10 F. D. Adam* — Xepheline Syenite in Ontario. 



in keeping with the purposes of this apparatus than the simple 

 spiral discussed above. 



9. Summary. — For the measurement of activity by the 

 above simple methods one would therefore couple the instru- 

 ment's figures 5 and 6 in series to the same shaft and read both 

 dials. It is conceivable however that the propeller blades pp 

 of figure 6 may replace the friction pulley p of figure 5, par- 

 ticularly if provision is made for rotating the propeller in a 

 liquid instead of in air. Suppose therefore that the dial and 

 index of figure 6 has been standardized both with reference to 

 the twist corresponding to one in degree of deflection and to 

 the speed corresponding to the deflections. Then in an instru- 

 ment of the type of figure 6, a single reading would at once 

 give the activity of the 'motor. This is the final outcome of 

 the method sketched in the above paragraphs. 



Washington, D. C, May, 1894. 



Art. II. — On the occurrence of a large area of Nepheline 

 Syenite in the Township of Dungannon, Ontario ; by 

 Frank D. Adams. 



While engaged during the past summer in making a geo- 

 logical reconnaissance of a portion of Eastern Ontario previ- 

 ous to a detailed mapping of the district for the Geological 

 Survey of Canada, a large area of nepheline syenite was un- 

 expectedly discovered. 



The district in question lies between Lake Ontario and the 

 Ottawa River, near the southern edge of the Archean pro taxis, 

 in the counties of Victoria, -Peterborough and Hastings, in the 

 province of Ontario, and comprises 3500 square miles, being- 

 sheet number 118 of the series of geological maps of Quebec 

 and Ontario now in course of preparation by the Geological 

 Survey of Canada. This tract of country which up to the 

 present time has been, geologically speaking, a terra incognita 

 was found to be occupied almost exclusively by rocks of the 

 Laurentian system. The Grenville series with numerous 

 heavy bands of crystalline limestone is extensively developed 

 in the southern portion of the district, while to the north 

 great tracts are underlain by what is believed to be the funda- 

 mental gneiss. In the extreme southeast corner of the district 

 certain rocks occur which have been referred by Mr. Vennor 

 to the Hastings Series. 



The stratigraphical relations of these several series in this 

 district have not as yet been determined, but will it is hoped, 

 be worked out as the detailed mapping is proceeded with.* 



* See 1; Preliminary Report on the Geology of a portion of Central Ontario." 

 Ann. Rep. of the Geological Survey of Canada, 1891-92-93. Part J. 



