50 ART 2. — B. KOTO: 



From P}ia-chhyëng^\ we left the coast and proceeded due 

 west on the elevated ground of Ktin-m'6ri, then over the Kir'ôki- 

 chili pass, through the terrane of the Hadong gneiss. Here the 

 eyes become gradually less numerous and smaller. At the 

 country-town of Po-söng ^\ the rock becomes normal orthogneiss 

 composed of automorphic, twinned plagioclase, and ratlier large 

 xenomorphic orthoclase with typical undulatory extinction, anhe- 

 dral quartz, and deep-brown biotite with pleochroic halos. In 

 short, it is a coarse granular, sheared granite rich in plagioclase. 

 It is difficult to say liow much it owes its present state to 

 mechanical crushing and liow much to piezocrystallization. Here 

 we observed a sudden change in the axis of schistosity fi'om 

 S.20 W. to N.20"E. 



Po-sövG Although Po-söng^^ lies on a small elevated fiat near the 



south coast, its waters drain northwards to the Söm-jin-gang, 

 and we were told tliat along its course, in the river-bed gold 



composed of only microcline and schorl. These seem to be dyke-rocks. Midway a dioritic dyke 

 reappears. 



Within a disüinco of 5 or 6 km, a black rook made its appearance with an external 

 appearance of a graphtte-schbt with blue spots of quartz. The microscope proves it to be a sheared 

 form of either (quartz-porphyry or quaitz-thorite-iiorphyiite. Its black color is due to the presence 

 of magnetite in the chloritic, film. All the components except quartz (abuniLint in liquid-in- 

 closures) were reduced either to minute grains or threads. Green schistose rock was also found 

 cleaving into irregular Klabs. It contains a large amount of qiiartz (8 vim) wliich is crushed 

 exhibiting undiüatory extinction. Threads of chloritic matter, found in streams, color the rock 

 green. 



It is evident that those icprcsent the mylonU'aed iii<ir<jln of the Chirl-san sphenoid. 



Gold placer is found at Powj-nai jyang, but its original home is unknown. From here to 

 l'o-sung all the rocks are sheared forms as is evinced by the inspection of specimens. My. route 

 touched the eumnTd of Fo-küixj. See page 68. 



1) iS W 2) See p. 49, fœtnote 5. 



3) The stretch from Po-söng to Xeitng-jtju was reconnoitered by Mr. F. Kobayashi who 

 found at Kat-turi a bed of psammitic muscovite- schist, a prolongation of the schist of Kang-jin^ 

 overlaid by n, grayish medium-grained sandstone and brownish I'elsophyre. The find of sand- 

 stone was of special interest to me ; for by its presence I was enabled to understand the forma- 

 tion of the graphite and much-altered sedimeotaries of Tong-pjJc, lying farther north. 



