122 B. KOTO 



black schists. Between Kamagata and Simo-sato, the strike runs 

 N. 15° E. with a gentle dip to S. E., being disturbed by two faults at 

 the village of Tôyama. After passing the anticlinal of Simo-sato in 

 the north-westerly direction, the strike changes to N". 70° W. with a 

 dip to N. E., and then the schistose complex disappears under the 

 greywacke-sandstone and Alluvium near the basin of Ogawa. 



(j) Relations of the Orography and Geology of 

 the Sambagawan Terrane. 



The axiom, that mountains of older geologic dates are insig- 

 nificant in their height when compared with those of younger origin, 

 holds true also in the case of Chichibu. The district under question 

 is circumscribed on all sides by mountain-ranges, built up of rocks 

 of various ages, the very centre of which is an extensive geologic 

 basin of the Pliocene- Tertiary of Omiya. 1'he north-eastern rim of 

 this caldron-like depression is formed by low hills of the ancient 

 Sambac^awan series. 



In travelling along the Nakasendo railway, we may notice a very 

 great contrast in the views of différent parts. The back-ground is 

 the tremendous esc:^.rpment of the Palaeozoic hornstone of Ryökami, 

 while the borderland is a low chain of the Sambagawan series which 

 is limited on the north by the two conical peaks of Mikabu, and on 

 the south the diabasic Ogiri-yama projects out from the surrounding- 

 hills. These heights are built up of the tuff-amphibolite of the Mikabu 

 series which directly overlies the Sambagawan rocks. On account of 

 its compactness of texture, the Mikabu series withstands the atmos- 

 pheric agencies better than the other, and thus a marked contrast has 

 resulted in the topography of this district. 



The hydrographie basin of the Sanchü hi the district of Kanra, 

 discharges its waters by Unishi in the form of the Kannagawa ; while 



