JOURNEYS THROUGH KOREA. 135 



of plagioclase and quartz in a fluidai glassy groundmass, now 

 greatly devitrified. The mass has gentle easterly dips. We have 

 here a good example of the coming together '^ of porphyrite and 

 felsophj^re, — a condition frequently met with in the southeastern 

 corner of the penisula. 



Leaving the gorge at Mul-geun, we were again on the open 

 flat of tlie Nak-tong-gang '\ and finally reached Fusan on January 

 19th, 1901, after having spent seventeen days in the Third 

 Traverse. 



Mäi-ka% or Makau 



(One of the Great Hetik-san Islands) 



Na-jyu Group. — There are a great many islands, large and 

 small, off the free port of Mok-plio, called by the Koreans collec- 

 tively the Na-jiju Group, because they were formerly subject to the 

 district office of Na-jyu. West of this Inner Na-jyu Group and 

 separated from it by the Na-jyu Canal (" the Single Canal " of 

 European charts), there lies another wliicli may conveniently be 

 called tlie Outer Na-jyu Group. It comprises two subgroups, 

 which are, counting from the north, the Great Heuk-san-tô, and 

 the Hydrographer islands, besides an isolated island Heuk-san-tô ^\ 

 or the " Black mountain Island." The last lies farthest from the 

 mainland and was in early days the last port of call for native 

 junks bound for South China. 



1) The same occius iu West Borneo. Easton says that diabases and quartz-porphyries 

 always appear in association. Both are i^robably to be considered as extreme members of the 

 differentiation-products of a magma, N.W. Easton. : " Geologie eines Theiles von West Borneo." 

 Janrhoek van het Mljmoesen in Niederlandsch Oost-indlc, Batavia, 1904. 



2) See page 16. 



3) fê Jn ê ■!) Wi Ul %• Tliis is better known among the Koreans as Ka-ka-to (pj" 

 ^ ^), aud as Ross Island by Europeans. 



