J3()0 Sciejitific Intelliyence. 



peculiar in its seven nioloculcs of water.— yi^iz. Akad. Wlss. 

 Krokdu, 1909, p. 344 ; quoted in Jtihrb. Mhi., ii, 25 ref., 1910. 



TuitAMTK and Alaitk are two new vanadium minerals, 

 announced but not as yet fully described by K. Nenadkewitscli. 

 Tliey come from the mines of Tjuja-niajun in the foothills of the 

 Alai mountains in Central Asia, and occur in a coarse granular 

 calcite. Turanite forms compact aggregates, reniform and radi- 

 ated in structure, and is stated to have the composition sCuO . 

 V,0^.2ll,0. Alaite is a decomposition product having a dark 

 red color and silky luster; to it the formula V./)^. II^O is 

 assigned. Analyses and full descriptions follow later. — Hull. 

 Acad. iSt. Pet., 185, 1909, noticed in Jahrh. Mia., i, 193 ref., 

 1910. 



11. Les Roches alcalines de Tahiti; par A. Lackoix. Bull, 

 de la Soc. Geol. de France, 4 ser., x, p. 91, 1910. — In this article 

 the writer describes a series of alkaline rocks from the valley of 

 the Papenoo River in Tahiti. The massive granular types 

 include nephelite-syenite, monzonite containing nephelite, thera- 

 lite, and essexitic gabbro. The calculation of the norm from the 

 chemical analysis of the latter shows it to fill an unnamed sub- 

 rang in the quantitative classification for which the terra 

 2H(penoose is proposed. Of attendant dike rocks, tinguaites, 

 camptonites, moncliiquites, and microgabbros are described, while 

 the eflfusives comprise phonolites, hauynophyres, basalts, and 

 picrites. Of most of these analyses are given. From this it will 

 be seen that the series presents a well-defined clan of typical 

 alkalic character. Regarding the occurrences, areas, and geo- 

 logical relations not much has, as yet, been learned, owing to the 

 denseness of the vegetal covering. 



Although the finding of new occurrences of alkalic groups of 

 this kind is always interesting from several points of view, it is 

 doubh'^ so in this case. The discovery of rocks of continental 

 types in this part of Polynesia in mid-Pacific is of wide geo- 

 logical importance. Moreover, it has been claimed by Marker, 

 Beeke, and others that the igneous rocks of the Pacific basin are 

 of sub-alkalic (alkaliealcic) nature, those not in this hemisphere 

 generally speaking alkalic. With typical alkalic groups, or 

 members, turning up in Hawaii, Easter Island, Clipperton atoll, 

 Samoa, Fiji, and now at Tahiti, it would be well, as Lacroix 

 remarks, to use the terras of alkalic and alkaliealcic (sub-alkalic) 

 groups, and to avoid the geographical designations of Atlantic 

 and Pacific, until further research has shown that the generaliza- 

 tions, on which these terms are based, are really well founded. 

 It begins to appear to the reviewer as if the rocks of the mid- 

 Pacific might belong to an alkalic petrographical province, and 

 the alkaliealcic to a broad circumferential belt related to the 

 edges of the continental platforms. l. v. p. 



