290 



B. KOTO. 



titiinite-bearing rocks in the field the biotite-ainphibolites in order to 

 discriminate them from other kindred varieties. Tlie Ijiotite-amphibole 

 o-neiss occurs usualJy in lenticular masses. Those of the other cate- 

 o-ory (gneiss-mica schists) show the following moditications, namely, 

 o-neiss-mica schist, two -mica schist, "'arnet- hi otite schist, and also 

 hornblende-biotite schist. The whole complex, consisting of the 

 above-mentioned rocks, attains a considerable thickness, as seen in the 

 exposure between the hilly stretches from Nakagura to Söri (E-F, PI. 

 XXV), where this tapper Takanuki was found to have the thickness 

 of 5,500 metres. 



The voluminous green mass of the (jrozaislio series is well exposed 

 alono' the banks of the Same-^awa whose river course runs nearly at 

 rio-ht anofles to the strike of the whole complex. Its basal member 

 lies in a somewhat elevated portion of the plateau on the west, while in 

 the eastern half of the section, towards the tertiary hills of Kadöno, 

 the younger series occurs, with a thickness which I venture to 

 estimate as probably not less than 10,000 metres. 



The uppermost rock of this series is a greenish, rather massive 

 schist, cropping out along the l)aiiks in a vertical position but with a, 

 slight inclination towards the east. It has the aspect of a clastic rock, 

 and is like a hardened dej^jsit of volcanic aslies. This is followed to 

 the west by alternjite bands of green schists and quartz rocks, intruded 

 into at times by a hornblende-iJTanite. A i)lack mica-schist accom- 

 panies these green schists. They gradually disappe;u', to give place at 

 last to a black, crystalline, horriblende scliist which occupies the basal 

 portion. AVhen we compare the extreme members of these schists, 

 side by side, they seem at first sight to hax'e nothing in common with 

 each other, but on close examination in the field they are seen to 

 form a lithological continuity and a harmonious whole. These green, 

 fissile rocks have much the same appearance as the clasto-pyroxenites 



