THE GREAT ERUPTION OF SAKURA-JIMA IN 1914. 203 



vacuoles and brownish glass-drops, the former appearing black by 

 total reflection. The dark-gray band (h) does not materially differ 

 from the preceding (a), excepting the presence of larger patches 

 of cordierite, irregularly distributed in glass full of vacuoles and 

 brown amorphous enclosures, which both lend to the rock the 

 grayish tinge. 



In summarizing wiiat is stated above, the cordierite-bearing 

 porcelain-hke éjecta, here called ceramicites, greatly resembles 

 earthenwares with various modifications resulting chiefly from 

 the difference of temperature at which the industrial products 

 are artificially melted and manufactured. These volcanic éjecta 

 compare well on one hand with the crystalline microtinite (p. 190) 

 and on the other with the cryptocrystalline lava-scums (p. 187), al- 

 ready briefly mentioned ; they are genetically related to one another 

 and aU three consolidated under comparatively low pressure, probably 

 near the open vent, as in the recent pumice of Asamayama. 



The components found in the éjecta are anorthite, sanidine, 

 cordierite, pyrrhotite, magnetite, hypersthene and siUimanite, besides 

 spongy glass ; the first two scarcely to be distinguished on account 

 of the absence of twinning structure. Noteworthy features are 

 the absence of quartz, muscovite and even biotite, the latter being 

 chemically akin to cordierite. The quartz is always mentioned by 

 the writers on cordierite-bearing éjecta as making a large bulk — 

 an error arising from misinterpretation of cordierite and feldspars. 

 There is little probability for the presence of a large amount of 

 quartz, the siHca being represented in the colorless glass. 



The pyrrhotite mentioned above is the characteristic com- 

 ponent of ceramicite, by its presence alone the writer is able to 

 recognize the éjecta from the rest of the projectiles. The colors 



