va 
bust, AE 
08 RSS SR RAN 
Mn é 
, wj 
1 
SE 
CRT 
A N:o 1) Igneous Rocks of Sviatoy Noss in Transbaikalia. 31 
| ov Mol. Mol. NEO 
ROTADE 
—--& " sr -==—=————>—  jpb py. wnwnnwnnninhlhNhhnxnmnhllbmlnnlxKeevv;=,=""U 
SiO, 51.03 | 851 | 57.93 | Orthoclase .....« (EN 
A1,O; | 20.15 | 198 13:48 | Albite ; us. Ca PE 11:49 
Fe,0, 2.02 | . 13 Anorthite..... » « 27.80 
FeO 7.48 | 104 9.06 | Nephelite . ... : ... 1:42 LE NA2 
MnO 0.21 3 Z sal 78.91 
MgO LST 44 2.99 rg 1.63 
CAO =729 130 |-8.85 | Diopside. RR SR 
:Na,O 4,24 68 4,63 FeSiO, 1.19 P = 13.19 
K,O 2.80 | 30 2.04 Mg,SiO, 2.731. 
: Olivine .. do. a. j9.87 
TiO, 1.20 | 15 1.02 Fe,SiO, 7.14 
PIO5 0:76 Hl te ARN 020 
20; Magnetite RR WENBRB0 
H,0O 0.42 SEARLIM EINES alise sket ös 2.28 
APablle idol Rre 1.68 A = "1.68 
| id Zz fem 20.17 
| 98.08 
[99.37 | 4 [100-00 ] 
Andose (II, 5, 3, 4). 
The Osann figures: 
S RA C F a C i n N 
35.95 >-6.067 6.81" 14:09 5.0 —- 5.0 10:0: 76:94" 0-82 
The mineral constituents, named in the order of their 
abundance, are plagioclase, biotite, hornblende, titanite and 
apatite. The plagioclase builds up a little more than a half 
of the rock-mass; the biotite is only a little more abundant 
than the hornblende. 
The plagioclase occurs in the form of isometric 
- polygonal grains and shows rarely a few twinning lamellae. 
The extinction angle in sections | PM is about + 6”, the 
refringence being considerably high as compared with the 
Canada balsam. The composition should therefore conform 
to Ab;,. No potash feldspar is actually present, the potash 
content entering into the biotite in which the ratio K.O: 
