Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/634

This page needs to be proofread.
10
GEOLOGICAL MEMOIRS.

strata of Castel' Gomberto, Laverda, and Sangonini may safely be ranked in the group now generally named "Oligocene," although, with regard to the geological constitution of the Alpine region, the denomination of "Upper Eocene" may be preferred. The fauna of Gomberto offers the most striking analogies with the fauna of the blue marls of Gaas and Lesbarritz; it contains an abundance of large species of Strombus, Cassis, and Natica; Cerithia and Trochidoe are, however, predominant. The fauna of Laverda, especially of the marls, includes some few species of Sinupalliate Bivalves, and is completely concordant with those of Oberburg (Styria) and Polschiza (Carniolia).

The basaltic tuffs of Sangonini, near Lugo, abound in Canaliferous Gasteropods, especially of the genera Fusus, Pleurotoma, Murex, and Tritonium: their fauna is strikingly analogous to the Eocene fauna of England; 20 species of it are common to the Inferior Oligocene fauna of N. Germany (Latdorf, Unseburg, Wolonirsleben, Helmstadt, &c.). The molluscan Upper-Eocene fauna of the Vicentine shows a remarkably tropical type, especially in the Gomberto strata, in this respect contrasting with the equivalent deposits of North Germany.

[Count M.]

{{center|On the Jurassic and Cretaceous Deposits of the Central Apennines. By Dr. C. A. Zittel.

[Proceed. Imp. Geol. Inst. December 15, 1868.]

The Tithonian and Lias group are particularly well developed. The Roman Apennines show important Inferior Cretaceous beds, but only scanty traces of Jurassics ("Dogger"). The succession of horizons is as follows in ascending order:—

1. Inferior Lias. Large masses of white limestones, with no organic remains except, in some few localities, imperfectly preserved Brachiopods, Gasteropods, and Avicula janus, Menegh.

2. Middle Lias. Light-coloured stratified limestones, with a great variety of organic remains (most of them new species), such as Ammonites Davoei, A. Ragazonii, A. Algovianus, A. Lavinianus, abundant Brachiopods, stems of Crinoids, &c.

3. Upper Lias, with abundance of Ammonites bifrons, A. Comensis, A. serpentinus, A. radians, &c., Phylloceras heterophyllum, P. Nilssoni, Terebratula Erbaensis, and T. Rozzoana.

4. Inferior Dogger. Yellowish marly limestones, with Ammonites fallax, A. scissus, A. Murchisonoe, and Phylloceras ultramontanum.

5. Aptychian Shales, with Aptychus punctatus and A. latus.

6. Tithonian horizon. Light-coloured marble-like limestones, with abundant Cephalopods, generally identical in species with those of Rogoznik in Galicia and of South Tyrol.

7. Neocomian white limestones, with Ammonites incertus, Phylloceras infundibulum, &c.

8. Rose-coloured limestones, with Fucoidal shales in their lower-most horizon.

9. Scaglia, as in S. Tyrol. [Count M.]