654 



CROSS, ID DINGS, P IRS SON, WASHINGTON 



The vesuvose-albanose (leucitite), Table V, illustrates the 

 case in which akermanite (melilite) is required to satisfy the 

 calculation. After allotting Si0 3 to leucite, nephelite, anorthite, 

 diopside, and olivine, there is a deficit of 0.069 rnol. Si0 2 . This 

 is adjusted by the introduction of akermanite according to the 

 formula, and the recalculation of diopside and olivine. It also illus- 

 trates the case of an intermediate rock, between Classes I and II. 



TABLE I. 



TOSCANOSE (GRANODIORITE) EL CAPITAN, YOSEMITE VALLEY, CAL. 



Bull. 168, U. S. Geo/. Surv., p. 208. 



SiQ 2 . 



Al 2 O a 



Fe s O. 



FeO ! 



MgO. 



CaO . 



Na 2 



K 2 Q. 



H 2 0+ 



H 2 0- 



co 2 



Ti0 2 



P 2 5 



S0 3 



CI . . 



MnO 



BaO 



SrO. 



ZrO a 



Per cent. 



71. ( 



is 



.90 



.62 



I -31 



• 54 

 2.60 



3-54 

 4.08 



■30 

 none 



tr 



.22 



. 10 

 none 



.02 



•15 

 .04 

 .02 

 .08 



100.60 



Mol. 



I.I8< 



156 

 004 

 0l8 



014 

 047 

 057 

 043 



003 

 000 



000 

 002 

 000 

 000 



000 



Orth. 



258 



43 



43 



Alb. 



342 



57 



57 



94 

 47 



47 



Cor. 



Hyp. 



27 



Quartz. 



464 



FORMULA. 



SiC 



K 2 0".AU0 3 .6SiOo 

 Na„O.AU0 3 .6SiO„ 

 CaO.AL632.SiOo " 

 A1„0 3 



MgO.SiOo - 

 (Fe, Mn)6.Si0 2 

 FeO.Fe^Oa 

 FeO.TiO„ 



464 X 60 

 43 X 556 

 57 X 524 

 47 X 278 

 9 X 102 



= quartz 

 = orthoclase 

 = albite 

 = anorthite 

 = corundum 



x 3 4 Xx3:i = h ^ erSthe " e 

 4 X 232 = magnetite 

 3 X 152 = ilmenite 



= 23 

 = 29 

 = 13 



84 



Sal 95-61 



02 J 



38' 



Fen 



class 1. 

 Sal 95.6. 



order 4. 

 66.8^ 5 



Fern 4. s 1 Q 27.8^3^1 

 Persalane. Britannare. 



rang 2. 

 K a O'+Na 2 0' _ 100 



CaO' 



Toscanase. 



47 3 



SUB RANG 3. 



K 2 0' = 43/5^3 

 Na 2 0' 57*^3^5 

 Toscanose. 



