EUEOPB. 59 



Note of an horizon abounding in Avicula contorta, which can he 

 traced in an interrnpted manner throughout the eastern part of the 

 island ; it is best developed in the Corte district. This bed (a shelly 

 marble) had hitherto been grouped with others as belonging to the 

 Nummulitic series. G. A. L. 



Doelter, Dr. Comelio. Die Yulcangruppe der pontischen Inseln. 

 [The Yolcanic Group of the Ponza Islands.] Denkschr, Tc. Ah, 

 Wiss. Bd. xxxvi. pp. 141-186. 



A notice of the earlier memoirs on these islands is followed by a 

 description of their geographical features. The geology of each of the 

 islands is then described in detail, the rocks of Ponza being classed, on 

 the basis of chemical and microscopical analysis, as Sanidine-plagio- 

 clase-trachyte, Sanidine-biotite-trach\i;e, Rhyolite, Pitchstone, Perlito, 

 Trachyte-breccia, and Tuff; those of Palmarola, as Trach}i;e-breccia, 

 Sanidine-trachyte, Lithoidite, Obsidian, Perlite, Pitchstone and Ehyo- 

 lite ; those of Zannone, as Rhyolite and sedimentary rocks ; those of 

 Yentotene, as Basaltic lava and Tuff ; and those of Santo Stefano, as 

 Trachytic lava and Tuff. The peculiar forms resulting from the con- 

 traction of the rock masses are described ; and a detailed account is 

 given of the relations which the various kinds of rocks bear to one 

 another. It is shown that the great eruptive veiu-like masses which 

 traverse the agglomerates in Ponza affect a radiai cirrangement, and 

 point to two centres of eruption, in a similar manner to the eruptive 

 masses of the Euganean Hills. The rocks of Ponza, of which several 

 new analyses are given, present interesting points of resemblance to 

 those of the Lipari Islands and the Euganean Hills. J. W. J. 



— . Yorlaujfige Mittheilung iiber den geologischen Bau der 



pontinischen Inseln. [The Ponza Isles.] Sitz. h. Ah. Wiss. Wien, 



mat.-nat. CI., 1 Abth. Bd. Ixxi. pp. 49-56 (with woodcut), also 



Boll. R. Com. cjeol. Ital. pp. 154-162. 



Divided into two groups : the two eastern isles Yentotene and St. 



Stefano are similar in structure to the volcanoes of the Phlegrean 



Fields, consisting of lava with tuffs ; the western, Ponza, &c. to 



the Transylvanian trachyte volcanoes, consisting of trachytes and 



radiating rhyolite dykes, which at the contact with the trachyte-breccias 



produce pitchstone. E. B. T. 



. Der geologische Bau, die Gesteinc und Mineralfundstiitten 



des Monzonigebirges in Tyrol. [Geological structure, ttc. of the 

 Monzoni district, &c.] Jahrh. Tc.-lc. geol. lleichs. xxv. Heft 2, 

 pp. 207-246, with 2 plates of sections, map, and 3 cuts. See 

 also Verh. Ic.-Tc. geol. lieicJis. pp. 81, 82. 

 Describes the varied igneous rocks, the name "Monzonite" being 

 applied to numerous varieties between Diorite and Syenite ; some con- 

 tain augito, others hornblende ; hornblende is also found in some of the 

 melaphyres. The localities for the minerals are mostly at the junction 

 with the limestone, the contact being of great influence. E. B. T. 



