THE CROWSNEST VOLC 4 NICS. 
33 
geosyncline. During this revolution, the Highwood laccoliths, 
and the Ice River laccolith were intruded. 
SUMMARY AND CONCLUSIONS. 
The Crowsnest volcanics consist of fragmental stratified 
pyroclastic rocks which exhibit several primary types occurring 
as fragments. These are, in order of abundance, trachytes, 
blairmorites, and latites. Tinguaite has been described by C. 
W. Knight 1 as also occurring. The trachytes are soda-rich varie- 
ties, and segirite-augite trachyte, and melanite trachyte have 
been recognized as separate types. The blairmorites are unusual 
rocks, ultra alkaline, soda-rich porphyries characterized by 
primary analcite in large quantities up to 71 per cent. The 
primary types have been altered only slightly. 
The fragmental volcanic rocks consist of both mineral and 
rock fragments of varying sizes and associations, characterized 
by minerals typical of alkaline rocks, orthoclase, sanidine, soda 
orthoclase, segirite-augite, analcite, melanite, titanite, etc. 
This occurrence of alkaline rocks between the well-known 
Montana alkaline localities, and the ultra alkaline intrusive mass 
of Ice river, B. C., forms a link in the chain of alkaline rock 
bodies occurring in the front ranges of the Rocky mountains, and 
the rocks of general region are considered to form a related group 
to which the name of the Rocky Mountain Petrographic Province 
is given. Inside of this large province, the relations of the in- 
dividual provinces are compared to the relation of single types 
in any given province. 
I Knight, C. W. Canadian Record of Science: vol. 9, No. S, 1905, p. 274. 
