KOTO : XOTES ON THE GEOLOGY 



pressions of the North and South China Seas. Tlie region 

 is alternately suhjected to strong ebbs and floods through the 

 influence of the branch currents of 

 the swift Kuro-shiivo from the 

 north and south, creating foamy 

 and turbulent waves, in conjunctin 

 with the steadily blowing heavy 

 north-easters, — the dread of coast- 

 ing navigators for ship- wrecks and 

 other deplorable accidents. 



I have not yet had oppor- 

 tunity to learn by my own inspec- 

 tion the geology of the Pescadores 

 Group ; but through the kind- 



FiG. 1. — Index inaj) of Taiwan to sliow 

 neSS of jMeSSrS. Y. Saito and the position of the islands dosmbed. 



T. Tada, I have obtained about forty specimens of rocks, which 

 no doul)t fairly represent the types that build up the crust of the 

 islands. In anticipation of a fuller report by Prof. Yokoyama, 

 who has made the islands the subject of his special study, I 

 may give here brief notes on the descriptions of rocks and the 

 inference drawn as to the probable geologic structure of this 

 interesting volcanic group. 



The islands are, broadly speaking, distributed within an 

 elliptical space. On the north of the Tropic of Cancer lie main- 

 ly the larger islands which are arranged after the manner of 

 Santorin. They resemble the latter not merely in general out- 

 lines, but they owe their very existence to tlie same cause ; both 

 are of volcanic origin. These Santorin-like islands are Gio-o, 

 Hoko, Hakusha, and Chii-don, the latter three fuse together, 

 especially duiing low tide, into one mass with the intervening 



