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A N:o 1) Igneous Rocks of Sviatoy Noss in Transbaikalia. 95 
alumina which is absent in unaltered limestone; this compound 
must clearly have been derived from the magma, too. On 
the second erystallization from the magma the andradite 
assumes the same composition, and still some alumina 
enters into the pyroxene now being formed. Therefore the 
alumina is now insufficient to form feldspars with all the 
alkalies present, and part of the soda goes to form aegirite 
with the ferric oxides richly present in the magma. Thus the 
magma is on the way to become an alkaline rock. 
The syntectic or hybrid sviatonossite magma may have 
been subject to further differentiation, either gravitative in 
the manner advocated by Daly), Bowen ?), and others, 
or in any other way. In the sviatonossite mass one may 
find much' schlieric development and indistinct primary 
veins, all these phenomena being suggestive of the squeezing 
out of liquid magma from a spongy mass of crystalline matter 
with interstices occupied by liquid magma, in the manner 
pointed out by Harker ?). Of all the possible differentiation 
products only the more salic ne have been met with 
on Sviatoy Noss. 
When only the garnet had been separated from the magma 
by settling down, the residual magma crystallized as a pyro- 
xene-syenite. The farther differentiated phase derivative from 
the sviatonossite magma is the aegirite-augite-granite, pro- 
bably representing the last Boro of the magma to be con- 
solidated. 
Part of the calcium carbonate dissolyed in the magma 
crystallized out in the form of calcite. Another part reacted 
with the siliceous compounds. Thus was probably formed 
the epidote as the latest mineral to separate. At places the 
calcium carbonate was changed to the anorthite compound 
to form carbonate-meionite. These scapolite-bearing varieties 
all contain abundant hornblende and probably represent the 
1) BR. A. Daly, »Op. cit., pp. 221—247 (New-York, 1914). 
2?) N. L. Bowen, »The later Stages of the Evolution of Igneous Rocks> 
Journal of Geology. Volume XXIII, Supplement (1915). 
3) Alfred Harker, »Fractional Crystallization the prime Factor in 
the Differentiation of Rock-Magmas», Congrés Géologique International. 
Canada 1913. 
