Geology and Mineralogy. 75 



smaller. The approximate maximum distances over which quartz 

 fragments may be lifted by moderately strong winds in single leaps 

 are estimated as follows: 



Gravel (8-l mm diam.) A few feet. 



Coarse and medium sand (1-J mm ) Several rods. 



Fine sand (i-i mm ) Less than a mile. 



Very fine sand (i-TV mm ) A few miles. 



Coarse dust (tb-jV 111111 ) 20 ° miles. 



Medium dust {^-i^ m ) 1000 miles. 



Fine dust (^ 4 mm and less) Around the globe. 



A striking result brought out is the comparative definiteness 

 with which the different grades are separated from each other by 

 the sorting action of the wind. In closing, the author discusses 

 briefly the relation of the facts brought out by his investigations 

 to the origin of the loess deposits, which in their mechanical com- 

 position certainly resemble atmospheric sediments. He does not 

 regard it possible, however, to reach a final conclusion from the 

 data at hand. 



13. Brief notices of some recently described Minerals. — Senaite 

 is a new mineral, related to ilmenite, described by Hussak and 

 Prior. It is found in rounded fragments and rough crystals in 

 the diamond-bearing sands of Diamantina, Minas Geraes, Brazil. 

 Crystallization like ilmenite, rhombohedral-tetartohedral (tri- 

 rhombohedral). Hardness about 6, specific gravity of crystals, 

 5*30, massive 4*78 to 4*22 ; luster sub-metallic and color black, in 

 thin splinters, greenish. Analysis gave : 



Ti0 2 PbO FeO Fe 2 3 MnO MgO Sn0 2 



G...4-78 57-21 10'51 4*14 20*22 7*00 0"49 0-11=99-68 



The formula (Fe,Pb) 0.2(Ti Mn) 2 is suggested, but doubtful.— 

 Min. Mag., xii, 30, 1898. 



Mossite is a name given by Brogger to a nisbo-tantalate of 

 iron occurring with yttro tantalite at Moss, Norway. It is found 

 in black tetragonal crystals with c = 0*644. The crystals are 

 mostly twins with (101) as twinning plane; they are often dis- 

 torted by elongation parallel to (111) as is sometimes observed 

 with rutile. An analysis gave (N6,Ta) 2 6 82*92, FeO 16*62, 

 Sn0 2 0*18 = 99*72, which corresponds to the formula Fe (N6, 

 Ta) 2 6 ; further it was found that N6 : Ta = 1 : 1. The author 

 shows that mossite is near tapiolite, which, however, is richer in 

 Ta 2 & and has c = 0*652. He has also made the interesting 

 observation that the crystals of "tantalite" which have long 

 been figured in the text-books, are in fact identical with tapiolite, 

 being twin crystals similar to those mentioned above. — Vid. Skrift. 

 Math.-nat. Klasse, 1887. 



Valleite is a mineral closely related to anthophyllite occur- 

 ring with the violet tremolite of Edwards, N. Y. ; it is described 

 by G. Cesaro. Crystallization orthorhombic ; occurs in colorless 

 prismatic crystals with the usual amphibole angles of 125° 30' 

 and 54° 30'. The cleavage is prismatic and pinacoidal. The 

 hardness is 4*5, specific gravity 2*88. Analysis gave : 



