216 PETROLOGY. 



Lang, H. 0. Yolcanic Ashes of Turrialba, Costa Rica. NachricM 

 Icon. Oes. Wiss. und G. A. Univ. Gottingen^ nos. 11-16. Noticed 

 in Nature, Jiilj^ 15, p. 222. 



Lasaulx, Prof. A. von. Elemente der Petrographie. Pp. viii, 488. 

 8vo. Bonn. 



Commences with a description of the methods of 'investigation. 

 Describes the rock-forming and commoner minerals. Gives an account 

 of the various structures of rocks, both crystalline and clastic. Enters 

 upon the classification of rocks, which he arranges primarily by their 

 composition, whether composed of one or of more mineral substances, 

 and subdivides according to their structure, whether crystalline, clas- 

 tic, &c., giving a full description of each species and its principal 

 varieties. T. G. B. 



Lemberg, J. Ueber die Serpentine von Zoblitz, Greifendorf und 

 "Waldheim. [Serpentine of Zoblitz, &c.] Zeitsch. deutsch. geol. 

 Ges. Heft iii. pp. 531-549 ; 2 woodcuts. 

 Contains a number of original analyses of Saxon Serpentines. The 

 rock which has yielded the serpentine of Zoblitz and Greifendorf pro- 

 bably consisted of olivine, garnet, and hornblendic minerals. F. W. It. 



Levy, M. A. Michel. De quelques caracteres microscopiques des roches 



anciennes acides, consideres dans leurs relations avec I'age des 



eruptions. [Microscopic Characters of old Acid Rocks in relation 



to the Age of the Eruptions.] Bull. Soc. Geol. France, ser. 3, t. iii. 



pp. 199-236, pis. iv, v. 



Describes the mineral composition of a considerable number of 



granites, elvans, granulites, and carboniferous porphyries (Porphyres 



anthraciferes), which are classed under two heads — the granitoid 



porphyries occurring at the base of the Lower Coal Measures, and the 



black porphyries forming interbedded coulees in the lowest beds of the 



same series. F. R. 



. Sur les divers modes de structure des roches eruptives, 



etudiees au microscope. [Modes of Structure of Eruptive Rocks, 

 studied microscopically.] Compt. Bend. t. Ixxxi. pp. 820-822. 



Lindstrdm, Axel. Bidrag till kannedomen om sammansattningen 

 hos nagra af de olika slagen af lera, och deras egenskap af jord- 

 forbattringsmedel. [The Classification of the different kinds of 

 Clays, and their properties respecting the Improvement of Land.] 

 Geol. foren. StocMolm Fork. Bd. ii. no. 26, pp. 473-483. 



Macpherson, Joseph. Breves apuntes acerca del origen perid6tico 



de la Serpentina de la Serrania de Ronda. [Notes on the Peri- 



dotic Origin of the Serpentine of the Ronda Mts.] An. Soc. 



Espan. Hist. Nat. vol. iv. part 1, 18 pp., 2 pis. 



Maintains the pcridotic origin of serpentine, the genesis of which is 



explained by one fourth of the base of the primitive rock having been 



