176 AKT. 3. — B. KOTÔ: 



y) The rocks of the new islets oif the northeast shore 

 (Text-fig. 11, p. 49) are ah-eady outhned elsewhere.^^ The sub- 

 marine lavas, of which they are bnilt up, are gray or blackish 

 gray, dull and pumiceous in color and texture, and not unhke 

 an imperfectly coked brown coal. The groundmass is characterized 

 by a frothy brown glass, in which fibrillated polysynthetic augite 

 needles (clino-enstatite) and a few skeletal plagioclase laths are mixed 

 with magnetite dust (PL XIX. Fig. 2). It is to be remarked that 

 hitherto no olivine was detected, except in the lava from Iwô-jima. 



The characteristics of the An-ei lavas are the sporadic ap- 

 pearance of anhedral olivine and the abundancy of pyroxene - 

 phenocrysts, especially in the Kômen area, of which hypcrsthene 

 abounds in preference to augite. These striking features distinguish 

 the An-oi lavas from aU the ancient lavas of Sakura-jima. 



§111. General Pétrographie Characters of 

 the Lavas of 1914. 



A. Massive Lavas. PI. XIX. Figs. 3-8, PI. XX. 1-4. 



a) Land Lavas in General.— The ' live ' lavas, stiU hot when 

 collected, are exclusively the so-called block lavas or of the ' a a ' 

 type, and petrographicaUy belong to hy per stliene- andésite, with 

 olivine as an accessory. The writer can find scarcely any 

 difierence between the recent lavas and those of 1779. They are 

 more or less slaggy, sempatic to dopatic, and raediophyric. 



1) See p. 54. 



