Sir 11. 1. Muidiisou on the Vents of Hut Vapour in Tuscany. 65 



north of Parma, seems to have beea the grand centre of serpentine 

 eruption, from whence such hues radiate, as marked by the protru- 

 sion at intervals of igneous rocks and the bauds of metamorphosed 

 strata which constitute the loftiest ridges of Italy (see fig. 6, p. &7)' 

 In this way, the serpentine bosses of the Apennines, between Bologua 

 and Florence, that trend from N.W. to S.E. — /. e. from the region 

 of chief eruption— though divergent from the line of the Apuan Alps, 

 and Tuscan Maremraa, are exactly coincident witli the major axis of 

 the Apennines or great back-bone of Italy, the culminating points 

 of which, as at the Gran Sasso d' Italia, 9530 feet above the sea, are 

 composed of eocene (nummuhtic) and cretaceous rocks reposing on 

 Jurassic. 



Again, if we turn from the east and look to the other great band 

 of eruption to the west of the coast of Italy, as marked by serpentines 

 protrutUng thro\igh the cretaceous and eocene dej)osits of Corsica, 

 we see (as graphically laid down by Pareto*) that it marks nearly 

 a meridian line. Looking then at Italy on the great scale, the geo- 

 logist may, I think, satisfactorily connect its dominant physical fea- 

 tures with former causes of upheaval. He sees that, as it is in the 

 highly convulsed and broken-up regioii where the Apennines bend 

 round to become conlluent with the Alps, the greatest masses of 

 serpentine have been emitted, so, exploring southwards from this 

 grand focus, he observes that bands of the same molten matter 

 have been intruded into dirergent cracks and fssures in the crust 

 of the earth, and extend in long lineai' directions to the S.E., S.S.E., 

 and S. Geological investigation establishes, indeed, not only this 

 fact, but also the important point, that such igneous matter was 

 simultaneously emitted ; since it has alone broken through and me- 

 tamorphosed sedimentary strata of the same age through several de- 

 grees of latitude. Now-, as few parts of Italy contain strata of higher 

 antiquity than liasso-jurassic, and as there is no evidence that its 

 submarine accimudations had ever been raised into dry land before 

 the cretaceous and nunnnulitic rocks were accumulated upon them, 

 we have a fair right to infer, that the linear eruptions of serpentine 

 and their accomi)animents of gas and heat, absolutely furnished the 

 Peninsula with those chains of hard and altered strata (each cor.- 

 tainiag subordinate parallels) whose features and contents have been 

 described on a previous occasion. In short, there is no reason to 

 believe, that Italy had any well-defined terrestrial existence until the 

 period of the post-eocene serpentinous eruptions. As Corsica, how- 

 ever, is only tiic northern prolongation of Sardinia which contains 

 Silurian fossils, and as both islands are characterized by a meridian 

 chain of ancient cry.stalline rocks, it is clear that a very ancient mass 

 of land ranged in that direction, as further proved by its old cry- 

 stalline and Silurian rocks being overlaid by palaeozoic coal plants 



* The reader who wisnes to become acquainted with the various lithological 

 characters of the rocks classed under the head of Serpentine, and which were all 

 emitted at the post-nummulitic penod„n)iist consult the works of Pareto on Li- 

 guria .Marittiina, and oti Corsica, hoth illustrated Uy excellent geological niajis. 

 Although the Marquis Pareto, following preceding authorities, has classed the 

 nummulite limestone with the chalk, I trust he will now agiee with me. 

 Phil. May. S. 4. Vol. 1 . No. 1 . Jan. 1 83 1 . F 



