108 TEh WY, TEQURINTEIR 
chiefly of albite with some aegerite (?). Ratio of the orthoclase and albite 
molecules combined, to the anorthite molecules, 35: 1. 
Afplite.— Average of two analyses of aplites from dikes in the Sierra 
Nevada granodiorites. Composed of quartz> orthoclase> albite> anorthite. 
Jour. GEOL., Vol. VII, 1899, p. 160. Ratio, 7.8:1. This is the most alkali 
rich granite in the Sierra Nevada. The amounts of feldspars here given are 
the result of a more exact calculation, and differ somewhat from the amounts 
given in the paper referred to. The biotite-granite of my former paper is in 
reality a quartz-monzonite, and its molecular composition likewise requires 
some revision. 
Granodiorite.— Lindgren. No. 103, Pyramid Peak. Amer. Jour. Sci., 
Vol. III, April 1897, pp. 306 and 310. Ratio, 4:1. Composed of ortho- 
clase > quartz> albite> anorthite. 
Monzonite.— Brégger, from Monzoni, described by him on page 24 of 
“Die Eruptionsfolge der triadischen Eruptivgesteine bei Predazzo in Siid- 
tyrol,” with a ratio of 3.8: 1. Composed of orthoclase> albite > pyroxene > 
anorthite > lepidomelane> hornblende> magnetite> quartz> apatite, zir- 
con, etc. This is taken as Brégger’s typical monzonite. 
Butte-grantte or guartz-monzonite.—Weed. JOUR. GEOL., Vol. VII, 1899, 
pp. 739 and 744. Average of four analyses of the granitic rock at Butte, 
Montana. Ratio, 3.7: 1. Composed of quartz> albite > orthoclase> horn- 
blende> anorthite> biotite, titanite, and apatite. 
Idaho Basin granite-——Lindgren. Eighteenth Ann. Rept. U. S. Geol. 
Surv., Part III, pp. 640-641. Ratio, 2.9: 1. Composed of albite> quartz > 
anorthite > orthoclase > hyalophane, apatite, titanite, magnetite, and calcite. 
Banatite.— Brogger. Average of analyses ‘of five banatites. JOUR. 
GEOL., Vol. VII, p. 149. The potash and soda given in the paper referred 
to are interchanged in both the average of the banatites and of the adamel- 
lites. Ratio, 2.5:1. Calculation approximate. 
Granitite—From Barr-Andlau. Rosenbusch. Die Steiger-Schiefer. 
Abhandlungen zur geologischen Specialkarte von Elsass-Lothringen, Vol. I, 
pp. 147-148. Ratio, 2.5:1. This appears to be the rock referred to by 
Brégger on page 62 of his paper on the Monzoni rocks. He states that it 
contains 35.5 per cent. of orthoclase; 31.5 per cent. plagioclase (Ab, An;); 
24 per cent. quartz; and Io per cent. magnesia-mica. Rosenbusch, however, 
in the paper above referred to states that this granitite contains about 27 per 
cent. orthoclase, 40 per cent. plagioclase, 24 per cent. quartz, and Io per 
cent. magnesia-mica. The rock represented in the table below, therefore, is 
Rosenbusch’s Barr-Andlau rock, and not the rock discussed by Brégger on 
page 62 of his paper. 
Quartz-mica-diorite or basic granodiortte——Turner. Seventeenth Ann. 
Rept. U. S. Geol. Surv., Part I, p. 724. Rocks of this type are to be found 
