96 B. KOTO 



and a few feeble traces of cleavage alone serve to indicate the presence 

 of otherwise unrecognizable felspar in the rock-mass. The precise 

 nature of the felspar could not be made out, simply because no favour- 

 ably orientated sections could be seen. Anyhow, the habitus of the 

 mineral coincides with that in the normal sericite-schist (cf. page 88). 

 As in the latter rock, the interposition of iron-glance and iron-mica 

 characterizes the felspar in this schist. 



Of the sericite the writer has nothing to say, except that it is, 

 as usual, colourless or of a light greenish tinge, and has a line fibrous 

 scaly structure. Light yellowish-green, rhombic dodecahedra of 

 garnet are tolerably abundant. 



In the Island of Sikoku, the piedmontite-schist is accompanied 

 by a blue glaucophane-schist, a brief description of which has been 

 already given in a separate paper. ^^ This rock seems to be absent or 

 at least has not as yet been found in the collections from Chichibu. 



The piedmontite-schist is characterized by its peculiar outward 

 appearance, of which enough has been already said, and this serves as a 

 good criterion in tracing out the lower division of the Sambagawan 

 series. 



(c) The Middle Division. 



Spotted graphite-schist, and Spotted chlorite-schist. 



The horizon of the |'iedmonti("e-schist marks the beginning of the 

 middle division. The rocks are principally of two types, viz., (I) the 

 spotted black schist and (II) the spotted green schist, whose mani- 

 fold alternations make up a considerable thickness, constituting the 



1) B. Koto, A note on glaucophane. This Journal, Vol. T. Part T. p. 8. 



