30 WILLIAM J. MILLER 
(light gray to dark gray) to almost pure plagioclase anorthosite 
(light gray to nearly white). In the northern portion of the area 
the light-gray anorthositic facies are most conspicuously developed, 
but they occur locally in all parts of the area. 
In thin section under the microscope the feldspars of the gray 
to nearly black facies contain myriads of dustlike inclusions, 
QWorden Pond 
Fic. 1.—Sketch map of part of central St. Lawrence County, New York, showing 
the location of the body of anorthosite-gabbro. Numbers indicate localities referred 
to in the text. 
probably ilmenite. No. 42 of Table I (see below) represents a thin 
section of a specimen of the typical very common dark-gray, 
medium-grained to moderately coarse-grained, non-foliated gabbro 
with ophitic texture from locality 9 (see Fig. 1). The labradorites, 
which range in length up to one-half an inch, are generally euhedral. 
All the pyroxenes (probably diallage) have narrow rims of horn- 
blende around them, but some hornblende occurs either in small 
