BULL. GEOL. SOC. AM 



VOL. 16, 1904, PL. 59 



Figure 2. — Pyroxene Core replaced uy Hornblende Kiotitb, and Quartz. PPL. X 90 

 PHOTOMICROGRAPHS OF META-GABBRO 



Figure 1 from 1 mile east of Waterloo mills, and figure si from 2 miles southeast of 

 Berwyn, Chester county, Pennsylvania. Photographed hy V. J. Keeley 



