248 The American Naturalist. [March, 



It is found at Makobsberg in black, platy masses, with a red streak 

 similar to that of hematite. As usually found it is slightly magnetic 

 in consequence of the inclusion of impurities. It dissolves easily in 

 HC1, and by H 2 S0 4 it is changed to a white mass consisting princi- 

 pally of Pb S0 4 . 



corresponding to (PbO FeO MnO) Fe 2 3 . Ferro-goslarite is a zinc 



sulphate from Webb City, Jasper Co., Mo., of the composition Zn S0 4 

 = 55.2 ; Fe S0 4 = 4.9 ; H 2 = 39.00 ; Impur = .8. According to 

 Wheeler 1 it occurs as incrustations on the walls of a large body of 

 zinc-blende, with which is associated marcasite and galena. Its for- 

 mation is due to the oxidation of the zinc and iron sulphides and their 

 subsequent crystallization from solution. It is slightly yellow to brown 

 in color, and is brittle. Its hardness is 2.5, and it loses water on expo- 

 sure to the air, turning to an opaque, yellow powder in the process. 

 Rowlandite. — Associated with gadoliuite and other yttrium min- 

 erals in Llano Co., Texas, Hidden 2 has found a pale drab-green sub- 

 stance that is transparent in thin splinters, and has a density of 4.515. 

 It is easily soluble in acids, leaving a gelatinous residue. Upon altera- 

 tion it yields a waxy, brick-red product. A partial analysis showed 

 the presence of SiO, = 25.98; T t O a etc = 61.91 ; FeO = 4.69; 

 U0 3 = .40; CaO=.19; Loss = 2.01, indicating the formula 

 R t "X$i0 4 ) a .— Offrttite* is a new zeolite from the basalt of Mt. Sim- 

 iouse, near Montbrison, in France. It occurs in very small, colorless, 

 hexagonal crystals, with only the base and prism well developed. Their 

 cleavage is basal. Density = 2.13 and composition : 



= (K 2 Ca) 2 Al Si u + 17 H 2 0. 



MoriniU* is a rose-colored mineral with a difficult cleavage par- 



*Amer. Jour. Sci., Nov., 1891, p. 430. 



