Explanation of Plate II. (Photomicrographs) 



Fig. 1. Phjllite, exposed near the Miiiamidani mine.' Ordinary Hght 

 Magnified 60 diameters. O, aggregate of graphitoid particles; S, micro, 

 grains of quartz mixed with flakes of biotite and sericite, showing 

 schistose structure. 



Pig. 2. Green slate with veiulets of quartz and epidote. Q, quartz ; E- 

 epidote ; SI, carl)onaceous slate containing al)undant chlorite flakes. 

 Ordinary light. Magnified GO diameter,-^. 



Fig. 3. Silicified slate adjacent to the Daisen vein. Niçois crossed. Magnified 

 GO diameters. The thoronglily silicified rock, mingled with flakes of 

 chlorite, is intricately traversed by quartz veinlets. Frequently, quartz 

 veinlets grade into highly silicified rock-portions. Q, cpiartz grains com- 

 posing veinlets. 



Fig. 4. Chloritized slate (green i^late) cut l)y (piartz veinlets. Ordinary light. 

 Magnified GO diameters. Q, quartz veinlets ; Ch, chlorite in aggregate 

 of flakes ; S, siliceous slate rich in quartz grains. 



Fig. 5. Uralite-diabase, exposed near the Mannen adit, Akéuobé. Ordinary 

 light. Mag uified GO diameters. U, luraHte ; F, kaolinized feldspar. 

 Note the iutersertal (or, in places, ' ophitic) structure. 



Fig. G. Quartzite. Loc. — Near the Hyakken mine. Niçois crossed. Magnified 

 GO diameters. Nt:>te that this is composed (jf inequidimensional quartz 

 grains. 



