116 B. KOTO 



4. — The next locality in which the Lower Sambagawan may be 

 seen, is along the Sambagawa itself, which flows into the Kanna 

 river close to the town of Onisi, in the district of Miclono, Kôzuke 

 province. This rivulet has an easterly course with a slight trend to 

 the south, thus harmonizing well with the general strike of the whole 

 series. Along this tectonic valley of about o km. in length beginning 

 from Imogaya, just at the foot of the Eastern Mikabu, the entire 

 complex of the Sambagawan series is typically developed ; and if 

 any one is desirous of convincing himself of the stratigraphie order of 

 the complex, this is just the place for him. 



The general strike is N.70°W. with variable dips to S.A¥. ; 

 but, where the transversal faults run across the valley (altogether 3 

 principal ones as in Profile IV), the geotectonic condition is con- 

 siderably disturbed, and the outcrops of the piedmontite-schist and 

 normal sericite-schist are then laid bare for inspection. As can be 

 seen in Profile IV, two large faults occur in the lower course at 

 Siosawa and Tsukiyosi respectively, causing a depression in the one, 

 while the northern side has been thrown up to a considerable 

 height, forming the fantastic cliff of the Tsubori-iwa (200 ft.). This 

 cliff is composed of chlorite-amphibolite of the Middle division, 

 and at its foot, along a deep ravine, the Lower Sambagawan crops 

 out to day-light. 



5. — The last outcrop which the writer has to mention lies at the 

 north-western corner of the geologic territory of the Sambagawan 

 series, being exposed just to the south of Ol^ata, at the entrance of tlie 

 long valley of Akihata. Here the piedmontite-schist makes a small 

 saddle with the strike ISF. 50° W., the dip being very steep toward the 

 north (Todonjki), and tlien vanishes again from sight on the north 

 under the vertical cliff of the Tertiary sandstone and conglomerate of 

 the Chögonji-yama (str. E. 20 S.) to be seen no more in this region. 



