58 AT^'T. 2.— r.. KOTO: 



from the divide at Näm-ni-Ji/rnu/ '■, and went along the south foot 

 of Ok-mäi-san to catch a ghmpse of tlie southern entrance (Ph 

 VII. ßg. 3) of the well-known whirlpool of Mi/öng-i/ang-jin "\ The 

 channel between this (San-chl-nön^^) and that {P[i'ôh-plm-chifông) 

 side of the Island of Chin-do is only H hn wide, popularly called 

 the Narrows of Py'ôU-pha-chywig '\ Tlie water was at the time run- 

 ning southeastwards like a rapid stream. The rock is the same 

 brecciated felsophyre. 



The above-mentioned Ok-mai-san ^^ stands close by the shore, 

 and is composed of a thick, whitish clayey rock which is ex- 

 tensively quarried and carved into fine cigarette-boxes. In Seoul 

 we find them abundantly in the shops side by side with the still 

 finer, blue or yellow ok-tol ''^ boxes and utensils from Tan-chhycn 

 in Ham-gißng-Do. This unctuous white claystone of moderate 

 compactness is seen under the microscope to consist of a pure 

 amorphous and isotropic powder of clayey matter locally im- 

 pregnated with beautiful hematite granules whose presence causes 

 the carmine-red patches in the rock '■ . 



I attribute the formation of this thick white clay to a local 

 sedimentation of decomposed felsophyric substance shortly after 

 the eruption of the effusive, and the post- volcanic action upon 



brownish-red felsophyre of the aspect ami texture of schalstein, overlying the typical quartz- 

 tsingtauite ; the Litter is developed all the way as far as Tok-nai-jyang. From So-chhang west- 

 wards, the same red felsophyre with overlying, fine, parallel-planed tnfiite and shale (N. 7U°E., 

 dip. S.E.) were seen as far as the ferry and even Mok-pho, 



1) m ffl *^ 2) Rl # ^ 3) Htt^ 4) If-iè^ 5) ^Jim 



6) The so-called Korean jade. 



7) The stone quanied here is, therefore, called hoa-ban-sok or the dappled pink stone. A 

 chemical analysis of it has not yet been attempted ; but the experiment made on its refractory 

 property gave the following resiilt : 



No. 1 Above No. 30 of the Seger normal cone 



No. 2. . . . 



No. 3 



No. i 



