226 Some Recent American Petrological Literature. 



V. — Some Recent American Petrological Literature. 



{Continued from p. 179.) 



"The Igneous Geology of Carrizo Mountain, Arizona," by "W. B. 

 Emery. Araer. Journ. Sci., vol. xlii, pp. 349-63, 1916. 

 This region includes various intrusive bodies : sheets, sills, dykes, 

 and a large laccolith of diorite-porphyry. The presence of six 

 volcanic plugs also indicates extrusion, though all flows have been 

 removed by erosion. 



" Contributions to the Geology of Java and Celebes," by J. P. 

 Iddings and E. W. Morlev. Journ. Geol., vol. xxiii, pp. 231— 

 45, 1915. 



The rocks from Java described in this paper include lencite-tephrite, 

 leucitophyre, shoshonite, basalt, and varieties related to kentallenite 

 and borolanite. Those from Celebes comprise nepheline-syenite,. 

 kentallenite, trachyte, and marosite. Pull petro graphical descrip- 

 tions and analyses are given. 



" Contributions to Sardinian Petrography. I. The Rocks of Monte 

 Ferru," by H. S. "Washington. Amer. Journ. Sci., vol. xxxix, 

 pp. 513-29, 1915. 



A detailed petrographical description, with analyses, of certain 

 trachytes, phonolites, basalts, and analcite basalts from this well- 

 known locality. . . 



"Primary Analcite of the Crow's Nest Volcanics," by J. D. 

 Mackenzie. Amer. Journ. Sci., vol. xxxix, pp. 571-4, 1915. 

 A reply to criticisms on some previously published work, the point 

 at issue being as to whether the analcite is primary, or formed by 

 alteration of leucite by sodium solutions in salt lakes. 



" Relation of Ore Deposits to different types of Intrusive Bodies in 

 Utah," by B. S. Butler. Econ. Geol., vol. x, pp. 101-22, 1915. 

 The ore deposits associated with laccoliths and more deeply 

 truncated stocks are of little commercial importance, while those 

 connected with apically truncated stocks are of great value. This is 

 attributed to the concentration of mobile metal-bearing vapours or 

 solutions near the apex of the stocks, in which differentiation was more 

 complete than in the laccoliths. In the case of the more deeply 

 truncated stocks the metalliferous portion has been removed by 

 erosion. 



" The Ternary System MgO-Al 2 Os-Si0 2 ," by G. A. Rankin and 

 H. E. Merwin. Amer. Journ. Sci., vol. xlv, pp. 301-25, 1918. 

 The temperature-concentration relations of crystalline phases in 

 equilibrium with liquid are discussed and represented by diagrams 

 and a model. A ternary compound, 2Mg0.2Al20s.5Si0 2 , was found 

 in two forms with a transition point at about 950° C. It is very like 

 cordierite. The effects of FeO on magnesian minerals and rocks are 

 also considered. 



