DYNAMICAL GEOLOGY. 289 



America, in Patagonia, the Argentine Republic, Chili and 

 Peru, and at the southern extremities of Australia and 

 Africa. 



Darwin, in founding his Coral-reef theory, assumed that a slow 

 subsidence had taken place over a vast region of the Pacific 

 and Indian Oceans. In spite of a very large number of data, 

 however, it has not been possible to formulate any definite law 

 of secular variations. Movements of elevation and depression 

 are reported in various latitudes, and are frequently known to 

 take place in opposite senses at localities adjacent to one 

 another. When Dana in 1849, from his observations in the 

 Pacific Ocean, concluded that elevation was in progress in the 

 region around the North Pole, and subsidence in the areas 

 near the Equator, he formed his opinion upon insufficient 

 data. The general truth has, however, been established, that 

 relative changes of level are still in progress along many of the 

 coast-lines, and that since the Diluvial epoch dislocations have 

 been produced, measuring 300-1500 feet. In many cases 

 these movements are slowly and imperceptibly accomplished, 

 in others they occur with convulsive suddenness. Sartorius 

 von Waltershausen in 1845 distinguished the former as 

 Secular, the latter as Instantaneous fluctuations of ground- 

 level. 



Von Humboldt and Von Buch had directed attention 

 to local movements of land in connection with volcanoes and 

 earthquakes, and the example of this character most frequently 

 cited in literature is the temple of Serapis at Pozzuoli, in 

 the Bay of Naples. The columns of the ruined portico are 

 marked by the borings of a marine mollusc at a height of 

 thirteen feet above the present surface-level of the Bay. In 

 1803, Breislak in the French edition of his text-book explained 

 the phenomenon on the hypothesis that the Serapeum had 

 subsided and had remained for a period stationary at the 

 water-level indicated on the pillars by the mollusc borings, but 

 that afterwards a period of emergence and uprise had succeeded. 

 This explanation was strongly opposed by Wolfgang von 

 Goethe. The great poet would not listen to any arguments 

 in favour of oscillations of level; in his opinion, the former 

 submersion of the temple had been due to an enormous flood. 

 Breislak's view has, however, been supported by several 

 leading British scientists, Babbage, Forbes, Poulett-Scrope, 

 and Charles Lyell. The excellent treatise published by 



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