466 PETROLOGICAL ABSTRACTS AND REVIEWS 



quantitative classification. These are: Ouenose (III. 5. 5. 4-5); 

 Caledonose (I. 5. 5. 4-5); Thiose (IV. 1(2]. 1(2]. 2); Naketose 

 (IV. 2 [ 3 ]. i[ 3 ]. 2); Koghose (III. 4 . 4- 4-5)- 



In the gabbroic series, Si0 2 , A1 2 3 , and CaO increase together, while 

 FeO and MgO decrease. Because of the basicity of the feldspars the 

 most feldspathic phase is the poorest in Si0 2 . In the dioritic series, the 

 proportion of lime is nearly constant, silica varies irregularly, A1 2 3 and 

 alkalies increase with the feldspar content. 



There are also dikes composed almost wholly of magnesiochromite ; 

 these locally contain chrome-bearing diopside and bronzite, and are 

 associated with anorthosites. 



F. C. Calkins 



Leiss, C. "Neues Mikroskop Modell VIb fur krystallogra- 

 phische und petrographische Studien," Zeitschr. Kryst., 

 XL VIII (1910), 240-42. Fig. 1. 

 A large microscope similar in construction to the Hirschwald micro- 

 scope (Fuess Via). It differs, however, in having an Abbe condenser 

 and Ahrens polarizer, and a large, flat micrometer stage. Like the 

 Via microscope, the upper and lower nicols can be rotated simultaneously. 

 This does away with the cap nicol and permits the use of a large tube, 



giving an extra large field. 



Albert Johannsen 



Skeats, Ernest W. "The Volcanic Rocks of Victoria," Austra- 

 lian A ssociation for the A dvancement of Science , 1909, 173-235. 

 PI. 4, numerous analyses. 

 This paper was read as the Presidential Address, Section C, of the 

 Australian Association for the Advancement of Science. It contains 

 a summary of the present knowledge of the Victorian volcanic rocks 

 and has appended a bibliography of 268 items, dealing wholly, or in part, 

 with these rocks. The geographical distribution is shown on a map and 

 the geological range was determined to be from Basal Ordovician ( ?) 

 to recent. Petrographically the rocks are rhyolites, dacites, basalts, 

 quartz porphyries, granite porphyries, diabases, serpentines, quartz 

 keratophyres, melaphyres, solvsbergites, limburgites, and the new 

 rocks anorthoclase trachyte, anorthoclase-olivine trachyte, olivine- 

 anorthoclase basalt, olivine-anorthoclase andesite, and macedonite. 

 Petrographical descriptions, not as complete as might be desired, espe- 



