Physical Structure of the Site of Rome. 3 



east by east of Rome, and rises 9521 feet above the Mediter- 

 ranean ; the other // Velino, about twenty miles south and by 

 west of the former, and immediately north of the Lacus Fucinus, 

 now II Celano, which is 8182 feet high. The next greatest 

 height is at a considerable distance, about forty miles north-west 

 of Florence, II Cimone di Fanano, which is 7000 feet above 

 the sea. 



Where they approach the Alps, the Apennines are composed 

 of a mixture of primary rocks, viz. mica-slate, clay-slate, granu- 

 lar limestone, granite, and serpentine. The same rocks also oc- 

 cur at the southern extremity of the chain in Calabria, but they 

 form only a small portion in the intermediate space. The coun- 

 try on the two sides of the range presents considerable difference 

 in geological structure; that next the Adriatic being wholly 

 composed of secondary rocks, with the exception of some inso- 

 lated patches of serpentine here and there ; while oti the Medi- 

 terranean side there is an extensive tract, chiefly along the shore> 

 of primary and transition rocks, with only occasional patches of 

 secondary strata in it. On this side also, all the volcanic rocks 

 are found. 



The principal rock in the north-western part of the Apennines 

 is a kind of sandstone and slate, well known to geologists by the 

 names of Greywacke and Greywacke-slate^ the latter containing 

 subordinate beds of limestone with organic remains. There are 

 also considerable hills entirely composed of transition limestone, 

 many of which produce varieties of marble used for agricultural 

 purposes, &c. The statuary marble is a different rock, and be- 

 longs to the primary class. 



These rocks extend southwards as far as the neighbourhood 

 of Cortona, but do not exclusively compose the Apennine ridge 

 to that point. The rock which may properly be termed the 

 rock of the Apennines is a limestone, but more modern^ geolo- 

 gically speaking, than that already mentioned. It is not confined 

 to the principal chain, but extends also into the lower country^ 

 forming here and there detached hills. In Tuscany it covers in 

 many places the older rocks, and here there are a great many 

 limestone hills quite detached from the main range. On the 

 eastern side of it, there is no calcareous hills distinctly separated 

 from the Apennines, except one forming a promontory on th^ 



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