DOLEUITES AND RHYOLITES OF NATAL AND ZULULAND. 157 



PLATE IV. 



Fig. 1.— Contact-dolerite from Umhlali, Natal (p. 146). Porphyritic 

 felspars micropegmatitically intergrown with quartz in variolitic base. 

 The felspars are represented as seen l^ietween crossed nicols. Magnifi- 

 cation 60 diam., 1-in. objective. 



Fig. 2. — Contact-dolerite from Intambanana Creek, Znhiland (p. 146). 

 Fantastically arranged strings of angite and magnetite in variolitic 

 base. Magnification 60 diam.. 1-in. olijective. 



PLATE Y. 



Fig. 1. — Olivine-norite from Umqueme Range, Znluland (p. 147). 

 Intergrowth of enstatite and angite, with felspar (as seen between 

 crossed nicols) and olivine (left lower corner). Magnification 60 diam., 

 1-in. objective. 



Fig. 2. — Enstatite-dolerite from north of Umhlatuzi crossing, Zuln- 

 land (p. 148). Phenoeryst of enstatite (in centre) surrounded by zone 

 of angite. Magnification 60 diam., 1-in. objective. 



PLATE VI. 



Fig. 1. — Hybrid rock from five miles above crossing of the Mapamulo 

 and Isidembeni roads overUmvoti river, Natal (p. 150). Small reddish- 

 browai biotites and pale green augites with enstatite in felspar-mosaic. 

 Magnification 60 diam., 1-in. objective. 



Fig. 2. — Grranophyre from Umhlali Beach, Natal (p. 151). Small 

 felspar prisms siirrounded by skeletal crystals of quartz, which in 

 turn are surrounded by spherulitic material. Magnification 60 diam., 

 1-in. objective. 



VOL. 2, PART 2. 12 



