte Nuovo in 1538. This raising of the land was confirmed on 

 a larger scale for the whole Bay of Naples during the Vesuvian 

 eruption of April, 1906 (cf. Quarterly Journal of the Geological 

 Society J No. 247, 1906), by Professor Lorenzo, who found the ele- 

 vation of the land at Pozzuoli ^to be six inches, and at Portici one 

 foot. 



4. The foundations of both ^tna and Vesuvius were laid in 

 the sea. 



5. Professor Suess cites the most ample evidence of raised 

 beaches and other sea marks high above the present strand in almost 

 all parts of the world. As these heights are very unequal, they can- 

 not be explained by a simple sinking of the sea level, but there must 



PROC. AMER. PHIL. SOC. , XLV. 184 U, PRINTED FEBRUARY 20, I907. 



