THE GREAT ERUPTION OF SAKURA-JIMA IN 1914. 163 



dae to the predominancy of fine feldspathic microlites over those 

 of augite in light-brown glassy base. Both types are found inter- 

 mixed, a fact which seems to justify us^ in putting both together 

 in one group. 



§ II. The Lavas of the Historic Period. 



A. The Lavas of the Bummei Eruption/^ 1471-1476, 

 Including the Nabé-yama and Ebino-tsuka Adventives. 



«) The Urano-maye Lava-field of 1471. (I^iist Side.) 

 PL XVI IT. Figs. 2 and 3. 



a) General.— Taken in a broad sense, the grayish and salic, 

 porous and light lava of Kita-daké, which, constitutes the general 

 foundation of the insular volcano of Sakura-jima, difiers fi^om all 

 the later lavas, irrespective of historic or pre-historic, which are 

 dark and basic, slaggy and heavy. 



The femic jwe-liistorlc lavas already briefly outlined as the 

 Kabano (?), Minarai-daké and Naka-daké lavas welled out in 

 streams, or built up mighty cones during the mature age of the 

 volcano to a height of more than 1,000 m. Although dark in 

 color, the three lavas are r/u//-black, owing to the predominance 

 of feldspathic microlites in the groundmass, oi' else of light- brownish 

 color of glassy base. Among the pyroxenic phenocrysts, Ivypersthene 

 usually predominates over augite^ indicative of a ratlter salic nature 

 of the magma, representing a transitional stage to more femic historic 

 lavas to he considered immediately below. 



1) See (tiitc, p. 42. 



