224 PETKOLOGY. 



Wiik, F. J. Mineralogiska och petrografiska meddelanden. 

 [Mineralogical and Petrographical Communications.] 8vo. 



Contains the results of the author's microscopic study of certain 

 rocks of Finland. The rocks are gabbros, diabases, and diorites. 

 Several minerals are also described. [See Mineralogy.] Finds that 

 many of the rocks previously regarded as hypersthenite contain no 

 hypersthene ; some are olivine-diabase, others olivine-gabbro. E. W. R. 



Woldrich, Prof. Dr. J. KUnstliche Granit und Basalt-schlacken 

 aus Bohmen. [Artificial Granite and Basalt from Bohemia.] 

 Verh. k.-Jc. geol. Heichs, pp. 80, 81. 



Notice of vitrified forts : in one of granite the blocks are glazed 

 superficially and sometimes fused : the second at Yladar of basalt 

 shows the melted rocks to have flowed in places over the unmelted ; 

 pieces of charcoal are enclosed in the fused stone. E. B. T. 



Zickendrath, Ernst. Der Kersantit von Langenschwalbach in Nas- 

 sau. [The Kersantite of Langenschwalbach.] Pp. 32. 8vo. 

 Wurtzhurg. 



Describes the rock petrographically, microscopically, and chemically, 

 and gives his methods of analysis in detail. Shows that kersantite in 

 a fresh state consists of oligoclase and mica, with a little augite, 

 quartz, apatite, and magnetite. As products of decomposition it con- 

 tains pyrites, melanolite, and various carbonates. Kersantite belongs 

 to the older eruptive rocks ; it occurs in the Lower Devonians of Nas- 

 sau and in the Hundsriick, in Silurians near Brest, and in gneiss in 

 the Yosges. Chemically it stands close to the minette of the Oden- 

 wald. No essential difference exists between kersantite and kersanton ; 

 hence the latter name should be abolished. F. W. R. 



Zirkel, Dr.F. [Shower of Yolcanic Ashes in Norway.] H. Jahrb. 

 Heftiv. pp. 399-401. 



The shower of volcanic ashes which fell in Norway on March 29 and 

 30, 1875, is supposed to have been blown over from Iceland. Speci- 

 mens were collected from the snow in Sondmon. The author describes 

 their microscopic characters. F. W. R. 



. Die Struktur der Yariolite. [Structure of Yariolite.] Ber. 



h. sacks. Ges. Wiss. p. 210. 



Ueber die Zusammensetzung des Kersanton. [Composition 



of Kersanton.] Ber. 7c. s'dchs. Ges. Wiss. 



See also : — 

 Abich, Prof. H. Quartz -trachyte, Caucasus : p. 47. 

 Anon. Columnar Basaltic Rocks, Staffordshire : p. 2. 

 Botti, U. Serpentine Conglomerate : p. b2. 

 Brogger, W. C. Occurrence of Apatite in Norway : p. 53. 



