648 LEWIS G. WESTGA TE 
where such an aggregate is examined microscopically it is 
seen to be composed of feldspars of different species which 
show no evidence of crushing. One section (Fig. 3) showed 
such an aggregate consisting of a very irregular Carlsbad twin of 
orthoclase at its center, partly or completely enclosing irregular 
grains of orthoclase, plagioclase, and microcline, all containing 
small rounded grains of quartz. There was no evidence of 
crushing; no evidence of derivation of the smaller grains from 
Fic. 3.— An “auge” of the “augen”’-gneiss (X 18). The dark area on the 
upper right side is beyond the border of the section. Opposite, below, is the border 
of clear feldspar grains with a little biotite. : 
the central orthoclase grain. About this central aggregate was 
a zone of clearer feldspars. The red cores, then, of the ‘‘augen,”’ 
both single grains and aggregates, are original crystallizations. 
The case may be somewhat different with the white rims which 
in many cases surround the red cores. These do show some 
evidence of crushing, and may be in part derived from periph- 
eral crushing of the red cores, possibly accompanied by some 
recrystallization, for the feldspars here have a fresher appearance 
