56 ART 2. — B. KOTO : 



formation, Latei", Mr. Yaek '^ on n\v snggestion made two journeys 

 in Korea, and discovered a Jurassic bed in tlie Ki/ông-sang 

 formation wliose higiier liorizon is built uj) of a complex of por- 

 pliyrites and green breccias, of considerable thickness '\ Now at 

 the base of the porphyritc rocks, tliere occurs not infrequently 

 quartz-poi-phyries (rhy elite) and their derivatives, for example near 

 Masan-pho. 80 L am rather inclined to consider the quartz- 

 porphyries to 1^0 the basal member of the eruptive Kyöng-sang 

 formation. So far as my knowledge goes, no young deposits 

 are observed upon the formation except Alluvium ; and from its 

 close relation to the underlying Jurassic bed, the Upper Kyong- 

 JuEAssK! saiKi formation, inchidimi ihc nuart.i'-porphur/L must he of Jurassic or 



K0CIKS • ' , J X 1 . ,' 



posl-Jurassic age. 



From the elevation, Phyöiig-sii-cJihi, already mentioned, we 

 saw to our left a low, regular equatorial ridge which is evident- 

 ly the western continuation of that of Kang-jin. In front of us 

 was a depression. On tlîo south, tlie reef of Söng-mim-san runs 

 westwards. Having crossed a flat of rice-field after about G hu, 

 we finally came to tlie foot of a pass where the road divides, 

 one leading to Yon g- an and the other south-west to the monas- 

 tery of Tai-diin-s((n. We climbed the pass ""'^ and found the 

 same quartz-porphyry, besides a pinkish compact felsophyre ex- 



1) This Journal, Vol. 20, Article 8. 



2) Rinne (Zeitschr. d. I), geol. Gesell. 56, 19U1.) Lus t^iveu a partial prulile of Scliuiliug- 

 schan (Ling tan) off Kiau-chaii liay where a complex of shale ami sixndstone is inteibanded 

 with aplite iiud p^rphyrite, and the whole is covered with porphyrite-breccia. The Kiau-chaii 

 sedimentaries are sjiid to be of the Carboniferous or Triassic, but ours are of the Jurassic or 

 post-Jurassic. A feature of great interest attaching to Einnc's section is an intercalation of 

 sheets, or eventually dykes of aplite and porphyrite with a top cover of breccia. The rocks 

 and their mode of occurrence iinmistakably resemble the Upper Kyöng sang formation. So far 

 as I understand the geology of Korea, porphyrite and its derivatives together with felsojjhyre 

 and its tuffs are older than masanite (graniteporphyry), which occurs in shallow laccoliths, 

 arching up and intruding into the sheets of porphyrite and felsophyre, 



3) U-seiil-ühhi ^ m i^- 



