46 Transactions of the Royal Canadian Institute 



Mesozoic Formations. 



Heavy oil has been found in the deposits of Mid-Cretaceous age. 

 These form the lower members of the series of deposits which have filled 

 the basin described as the Western basin of the Palaeozoic formations. 

 The first or earliest of Mesozoic age are Jurassic marine sediments which 

 were spread over the western part; following these are Lower Cretaceous 

 fresh water and shore sediments with coal, which occupy the western 

 margin and are found also in the broken area of the mountains. Farther 

 into the basin the succeeding marine sediments followed as the depression 

 extended eastward. In the sands representing the shoal water of this 

 advance and in the shales associated with the sands of the western part 

 at least, accumulations of gas are found with occasional signs of oil. 

 The sands of the formation intermediate between the Lower Cretaceous, 

 and the shales and sands of the Upper Cretaceous, and probably partly 

 included in the lower part of the Colorado formation, so far as now 

 known are the principal oil bearing beds. These have been pierced in 

 several bore holes in Southern Alberta and heavy oil or asphalt was 

 obtained which is assumied to be the origin of the distillate found in the 

 foothills. In the northern margin of the basin these deposits form the 

 Tar sands of the Athabaska. Attempts are being made to find, at a 

 distance from the outcrop, areas where this oil will be fluid enough to 

 provide commercial oil wells. The borings at Peace river are for this 

 purpose. An outline of the basin is shown in Fig. i. 



In Manitoba the shales of the upper part of the Colorado formation 

 are impregnated with oil. These oil-shales are found exposed in the 

 Pembina river valley and from well records are found to underlie a large 

 part of the Pembina escarpment. Another exposure is on the north side 

 of the Pasquia Hills in the northern part of the province. These although 

 of great thickness have not been found to be rich enough in oil for 

 present exploitation; seven gallons of crude oil to the ton being found 

 in samples taken at random and about 22.5 lbs. of sulphate of ammonia. 



The present production from the Cretaceous beds is principally in 

 the foothill area southwest of Calgary where a distillate of the heavy 

 oil of the bottom of the basin, after traversing the porous beds of the 

 western uprise is condensed and trapped in the outer fold. A light oil, 

 nearly a gasoline, is found in the wells and the accompanying gas also 

 yields gasoline. The field produces from forty to sixty barrels of gasoline 

 and kerosene per day. Light oil has also been found in the mountains 

 near the International Boundary in what appears to be an overthrust 

 of Cambrian rocks on Cretaceous and is also probably a distillation pro- 

 duct. On the eastern side of the great Alberta basin heavy crude oil is 

 obtained in Peace river valley. This appears to be from the same horizon 



