Dr. C. 8. Du Riche Preiler—The Tuscan Archipelago. 273 
recent geological epochs have been both the cause and the effect of 
great changes no less on the mainland of the peninsula than in the 
Mediterranean itself. 
2S 
pert a ‘ 
Carrara 
born 
* Volterra 
Maremma 
Hulls. 
The islands composing the Tuscan Archipelago, and situated, 
roughly speaking, at about thirty miles from each other, are 
Gorgona, Capraja, Elba, Pianosa, Montecristo, Giglio, and the 
promontory, practically also an island, of Argentario. 
The most ancient rocks of the Tuscan Archipelago are the 
pre-Silurian schists and serpentines of Gorgona, Giglio, Argentario 
and the eastern part of Elba, bearing analogy not only with the 
same series of Sardinia and the north-eastern part of Corsica, but 
also generally with the Archean and Cambrian series of the Alps. 
In the eastern part of Elba, these schists and serpentines underlie 
the Upper Silurian fossiliferous schists, and although Dieulefait 
refers the Corsican serpentines to Trias, or at all events declines to 
accord them a greater age than Permian, their analogy with the 
Elban rocks stamps them as undoubtedly pre-Silurian. 
The rocks overlying the Upper Silurian strata in the islands 
of Giglio, Argentario, and also in the Maremma hills, have been 
referred to Permian from their analogy with the schists of Monte 
Pisano, the highest peak of the Carrara mountains where Permian 
fossils have been found. 
Of the secondary formation, Trias is conspicuous by its absence 
in the whole of the Archipelago, and Infralias, which is also re- 
presented in the Maremma hills and in Corsica, rests directly not only 
DECADE III.— VOL. X.—NO. VI. 18 
