82 TRANSACTIONS OF THE [FEB. 18, 
dulatory extinction and zonal structure. Dust-like inclusions 
are often present and are arranged in more or less parallel rows 
which sometimes extend across the cracks from one grain to an- 
other. The quartz also occurs as “ Augen” as previously men- 
tioned, but in this case contains few inclusions. Each Auge or 
eye is made up of a number of grains of different orientation. 
Intergrowths with plagioclase are not uncommon, especially 
around the edge of the feldspar Augen. They are very similar 
to those figured by La Croix in a gneiss from Ceylon.* Grims- 
ley+ and Hobbst have also described the occurrence of micro- 
pegmatite in metamorphosed rocks, but the latter finds it in 
those portions of the rock where mechanical movement has been 
a minimum, whereas in the Harrison gneiss it occurs in that 
portion which seems to have been most crushed. 
a 
MIcROPEGMATITIC INTERGROWTH OF QUARTZ AND PLAGIOCLASE ON 
BorRDER OF ORTHOCLASE ‘“ AUGE.” 
Plagioclase is as abundant as the quartz and in some sections 
predominates over it. The sections are generally partly allotrio- 
morphic, and usually twinned after the albite law, sometimes 
in addition after the pericline and rarely after the Carlsbad law. 
The extinction is about 20° 
The twinning lamelle are often bent and cracked, and the 
cracks are filled with quartz. Micropegmatite has been men- 
tioned under quartz. While the plagioclase sometimes occurs 
* Bull. French Min. Soc., Vol. XII., p. 302, 1859. 
+ The Granites of Cecil County, Md.; Journ, Cin. Soc. Nat. Hist., April-July, 1894. 
{Phases in the metamorphism of schists of Southern Berkshire, Bull. Geol. Soe. 
Amer. IV., p. 167. 
Se 
