38 '^'ol. XLm., Art. 5.— T. Kalo : 



forms a small boss in association with dioritic offshoots, near the 

 chief vein. This rock clearly represents, as already discussed, an 

 acid segregation from the dioritic magma, and it is, ia all pro- 

 bability, connected genetically with the adjacent vein. 



The Daijukô parallel veins are probably related to. the altered 

 diorite mass exposed along the road leading from Akénobé to- 

 Fadono. 



In conclusion, it seems highly probable that the ore-bearing 

 solutions rose from deeper and at the time unsolidified portions of 

 the magma through the upper solidified portions. It is suggested 

 by the presence of a boss or an apophysis of the leucocrate, 

 akenobeite, that the later solidified portions of the magma werà 

 acid in nature and rich in volatile mineralizers due to a process 

 of magmatic differentiation. It is also probable that in the future- 

 more offshoots of diorite and acid differentiation-products will be- 

 discovered in this district by underground explorations. 



VI. The Copper-Tin Veins. 



Under this heading the writer confines himself to the structure, 

 character of mineralization, and alteration of the wall-rocks of the 

 Daisen vein, of which more complete observation and more careful 

 study of thin sections have been made than of any others. As a 

 matter of fact, the Daisen vein is worthy to be taken as represent- 

 ative of the copper-tin veins of this district, since it is the most 

 productive vein and other veins now being worked or once worked, 

 such as the Nihonmatsu, Sekiei, Otaké, Kemuriyama, etc., show a 

 strikings imilarity to it. Consequently, the conclusions derived from 

 the Daisen vein apply to the remainder of the similar veins in this- 

 district. 



