68 



Scientific Intelligence. 



1910 



Russia - - 



Canada • 



New South Wales - 



Columbia - 



United States, domestic crude 



United States, from foreign and domestic matte and 



bullion . 



Borneo and Sumatra 



275,000 



*30 



332 



10,000 



390 



f 1,000 

 *200 



286,952 



* Estimated. \ Refined. 



12. Les- Syenites IFepheliniques de VArchipel de Los et leur 

 Miner aux ; par A. Lacroix. Nouv. Arch. d. Mus. (5), iii, 1-132, 

 pi. i-x. 1911. — It is indeed remarkable what a variety of types 

 of rocks, mineralogical and structural, are afforded by the highly 

 alkalic magmas. This observation is, in fact, almost trite, since 

 nearly every few months there occurs some new example of it. 

 The variety of minerals which may be present seems almost end- 

 less, and new ones constantly present themselves. These features 

 are strikingly illustrated in Lacroix's last work on rocks of 

 this family. The Los Islands are a group of three small islands 

 close to the shore of French Guinea on the west coast of Africa. 

 The existence of nephelite rocks in them was first made known in 

 1887 by Giirich, and Lacroix himself has published at several 

 times preliminary notes on material brought from them. The 

 present work is based on rather full collections made by several 

 persons, and the information obtained permits the publication of 

 a preliminary geologic sketch-map. 



In addition to types of nephelite-syenites with segirite and with 

 alkalic amphibole the usual members of this clan are well repre- 

 sented ; pulaskite, aplites with nephelite, syenites with lovenite, 

 with hiortdahlite, with hauyn and with sodalite, tinguaites, and 

 micro-monzonites, micro-essexites, micro-theralites, micro-shon- 

 kinites, camptonites and monchiquites are among the varieties 

 present. Of especial interest is an occurrence of lujavrite in the 

 midst of an area of pegmatite and of tawite (rock composed 

 essentially of sodalite) recalling those of Greenland and Kola. A 

 special type of lamprophyre, consisting of phenocrysts of andesine- 

 labradorite, augite, apatite and titanomagnetite in a groundmass 

 of andesine laths, biotite, titanite, and a little barkevikite and 

 augite, which is neither a camptonite nor a kersantite, is called 

 (not very happily to English ears) topsailite, from the name of 

 the cape upon which the dike occurs. The chemical composition 

 of this is as follows : 



Si0 2 , AI0O3, Fe 2 3 , FeO, MgO, CaO, Na 2 0, K 2 0, H 2 0, P 2 5 



48-88 20-56 3-34 5'29 3'09 8-34 4-75 2-56 0-32 073 

 In the quantitative classification this is andose. 



Ti0 2 



1-69=99-55 



