182 
MR. C. BARRINGTON BROWN AND PROFESSOR J. W. JUDD 
of white crystalline limestone, then a wide bed of white granular limestone, which 
abuts against a crystalline limestone of a few feet in width, in which are bands 
of reddish-brown mica crystals, graphite, small crystals of felspar, reddish spinels, 
and light green augite. This passes into a coarsely crystalline semi-opaque limestone 
(the matrix of the ruby) of about 20 feet in width ; beyond which comes white 
crystalline limestone extending for some 90 feet, to where it is seen in some caves, of 
a coarsely crystalline variety. 
Although the bedding of these is somewhat obscure, yet they evidently dip 
slightly to the southward. 
The quarry, which is in the coarsely crystalline semi-opaque limestone above 
mentioned, is 20 feet wide at the face, and has been cut in for 15 feet, to where a 
small drift in its bottom has been advanced a short distance, making the entire length 
of the cutting at that part some 30 feet. 
The rubies are found in the rock over a space of 6 feet in width, extending almost 
vertically from the bottom of the quarry to the surface of the ground ; while the 
direction of the productive portion slopes to the south at an angle of 70°. On either 
side of this the rock changes from a bluish-grey to pure white. Along the centre 
line, where the rubies are most numerous, are small developments of a greyish mineral 
(diaspore), enclosing small crystals of iron pyrites, and where these occur the miners 
assert that the rock is the most productive. There is also a small irregular vein-like 
structure of the same mineral traversing this part for a short distance. Besides these 
there are small dull-greenish crystals of disaspore, and light green crystals of augite. 
In some of the specimens I obtained by blasting, magnetic pyrites was found in 
contact with the rubies. 
At the mines close to Bobedaung village there are some fine beds of statuary marble, 
similar to those seen at the ruby quarry at Mogok ; and here the adjoining coarsely 
crystalline limestone has been quarried for the rubies it contains. 
This band is evidently the western extension of the one in which the Mogok quarry 
is situated. A cave working near by, called the Royal Loo, was formerly considered 
to be a very rich one. Moung Guy, a Mogok mine owner, informed me that when 
this mine was opened many years ago, the bones of a large animal were discovered in 
the ruby clay and loam in the cave’s entrance, amongst which a number of fine rubies 
were found. He had seen one of these bones some ten years ago, and from his des¬ 
cription it was evidently a rib of four inches in width. 
Between Thaungla and Pyanbin, in the continuation westward of the same band, 
rubies have been found in the limestone matrix. 
7. Granite. 
There is a large exposure of grey granite near Kabein, which there was no oppor¬ 
tunity of examining, except a very small portion of it crossed on the new road. This 
is probably a pegmatite. C. B. B. 
