GEOLOiilC STRUCTURE OF THE RIUKIU CURVE. 57 



sides. The outline is rectangular and the island is elevated DS-l ft. 

 above the sea-level. According to Mr. Saitö the rock of this island is 

 also entirely basaltic andésite. 



PART IV.— Geology of North Formosa and its Relation 

 to the Riukiu Islands. 



Xorth Formosa consists of Tertiary sediments, pierced Ijy andésite 

 at the northern end. The Tertiary strata, which are never horizontal, 

 are, on the whole, comparatively regularly folded. According to Mr. 

 R. Yamashita eight parallel series of coal-seams are exposed in this 

 district. 



1st., (the uppermost), The Kusshaku series, with one seam, 

 running through Okutsu, north of Kusshaku, Chösökei and 

 Gyokö. 

 2nd., The Shinten series, with t\V(3 seams, running thrcxigh the 



west of Okutsu, Shintengai, Sekiteigai and Chösökei. 

 ord., The Keibi series, with two seams, running through 

 Ökeikö, Shösokö, east of Keibigai, Shinkogai, Fushirin, 

 Sekikan, Sökei, and Banshikö, and south of Zuihö. 

 4th., The Shinkyakutei series, with two seams, running through 

 Basozan, Chöhö, Reisuikö, Gyühö, N^anseikaku, Jûgofun, 

 Rokuchöri, Sanchöri, Xanközan, Hakuhöshiko, Goto, Shi- 

 kyakutei, and Shin-ö-kö and south of Hatto. 

 5th., The Denryökö series, with huv seams, running through 

 Xaikoköko, Parenkökö, Hokukokö, Yürakökö, Köshinai, 

 Sekikökö (near Kelung), Denryökö and Hatto. 

 6th., The Gwaibokuzan series, with two seams, running through 

 Xaikosankyaku (north-west of Shakkö), Jüshifun, Rokuryö, 

 Daiburon, Daikanrin, Xaibokuzan and Gwaibokuzan. 



