84 ß. KOTO 



has lately induced the writer to make a somewhat closer study of these 

 ancient schists. 



The rock-components of the Cliichihu schists are of a crystalline 

 natm'e as in those of normal types ; the texture of the rocks is, 

 however, less perfectly developed, some being compact, others thick- 

 handed, while the third is wrinkled and corrugated by mechanical 

 action due to the earth's movement. All our schists in common 

 present a phjllitic aspect ; but the use of that name should here be 

 guarded against, for to the term phyllite, geologists attribute some- 

 times a eeochronic meaning; on account of its usual occurrence in the 

 crystalline schist system ; sometimes we understand it petrographi- 

 cally as having green ov colourless fibrous scales — the phyllitic 

 constituent, and also as having a schistose structure. 



The most characteristic components of our schists are sericite, 

 epidote, and calcite. The presence of these already bespeaks the 

 nature of the rocks in question ; for in the genuine crystalline schists, 

 these minerals are often totally absent. 



Taken in îieneral, our rocks have a close relation to the so-called 

 'Casanna Schiefer,' or Studer's 'aeltere graue Schiefer' of the Alps, or 

 to the sericite-gneisses, and sericite-schists of the districts of Nassau, 

 and Taunus, in Germany. 



The whole series of the rocks in question may be found along 

 the Sambagawa valley,^^ north-west of a small town Onisi,^) Kanra 

 district, where it is developed in its full proportions, and where 

 interesting exposures may be seen. The writer proposes now the name 

 of the Samhagawa .^ieries to the metamorphic schists of this district. 

 It is a name which does not involve any theory, and may be used by 

 any party in the case of a controversy respecting its age. This 

 designation may not be of a mere local value as the same series recurs 

 in other parts of Japan, especially in the Island of Sikoku. 



