GRANITE-GNEISS IN CONNECTICUT 649 
than those in the central part of the ‘‘augen.” Yet the absence 
of evidence of extensive crushing, and the fact that many of the 
“augen’’ consist wholly of white aggregates of feldspar which 
under the microscope show no evidence of crushing, lead us to 
suspect that even these white aggregates, which sometimes 
occur as borders around the red cores and sometimes constitute 
‘‘augen’”’ by themselves, may be, in large part, original crystalli- 
zations. The fact that these ‘“‘augen” do not include to any 
extent plates of biotite, but that the lines of biotite flakes curve 
around them, seems to point to the formation of the ‘‘augen’’ 
previous to the complete solidification of the rock. The ‘‘augen’’- 
gneiss, like the granite-gneiss of which it is a local variation, is 
of igneous origin. If we suppose that the first step in its forma- 
tion was the separation of small orthoclase individuals or aggre- 
gates of feldspar, mainly orthoclase, but containing plagioclase 
and microcline, which received their parallel arrangement before 
the final solidification of the rock, and which may have been 
subsequently somewhat reduced by crushing, we shall have the 
most probable explanation of the ‘‘augen’’-gneiss phase of this 
granite-gneiss, 
The foliation of the granite-gneiss does not seem to be in 
the main a dynamic result. Evidence of crushing is found in 
many sections in the form of wavy extinction of the quartz and 
lines of finer material between the larger quartz and feldspar 
grains, and crushing may be responsible in part for the parallel 
structure of the rock. Yet in many sections of the well-foliated 
gneiss the microscope shows no evidence of crushing at all. It 
seems more likely that the arrangement in a common plane of 
the biotite and, in the ‘““‘augen’’-gneiss, of the often rather tab- 
ular grains of orthoclase is a result of movement in the partly 
solidified magma. The character of the schlieren points to the 
same conclusion. In ordinary granites the schlieren are not 
stretched, but are roughly equidimensional, and such we may 
suppose their original form to have been in the present case. 
Had they been drawn out to their present distorted condition 
subsequent to the solidification of the rock, they could hardly 
