A N:o 1) Igneous Rocks of Sviatoy Noss in Transbaikalia. 89 
description of the contacts and enclosed fragments to a late 
chapter before entering into the discussion of the genesis. 
Fragments of alien rocks are common in the sviatonossite. 
These fragments are of various kinds. At points 59 B—62 B 
were observed such of amphibolite, evidently derived from 
the surrounding amphibolite masses. At point 61 B, where 
the sviatonossite presents an aplitic development, such 
amphibolite-fragments are surrounded by assimilation-zones 
containing much long-prismatic hornblende. That rock at 
point 62 B bounding the intrusive sviatonossite mass is a 
mylonitic gneiss, green-coloured from chloritic minerals. 
More interesting are the phenomena at point 64B k. 
The summit of the mountain ridge (point 64 B Ah) consists 
of light granite, somewhat richer in biotite than what is usual 
in the aplitic dikes. This rock also contains many ampbhi- 
bolite fragments. So far as could be concluded from the 
discontinuous exposures between the summit and point 
64 B k, the granite passes gradually into the aplitic sviato- 
nossite. In this rock are enclosed numerous fragments of 
andradite-skarn. Similar fragments, found here and there 
in the granites on Sviatoy Noss, occur here on a larger scale 
than elsewhere and seem to be characteristic of the sviato- 
nossite, having also been found at point 51 A. 
The typical aspect ; 
of such a fragment is 
illustrated by fig. 8. The 
skarn-rock in itself is 
nonhomogeneous, con- 
taining portions of cry- 
stalline limestone, in 
which are embedded 
frequent crystals of RR dl 
diopside-hedenbergite. ERE NR | 
The andradite-skarn Fig. 8. A fragment of skarn 
forms something like in sviatonossite. Sviatoy Noss. 
distorted veins, as though it had eaten itself into the 
limestone, of which only remnants have been preserved. 
Some fragments contain more limestone and some were ob- 
Sviatonossite 
Limestone 
with diopside 
Andradite- 
diopside skarn 
1 
