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SU 
A N:o 1) Igneous Rocks of Sviatoy Noss in Transbaikalia. 69 
phase-rule. The inconstancy of the amphiboles and the 
lime-garnets in contact with each other is undoubtedly of a 
very general nature, in the igneous as well as in metamor- 
phic rocks. So it is here: when the andradite disappears, 
one may find hornblende forming individual crystals, besi- 
des the pyroxene. The hornblende has quite the same pro- 
perties as that intergrown with the pyroxene. All the other 
minerals also are the same as in the sviatonossites, and no 
further description is necessary here. 
BÄR YI TonTene-horn bilen der SR VE KSR 
nite. Many specimens are exceedingly similar to those of 
the former group, but contain scapolite. Their other con- 
stituents are phenocrysts of perthitic feldspar and granular 
feldspar, being chiefly potash feldspar (in some ' slices no 
plagioclase could be detected), green pyroxene of the aegirite- 
augite series, dark bluish green common hornblende (P = b; 
c:y = 29"; a = light brown <p. = brownish green <p = 
bluish green;. 2 V 60”), titanite, apatite. and epidote, 
the last-named being 'sometimes abundant enough to be 
called an ordinary constituent. The mineral determined as 
scapolite is prominent among the feldspar. mass by its 
refringence which is higher than that of the plagioclase 
(Abgs), and lower than that of the apatite. Its highest inter- 
ference colour in a section of usual thickness (about 0.025 
mm) is the violet of the 1st order. Hence the birefringence 
should be about 0.023 or 0.025. The mineral is uniaxial and 
negative, having two distinct cleavages at right angles to 
each other and parallel to axis c. These characters make it 
certain that we have here a scapolite of the wernerite series. 
It is rather abundant and, as a rule, associated with the 
coloured minerals. It is idiomorphic towards the feldspars, 
a fact of importance as-proving the primary origin of this 
mineral. 
The occurrence of scapolite in this syenite is interesting 
as an example of a carbonate-bearing mineral of magmatic 
origin. Other examples are cancrinite and, as we know at 
present, calcite. The last-named is also present as a primary 
mineral in many of the sviatonossites. 
