JOUENEYÖ TlIliOUGH KOKEA. 77 



We now took the route to Nam-uon passing over hills of 

 gncissoid granite of white porphyritic structure, fast falling into 

 debris and decomposing into bare red earth, and after two hours 

 wo were at the ferry of Chyök-söng-Jln (115 m). 



The cliff (PL XI [. ßg. 3) on the otlier side readily attracts 

 the attention of a geologist, for it rarely happens that one sees 

 to full advantage the back of a schistose plane of coarse lamel- 

 lar biotite- orthogneiss in its horizontal, regular extension. The 

 road led through a gully of this rock where we had an excep- 

 tionally good opportunity to observe the various stages of schis- 

 tosity and the contact with the overlying muscovite- schist. The 

 underlying rock is an intensely mylonitized orthogneiss rich in 

 biotite, and is of the habit of the one found at the Kamnam- 

 cliJii in my first traverse '\ The complex has variable directions 

 of stretching ; but generally speaking, it is N. 20" E., and dips 

 50 ' S.E. The ridge runs in the same direction soon ending on 

 the south at about 2 km distance ; northwards also it extends 

 only 4 km, gradually becoming lower as one proceeds. 



The orthogneiss is conformably overlaid by the psammitic 

 muscovite- schist of the Kang-jin type, together with black and 

 green phyllites. It was of great interest to me to observe the 

 contact. The parallel- planed muscovite- schist, which was origi- 

 nally fine sand, is impregnated and veined with granitic material 

 at the plane of junction, indicative of the igneous origin and 

 later age of the orthogneiss. The complex of the gneiss and 

 schist belongs to the same geological unit as those of Kang-jin'^, 

 Ok-koa ^\ and Neung-jgu *\ If the patches be connected on a 



1) See page 51, footnote 6. 



2) See i)fige ^4. 



3) See page 69, the Thong-myöng-san rock. 



4) See footnote 3, page 50. 



