THE MONTEREGIAN HILLS 



271 



and 2.62, that of the smaller feldspars is between 2.591 and 2.56; 

 that is to say, the smaller feldspars approach more nearly to 

 pure orthoclase in composition. They consist chiefly of minute 

 intergrowths of orthoclase with albite, or of either of these with 

 microcline or anorthoclase. No lime-soda feldspar could be 

 recognized in any specimen of the rock. 



Nepheline and socialite. — These minerals are quite subordinate 

 in amount, although they are seen in nearly every thin section. 

 Both minerals present the same characters and occur in the same 

 way as in the essexite, lying chiefly in the corners between the 

 other constituents being penetrated by the latter, but also occur- 

 ring as inclusions in the feldspar. They are, as a general rule, 

 much altered to the same decomposition product seen in nephe- 



VII. Pulaskite (laurvikose), Mount Johnson, Quebec. 



VIII. Pulaskite (laurvikose), Shefford mountain, Quebec. {American 

 Geologist, 1 901, p. 211.) 



IX. Nordmarkite (nordmarkose), Shetford mountain, Quebec. {Ibid., 

 1901, p. 209.) 



X. Sodalite syenite, Square Butte, Montana (differentiation product of 

 shonkinite). 



XI. Umptekite, Red Hill, Moltonboro, New Hampshire. 



XII. Pulaskite, Fourche mountain, Arkansas (original locality). 



