IQ Vol. XLUI., Art. 5.— T. Kutô : 



less defined. Usually the uralite is characteristically fibrous in 

 structure and strongly pleochroic, from bright green to yellow. The 

 original form of augite is usually obliterated and has become flaky 

 and bent, although occasionally the transition of the prismatic 

 cleavage from augite to liornblende is observed in basal sections. 

 Iron ores, chiefly of secondary formation, are scattered in fair 

 quantities through the rock. Abundant chlorite, in clusters of 

 minute granules and in large flakes, is developed in some parts. 



The rock is occasionally cut by voinlets consisting of xeno- 

 morphic grains of fresh albite mingled with chlorite flakes and 

 epidote grains. The epidote is almost colourless in thin section 

 and is characterized by bright speckled interference colours. 



Radiolarian State. A bed of brownish red slate containing 

 RacUolaria remains has been found in the Minamidani area, where 

 the rocks are generally more or less metamorphosed. This is also 

 a characteristic member of the Paleozoic forination of Japan. 



(B) The Mesozoic Formation. 



In the environs of the Daijukô mine, the country rock consiscs 

 of black slates intcrstratified with gray slate, sandstone and con- 

 glomerate beds. A lenticular limestone is also found at a spot in 

 the black slate terrane. Thus it differs conspicuously in character 

 from the green slate complex developed in the environs of the 

 Daisen mine. 



The black slate complex now under consideration has a general 

 strike of N. 20°-40^ E. and dips towards N. W. at an angle of 

 20^-30°. Thus, the strike and dip of this complex differ very 

 slightly from those of the green slate complex. In this district 

 the two complexes are bounded by a great fault as shown in the 

 annexed geological map (PI. I.). 



