Geology and Mineralogy. 65 



tion by Prof. J. W. Judd of the specimens collected. The follow- 

 ing pages are quoted from the source named : 



" The famous ruby district of Upper Burma was almost unknown 

 to Europeans before the annexation of the country by the British. 

 It is situated about 90 miles N.N.E. of Mandalay, and about 11 

 miles E. of the military post of Thebayetkin, on the Irrawaddy. 

 The tract, so far as explored, is about 26 miles long and 12 broad, 

 and lies at elevations varying from 4,000 to 5,500 feet above the 

 sea-level. The principal mining center in this district is Mogok, 

 and the present workings for rubies extend over an area of 45 

 square miles ; old workings, however, being found over an area of 

 66 square miles. The principal mining operations are carried on 

 in the three valleys of Mogok, Kathay, and Kyatpyen ; but there 

 are some smaller outlying districts, in which mines were formerly 

 worked, in the Injouk Valley, near Bernardrnyo, at Wapudoung, 

 11 miles E. of Thebayetkin, and at Launzee, 8 miles S.W. of 

 Kyatpyen. There is also a small tract of ruby-bearing rocks 

 (crystalline limestone) at Sagyin, 24 miles N. of Mandalay; and 

 it is asserted by the natives that two other limestone hills, 15 

 miles N. of Sagyin, have yielded rubies ; while old ruby workings 

 were found in making the railway at Kauksay, 30 miles S. of 

 Mandalay. It is also probable that ruby-bearing limestones, and 

 the alluvial earths derived from them, may be found in portions of 

 the adjoining Shan States. Indeed, at a point about 25 miles south-, 

 ward from Mogok, in the Shan State of Mainglon, Dr. F. Noet- 

 ling, of the Geological Survey of India, has found that rubies 

 have been obtained from the alluvium of a stream that flows 

 from the mountains that lie considerably to the S.E. of the Mogok 

 District. 



The rubellite (red tourmaline) of the same district was found 

 by Mr. Barrington Brown not to occur in association with the 

 rubies, but to come from certain gneisses and schistose rocks. 

 The locality which yields this gem, so highly prized by the Chi- 

 nese, is Nyoungouk, 10 miles S.E. of Mogok ; the alluvium which 

 yields the rubellite appears never to contain rubies and spinels. 

 Black tourmaline (schorl) has been extensively worked, as shown 

 by Dr. F. Noetling, in the Shan State of Mainglon, not far from 

 the rubellite locality. 



In the mountainous tract which includes the ruby districts, the 

 general trend of the hill ranges is from east to west. The bot- 

 tom of the Mogok Valley, in which the principal workings are 

 situated, lies at a height of 4,100 ft. above the sea; while the 

 loftiest mountains of the range to the north and east are the 

 Chenedoung Peak, 7,362 ft., and the Taungnee Peak, 7,775 ft. 

 above the sea-level. The alluvia of the valleys of Mogok, Kathay 

 and Kyatpyen are formed by streams flowing southwards from 

 this mountain chain ; while those of the valleys of Injouk and 

 Kabein are deposited by streams flowing in the opposite direc- 

 tion. The district, which is a somewhat malarious one, has an 

 annual rainfall of about 80 inches ; but in March, April, and 

 May, the supply of water for mining operations is deficient. 



Am. Jour. Sci. — Fourth Series, Vol. I, No. 1. — January, 1896. 

 5 



