6tf SCIENCE PROGRESS 



which have been attributed by Bowen to the latter process, 

 have usually been built up by successive intrusion. 



Dr. A. Scott has reviewed the evidence for the occurrence of 

 primary analcite and analcitisation in igneous rocks (Trans. 

 Geol. Soc. Glasgow, 1916, 16, 34). Working principally on 

 Scottish rocks he shows that the relatively great abundance of 

 analcite, its textural relations to the other minerals, and the 

 incontestable evidence of analcitisation provided by these 

 rocks, leaves little doubt as to the primary nature of the 

 mineral. 



The available petrographic data for the Pacific islands is 

 summarised by R. A. Daly (Bull. Geol. Soc. Amer. 1916, 27, 

 325). While still scanty the facts lead to the conclusion that 

 the Pacific is underlain and has been underlain for a long time 

 by a primary magma of basaltic composition ; that pyroxene- 

 andesites and ultrabasic types are direct differentiates of 

 this magma ; and that the alkaline types found may possibly 

 be syntectics due to the solution of small quantities of limestone 

 in the primary basalt. 



Dr. A. Holmes describes a new collection of rocks from the 

 Lucalla River, Loanda, which contains porphyritic basalts (like 

 the Markle type of Scotland), nephelinite, alkaline trachytes, 

 and augite-andesite (Min. Mag. 191 6, 18, 58), thus proving a 

 further extension of the Cretaceous or Tertiary alkaline series 

 of Angola. 



A series of Archaean igneous rocks from Virginia, which is 

 comparable to the charnockite series of India, is described by 

 T. L. Watson and J. H. Cline (Bull. Geol. Soc. Amer. 1916, 27, 

 193). It consists of quartz-bearing hypersthene-andesine- 

 syenite (equivalent to the intermediate variety of charnockite), 

 unakite (epidotic syenite), granite, norite, and pyroxenite, thus 

 ranging, like the charnockites, from acid to ultrabasic. 



Economic Geology. — In his presidential address to the Glas- 

 gow Geological Society on " The Geological Factors affecting 

 the Strategy of the War, and the Geology of the Potash Salts " 

 (Trans. Geol. Soc. Glasgow, 1916, 16, 1), Prof. J. W. Gregory 

 points out the strategical significance of the coal, oil, and iron- 

 ore fields of Europe. Many of these fields are near the frontiers 

 of the countries concerned, and have rendered inevitable the 

 maintenance of large armies to defend them. The tenacity 

 of the German hold on Belgium and Northern France is partly 



