32 



Vol. XLIII., Art. 5.— T. Katô 



Fig. 7. Diagram Hi atic sketch of veiu ] iece fiom Hyakken, 



showing symmetrical crnstiüed biructure. 



K, country rock ; Qc, quartz with specks of chalcoi^yrite 



and bornite, rarely with wolframite plates; F, 



fluorspar ; C, chalcopyrite ; Q, quartz. 



It is very striking that the above-mentioned parallel veins are 

 diverse in character, in spite of tlie fact that they are located in 

 a limited area. The tin content is largest in the Daisen vein and 

 decreases gradually toward the northeastern part of the area ; the 

 Daisen and Nihonmatsu veins contain much cassiterite and are 

 worked for tin ore as well as copper ; the Sekiei vein contains 

 less cassiterite than the above two ; the Hyakken vein contains 

 only an insignificant quantity of tin ore and is worked chiefly for 

 copper ore ; the Shôtoku vein is believed to contain almost no 

 tin -stone. 



Besides the above-mentioned parallel veins, there are a few 

 veins^) belonging to the same group, or running in the same 



1) The Mannen vein, and Kusakané and other veins to the south of the Daisen mine belong 

 also to this group. The Kemuriyama vein, on the southern side of the Akénobé Eiver, just 

 opi)Osite to the Mannen vein, beloTigs also to this group. It is a copper-tin vein, and rich tin 

 ore was once extracted from it. The Ein'ei and Shiroiwa veins are nothing bnt faulted and 

 Bei^arated blocks of the Daisen vein. 



