172 
MR. C. BARRINGTON BROWN AND PROFESSOR J. W. JUDD 
Crossing the Yevoo, a quarter of a mile below Kathay, is a hard set of gneiss rocks 
showing a slightly contorted foliation, which forms a small fall. 
In the gneiss from Kyatpyen valley head to Bolong there is an extensive exposure 
of pegmatite, of a coarsely crystalline texture, the greater portion of wdiich is made 
up of large felspar crystals which have a satiny lustre. This rock differs from its 
other developments in having a large amount of whitish mica. 
Not far from Pingu hill, on the west, there is a small section disclosing the junc¬ 
tion of the gneiss and a limestone band. Here, at the plane of contact, the rock is 
of a nearly black colour, resembling a hornblendic gneiss ; and is in a band 4 feet in 
thickness, inclining south-west at an angle of 35°. This rock also occurs near Kyat¬ 
pyen valley head, near Welloo, at No. 13 mine, and near Dattau ; and is evidently a 
continuous band adjoining one of the great limestone masses. 
On the north side of Pingu hill, which is very steep and joined by a ridge from 
Kyauktaing, the rocks are of gneiss. Then for 50 feet of the ascent these, in large 
blocks, are mingled with masses of the limestone. They have evidently slipped dowm 
the uneven surfaces of the limestone beds, and in some instances have fallen into the 
open cavities in that rock. On the top of the hill the gneiss forms a thin layer, 
dipping south. From Panma, on the south, the winding path leading to the summit 
(5,6(30 feet) is on a comparatively easy slope over gneiss, until near the top, where 
there are thin limestone outcrops. The first portion of the ascent is of white pegma¬ 
tite, succeeded by grey gneiss higher up. Near the top are some curious gneiss 
bands of 2 feet in thickness, which are very friable, somewhat resembling an altered 
sandstone. A block of limestone near the summit has a band of greenish rock in it, 
inch in thickness, of a gneissose character. 
At the foot of Mandalay hill, not far from the late King’s Palace, are bands of 
pegmatite of white, greenish, and reddish colours, in which is an interfoiiated band of 
crystalline limestone, containing brownish mica crystals. 
6. Crystalline Limestone. 
I have deemed it advisable to give a description of this rock, and its mode of 
occurrence, separately from that of the gneiss in which it forms great bands, owing to 
its very interesting nature. As far as the limited investigations of the geology of the 
district went, it was only possible to partly trace out the extension of some of the 
larger bands, from the head of Mogok valley to Kabein ; and even the result of this 
work, to a great extent, must be looked upon as provisional only. 
The outcrops of this rock are easily discerned crossing the mountain sides and 
spurs of the open portions of the country, in the form of dark grey masses rising- 
above the surface of the enclosing gneiss. Their true white colour is completely 
disguised by a dark greyish lichen , which coats and clings tenaciously to their surface. 
On the other hand, on many parts of mountain slopes their continuity is completely 
