Vol. XLIII., Art. 5.— T. Katö: 



mingled with a small quantity of quartz grains makes up the 

 main bulk of this sch'stose rock. 



Quartzite. This occurs occasionally in the form of a thick 

 intercalation in the slate complex, forming cliffy walls along its 

 strike, as on the mountain-slope northeast of the Daisen mine (Figs. 

 4, 5) and in several other places. It is hard and compact, white or 

 grayish white in colour, often stained with limonitic substance and 

 manganese oxide along the cracks and irregular joints in which it 

 is very rich. As can be seen under the microscope, it is com- 

 posed of inequidimensional grains of quartz, larger grains being 

 scattered like phenocrysts through an aggregate of minute grains 

 (PI. IL, Fig. 6). It is evident that the rock has undergone intense 

 granulation, because the larger grains often show undulatory extinc- 

 tion and their margins grade into cataclastized fine grains. The 

 rock is contaminated with microscopic flecks and stringers of 

 limonite, and is intricately traversed by fine veinlets consisting of 

 quartz grains. 



J^ig. 4. View of the village of Akénobé and the Daisen mine, seen from north. 

 d = Daisen mine. m = Meisti mine. Q = quartzite clitï. 



