THE GREAT ERUPTION OF SAKURA-JIMA IN 1914. 207 



ß) Wliite porcelain-like masses flecked witli cordierite, being 

 a breccia of an old andésite. Cordierite is formed by tlie 

 reaction of constituents of new andesitic magma upon a 

 metasilicate of the preexisting one. 



y) Fragments of breccia cemented with opal-like matter, the 

 fragments themselves being aggregates of cordierite crystals. 



Taking into consideration wdiat has been actually observed of 

 the éjecta and what others have said of similar projectiles, the 

 writer is forced to the following conclusions from the data given 

 below : 



1) The cordieritiferous éjecta or ceramicites greatly resemble 

 ceramic w^ares. 



2) They contain primary glass-enclosures and air-pores.^-* 



3) There are no biotite nor amphibole (with the exception 

 of tremolite), both only crystallize under intratelluric en- 

 vironment, the cordierite being the vicariate of biotite. 



4) Quartz, so frequently spoken of as making a large bulk, 

 seems to ])e for a greater part due to misinterpretation of 

 either cordierite, feldspar or some other colorless minerals. 



5) The small, grayish, dough-shaped lava-foams, in which 

 cordierite and feldspars are frequently found, make gradual 

 transitions to the solid éjecta or ceramicites. 



6) The minerals composing the ceramicites are of light 

 chemical elements, and colorless, excepting a subordinate 

 quantity of fcTriferous minerals, viz., hypersthene and diop- 

 side. 



All in all, the wTiter is disposed to think that the cordieriti- 

 ferous éjecta of Sakura-jima are of primary leucolithic consolida- 



1) The presence of gas-bubbles is the sign of melts at low pressure, and the gas contained 

 may be the one originally caught up between subcrystals, or occluded from air. 



