48 GEOLOGICAL MEMOIRS. 



The miners being employed at places far distant from each other, 

 it was not possible to determine the form and extent of the subterra- 

 nean circle of commotion, by means of which it might haye been 

 possible to have determined, at least approximately, the depth of the 

 focus of commotion. [Count M.] 



On some Fossils /rom the Dolomite of Monte Salvatore, near 

 Lugano, Canton Tessin. By M. Fr. v. Hauer. 



[Proceedings Imp. Acad. Sc. Vienna, March 15, 1855.] 



Since L. v. Buch investigated the mountains around the Lake of 

 Lugano, they have been frequently studied by geologists *, and espe- 

 cially the Monte Salvatore. Abbe Stabile of Lugano, however, has 

 been the first to discover a considerable number of determinable 

 organic remains in the dolomite of Monte Salvatore. 



These fossils were forwarded to M. Fr. v. Hauer, at Vienna, for 

 examination ; and M. Merian has determined them as belonging, for 

 the most part, to known species peculiar to the Muschelkalk. 

 Amongst these fossils, Halohia Loinmellii and Chemnitzia tenuis are 

 remarkable, as previously they were only known to occur in the 

 Hallstatt and Cassian beds, forming the upper subdivision of the 

 Alpine Trias f. [Count M.] 



Introduction to the Knowledge of Rocks, with reference to their 

 Geological relations and to their practical use in the Arts, Build- 

 ing, and Agriculture , By Prof. A. Erdmann, Fellow of the Royal 

 Acad. Sciences, Stockholm ; Knight Ord. North Star. pp. 207, 

 8**. Stockholm, 1855. With woodcuts. 



[Vagledning till bergartnemas kannedom, o. s. v.] 



In this elementary work on the properties and nature of rocks, the 

 author first notes (chapter 1) the general characters, — crystalline, 

 mechanical, and amorphous ; fossiliferous and unfossiliferous. In 

 chap. 2 he reviews their structural conditions ; in chap. 3 the 

 various characters of internal and external form, — the former result- 

 ing from contraction and from stratification ; the latter seen in layers, 

 veins, and masses. Chap. 4 is stratigraphical ; and chap. 5 notices 

 the destruction and weathering of rocks. The geological formations 

 and their order of succession are given in chap. 6 ; and, lastly, chap. 7 

 comprises the classification and detailed description of the rocks and 

 mineral masses. In this chapter, the author, after rem.arking that 

 the different rocks often pass one into another, and noticing the diffi- 

 culty of systematizing the several varieties, divides the rocks into 

 (class 1) those of chemical origin, viz. the quartz, limestone, salt, iron, 

 coal, felspathic, micaceous, amphibolic, pyroxenic, and serpentine 

 groups, — and (class 2) those of mechanical origin, viz. the breccias, 

 conglomerates, sandstones, schists, tuffs, and loose materials. 



[T. R. J.] 



* Amongst these may be named Breislac, Girard, Lavizzari, Brunner, Merian, &c. 

 f Vide antea, p. 17. 



