120 B. KOTO 



flank, the gneiss is considerably disturberl for only a short distance by 

 t\vo dykes of serpentine, but this serpentine by no means constitutes 

 the normal stratified member of the Upper division. It is generally 

 accepted by the geologists of our Geological Survey that all serpentines 

 should form a schistose member of older schists ; that is to say, they 

 are derived from olivine-schist and the like. The writer is not able to 

 agree wholly with them in regard to this point. The serpentine occur- 

 rences hitherto known in Chichibu always seem to point out that the 

 rock has been derived from the diabasic, and gabbro rocks, although 

 all serpentines in other districts may not necessarily be of like origin. 



In this profile, the Upper Sambagawan is developed in its full 

 proportions, and generally speaking, strata are horizontal with a slight 

 dip to the east. 



Profile II, EF — is taken from the region, 7 km. to the 

 north of, and parallel to, the preceding, for an extent of about 

 5 km. between Sueno and Hon-nogami across the village of 

 Fuppu. The strata all dip slightly to the east. The greater part of 

 the section is occupied by the Middle Sambagawan, while the higher 

 horizon is covered at two prominences by the Upper Sambagawan. 

 The whole complex seems to have been greatly disturbed at its 

 middle by numerous dykes of serpentine ; the highest part of the 

 pass is capped by the amphibolite of the Mikabu series. Near Sueno 

 on the east-, and Hon-nogami on the west along the Kami-Hiradani 

 valley, the graphite-sericite-schist with large nodules is developed 

 in its typical form. 



Profile III, G H — presents exclusively the rock-groups of the 

 Middle Sambagawan. It extends from Genda, lying to the west of 

 the town of Kodama to Öda, along the banks of Minaregawa, for a 

 distance of nearly 6 km. For the study of the Middle Division, the 

 river-banks are worthy of personal inspection in order to get an insight 



