[ADAMS A BARLOW] ALKALI SYENITES OF EASTERN ONTARIO 27 



difference in colonr, the garnet being brownish or reddish brown in thin 

 sections, while the eucolite is pale yellowish. In a heavy solution, euco- 

 lite falls with the hornblende and garnet and can only be separated with 

 the greatest difficulty from these minerals. By magnetic separation 

 several times repeated, fairly pure material is obtained, but hardly pure 

 enough for purposes of chemical analysis. It is lilcely that further and 

 more careful search in this region Mali show a larger and more abun- 

 dant supply of this mineral. 



Molybdenite. — This mineral is occasionally found and occurs usually 

 in small phites and scales and less frequently in crystals. 



Apatite. — This mineral is a very common constituent of the nephe- 

 line syenite, but it is usually present as a very subordinate accessory con- 

 stituent and in very small, often microscopic, crystals. In some locali- 

 ties, especially in association v/ith the magnetite on lot 30, con. XIII of 

 Dungannon, comparatively large crystals of apatite may be obtained, 

 while in the north-west corner of Faraday, similarly large and well de- 

 fined hexagonal prisms, terminated by planes of two pyramids, have been 

 collected. Occasionally these crystals were noticed growing together in 

 parallel position, the resulting individual simulating a twin crystal. 



Magnetite.- — This mineral has a very general distribution through- 

 out the whole mass of the nepheline syenite, although its complete and 

 unexpected absence from occasional outcrops representing even the 

 more basic phases of the rock is noteworthy. It is usually present, 

 however, and is certainly one of the more importani) of the accessory con- 

 stituents. Individuals in thin sections under the microscope often show 

 fairly good crystalline form, but the grains are usually somewhat rounded 

 and irregular in outline. The mineral is most conspicuous and abun- 

 dant in the more feldspathic variety, especially the red syenite. In 

 many places the magnetite has differentiated out from the rest of the 

 rock :and forms large and important masses of this mineral, much of 

 which is free from any other admixture. Attempts have sometimes 

 been made to work some of these masses in the hope that they would 

 ultimately become producing mines. At one locality on lot 30, con. 

 XIII of Dungannon, considerable development work, consisting chiefly 

 of stripping and blasting, has revealed the presence of considerable 

 bodies of very pure magnetite which, however, judging from analogous 

 occurrences accompanying the red syenite and which have been analyzed, 

 would in all probability contain titanium. The mineral here has a very 

 perfect octahedral cleavage. In certain localities in Dungannon, and 

 especially in the north-west corner of Faraday, perfect octahedrons of 

 magnetite can be occasionally secured weighing several pounds. (See 



