THE OIL-FIELDS OF KASTERN CANADA. — ELLS. 603 



upper Peace rivers, in the district north of Edmonto'n, also 

 telong to the same horizon. The recent flows of natural gas 

 which have been struck at Calgary and at Medicine Hat in the 

 country of the plains, are also from strata of Cretaceous age. 



In Europe it is also of interest to note that the oil-wells, in 

 so far as these are at j^resent productive, belong to recent 

 rather than to I'alipozic times. Thus in Italy petroleum is 

 found in Tertiary sediments along anticlines which follow gen- 

 erally the trend of the Appennines; in Germany in the 

 Tertiary in part and partly in the underlying Jurassic; while 

 in Great Britain, France, Spain, and Switzerland, in Europe, 

 and in Alg-eria and Egypt in Africa ; it occurs also in rocks per- 

 taining to the Cretaceous and Tertiary formations. 



It will be .seen, therefore, that in the greatest number of 

 petrolemn producing countries the mineral is obtained from 

 formations which are quite recent as regards the geological 

 scale. Coming nearer home, however, we find, as a rule, 

 that petroleum pertains rather to rocks of Palaeozoic age. In 

 Canada these have usually been assigned to the Devonian sys- 

 tem, since it was long supposed that it was from these forma- 

 tions that the wells derive their flow of oil; but in the United 

 States some of the most productive wells are sunk in formations 

 as far down as the Trenton. On this continent, therefore, there 

 appears to be a marked line of separation as regards the horizon 

 of both coal and ])etroleum, between the occurrences east of a 

 line defined by the Mississippi river for the United States side 

 of the boundary, and by the eastern edge of the prairie country 

 in Canada w^hich divides the deposits of Palaeozoic age on the 

 east from those of Cretaceous and Tertiary ag"e on the west. 



In character also petroleum varies greatlv in different dis- 

 tricts. It ranges from a highly fluid condition a'nd a light 

 colour in some areas, to a thick and exceedingly dark coloured 

 substance in others ; the specific gravity of the mineral, accord- 

 ing to observations made by Boverton Redwood, having a 



