224 J. D. Dana — History of the Changes in Kilauea. 



basalt glass one inch thick would be sufficient to make a 60-inch 

 layer of the spongy material ; and probably a 75 to a 100-inch 



Cells of the Thread-lace Scoria. 



layer of the much more common, coarser variety, in which are 

 some large vesicles occasionally half a cubic inch in size. 



