8 ART. 12. — B. KOTO : 



This is a grayish-green, even-schistose and silky-h;strc(l rock, 

 mainly composed of an extremely thin-lamellar, optically anomalons 

 chlorite, which is arranged ])arallel on a ground of dust-filled plagioclase 

 with interdigitate, granoblastic structure. Tlie vitreous plagioclase is 

 sometimes simple-twinned extinguishing light from 12° to 15° with 

 reference to the suture of the twins ^\ The magnetite is both automor- 

 ])hic and xenomorphic, and dissolves in HCl. Iron-pyrite is found 

 intermixed with the magnetite. There occurs abundantly an ineqni- 

 grannlar mineral resembling epidote (fig. l.\ the microscopic grains 

 of which have sometimes an acute rhombic shape. It extinguishes 

 light diagonally, and has a high double-refraction. The grains of the 

 mineral resemble tlie drop-like granules which compose leucoxene. 

 Absolute identity witli common epidote is not proved. They may 

 perhaps be either Titanitc or Orthitc. We find the same in pied- 

 montite-schist -' and chlorite-schist near Tokushima, Awa Prov., Ja])an. 

 One finds something similar in shape to the present mineral in Rosen- 

 busch-WÜlfixg's "Physiographic", Bd. I. Tafel IX. fig. 3, where it 

 is identified as quartz. There is also found a colorless, microscopic 

 megaphenocryst of unknown mineralogical nature with low bire- 

 fringency. 



The rock is simple in mineralogical composition, and no accessories 

 except hypidiomorphic tourmaline and problematic titanite, are seen in 

 the slides. Locality: Neureum-ho'jai'^^ . 



d) Argillite. (PL I. fig. 4.) 



Composition : Essential: Albite, quartz, sericite. 



1) This ;igree> well with the albite-twia after the albite law cut nearly at right angles 

 to n. P. Kozlozsnik: " Ueber die metnmorphen und paläozoischen Gesteine der Nagybihar." 

 Mitlheil. aus dem Jahrb. d. Kön. Ung. Geol. Amtalt, B,I. XV., 2. Heft, S. 150, 1906. 



2) I intentionally omitted to mention this microscopic component (PI. I. fig. 1.) in my 

 paper on "Some Occurrences of Piedmontite in Japan (this Journal, Vol. I. Part III. 1887) 

 as the nature of it w.as entirely unknown to me. Since, then, T have seen not infrequently 

 tlic same mineral in metamorph'c s-chi.sts of tiiis country, and, no doubt, it may also be found 

 in analogous rocks in other countries. 



3) mm 



