2o6 PHYSIOGRAPHY. [chap. 



again and again, rising at one time and falling at another. 

 And probably, such changes have been effected, for the most 

 part, quietly rather than violently ; by slowly-acting forces 

 working through long periods of time rather than by sudden 

 disturbances. 



It would, perhaps, be difficult to point to any clearer proof 

 of such gentle oscillations of level having taken place within 

 the memory of man, than that afforded by some well-known 

 ruins on the shore of the Bay of Naples. Although this 

 illustration has been used by Sir Charles Lyell and other 

 writers, it is, nevertheless, well worth referring to again, since 

 it shows most instructively the kind of evidence on which 

 geologists rely in proof of the instability of the surface of 

 the land. 



About the middle of the last century, the attention of some 

 Italian antiquaries was attracted by three stone columns, 

 almost concealed by a growth of bushes behind a villa very 

 near to the sea shore, in the western part of Pozzuoli, a town 

 seated on the Bay of Baije, about seven miles from Naples. 

 These columns were buried to a considerable height in an 

 accumulation of soil, the removal of which brought to light 

 the ruins of a magnificent building. A square floor, paved 

 with marble, and measuring seventy feet in the side, showed 

 the magnitude of the central court. This area had originally 

 been covered with a roof supported by forty-six noble columns, 

 some wrought in granite and some in marble, still remaining 

 more or less perfect. It was assumed by the antiquaries of 

 the day, apparently on very slender grounds, that the build- 

 ing had been a temple dedicated to Serapis, an Egyptian 

 divinity, whose worship had been introduced into Rome. 

 Just behind the building is a hot spring, from which water had 

 been carried, through a marble channel, to a number of small 

 apartments built around the central court. This has led to the 



