The Quarterly journal of the Geological Society of London . Photo. Be T<ros«. Quart. Journ. Geol. Soc. Vol. LXX, Pl. LI I. 3. x O. Photornicro. IGNEOUS ROCKS FROM GUNONG BAKAU. Vol. 70.] TOPAZ-BEARIXG- EOCKS OF GUNONG BAKAU. 381 the magma attacked to boil up and consolidate in the granite asan intrusive vein-rock. Segregation of the first-formed mineralsduring cooling led to the irregular distribution of the constituentminerals in the veins. I am indebted to Dr. H. H. Thomas, , for assistance inpreparing the photomicrographs reprodu
The Quarterly journal of the Geological Society of London . Photo. Be T<ros«. Quart. Journ. Geol. Soc. Vol. LXX, Pl. LI I. 3. x O. Photornicro. IGNEOUS ROCKS FROM GUNONG BAKAU. Vol. 70.] TOPAZ-BEARIXG- EOCKS OF GUNONG BAKAU. 381 the magma attacked to boil up and consolidate in the granite asan intrusive vein-rock. Segregation of the first-formed mineralsduring cooling led to the irregular distribution of the constituentminerals in the veins. I am indebted to Dr. H. H. Thomas, , for assistance inpreparing the photomicrographs reproduced in PL LII. EXPLANATION OF PLATES LI & LI. Fig. 1. A quartz-topaz vein in Quarry C : note the flat top. (See p. 368.) 2. Section in Quarry C, showing the reaction-border of schorl-rock. Plate LII. [Microscope-sections of the Grunong Bakau rocks. The numerals referto the numbers of the slides in the Authors collection.] Fig. 1. Quartz-topaz rock. Gunong Bakau. Slide No. 2312. Ordinarylight. X 19 diams. The figure shows topaz with well-definedcleavage, and quartz, also a few scattered grains of cassiterite. 2. Quartz-topaz rock. Quarry
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Keywords: ., bookcentury1800, bookdecade1840, bookidquarte, booksubjectgeology
