76 AKT 2. — }>,. KOTO : 



appear as far as Tam-jjang which is located on the whitish 

 compact masanite whose fine porphyritic components are biotite, 

 quartz, and epidotized feldspars. Tam-yang (90 m) is at the 

 north head (PI. XII. fig. 1) of the Na-jyu plain, skirted by a 

 sharp ridge with the south-west trend of the Upper Kyong-sang 

 formation. 

 Tam-ïanu From the cumnai of Tam-yang we turned eastwards along 



the boundary line of the eye-gneiss and the compact masanite '\ 

 the latter capping tlie gneiss with a northwesterly dip. We 

 gradually ascended the flat-topped hill of Pang-chliyuk-chhi (140 

 m)'^, viewing on the east the isolated rocky point of Ami-san 

 which is built up of fine eye-gneiss. This flat-topped elevation 

 is the water-parting that divides the waters of the Yellow Sea 

 from those of the South Sea. 



CHHYANG 



^u**- We then descended and followed a river in the eye-iineiss 



terrane dow^n to Sun-chliyang where our route joined that of 

 Messrs. Yabe and Inouye '*\ The cumnai lies in a denudation- 

 hollow in granitic rock, which, like many other Korean basins, 

 was formed by simple erosion and beveling. The environs pre- 

 sent the bare " bad lands " scenery. To the north one sees a 

 group of isolated tops, like Ami-san already mentioned, of eye- 

 gneiss, which borders on the diagonally-running ridge of the 

 porphyritic hinterland of the No-ryong system. To the south lies 

 the waU-like ridge of muscovite-schist ^^ of Ok-koa beyond liil- 

 locks of eye-gneiss. 



1) This ^vllite eruptive forms the hill surrounding the well-known ancient castle of Chhyu- 

 uöl-san (fk M ]h)' 



2) m mm 



3) See imge 69. 4) See ante, page 69. 



