ßß ART. 2,- s. YOSHIWAKA : 



axis of the ishind. Tlie arrangement of i.slands in the subgrouj) nnd 

 their stratification of rocks are probably diu; to tlic last folding of the 

 Riukiii Curve. 



The outer sedimentary zone of the Jiiukiu Curve is made up of 

 Tertiary sediments, and extends through Tanega-shima, Kikaiga- 

 shima, the islands lying on the east of Okinawa, and the southern part 

 of Okinawa-jima. Some islands are elongated from north to south, 

 and Tanega-shima, Kikaiga-shima and others have the strike of rocks 

 coinciding with the direction of the Curve. Comparing the character 

 and stratification of the Tertiary of the iihove regions on the one hand, 

 with those of Formosa and the Yaeyama subgroup on the other, I have 

 found the following differences. (1) The rocks are, in the former, 

 loose sandy shale, without any hard rocks or limestones such as are 

 found in the latter. (2) There are, in the former, very small fossils, 

 mostly of existing forms, in contrast with those in the latter. (3) 

 There are brown- coal seams in the latter, while in the former we find 

 lately appearing remains of wood in Okinawa-jima and a few other 

 islands. (4) The rocks in the former are very irregularly inclined, 

 and sometimes are quite horizontal as in some places in Okinawa-jima. 

 Thus the Tertiary of the northern half of the Riukiu Curve is proba- 

 bry later than that of the southern half which belongs to Miocene. 

 In this curve the deposits later than the Tertiaries are only the raised 

 coral reefs, with Recent coral-reefs, sand &c. As mentioned in my 

 "note on the raised coral reefs in the Riukiu Curve" (1901), the 

 raised reefs are horizontally bedded, but quite irregularly distributed, 

 thus showing that the folding of the Curve had taken place before 

 the building of the reefs. The distinct zones of rocks, (namely, the 

 inner neovolcanic, the median Palœozoic, and the outer Tertiary,) 

 coincide with those in the Peninsula of Malacca, the Andaman Isles 

 and the Nicobar Isles in the Indian Ocean, with the Banda Isles, in 



