JOURNEYS THROUGH KOREA. 169 



ß) The tourmaline-microcline-pertliite. Tliis is a very coarse 

 maslied rock consisting of perthite, quartz, schorl and muscovite. The 

 latter two are idiomorphic, while the other two are xenotc orphie 

 though the perthite is idiomorphic with reference to the quartz. A 

 plate of the microcline cut in the direction of the (001) cleavage 

 piece shows it to be made up of parallel bands of irregular lamellae 

 with their axis nearly at right-angles to the P/M edge (a specimen 

 from Chyo-söng, 12 l-m east of Fo-söng ^\ The untwinned laraellfe have 

 the extinction-direction ± 17° with P/M ; while the twinned have 

 5° with P/M ia ths same senss. The (010) cbavage-facs has 6° in 

 the simple, and 17^° in the twinned with P/M in the obtnse 

 angle in both cases. Here we have therefore the microcline-perthite 

 with microcline base alternating with albite bands. Apparently simple 

 xeuomorphic plates of feldspar in other tourmaline dyke-rocks are 

 likewise probably microcline though I have no ground for denying 

 the presence of orthoclase in association with it. The qu irtz is granulat- 

 ed and highly charged with liquid inclosures. In short, the present rock 

 is the raylonitized tourmaline-microcline-microperthite. This sheared 

 dyke-rock occurs at places too numerous to mention. During my 

 journey I saw extensive occurrences of it between Chln-an and Song- 

 dam-^ at tlie west of the Yuk-slm-nyöivj pass. Generally speaking, it 

 appears along the proto-axis and west of the granitoid belt in 

 contrast to the melauocrato which being represented by adamellite ^^ as 

 already referred to, is chiefly confined to the east margin of the belt. 



V. The Kydng-sang Formation 



On the first geologic map ever made of the peninsula (1886) 

 by GoTTSGHE, nearly the whole of the Kymg-sang province was 

 embraced in the Carboniferous. During my reconnaissance jour- 



1) Ä feS« C.^ ^ :^ ra) See ante, page 50. 2) See ante, page 126. 

 3) Ortho-hornblende-gneiss. See ante, page 84. 



