66 -^^T- 2. — B. KOTO : 



with the strike N. 25' E., and the dip N.W. South of the 

 Archaean terrane is the inasanite region of Y'ông-am, ah'oady 

 referred to. 



ÎSVM-I'HÏONG 



^o From Nam-phy'ông to Hoa-öun, we find at first felsophyre and 



its breccia which occupy a large area, extending as far as Neiing- 

 jyu '\ tlie rocks being hght-green or brownish-red according to 

 the stage of decomposition. Massive greenisli porphyrite comes 

 next, near Iloa-sun, where felsophyre reappears from below. 



From here Messrs. Yabe and Inouye went sixteen kilometers 

 to Tong-polx, finding at about one fourth of the distance (4 hn) a 

 schistose biotite-granite in which the eyes of feldspar are scarce- 

 ly discernible. It is then replaced b}^ a wonderful complex of 

 highly altered rocks with the appearance of phyllite, sandstone, 

 schalstein, and the like, whicli the microscope shows to be 

 metamorphosed and crushed eruptives and sedimentaries. 



i. One rock is a flagstone of fine-sandy appearance. It is 

 composed of banded spherulite rocks, such as are frequently 

 associated in the effiisive form of Hparite and quartz -porphyry. 



ii. Another rock looks like a flaxseed iron ore — a kind of 

 red hematite witii granulated surface. The granules appear 

 under the microscope to be fragments of quartz cemented by fine 

 crystalline particles which are mixed up wdth lamellae of musco- 

 vite and dust of red hematite. It is an altered ferruginous tuff'. 



iii. The third is a grayish, highly lamellar muscovite-schist 

 with enclosed quartz grains which cause the wavy surface of 

 its cleavage-plane. To my great astonishment, the grains under 

 the microscope turned out to be the so-called porphyry-quartz with 



1) See footnote 3, p. 50. 



