JOÜKNEYS THROUGH KOREA, 109 



also show ottrelite and pyrites. The rock is therefore ottrelite-hiotlte- 

 schist. It represents an altered prodnct of the sandy portion of 

 a sedimentary, as the sericitic member does of the arkose and 

 clayey portions. Next in ascending order comes (3) a coarse 

 colorless quartzite which may be a dyke or a normal member, but 

 I cannot decide wliich. This is again overlaid by (4) a Garbenschie- 

 fer with stripe-flecks, 2 cm long, making gradual transitions to (5) 

 normal greenish silky phulUtc. Tiiese flecks are spots where 

 coaly particles accumulated in the colorless, homogeneous 

 crystalline ground of unknown nature, probably plagioclase" 

 Weathering gives to the last two rocks the rusty brown color 

 which characterizes the surrounding hills. 



The age of these highly metamorphosed sedimentaries cannot 

 be stated with certainty, but I include them at present in the Me ta- 

 mer phic Mesozoic for lack of facts which necessitate a change 

 to another time division in geological chronolog3^ Rocks akin to 

 the present sediment-metamorpliics have already been noticed'^ 

 as occurring at Tong-pok and Mu-an'-\ These however, differ in 

 that the rocks were originally partly pyroclastics, partly massive- 

 eruptives, and only a few were true sedimentaries such as 

 graphitic-anthracite bed and limestone-conglomerate. Moreover, 

 the Ihng-pok rocks are highly cataclastic and deeply metamorphosed, 

 and bear the stamp of katogene, while the Kun-san schists show 

 anogene metamorphism. 



From a hill top one can see to the west din-ing èbb- tides an 

 extensive mud flat due to the tidal difference of 15i feet on 

 this coast. When the tide returns the Keum-gang becomes 1-2 

 fathoms deep for 35 hn up-stream as far as Kang-ggong"^ which 



1) See ante, pages 66 ami 68. 2) See cmte, page 72. 



^) urn 



