2 AKT. 3. — B. KOTÙ : 



Professors M. Uyeda and K. Yamaguchi, of the Female Normal 

 School of Kagoshima, for their valuable assistance in collecting 

 specimens of lavas and éjecta, and in securing photographs of 

 Sakura-jima before and after the recent eruption. The writer is 

 also indebted to Professor E. Junker, of the First Higher School 

 here, for valuable suggestions during the preparation of the manu- 

 script. Thanks are also owing to many other friends and col- 

 leagues, whose assistance by their publications and in supplying 

 information is acknowledged in the text. 



Part I. General Outline of the Geologic Structure 

 of Southwest Japan. 



§ I, Geographic and Geologic Situation of 

 Southwest Japan. 



Among the insular garlands of Eastern Asia, there is an 

 outwardly bending curve of island chain (Fig. 1) that stretches 

 over Q^ degrees of latitude, and hangs at the north end of Taiwan 

 and the southern terminus of Kyûshû, the latter l^eing one of the 

 three islands that constitute " Old Japan." 



This linking chain is the E y ii k y ù a r c, which the writer lias 

 long considered as the geographic and geologic homologue^^ of the 

 Lesser Antilles with the classic volcanic islands of Martinique and 



1) C. Brown acquainted ns with tlie geologic homologixe of the i:)lateaus of Tibet and the 

 Shan States of Yimnan, l)oth being elevated ancient ocean-floors now undergoing abrasion and 

 reduction to peneplains. The outer edge of each is bounded by a scarp exixising a zone of 

 Archean and Paleozoic rocks which built up the Himalayan chain in the former, and the 

 meridional western Yunnan ridge in the latter. In each case the zone is bounded by a great 

 fault, making escarjjment and at the same time forming the inner edge of the fore-dee}) (the 

 Ganges and Irrawaddy) that separates the edge referred to from the foreland (the Decoan and 

 Upper Burma). Lastly, in front of the zone there occur faulted Tertiary strata (the Sub- 

 Himalayan zone and the Tertiary of U]i]ier Burma). 



