8 GEOLOGICAL MEMOIRS^ 



that a further union of some of them is probable. They are cha- 

 racterized by great diversity of the rocks composing them, which 

 include crystalline slates and numerous eruptive rocks, especially of 

 the trachytic and basaltic groups, occurring side by side with sedi- 

 mentary deposits of various ages. The Silurian formation is indi- 

 cated by a fragment of a species of Lichas 5 and some red sandstones, 

 probably the analogues of similar rocks in Siberia, may also be re- 

 ferred to the Silurian, on account of their containing certain Trilo- 

 bites, Orthoeeratites, and Brachiopods. On Aliaska there is a black 

 sandstone, with Ancella mosquensis, which the author refers to the 

 Neocomian. Other deposits are said to belong to the Gault and the 

 Turonian. Aliaska also furnishes Miocene fossil plants. 



[Count M.] 



3. On the Geological Structuee of the Italian Peninsula. 

 By Prof. Ed. Suess. 



[Proc. Imp. Geol. Inst. Vienna, May 7, 1872.] 



The true Apennines, or, in other words, the chain of the Gran Sasso, 

 the main orographical line of Italy, present no rocks identical with 

 those of the central chain of the Alps, and, when compared with the 

 Alps, exhibit only the structure of a folded secondary zone, analogous 

 to the cHff-zone of the Carpathians, The true tectonic axis of the 

 Apennines runs parallel to the western border of Italy, from the Gulf 

 of Genoa, through the Tyrrhenian sea towards Calabria. Old 

 schistose rocks, such as occur in the inner zone of the Alps, are 

 present throughout the Apuan Alps, the islands of the western coast, 

 and the " Catena metallifera," and extend to the promontory of 

 Circe and the island of Jannoue, far to the south of Rome, in larger 

 and smallei chains, reefs, and fragments resembling the scattei'ed 

 remains of a ruined mountain -chain. In the south, in Calabria and 

 the north-eastern extremity of Sicily, crystalline rocks appear over 

 a great extent ; and here the tectonic significance of the above- 

 mentioned fragmentary old schists is clearly manifested. Gneiss 

 appears near Messina in the Peloritan region, followed towards the 

 south-west by younger deposits ; and even near Taomina these old 

 deposits are overlain by Devonian, Triassic, and Liassic beds, &c. 

 This succession of beds, lately described by Prof. Seguenza, has its 

 analogue rather in the Korthern than in the Southern Alps, and 

 therefore represents the stratigraphical head (^SchichtenJcoj)f) of a 

 western subsidiary zone. 



The mountains of Calabria are of decidedly Alpine type. Three 

 central massifs may be traced among them) viz. : — 1. The massif of 

 Aspromonte, falling abruptly on all sides towards the Tyrrhenian sea ; 

 2. the massif of the Sila ; 3. the massf of Monte Cocuzzo, which is 

 also abrupt towards the Tyrrhenian sea. 



The large white limestone chain in the Basilicata, which rests on 

 the old crystalline rocks to the east of the ancient Sybaris, consti- 

 tutes the stratigraphical head of the easterijteubsidiary zone. At its 

 foot, near San Donate, cinnabar is worked fipfed quartzite, just as in 



