F. D. Adams — New Nepheline Bock. 269 



Art. XXIV. — On a New Nepheline JRochfrom the Province 

 of Ontario, Canada; by Frank D. Adams. 



[Published with the permission of the Acting Director of the Geological 

 Survey of Canada.] 



In a paper which appeared in this Journal some years since,* 

 the discovery of a large body of nepheline syenite in the town- 

 ship of Dungannon, in eastern Ontario about 85 miles northwest 

 of Kingston, was recorded. As stated at the time, this occur- 

 rence is of large dimensions and the rock constituting it is in 

 many respects remarkable in character. The discovery was 

 one of the first results of a geological survey of this part of 

 Ontario — at that time, geologically speaking, a terra incognita 

 — which had just been undertaken by the writer for the Geo- 

 logical Survey of Canada. As the survey was continued during 

 several succeeding summers, many additional occurrences of 

 nepheline syenite were discovered and mapped, and as the result 

 of more extended study the area is now known to present one 

 of the most extensive and interesting developments of nephe- 

 line-bearing rocks which are known to occur anywhere. The 

 geological maps of the area in question, by Dr. Barlow and the 

 writer, are now completed and are being engraved, and it is 

 expected that they, with the accompanying report, will be ready 

 for distribution shortly. During the progress of the survey, 

 Prof. Miller and Dr. Coleman of the Ontario Bureau of Mines 

 visited the district and described certain of the occurrences of 

 the nepheline syenite in papers published in the Reports of the 

 Bureau and elsewhere. 



When engaged in elaborating their Quantitative System for 

 the Classification of Igneous Rocks, Messrs. Iddings, Cross, 

 Pirsson, and Washington found that certain subdivisions of 

 their scheme had no representatives amongst the rocks hitherto 

 described. One of these subdivisions was Order 8 of the Per- 

 alkalic Persalanes, to which would belong nepheline syenites 

 very poor in feldspar and very rich in nepheline, with perhaps 

 allied varieties of related rocks. As it has been mentioned in 

 the paper on the Dungannon nepheline syenite, that in that dis- 

 trict rocks composed almost exclusively of nepheline occurred, 

 the authors of the Quantitative Classification suggested that 

 this order might be called Ontarare. No analysis, however, of 

 any of these rocks had then been made, so that their precise 

 composition remained somewhat doubtful. The name Onta- 

 rare, however, was given to the order, the present writer under- 

 taking to make good the claim of the Province to the bestowal 

 of the name, by describing an Ontarare from the district in 



* F. D. Adams : On the Occurrence of a Large Area of Nepheline Syenite 

 in the Township of Dungannon, Ontario, this Journal, July, 1894. 



Am. Jour. Scl— Fourth Series, Vol. XVII, No. 100.— April, 1904. 

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