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PENNSYLVANIA ANORTHOSITES 
29 
GENESIS OF ANORTHOSITES OF PIEDMONT 
PENNSYLVANIA 
By Isabel F. Smith 
Bryn Mawr, Pa. 
A small body of anorthosite which occurs about forty miles 
northwest of Philadelphia appears to present features giving clue 
to the mode of origin of the mono-mineralic eruptives. This 
rock mass occurs near the town of Honeybrook in the Piedmont 
belt of eastern Pennsylvania. In outline the area occupied by 
the anorthosite is elliptical, and it comprises approximately twenty 
square miles. (Fig. 1.) 
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es ftCXtnOHT UI*LANi>A £33 T^rinASIC. UOWl.fiNS8 ■■ / 1 H 0 RT< 106 tTe AREA 
Figure 1. Location of Honeybrook Anorthosite 
