246 The American Geologist. October, 1896 
by an irregular, narrow border of secondary ([iiartz. Another 
section of an -'auge" (No. 15), cut in a similar direction, 
showed the same small extinction angle; and evident grano- 
phyre structure was noticed in some of the bounding feldspar 
grains. This "auge" was bent, show^ed the usual wavy ex- 
tinction and was surrounded by a crushed rim of feldspar and 
quartz, the former being in excess. Wavy extinction was also 
noticed in some of the quartz grains. 
In one case (No. 13) a section of an "auge," perpendicular to 
the twinning plane, showed the crystal to be much bent and 
cracked, with the undulatory extinction very marked (Fig. 3) 
and the usual crushed rim of mineral fragments. 
Fig. ;{. Section of an orthoclase "auge'' (Carlsbad twin), sliowing wavy extinc- 
tion and bendingr, surrounded bj cruslied rim of mineral fras^ments. As seen with 
crossed nicols (No. 13). 
The quartz individuals do not appear as " augen," for in 
the metamorphism that the rock has undergone they seem to 
have been more broken or crushed. In a few cases elongated 
individuals, parallel to the general schistosity, have been 
seen. It is also to be noted that the wavy extinction is less 
marked in the quartz than in the feldspar individuals, which 
seem to have adjusted themselves to the strain. In most cases 
the absence of inclusions in the " augen " is very marked and 
stands in strong contrast to the conditions which exist in the 
gneissic rocks farther south in Westchester Co.* The quartz 
sometimes extends into the " augen," forming corrosion bays 
(No. 6). 
*H. Ries. On a Granite-diorite from Harrison. Westchester Co.. N. 
Y. Trans. N. Y. Acad. Sci., xv. 
