PETROLOGICAL ABSTRACTS AND REVIEWS 639 



Powers, Sidney. "Volcanic Domes in the Pacific," Amer. Jour. 

 Sci., XLII (1916), 261-74, figs. 5. 



Gives data on various volcanic domes, showing size, composition, and 

 important features. Viscosity is the principal factor which determines 

 whether the magma shall appear as a flow or dome. In some cases a flow 

 comes first, then a dome; in others the dome comes first and the lava later 

 breaks through the crust. 



Powers, Sidney. "Granite in Kansas," Amer. Jour. Sci., XLIV 

 (1917), 146-50. 



An earlier report on the granite ridge mentioned above (Moore, Ramond C, 

 Bull. Amer. Asso. Pelro. Geol., IV, 1920). 



QuENSEL, Percy. "De kristallina Sevebergarternas geologiska 



och petrografiska stallning inom Kebnekaiseomradet," Geol. 



Fbren. Forhandl., XLI (1919), 19-52, figs. 15, pis. 2, profile i. 



Describes the crystaUine schists from Kebnekaise, in Lapland. An 



analysis of a feldspar-rich "gneiss-mica-schist" is given. 



QuENSEL, Percy. "Zur Kenntnis der Mylonitbildung, erlautert 

 an Material aus dem Kebnekaisegebiet," Bull. Geol. Inst. 

 Upsala, XV (1916), 91-116, pis. 4. 

 The mylonites from Kebnakaise are regarded as primarily derived from 

 igneous rocks, though some sediments may occur among them. 



QuENSEL, Percy. "tJber ein Vorkommen von Rhombenpor- 



phyren in dem prakambrischen Grundgebirge des Kebnekaise- 



gebietes," Bull. Geol. Inst. Upsala, XVI (1918), 1-14, pi. i. 



Describes a rhombic porphyry in which the feldspar is a microcline anti- 



perthite (OriAbjAnz). It is microperthitic and zonal, with a central portion 



of plagioclase surrounded by pink potash feldspar or white albite. The change 



from center outward is not gradual, but abrupt, and seems to indicate a sudden 



change in the chemical character of the magma . 



Quirke, Terence T. "Espanola District, Ontario," Mem. 102, 

 Canadian Geol. Surv., 191 7. Pp. 92, map i, pis. 6, figs. 8. 

 The Espanola district is 43 miles west of Sudbury, and comprises an area 

 of 116 square miles. The rock formations are principally Huronian, with older 

 metamorphosed sedimentary schists and slates, and intrusive greenstones and 

 granite. The Huronian rocks are cut by diabase dikes and sills, more or less 



