84 TRANSACTIONS OF THE [FEB. 18, 
host but usually ir groups. The extinction of the plagioclase 
inclusions also differs from that of the orthoclase. In addition, 
there are a few included quartz grains and hexagonal plates of 
biotite. The two types of feldspar inclusions are usually gath- 
ered in groups by themselves. 
Lawson has described and figured an almost parallel case from 
a granite diorite in California,* in which the large Carlsbad 
INCLUSION OF PLAGIOCLASE AND BroviTE (M) IN ORTHOCLASE AUGE. 
twins of orthoclase contain numerous inclusions, but their ori- 
entation seems to be influenced by the orthoclase. Apart from 
the Augen the orthoclase does not contain many inclusions. No 
intergrowths of quartz and orthoclase were seen. 
Microcline, though present, is rare. It sometimes occurs in 
the Augen, containing the same inclusions as the orthoclase, and 
in some instances seems to be paramorphic after the latter. 
While inclusions in feldspar of metamorphosed rocks are not 
rare and have been noted by Wolff,+ Hobbs,{t Weinschenk§ and 
others, nevertheless, they do not seem to be so abundant as 
those in the Harrison granite-diorite. 
Prof. G. H. Williams || has described a parallel case from the 
norites of the Cortlandt Series, in which the plagioclase occurs 
as inclusions in the orthoclase, and states that when they occur 
*Geology of Carmelo Bay, Bull. Dept. of Geol., University of Calif., Vol. I., p. 59. 
+Bull. Mus. Comp. Zo6l. XVI., No. 10. 
Tl.7c. 
2Beitrage zur Petrographie der Ostlichen Central Alpen. Abh. k. Bayer, Acad. der 
Wiss. II. Classe, XVIII., Bd., III Abth. 
| Amer. Jour. Sci., iii —X X XIII., 140. 
