266 Canadian Record of Science. 



is aware it has never been noted occuring under the conditions 

 here described. It is found in crystal-tuffs and breccias having 

 the mineralogical and chemical composition of trachyte. Its 

 form and relation to the minerals with which it is associated lead 

 to the belief that it is a primary constituent of these volcanics. 

 In other words, the analcite has been deposited from showers 

 of volcanic debris, simultaneously with the other materials, and 

 was therefore a primary constituent of the partially consolidated 

 magma which gave rise to these rocks. Its primary nature is 

 further discussed in a later part of this paper, but it may be 

 noted here that it was only during the past fifteen years that 

 analcite has been recognized as a primary constituent of 

 igneous rocks. Rosenbusch still regards it as a secondary 

 mineral. 



The fact that analcite is found in a crystal-tuff of the 

 composition of a trachyte, is believed to establish a new rock 

 type, and the name Blairmorite 1 is here suggested for it. This 

 point is more fully discussed later on. 



Therock specimens studied in this paper are nearly all from 

 the museum of the Canadian Geological Survey. The collection 

 was originally placed by Dr. A. E. Barlow of the survey, in the 

 hands of Dr. C. W. Dickson, now of Queen's University, 

 Kingston, for investigation, but as opportunity failed Dr. 

 Dickson he very kindly placed the specimens in the writer's 

 hands. The work was carried on in the geological labora- 

 tories of Columbia University, New York. To Professor 

 Kemp and Dr. Berkey of Columbia University, the writer 

 would express his acknowledgement for advice and assistance. 

 The writer's thanks are, however, especially due to the 

 authorities of the Geogolical Survey for the opportunity given 

 him to study a suite of rocks which have proved to be of ex- 

 ceptional interest. Dr. Adams of McGill University, Mon- 

 treal, added a few specimens to the collection, and also furn- 

 ished some details of an interesting rock-cut on the Crows 

 Nest branch of the Canadian Pacific Railway, four miles east 

 ■ of Crows Nest Lake. 



i. The town of Blairmore is located on the Crows Nest branch of the Canadian 

 'Pacific Railway; it is less than two miles from some exposures of the volcanic rocks 

 ihere described. 



