



Anakite-Trachyte Tuffs 



and Breccias. 



271 











Table I. 















A 



B 



C 



D 



E 



SiO„ 







54-39 



57.06 



55-8 



53-9 2 



54-55 



MA 







22 OS 



21. 48 



24.1 



24.60 



23.18 



F^A 







2.8 5 



•'3 









CaO 







.29 



.16 









MgO 







.27 











Na„0 







"•75 



1 2.20 



12. S 



12.23 



14.09 



K 2 







1.03 







1.30 





H 2 at 



I IO° 



•55 



•53 









H„0 over 



I IO° 



7-97 



8.38 



8.8 



8 50 



8.18 



ioi.iS 99-99 IOI -5 IOO -55 100.00 



A. From railway cut near the town of Blairmore on Crows 



Nest branch of the Canadian Pacific Railway, Alberta, 

 Canada. 



B. Wasson's Bluff, Nova Scotia, Canada. Bull 207, U.S. 



Geo. Sur., p. 8. 



C. Brevik, Dana's system of minerology, p. 597. 



D. Heldburg, " " " " p. 597. 



E. Theoretical composition. 



The Primary and Secondary Nature of Analcite in 



Igneous Rock. 

 During the past fifteen years the primary and secondary 

 nature of analcite in igneous rocks has been the subject of a 

 good deal of discussion. It was originally thought to occur 

 only as a secondary product, which view is still held by Rosen- 

 busch. The work of Lindgren, 1 (who first recognized analcite 

 as a primary mineral), Pirsson, Cross 2 and others 3 now leaves 

 little doubt that analcite may occur as a primary constituent 

 of igneous rocks. Monchiquite, which was originally described 

 as consisting of olivene and augite in a glassy ground mass, is 

 a good example of a basic analcite-rock. Prof. Pirsson 4 showed 



1. Proc. Cal. Acad. Sci. Series 2, Vol. III., July 1890. 



2. Repcrt U.S.G.S., 1895, Part II , page 16. Journal of Geology, 1897, page 684. 



3. Washington, H. S ; Am. Jour. Sci., 1893, VI., p. 182-186. Evans, Quart. Jour. 

 Geol. Soc, vol. 57, 1901, p. 38. Ogilvie, Jour. Geol., vol. X., 1902, p. 500. Pirsson, 

 Am. Jour. Sci., 4th Ser., vol 13, 1902, p 161. Pirsson, Bull. 237, U.S.G. Sur. 1905. 



4. Jour. Geol., 1896, p. 678. 



