222 PETROLOGY. 



resembles the porphyrites of the Nahe district ; they form a well- 

 characterized group of rocks which stand between the quartz-porphy- 

 ries and mclaphyres. E. W. 11. 



Studer, Herr B. Die Porphyre des Luganer Sees. [Porphyries of 

 the Lake of Lugano.] Zeitsch. deutsch. geol. Ges. Heft ii. pp. 417- 

 421. Translated in Boll. E. Com. Geol. Ital. pp. 372-378. 

 No two rocks appear to be more distinct petrologically than the red 

 and black porphyries of Lugano. Yet fresh specimens from the tun- 

 nel near Maroggia, on the Gotthard railway, have yielded very similar 

 'results, regard being had to the presence of free quartz in the red and 

 of magnetite in the black rock. The analyses are given. F. W. R. 



Szabo, Prof. J. 1. A trachyt Keples Szaszka Kornyeken. II. Uj-Mol- 

 dova nemely eruptiv Krystalyos Kozete. [I. The trachytic forma- 

 tion in the environs of Szaszka. 11. On some eruptive crystal- 

 line rocks of Uj -Moldova.] Foldtani KozVony V. K. Budapest. 

 In the S.E. of Hungary (Banat) many kinds of eruptive rocks 

 occur, united by Cotta under the name of " Bauatite," by Von Hauer 

 of Syenite. The author finds that those of Szapka and Uj -Moldova 

 are chiefly andesine quartz-trachytes with granitic structure, very 

 similar to those in Transylvania in the valley of Koros, w^hich have 

 been called by Stache Dacites. At Uj-Moldova a basalt is found in 

 the midst of this trachyte forming two dykes. Its mineralogical con- 

 stitution is remarkable ; it contains no felspar, but a great quantity of 

 microscopic augite-magnetite, microscopic black mica, some amphibole 

 and olivine. The base is a zeolitic mineral, especially Thomsonite ; 

 hence the author calls it a Thomsonite basalt. Nearly 50 p. c. of this 

 rock is soluble in hydrochloric acid. Analcime and calcite occur in 

 cavities as secondary products. J. S. 



Tbrnebohm, A. E. Mikroskopiska bergartstudier. [Microscopical 



Eock Studies.] Geol. foren. Stockholm Forli. Bd. ii. pp. 322, 329, 



393-401, 431-437. 



i. On the Rhombic porphyry (Rhombporfyren) near Kristiania. 



ii. On some amorphous traps (from the Samuel- Anders mine ; from 



Eloda parish Dalecarlia ; from S. of Torsakers church, Sodermanland ; 



and Sordavalite from Sordavala, in Pinland.) iii. Phonolite from Elf- 



dal. G. A. L. 



Tschermak, G. Felsarten aus dem Kaukasus. [Rocks from the 

 Caucasus.] Min. Mitt. Heft iii. p. 22. 



Describes eruptive rocks collected by E. Favre during his second 

 journey through the Caucasus. Some are from eruptions between 

 sandstones and slates referred to the Lias and L. Oolites ; these rocks 

 are diabase and porphyries. Others from outbursts through the slates, 

 and are associated with Neocomian beds, which they appear in places 

 to have disturbed ; these are melaphyres and augitic porphyries, also 

 orthoclase-porph}ry. F. W. R. 



