Vol ano ÔsLitna, Idzn. 



21 



Lava 



^lT^>'^vVl 



Scorire 



Other ejt'cta 



Fig. 11. Diagrammatic representa- 

 tion of the ideal structure of a parasitic 

 cone. 



from tlie side vents which were • afterwards, buried under later 

 ■éjecta. Fig. 11 is a diagrammatic representation of the ideal 

 structure of a parasitic cone according to this inference. 



As to the order of the forma- 

 tion of these parasitic cones no 

 reliable statement is possible, since 

 the geologic condition of each of 

 tliem and their mutual relation are 

 not known. Takenohira (20) ap- 

 pears, however, to be the most re- 

 cent, for it is the least covered by 

 later éjecta and its original form is 

 nearly perfectly preserved with a bowl-shaped depression, to the 

 north of the highest point, which must represent the crater. 



The parasitic cones are arranged mainly along the major axis 

 of the island, N.N.W.— S.S.E. This shows that the main flank 

 eruptions took place along the line running in the direction N'.N.W. 

 — 8.S.E., and that this afforded one of the factors for the exten- 

 sive development of the skirts of the somma on the northwestern 

 and southeastern sides. 



Explosion-Craters of Phreatic Origin.— At the southeastern 

 foot of the somma there are two explosion-craters : Habu'^ (3e) 



and Hikubo'^ (3e). 



Habu (Figs. 12 & 13) is a harbour at the southeastern end 

 of the island (3e). Nearly circular in shape it is about 300 m. 

 broad, and is connected with the open sea by a narrow channel. 



The surrounding wall is precipitous, with an average height 

 of about 50 7^?. On this wall, lavas and éjecta are exposed in 

 alternate layers as shown in I'ig. 13. 



1) i*î? 



2) b ^ ;J^ 



