308 REVIEWS 



A new feature in this report is a series of 25 maps of these counties 

 showing the minable coal areas of as many different coal horizons. 

 Under separate cover are topographic and geologic and structure contour 

 maps. 



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Oil and Gas Fields of Ontario and Quebec. By Wyatt Malcolm. 

 Geol. Survey Canada, Memoir 81, 1915. Pp. 248. 



This memoir has been prepared chiefly for those interested in the 

 commercial development of oil and gas. It treats of the lithology, 

 stratigraphic relations, and areal distribution of the geologic formations 

 from the Potsdam to the Chemung. The predominant structural fea- 

 ture is a gentle dipping of the strata to the southwest away from the 

 pre-Cambrian axis. The northeastern extension of the Cincinnati 

 anticline reaches into Ontario. 



The productive horizons are not limited to one formation. Gas is 

 found in the Medina, oil and gas in the Guelph and Salina, and oil in 

 the Onondaga. The production of gas has increased steadily, but the 

 oil output reached a maximum in 1907, and since then has fallen greatly. 



Analyses of gas from different fields show a surprising uniformity of 

 composition. The writer of the report believes this to be incompatible 

 with a local and separate origin of the gas for each field. 



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Arisaig-Antigonish District, Nova Scotia. By M. Y. Williams. 

 Geol. Survey Canada, Memoir 60, 19 14. Pp. 173, maps 2. 



The chief interest in this memoir lies in its contribution to stratig- 

 raphy. Careful attention had been given already to the region, for 

 in it lies the key to the stratigraphy of a considerable area. The purpose 

 of this investigation was to work out in still greater detail the sedi- 

 mentary record and the ages and relations of the igneous rocks. 



Of the Paleozoic systems, the Cambrian and Permian are missing. 

 Where possible, correlations are made with the type sections of Europe. 

 Separate chapters are reserved for structural and historical geology. 

 Igneous geology is given the same careful attention as the sediments. 

 The igneous rocks are limited largely to acid and basic intrusives in the 

 Ordovician, and to intrusive diabase sheets in the Mississippian. 



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