ADAMS & barlow] ALKALI SYENITES OF EASTERN ONTARIO 47 



selvage along the southern side of the limestone and can be traced to 

 the west across the neighbouring lots. To the south the relations of the 

 syenite to the granite of the bathyliths are obscured by drift. The 

 nepheline syenite has a banded structure, some bands consisting of al- 

 most pure nepheline, while in others the iron-magnesia constituents 

 preponderate; there is also in many cases a variation m size of grain in 

 different bands. Masses of coarsely crystalline calcite, evidently frag- 

 ments from the adjacent limestones, are occasionally found as in^ 

 elusions in the nepheline syenite, the nepheline and other constituent 

 minerals of the syenite growing into these inclusions, as if the lime- 

 stone was being replaced by them. Under the microscope the rock is 

 seen to be composed essentially of nepheline and a deep green hornblende 

 allied to hastingsite. The relative proportions of these two minerals 

 vary in different slides. A considerable amount of calcite is present in 

 large individuals with irregular and usually curved outlines, which lie 

 between th0 other constituents of the rock. A plagioclase feldspar and 

 microperthite are present in very subordinate amount, together with a 

 few rounded grains of sphene. The structure of the rock is allotrimor- 

 phic. None of the constituents possess any approach to good crystalline 

 form, but come together along curved or straight lines and are quite 

 irregular in shape. 



About four miles to the east of this occurrence and associated with 

 the same band of limestone. Dr. Miller (^) has observed a mass of white 

 syenite carrying brown corundum. The rock is stated to form a hill 

 about half a mile east of Leafield Post Office in the north-east comer of 

 the! township of Cardiff, and was also found at the roadside about half 

 a mile south-east of the same point. Some of the syenite in the hill 

 has a quite strongly marked porphyritic structure. No description of 

 this rock is given, but it is apparently free from nepheline and allied to 

 the alkali syenites associated with the nepheline syenites in the township 

 of Methuen and elsewhere in the area. This occurrence was not visited, 

 but its position, as indicated by Dr. Miller, has been shown on the Ban- 

 croft sheet. 



In the township of Wollaston, only a single occurrence of nepheline 

 syenite is known, and this is a small one. It is found on the- road which 

 runs on the line between the townships of Wollaston and Faraday, on 

 lot 9. On account of the fact that the country here is rough, the road 

 does not follow the exact line on which it is supposed to be laid out. l)ut 

 winds to and fro across the boundary. On lot 9, at the point where the 

 nepheline syenite occurs, it bends to the south and is almost exactly on 



^ Report of the Ontario Bureau of Mines, Vol. VIII, page 216. 



