Volcano Ôshima, Idzn. 39 



did view. The peculiar feature of this projection was noticed for 



Fig. 24. A cliagrammatic sketch bhowing the &tructnre of Cbignsaki. 



a Lavas of the igneous body of Chigasaki. 



h Ejecta of the same. 



c A layer consisting of small lava-fragmont.s. 



d Talus accumulation of the blocks of c. 



e ...Skirt of the somma. 



the first time by D. Satô^^ who suggested that it might be either 

 the remains of an old volcanic body or a half- destroyed parasitic - 

 cone. ÔHASHf\ on the other hand, is of opinion that it is merely 

 nothing more than a part of the skirt of the somma. Feied- 

 LAENDER^\ OU the othcr haiid, considered it as a parasitic cone. 



The structure being examined in detail, however, it becomes 

 clear that Chigasaki is neither a mere part of the skirt nor a 



parasitic cone. 



Fig. 24 represents a diagrammatic sketch showing the structure 

 of Chigasaki. The liill is underlain by a demolished igneous body 

 consisting of lavas (a) and éjecta {h) which dip northwards. 



The lava is oHvine-rich basaltic with large megaphenocrysts of 

 anorthite, and differs fi-om the most widely distributed somma 

 lava. Over the abraded surface of this igneous body is a layer of 



1) "Geological Notes on Ôshima, Idzu," Jcrnr. Geo<jr. Tölcß, Vol. XIV., Ko. 162, 1902 



(in Japanese). v\'tT ^^ iQr 



2) "On the Geology of Volcano Ôshimn,'' Jmr. (kogr. Soc. Tokyo, Vol. XML. ^o. lyo, 



1910 (in Japanese). , 



3) «' Über einige japanische Vulkane," M-Uteilungm der Deutschm Gesellschaft fur ^atiü- una 



Völkerkunde Ostasiens, Bd. X., Teil 1, 1909. 



