ON THE RUBIES OF BURMA AND ASSOCIATED MINERALS. 
169 
The gneiss from the valley of Kyatpyen westward to Wapudoung is of the ordinary 
finely-foliated, grey variety, which near Shwaynambin shows a contorted foliation. 
There was no opportunity of examining the rocks more than superficially in passing 
over the road from Kabein to Thebayetkin, as the journey was performed on horse¬ 
back in long- stages, which left little time for stoppage on the way. 
The strike of the foliation, and apparent bedding, varies from north-east and south¬ 
west on the south side of Mogok valley, to east and west on the southern slopes of 
Toungnee ; then from south-west and north-east from Sagiwa to Pingu hill, and in a 
general east and west direction to Kabein, and, as far as could be made out, con¬ 
tinuing in that direction to a point halfway between Narnpan mountain and Kauk- 
labin, where it curves round to the northward. Its dip is in a southerly direction at 
right angles to the strikes above enumerated, generally a.t angles of from 20° to 80°, 
while in a few places it is vertical, as seen in the Chenitaung range near Zelatne- 
taung. On the mountain side near Wapudoung it dips west at an angle of 45°, and 
evidently in the vicinity of that place it becomes horizontal, or nearly so, for beyond 
to within one quarter of a mile of Thebayetkin one of the great inclosed layers of 
crystalline limestone—the outcrop of which is seen in the gneiss on the mountain 
side above mentioned—assumes an almost horizontal position, forming the rock sur¬ 
face onwards. In two places only on this portion of the road are the gneissic rocks 
seen ; one appearing about two miles west of Wapudoung, and the other some three 
miles from Thebayetkin. The first is where gneiss and pegmatite form a band for 
about half-a-mile ; and the second where thin beds of gneiss crop out at very low 
angles in the crystalline limestone. 
Crystals of garnet are more or less disseminated through the gneissic mass, and it 
is possible it contains rubies and spinels as well, but no evidence of this has yet been 
obtained. 0 
On the path leading from Mogok to Ongain the foliation of some gneiss beds is 
slightly contorted, and dips at an angle of 80°. 
Between No. 4 and No. 2 mines there is a large exposure of fine-grained, grey 
gneiss 40 feet in height, the foliation of which dips southwardly at an angle of 75°. 
On the mountain side on the road from Mogok to Howet there is an exposure of 
solid grey gneiss 80 feet in height, of a fine-grained variety, containing garnets. 
Lower down the hill in the same mass are interfoliated lawyers of coarse, white, 
granular gneiss containing garnets of rounded and lenticular forms, very impure and 
oxidized in parts. Amongst them are flat, black crystals of a micaceous character. 
This section is an exceptional one as regards the inclination of the foliation, which 
inclines to the northward. 
The dividing ridge between Mogok and Momeit valleys is very precipitous between 
the pathway in the pass and Chenitaung peak, where an extensive section is exposed 
of bands of gneiss dipping evenly to the south-east at an angle of 35°. So regular 
are these bands, that from a distance they greatly resemble beds of sandstone. 
MDCCCXCVI.—A. Z 
