ÉE- 
É 
d 
| 
hb 
NM 
å 
; 
A N:o 1) Igneous Rocks of Sviatoy Noss in Transbaikalia. 75 
Peqgmatites in the sviatonossite series. 
The svenitic rocks with and without andradite are 
frequently cut by dikes of pegmatite. Most of these consist 
of an ordinary granite-pegmatite containing red potash 
feldspar and. bluish quartz, while others are poor in quartz 
and have plagioclase as the principal constituent. These 
dikes also contain many large crystals of colourless diopside 
(baikalite) and large well-formed crystals of titanite. They 
do not in any respect differ from such dikes so commonly 
found in the limestones and migmatitic terranes rich in lime- 
stone in the widespred area of crystalline rocks all around 
Lake Baikal. They often contain graphite. 
Chemical Characters and Systematic Position of the Sviato- 
nossite series. 
The aegirite-augite-granite. We may begin 
the discussion of the general chemical characters of rocks 
of the sviatonossite series with the aegirite-augite-granite. 
This rock has the most decided alkaline character of the 
rocks from Sviatoy Noss hitherto investigated. Mineralogi- 
cally it appears in the presence of highly albitic plagioclase 
and a pyroxene rich in aegirite. From the chemical analysis 
the same appears on calculation of the norm. The amount 
of alumina being insufficient to form feldspar with all the 
CaO and Na,0, no normative anorthite is present and acmite 
must be introduced. 
Similar alkaline granites have been recorded from different 
parts of the world. A few analyses EG be quoted for com- 
parison. 
IE Aegirite-augite- -granite. Sviatoy Noss. 
II. Quartz.-lindöite, Frön, Christiania, analyst V. 
Schmelck. W. C. Brögger, »Die Eruptivgesteine des Kri- 
stianiagebietes, ID, p. 139 (1894). 
III. Soda-granite, Iviangusat, dsasäluärsnit S. Green- 
land, analyst C. Detlefsen. N. V. Ussing, »Geology of the 
