46 Y. KIKUCHI 



üf. (3, 7, Ijut only the halves of the two iiidividiials attached by 3/ 

 without penetratuig. 



Fig. 9. — Section of a porphyritic crystal within the hiva, niagni- 

 iied about 20 times, cut nearly parallel to the face F, consisting of the 

 nonfissured upper, and the fissured lower, halves in a parallel position. 

 These hidividuals consist of two principal twin-individuals a, (y, and 

 h. h, of the Albite type, the part c, c, showing an optical anomaly. 



Fi(j. 10. — Same as fig. 9, magnified 10 times, the rectangular 

 outline being f jrmed l)y J/, //. ^ t'l'y characteristic diagonal fissures 

 are here developed, similar to those of the lower half of fig. 9, the 

 upper right and the lower left corners being removed by the one set 

 of fissures which is more perfect than the other. A single lamella of 

 the Albite type traverses the middle portion. 



F'kj. 11. — Section of a porphyritic crystal, cut nearly perpen- 

 dicular to the zone F : il/, magnified 5 times, showing the broader 

 l-*ericline-lamellii?. 



Fig. 12. — Same as fig. 11, magnified 10 times, showing the fine 

 transversal Pericline-lamelke, and the broader vertical lamelhe rt, ?>, 

 probably of Albite and of Carlsbad types. Zonal structure is well 

 exhibited in this section under polarised light. 



Fig. 13. — Corrosion-figures on the cleavage-face 7' ; the acute 

 angles of the triangular impressions are pointed backward. 1'hey 

 are shown magnified in a, h^ c. 



Fig. 11. — The same as seen on the cleavage of F\ of the same 

 form as those on F, but the acute angles are pointed forward. Magni- 

 fied in a, h. 



Fig. Id. — The same of elliptical forms, on the cleavage-face of i)/. 

 The fine lines represent the direction of the trace of the "Rhombische 

 schnitt '' a, figure produced by hydrochloric acid ; h, by fiuoric acid, 

 magnified. 



Fig. IG. — The same as seen on the cleavage- face 37'; a, h as in 

 fio^. 15. 



