316 Y. KIKUCHI. 



often invaded by apophyses. As we proceed northward, the granite 

 gradually gains over the higher level, attaining its maximum breadth 

 just where the Watarase-gawa passes the boundary of the two Prov- 

 inces already named. Further north of this point, it again loses 

 itself under the sedimentär}' rock masses. The whole of these 

 phenomena suggests that a huge granitic mass has been forced 

 up from below, probably along a line of fissure running X. and 

 S., partially represented by the valley of the Watarase-gawa, into the 

 overlying stratified rocks. The accompanying «ketch map may serve 

 to illustrate the brief description just given. The altered zones 

 are marked at those places only where they have been actually 

 observed. 



The Granite developed in this region is composed of Quartz, 

 Orthoclase, and Biotite, with some accessory minerals ; Garnet, 

 microscopic Zircons, &c. The structure is usually uniformly granular; 

 sometimes porphyritie by the development of Orthoclase into large 

 tabular crystals having zonal inclusion of mica flakes. 



The thick strata of the Palaeozoic date (probably the ; Kobotoke ' 

 system of the Geological Survey) developed around this granitic 

 mass consist of hard sandstone, — the ' Greywacke '■ — Hornstone, 

 Slate, and some Limestone, all non-fossiliferous. Their direction of 

 strike is N". E., dip generally toward S. E. Wherever these rocks 

 come into contact with Granite they undergo peculiar alteration. The 

 hornstone is converted into a harder Quartzite, the fresh fracture of 

 which shows a fine granular saccharoidal appearance ; the sandstone 

 becomes more compact in texture and much mica is developed in it. 

 But that which concerns us here is the effect of metamorphism on the 

 Slate. The first sign of alteration of this rock is manifested by the 

 development in it of fine black specks, which examined under the 

 microscope are seen to consist of aggregates of black mica. This 



