168 Scientific Intelligence. 



6. The Gneisses, Gabbro-schists and associated Rocks of South- 

 western Minnesota ; by C. W. Hall. (Bull. U. S. Geol. Surv. No. 

 157, 1899, pp. 160, pi. xxvii.) — The territory from which the 

 material described in this paper was gathered embraces the val- 

 ley of the Minnesota River and the southwest corner of the State 

 of that name wherever gneisses are found. In the 120 miles of 

 the river valley there project through its flood plain many expos- 

 ures of gneisses, gabbro-schists, diorites and diabasic effnsives. 

 They often fill the entire valley one to two miles wide, rising in a 

 profusion of knobs and hills 50 to 100 feet above the river. 

 These exposures of crystalline rocks are described by districts, 

 with maps of each district, on which they are located. Their 

 geological relations are discussed and an account of their petrog- 

 raphy, which appears to be that of well known types, is given 

 with the addition of numerous colored plates. l. v. p. 



7. Brief Notices of some recently described Minerals. — Mttl- 

 lerite is a hydrosilicate of ferric iron described by Zambonini 

 from Nontron, France, which is the original locality of the related 

 nontronite (chloropal). It occurs in opaque incrusting masses of 

 a yellowish green color; it is quite soft and has a specific gravity 

 of 1-97. The mean of three analyses gave: 



Si0 2 Fe 2 3 Alo0 3 MnO MgO H 2 



48-S2 35-88 4"30 0"63 0-35 9-66=99-64 



This corresponds to the formula Fe 2 3 .3Si0 2 + 2H 2 0, which differs 

 from the accepted composition of nontronite only in having three 

 molecules less water. — Zeitschr. Kryst. xxxii, 157. 



Mblite is a name given by the same author (1. c, p. 161) to 

 partially investigated hydrosilicate of alumina and ferric iron 

 known from a single specimen, labeled "Allophane, Saalfeld, 

 Thuringia." It occurs in imperfect crystals (?) and stalactitic 

 forms of bluish-brown color and opaque ; the hardness is 3 

 and the specific gravity 2*18. An analysis gave : Si0 2 14 - 97, 

 A1 2 3 35-24, Fe 2 3 14-70, CaO 0-78, H„0 33-75 = 99-64. . 



Robellazite. Briefly mentioned \>y M. Cumenge as occurring 

 with the carnotite in Colorado. A partial chemical examination 

 by M. Debierne, it is stated, shows that it contains considerable 

 vanadium and also niobium, tantalum and tungsten with alumina, 

 iron and manganese as bases. — Bull. Soc. Min., xxiii, 17, 1900. 



Cttpro-goslarite. A cupriferous variety of goslarite described 

 by A. F. Rogers as forming a light greenish blue incrustation in 

 an abandoned zinc mine at Galena, Kansas. An analysis gave : 

 S0 3 [27-02], ZnO 23-83, CuO 6-68, FeO 0-13, H 2 41-76, insol. 

 - 58=100. — Kansas Univ. Q., viii, No. 2. 



Cubosilicite is a name given by Bombicci to the bright blue 

 form of silica in cubic crystals occurriug at Tresztyan, Transyl- 

 vania, and ordinarily regarded as pseudomorphous chalcedony, 

 perhaps after fluorite. This he classifies as a definite form of 

 silica (pseudo-isometric, mimetic) related to melanophlogite, sul- 

 furicine and cristobalite. — Mem. Accad. Bologna, viii. 



