130 B. KOTO 



uses, a bmall serpentine-quarry Avas worked until a few years ago, at 

 Yosino-iri in Misawa, for making small ornaments ; but it is now 

 entirely abandoned. 



The foregoing is only a few, short remarks on the serpentines 

 found within the confines of the »Sambajj'awan series ; but the u'reat 

 majority of its occurrences fall in the succeeding or Mikabu period, 

 where ophitic rocks occur in large detached masses within the am- 

 phibolite and pyroxenite, accompanied by a very interesting, secondary 

 glaucophane ; the treatment of these augite and h(.)rriblende rocks lies, 

 however, beyond the scope of the present paper. 



(I) Conclusion. 



The Sambati'awan is the lowest of the long; iceolo^j^ic series ever 

 found in the Chichibu district, covering an area of about 270 km., 

 and occupying the north-western rim of the central depression of 

 Chichibu. The main anticlinal axis runs from iSueno near Yorii on 

 the south-east to Obata on the north-west, with a trend of X. 70° W. 

 for a distance of 27 km., touching the northern side of the Samba- 

 gawa and also the upper course of the Hino valley ; and along this 

 line we really find good exposures of the Lower Division, and conse- 

 quently of the piedmontite-schist. The widest portion of this Samba- 

 gawan belt is traversed on the south by the Arakawa river and on the 

 north by the Kanna river, the strata dipping away gradually from 

 the main axis of elevation. 



The rock-complex which comes underneath, is probably mica- 

 schist and biotite-gneiss as developed in the Island of Sikoku ; but 

 this hypothesis cannot be established until an actual contact is really 

 ascertained ; what lies directly above is îi tliick series of gabbro and 

 diabasic derivatives and serpentines. 



To summarize the leading features of the three divisions, the 



