1 77 
ON THE RUBIES OF BURMA AND ASSOCIATED MINERALS. 
Another section, occurring near mine No. 15, is as follows (see fig. 8):— 
1. Coarsely crystalline white limestone, containing brownish mica crystals, in 
parallel planes giving it a schistose structure, which are most numerous 
at the plane of contact with the next band. 
2. Hard grey compactly crystalline grey gneiss, 18 inches. 
3. Coarsely crystalline limestone, 8 feet. 
4. Finely foliated grey gneiss. 
These dip to the south-south-east at an angle of 40°. 
Section near No. 15 Loodwin. 
It is difficult to find good sections showing the junction of the large limestone bands 
with the main masses of gneiss, where they could be easily observed. In those few 
places where an examination was rendered comparatively easy, it was seen that near 
the plane of contact the limestone has a schistose appearance, owing to the contained 
crystals of whitish and brownish mica being arranged in planes parallel to the foliation 
of gneiss. In that part also appeared to be a greater variety of accessory minerals, 
such as graphite, white opaque felspar, and violet-coloured spinel. Further away the 
limestone became more coarsely crystalline, passing into a sort of white opaque, or 
bluish and greyish semi-transparent calc-spar, in rhombohedrons which sometimes 
attain a size of over six inches across. 
The best section of the junction, as well as of one of the main limestone bands, is seen 
near Pyagone, where the latter, (probably No. 3 band) crosses through a ridge from 
Bobedaung. Even here it is difficult to accurately examine this, owing to the some¬ 
what broken surface of the outcrop, and to the covering of hill-wash upon it in 
places. The junction is very clearly defined in a small cliff-like section at No. 16 
mine. Here the grey gneiss, of an evenly and finely laminated variety, rests on the 
limestone, its foliation dipping to the south, like that of the latter rock, at an angle 
of 45°. Although the plane of contact is clearly defined, yet the gneiss firmly adheres 
to the limestone. Tracing the section northward it is as follows :— 
O 
2 A 
MDCCCXOVT.- A 
