70 NATURAL HISTORY OF 



ITALY. 



PASSING, for the present, the Alpine system without 

 notice, * we arrive at the Italian peninsula, reposing, 

 in its whole extent, upon an ignited gallery, in per- 

 petual activity, and producing a sea more fathomable 

 than the abysses of the Gulf of Lyons and the Genoese 

 offing. On the Tyrhenian coast, the changes most 

 readily ascertained, occur at the port and city of Pisa, 

 which were originally situated at the mouth of the 

 Arno, whereas they are now above four miles inland ; 

 and the Ansar streamlet, which, according to Strabo, fell 

 into the river close to the town, now terminates ten miles 

 distant. The volcanic soil* alike fertile and deleterious 

 in the maremmas, is in some places unstable, so that 

 even since the fall of the Roman empire, certain spots 

 about Baiae have been sunk below the level of the 

 sea, and again raised up above it, without entirely 

 overturning^ columns, such as those of the temple of 

 Serapis, all of which, at a certain elevation above their 



* Remarkable, however, for land slips, anciently more 

 numerous and extensive than at present. In the Alps, frag- 

 ments of Roman roads, with arched gateways, occur among 

 elevated precipices. Hannibal encountered a subsidence of 

 the road on his passage. Those of Mont Grenier, Dia- 

 blerets, Mont Chede, and particularly of the Rossberg, in 

 1806, are well known ; and that of Cernans, between Dijon 

 and Pontarlier, in the Jura, where the high read sank 300 

 feet, in 1839, is the last of importance. 



