THE 



CANADIAN RECORD 



OF SCIENCE. 



VOL. IX. OCTOBER, 1904. No. 5. 



Analcite-Trachyte Tuffs and Breccias from 

 South West Alberta, Canada.* 



C. W. Knight. 



(introduction.) 



In this paper are described a series of tuffs and breccias 

 found in the south west corner of Alberta, Canada, some five 

 miles west of the Livingstone Range. They have been carefully- 

 mapped in townships 7, 8, 9 and 10, ranges 3, 4 and 5 west of 

 the fifth meridan. Roughly speaking, the district lies about 

 twelve miles east of the eastern boundary of British Columbia 

 and some fifty miles north of the international boundary. 

 Their existence here has been known since the early eighties 

 when G. M. Dawson of the Canadian Geological Survey 

 referred to them in his report on the Rocky mountains. 2 



The occurrence of analcite (Na 2 0. A1 2 3 . 4Si0 2 . 2H,0) in 

 these pyroclastic rocks makes an interesting study. Its 

 presence has not been previously noted by other writers. No 

 microscopic or chemical descriptions of the rocks have been 

 written. The mineral has lately attracted much attention as 

 regards its origin in igneous rocks ; and its formula, which may 

 be written in various ways, especially as regards the interpre- 

 tation of its one molecule of water, 2 is still uncertain. Its mode 

 of occurence in south west Alberta is unique. So far as the writer 



*Published by permission of the Director of the Can. Geo. Survey. 

 1. Report on the Rocky mountains between lats. 49 and 5i°-3o'. Report of Can. 

 Geo. Sur. 1886. 



C7> 



CO 



Bull. 207, U.S. Geo. Sur. p. 8. Clarke and Steiger, 1902. 



