JODENAL OF THE COLLEGE OF SCIENCE, TOKYO IMPERUL UNIVERSITY. 

 VOL. XLIII., ARTICLE 6. 



Volcano Oshima, Idzu. 

 By 



Seitarô TSUBOI, Bigahmld. 



With 6 Plates and 42 Teai-fgures. 



I. Introduction. 



The present }3aper embodies the results of the writer's geologic 

 investigation of the insular volcano Oshima, in the province of 

 Idzu^\ conducted under the auspices of the Earthquake Investiga- 

 tion Committee and of the Imperial University of Tokyo. 



The field observations on which the present work is based 

 were carried out chiefly during two months in the summer of 

 1916, and supplementarily by making two trips in 1917 and 1918. 

 The laboratory study was performed during the writer's third 

 year course in the Imperial University and in the year after 

 graduation. 



In its present state the work is still far from complete, but 

 with the hope of contributing to the vulcanology of Japan the 

 w^riter has decided to publish the results so far obtained, deferring 

 the making up of deficiencies to a later opportunity. 



Here the writer wishes tc tender his hearty thanks to Pro- 

 fessor B. Koto for his great kindness in reviewing the manuscript 

 and for the valuable advice he has constantly given. 



1) P3.A^ 



