Volcjino OsLima, Ilzu. 97 



tuff" and "crystal tuff." Ashes occasionally form cendre granulée 

 or pisolite, as was found interstratified on the rmg-wall of the 

 somma, some 500 m. southwest of Kagamihata'^ (Ic). 



LapUli, — Thero are two kinds of éjecta of the lapilli grade, 

 viz. fragments of the pre-existing rocks and juvenile ones. The 

 latter which far predominate over the former are glassy and 

 scoriaceous, and often contain phenocrysts of calcic bytownite. In 

 most cases, lapilli form very thin beds, rarely exceeding 20 cm, 

 in thickness, between tlie ash and sand layers, though they some- 

 times form thick accumulations, as for example on the cliff opposite 

 to Fudeshima'^ (3d ; pp. 25-26). The surfaces of the ground in the 

 caldera and the apical part of the somma are loosely covered by 

 the lapilli of the central cone. 



Bombs — The larger blocks of the pre-existing rocks are 

 imbedded in asli and sand beds and form agglomerate beds, which 

 are however very rare. Bombs that originated in molten lavas 

 are scattered around the crater on the upper slopes of the central 

 cone. They are multifarious in shape — spindle-shaped, subspherical, 

 spheroidal, etc. Their size is also of wide range. A very large 

 specimen found near Kawajiri,^^ the lowest point of the crater 

 margin {K in Fig. 20, p. 33), has a diameter of over 1 m. Petro- 

 graphically, the bombs do not differ from the lavas of the central 

 cone, namely miharaite. Parallel arrangement of phenocrystic 

 minerals which is said often to have been observed in the bombs 

 of other volcanoes is not markedly seen in these. This may be 

 due to the high fluidity of the molten lava. It is an interesting 

 fact that bombs sometimes contain blocks of earlier lavas as nuclei 

 around which new lava -material s are coated. 



Pele's Mail's, — Among the éjecta of a peculiar form is black 



1) mi^ 2) mm 3) jn^ 



