PLATE III. 



Figs. 1 and 2. — A viiriely of tlic tliird modification of linie-silicatc horn- 

 IL'Ls built up almost solely of andraditc. The name garnctite or 

 garnetfels is given to sucli an aggregate. The garnet, as may 

 be seen in the figures, shows well-defined optical fields of the 

 rhombic dodecahedron type. Fig. 1 exhibits a combination of 

 optical pyramids and isomorphic shells — a case rarely observed 

 in anomalous garnets. P. 12. Magnified 15 in fig. 1, and 50 

 diameters in fig. 2 



Fig. 3. — Meta-diorite. Slide of an amphibolite-like rock intruding into 

 slaty mica-schist (PI. I. fig. 2). It is mainly built up of reedy 

 hornblende with secondary biotite in its centre as if both minerals 

 were derived from augite. The whitish patch is a mosaic of 

 albite. The whole aspect of the rock in the slide is typomorphic. 

 P. 16. Magnified 63 diameters. 



Fig. 4. — Porphyritic hornblende-granite, forming the mass of On-jin-san. 

 It is the ' ore-bringer ' and the originator of the contact-metamor- 

 phism of the Hol-gol region. A noteworthy feature of this rock 

 is the corroded aspect of the quartz which is moulded to ortlio- 

 clase. This texture is characteristic of the porphyritic granite. 

 Pp. 13-1-1. Magnified 18 diameters. 



Fig. 5. — Flow-ba.salt. The white patch in the centre of the figure is a 

 vesicle lined with highly biréfringent cuboidal grains of datolite. 

 P. 16. Magnified 50 diameters. 



Fig. 6. — Stielbasalt. Li the centre of the figure is seen a large piece of 

 corroded quartz, internally fritted and traversed with cracks and 

 externally fringed with radially arranged, violet augite-needles, 

 which become green at the contact with the ' quartz eye '. Pp. 

 15-16. Magnified 50 diameters. 



