162 ART. 3. — B. KOTÜ : 



eight-sided outline affords, however, a good diagnostic mark to 

 hypersthene, wliile the tabular (100) with twdnned basal section 

 that of augite. Parallel intergrowth with peripheral augite was 

 sometimes observed, but the reverse was only once noticed 

 (S. E. slope). The statement on the relative quantity of the two 

 ]3yroxenes should therefore not be taken in a strict sense, especially 

 the phenocrysts are not found in large quantity, as in the lavas 

 under question. Simple subhedral tabular (010) feldspars as well 

 as polysynthetic-lamellar, long- rectangular plagioclase are zonal- 

 structured. 



The hyalopihtic groundmass is fine and built up mainly of 

 minute augite needles and lesser and larger laths of feldspar in 

 brownish glass base with magnetite crystals. Specimens fi'om the 

 neighborhood present textural varieties ; some l^eing brownish and 

 slaggy, the other being fine in texture. But the mountain slope 

 is thickly covered with all sorts of ejected blocks of several erup- 

 tions, so as to make a proper selection difficult in collecting 

 specimens. 



ii. The lavas in the Kannon-zaki area (PI. XVII. Fig. 2) on 

 the southern shore are likewise black and rather vitreous owing 

 to the abundancy of glass in which the microlites are mostly re- 

 presented by augite, besides a few larger feldspar-laths. Olivine 

 was once noticed, and micronorite patches were also seen. 



iii. The Naka-daké lavas, which cover the («) top and 

 eastern slope and the (ß) coastal strip of the Nagasaki headland, 

 arc rather slaggy and colored brown in vesicular spaces through 

 oxidation of the pyroxenic components. The « typo is a jntch -black 

 vitroandesite having a groundmass of abundant brown glass with 

 augite needles only. It is a porphyritic obsidian (PL XAMl. 

 Fig. 4). The ß type (PI. XAMI. Fig. 5) is hyalopilitic and diiU-lMck 



