ON THE RUBIES OF BURMA AND ASSOCIATED MINERALS. 
153 
W. T. Blanford, # and the second edition of the same work by Mr. B. D. Oldham.! 
Interesting notes on this district are also to be found in Dr. V. Ball’s volume on 
‘ The Economic Geology of India ’ (1881), and in Mr. F. R. Mallet’s work on 
‘ The Mineralogy of India ’ (1887). 
Concerning the remarkably similar rocks of Ceylon, there seems to have been very 
little published in the interval between the appearance of the memoir of de Bournon 
(1802) and that of Lacroix (1889). 
Since the period, however, when de Bournon’s valuable memoir first made geologists 
and mineralogists familiar with the corundum localities of Salem and Ceylon, a number 
of works have been published, dealing with the general question of the mode of occur¬ 
rence of corundum and its associated minerals in other areas. In the Indian peninsula 
various authors have described the occurrence of corundum in Mysore, North Arcot, 
Travancore, Coimbatore, Hyderabad, the Central Provinces, Singbuhm, Monghyr, 
South Rewah, and the Khasi Hills. In South Rewah Mr. F. R. Mallet has given 
an account of a bed of corundum rock, in places at least thirty yards in thickness, 
intercalated with the gneiss series of the district.! The purplish, granular corundum 
rock of this locality is described as being associated with diaspore, fibrolite(?), para- 
gonite (euphyllite), and tourmaline (schorl); and the mass is said to be interfoliated 
with tremolite-schist, amphibolite, and white and green jade—the latter coloured 
with chromium compounds. 
Next in importance to the corundum deposits of the Indian peninsula are the great 
belts of corundiferous rocks of the eastern United States. These extend along the 
line of the Appalachian Mountains from Chester in Massachusets to Northern Georgia 
and have been well described by many authors, among whom may be especially 
mentioned John Dickson, § Dr. Charles Jackson, || Professor Shepard,H and Colonel 
Jenks while Mr. T. M. Chatard, of the U.S. Geological Survey, has given an 
admirable account of the chief localities and geological relations of the gem-bearing 
rocks.+t Along this line of country the corundum, occurring either alone or mixed 
with magnetite (emery), is found in veins of chloritic and vermiculite minerals (ripi- 
dolite, jefferisite, &c.), traversing dykes of chromiferous serpentine, which cut through 
the granites and crystalline schists of the mountain axis. The chief minerals asso¬ 
ciated with the corundum along this line of country are sillimanite (fibrolite), hercy- 
nite, cyanite, smaragdite, zircon, lazurite, rutile, pyrophyllite, and damourite. 
* Loc. cit., p. 26. 
t Loc. cit., pp. 38, 39. 
X ‘ Records Geol. Sitrv. of India,’ vol. 5, p. 20; ibid., vol. 6, p. 43. 
§ ‘ Am. Journ. Sc.,’ vol. 3 (1819), p. 4. 
|| Ibid., vol. 39 (1865), p. 65. 
H Ibid., vol. 40 (1865), p. 112; vol. 42 (1866), p. 42; vol. 64 (1868), p. 256. 
** ‘Quart. Journ. Geol. Soc.,’ vol. 30 (1874), p. 303. 
ft ‘Mineral Resources of the United States ’ (1883-4), p. 714, &c 
MDCCCXCVI.—A. 
X 
