132 B. KOTO 



be found in the " Graniilitmitte];>ebir""e " in Saxonv. also in the 

 Tanniis, and the Ardennes. 



To the present writer, it seems highly probable that the whole of 

 the Sambagavvan rocks represents a dynamometamorphi'- state of 

 originally diitereiit rock-types. The normal sericite-schist may have 

 resulted from a coarse graywacke, while the epidote-sericite-gneiss 

 may have been changed from a tine variety. The chlorite-amphibole- 

 schist miiiht have been derived from a basic tufaceous material of an 

 erLlpti^"e rock or rocks, whereas the graphite-seficite-schist may have 

 its origin in a carbonaceous slialc. 



We have rocks ana]o<i'ous to the îSambayavvan series in the 

 higher strata — transition-system — but with quite a dissimilar aspect. 

 Between the Sainbagawan and the Upper Carboniferous Fusnlina lime- 

 stone in Cliichibu, there lies a thick complex of rocks, being made up of 

 alternate layers of arkose graywacke-sandstone, black slate, hornstone, 

 adinole slate, diabase sheets, diabase-tutfs, schalstein, etc.— these are 

 now comprised under the name of the ? ])ve-C'arhonifero'us. To the 

 writer, the »SambagMwan rocks seem not materially to differ from 

 these, except that the former have now been changed into apparently 

 unlike rocks. The sericite-gneiss near Döbeln in the ' Granulit- 

 gebirge ' in Saxony is, according to J. Lehmann,!^ a metamorphosed 

 graywacke. Thus the supposition, that our sericite-gneiss and sericite- 

 schist may liave resulted from a felspar-graywacke-sandstone. appears 

 not entirely impossible, and the same may be said of the graphite- 

 sericite-schist which was once a black carbonaceous slate. 



One fact should not here be passed unnoticed ; i. e. the richness of 

 felspar in (jur graywacke-sandstones ; indeed, that mineral makes up 

 the great bulk of the constituents of the rock. In ordinary sandstones 

 formed by the deposition of washed sands along the shores and river- 



1) ' Entstehung- der altkryst. Schiefer.' Bonn. 1884. 



