ON THE RUBIES OF BURMA AND ASSOCIATED MINERALS. 
179 
it into its descent northwards, where they are crossed on the road from Kathay to 
Bernardmyo. 
Besides the band above mentioned, another one is seen on the western side of 
Kathay valley, which is probably the western extension of that at No. 1 mine. 
Where the new road crosses it the cuttings disclose 60 feet of crystalline limestone, 
then 30 feet of gneiss, and then 120 feet of limestone. To the east of this section 
there is a deep depression, in which this band is seen, but beyond, all the way to 
Mogok, its outcrop is not again visible at the surface. It is hidden by the alluvium 
of Kathay valley, but at mine A, at Kyatpyen valley-head, at Ya-a, and at 
Kyaukpyasa, it is seen again. At the latter place one portion of it constitutes a 
peak composed of coarsely crystalline limestone 40 feet in width, rising 50 feet above 
the gneiss on its north side, and forming a precipice on the south side of between 
300 and 400 feet in height. A large solitary crystal of light-coloured mica of 4 inches 
across is seen in one part of it. 
This variety of rock is met with in other places, viz. : on the mountain slope on 
each side of Taungnee pass and elsewhere, rising from the surface of the limestone in 
narrow, uneven developments, which greatly resemble the ruined walls of an old 
fortress, some being 15 feet in thickness, and as much as 30 to 40 feet in height. 
Halfway between Mogok and Kathay are the outcrops of two small bands of 
limestone, which are probably an extension westward of the two seen in the Mogok- 
choung falls. 
In the limestone bands No. 4 and No. 5, on Letnytaung spur, there are bands of 
coarse pegmatite containing large black mica and tourmaline crystals. One of these 
in No. 5 is 15 feet in thickness, and it is difficult to determine whether it is intrusive 
or not. It appears to be more vertical than the enclosing rock. 
On the pass at the head of Kyatpyen valley there is a section showing a junction 
of whitish porphyritic pegmatite (in which are large crystals of felspar) and coarsely 
crystalline limestone. The former rests upon the latter, adhering firmly to it, and 
seems to fill the inequalities in the limestone surface. These dip south at an angle 
of 40° (see fig. 10). In places we find an interfoliation of white and grey limestones 
(see fig. 9). 
From Kabein, the new government road runs in west-north-west direction past 
Kinua to Shwaynambin, leaving the main limestone outcrops to the south; but not far 
on from Kinua a high peak of gneiss on the right is seen, capped by a band of limestone 
dipping north-west at an angle of 20°. It would appear that a great boss of granite, 
which I had no opportunity of examining, has forced up the gneiss and altered the 
dips from southwardly to northwardly. Before arriving at Shwaynambin a band of 
limestone is seen in the gneiss, and another small one a little past that village. 
From this the general direction of the road to Nampan mountain is south-west, so that 
it again crosses limestone bands, which are undoubtedly some of those extending 
westwards from the ruby mines. The first of these, which is crossed between 
2 A 2 
