50 



PERCY QUENSEL 



Fig. 8 a. \'csicular aphyric feldspar basalt columnar structure- . 



I see Fig. 9 . 



30. I'ortezuclo, Masatierra 



Fig. 8 b. Same specimen as Fig. 8 a, magnified x 65. Vesicle in upjier right corner filled with 



opal. Portezuelo, Masatierra. 



