57o 



S. KOZU 



Magnetite clouds the base as minute grains or dusty particles, 

 and their abundant presence affects the color of the rock. Apatite 



appears mostly as inclusions 

 in feldspar. 



The second type collected 

 from Ohama in Fukae-shima 

 is more crystalline. Alkali- 

 feldspar appears locally in 

 the crystalline part as the 

 border of the plagioclase of 

 the.groundmass. The augite 

 crystals are comparatively few 

 and occur in small anhedral 

 forms. The magnetite crys- 

 tals are more numerous in 

 this type of rock than in the 

 first one, are somewhat larger, 

 but are also anhedral in shape 



(Fig- 7). 



The third type collected from Masuda in Fukae-shima is holo- 

 crystalline, and in some parts has typical ophitic texture. The 



Fig. 4. — Microphotograph of the first type 

 of the first group, magnified 30 times. The 

 minerals seen in the figure are olivine micro - 

 phenocrysts and andesine prisms. 



Fig. 5 Fig. 6 



Figs. 5 and 6. — Showing irregularly outlined olivines. 



X55 



mineral components are andesine, alkali-feldspar, augite, olivine, 

 magnetite, and apatite. The andesine is distinctly cracked, with 



