134 ART 2. — B. KOTO: 



walled on our left (north) by a sheer precipice of many hundred 

 feet, exposing thick bands of rod breccia which dip slowly east- 

 wards ; while the right or depressed side was a series of dis- 

 continuous hills. The road follows the axis of the V-shaped 

 valley bottom. 



Not far from Yöng-san we observed a change in the nature 

 of the rock from sedimentary to igneous. The latter is the 

 eruptive (Upper) Kyömj-sang formation. The best exposm-es were 

 seen at Chl-tarl ^^ where the fusion-breccia, consisting of 

 frao'ments of greenish and reddish volcanics, becomes almost 

 massive. It is an ancient lava-flow. In appearance it resembles 

 an augite- andésite ^\ though geologically it is inseparable from 

 the diopside-porphyrite which has been frequently mentioned. 

 The greenish porphyrite is characterized by the presence of chlo- 

 rite and epidote, and the reddish variety by iron-glance, At 

 Ku-pah ^^ at the south foot of Chyong-nam-mn '\ I saw gold-wash- 

 ing being actively carried on in tlie sand, the excavations being- 

 carried to a depth of 40 feet in the gravel of the breccia, This 

 is a new type of the occurrence of gold, but the original home 

 of the precious metal is not definitely known. 

 s.or-xAN.;- At Sam-nang-Jln, now a railway junction, we were still in the 



jt-nction region of porphyrite imich weathered and colored green by chlorite 

 and epidote. After having made 4 hn on a sandy flat, we turned 

 southeast where the Nak-tong-gang river takes a southeasterly 

 course through the gorge of the Kkachhl-uôn "^ gate. The narrows 

 are built up of reddish, brecciated felsophyre with the phenocrysts 

 1) ^m 



'2) This is probably the same rock as that found near IMil-y.ing, and described by T.H. 

 Holland under the name of andésite. "Notes on Kock-specimens from Korea.'' QJ.G.S. 

 1891, p. 181. 



3) it +1' i) fô m Hi 



5) îïS ^ ^ PI- XXXII. fig. 3. See ante, page 10. 



