168 



ART. 3. — B. KOTü 



is seen to full 

 advantage, overlaid 

 by the sheet of the 

 Kita-daké lava, that 

 constitutes together 

 with the underlying 

 the main body of 

 Sakura-jima. It is an 

 excellent exposure to 

 get a glimpse into the 

 structure and rock- 

 nature of old lava. 



No. 2. The next 

 circular bocca (Text- 

 fig. 34 [2]), 64 m. dis- 

 stant from the first, is 

 rather small with a 



Fig. 34. — Vents Nos. 1-2 of the Byôbii-hira lava-field of 

 1475-1476. Cf. Geologic Map. 



diameter of 130 m. and a depth of 40 m., but is a typical deep 

 clear-cut and impenetrable venthole, this time of new black lava, 

 densely forested with Cryptomeria japonica. One cannot find the 

 spot unless one stands on the very edge of the pit. 



No. 3. The third pit in the series lies at about the same 

 distance from No. 2, as the latter is separated from No. 1. It is 

 a shallow basin (Text-fig. 35 [3]) filled with éjecta, which are also 

 spread about over the neighborhood. 



No. 4. The last and the lowest pit (Text-fig. 35 [4]) lies a 

 little apart from the preceding No. 3 pit. In its form and forested 

 condition it closely resembles No. 2., the only difference being the 

 smallness in size and the deep bottom (100???.). 



These four ventholes are arranged in a series on the slope in 



