148 Coleman — J^ejyheline and other Syenites in Ontario, 



be fouad in the reports of the Geological Survey of Canada,* 

 where rocks containing red and white feldspar, some grains of 

 orange-red elaeolite, and a few zircons, are said to occur in 

 Pic Island and the mainland to the north ; and of the Bureau 

 of Mines,f where the occurrence of augite syenite and other 

 associated rocks is referred to, though the nepheline rocks 

 were overlooked. Acknowledgments must be made to Pro- 

 fessor L. Y. Pirsson and Dr. H. S. Washington for having been 

 good enough to send chips and larger specimens of various 

 nepheline syenites and related rocks from other localities 

 which have proved most useful for comparison ; and to Profes- 

 sor Pirsson for suggestions as to rock relationships. 



Nepheline Hyenites. 



The syenites and associated rocks are very well exposed 

 between miles 818 and 822 in the numerous rock cuts and 

 cliffs where the railway winds along the rugged shore of Lake 

 Superior, so that an almost continuous section is presented. 

 The first nepheline syenite observed is just east of the long 

 trestle at Ped Sucker lake, where it forms irregular dikes and 

 larger masses in gabbro, which appears to be the older rock 

 of the two; and similar relations are found at the rock cut 

 west of the trestle, though red syenite interrupts it at the third 

 cutting. Beyond this, toward the west, hills of nepheline 

 syenite rise 200 or 300 feet above the lake and continue with 

 few interruptions to Port Coldwell station and the next cutting 

 beyond it, the last point where it was observed being a little 

 beyond mile 822. The second cutting west of the station is in 

 red syenite. The rock varies from almost compact to very 

 coarse-grained kinds having crystals an inch or more long ; 

 and in color from pale to dark gray, sometimes running into 

 purplish tones or having brillant red spots. The black horn- 

 blende and augite crystals stand out sharply giving a fresh look 

 to the rock, which unfortunately is not borne out in thin sec- 

 tions. In some specimens the hornblende crystals are long 

 slender prisms, but in others they are short and stout. 

 The different textures are often mixed intimately, fine-grained 

 parts enclosing coarser grained ones or the opposite ; and 

 large or small blocks of the gabbro mentioned above are 

 enclosed in the nepheline syenite. Dikes of a fine-grained pur- 

 plish gray rock, sometimes with the look of an amygdaloid, cut 

 the syenite ; and last of all, there are sharply defined dikes of 

 black diabase. 



In general appearance the nepheline syenites are very dif- 

 ferent from those of Eastern Ontario, never showing the 



* 1846-7 ; also 1863, p. 80. tl897, p. 147. 



