BULL. GEOL- SOC. AM. 



VOL. 16, 1904, PL. 30 



Figure 1.— Seljapat.r Palagonite (X 20) 



Figure 2.— Botryoidal dentrifieu Glass Mass (X 32) 



Figure 3.— Holyokeite Ground of the coarse porphyritic 

 Diabase (X 32, polarized light) 



Figurk 4. — Material from a holyokeite Dike (X 32, 

 polarized light) 



PALAGONiTE, DEVITRIFIED GLASS, AND HOLYOKEITE MATERIAL 



