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Y. The Rubies of Burma and Associated Minerals : their Mode of Occurrence, Origin, 
and Metamorphoses. A Contribution to the History of Corundum. 
By C. Barrington Brown, Esq ., Assoc. R.S.M., F.G.S., and Professor 
John W. Judd, C.B., LL.D., F.R.S., F.G.S. 
.Received February 6,—Read March 7, 1895. 
[Plate 6.] 
Contents. 
Page. 
I. Introduction.. 151 
II. Geographical Distribution of the Ruby-bearing Rocks in Upper Burma.156 
III. Physical Features of the Ruby-mining District .159 
IV. Geological Structure of the District. 
1. Hill Wash..161 
2. Alluvium. 164 
3. Sandstone. 167 
4. Mica Schist.167 
5. Gneissic Rocks. 168 
6. Crystalline Limestones.172 
7. Granite.182 
V. Economics. 
Mines (a.) Twinlones. 184 
„ ( b .) Hmyaudwins.185 
„ (c.) Loodwins ..186 
,, ( d .) Quarry Mines.186 
VI. Petrology. 
1. Gneisses, Granulites, and Schists . .. 194 
2. Acid Rocks—Pegmatites, Aplites, Ac. 196 
3. Basic Rocks—Pyroxene Gneisses and Granulites, Pyroxenites and Amphibolites 199 
4. Crystalline Limestones—Cipollinos, Calciphyres.205 
5. Gravels and Earthy Deposits.208 
VII. Mineralogy. 
1. Association of Minerals in the Gem-localities of Burma.208 
2. Origin of the Corundum, Spinels, and other Minerals occurring in the Lime¬ 
stones of Burma.214 
3. Metamorphoses of the Rubies and Associated Minerals of Burma.218 
VIII. Summary of Results.225 
I. Introduction. 
In the year 1798 Greville established and named the mineral species “ corun¬ 
dum ,'” the crystallized oxide of aluminium ; and in an appendix to Greville’s paper, 
8 . 4.96 
