42 Transactions of the Royal Canadian Institute 



Palaeozoic FoRkATioNS. 



Ate these formations were deposited about the old continental nucleus, 

 during the period of its greatest depression, they now form, or underlie, a 

 largte part of the present surface. They have, however, in large areas 

 been stripped from the old continent during the long period through 

 which they have since been subject to erosion. In the subsequent changes 

 of elevation, the differential movements were impressed on the beds in 

 the form of undulations, thereby facilitating the collecting of any con- 

 tained oil in pools, but where the stresses were very great the deforma- 

 tion reached the proportions of destruction. 



Of the original measures surrounding and partially covering the 

 ancient continent, not only has a large part been removed by denudation, 

 but great zones are fractured, folded, and crushed. From these zones 

 much of the broken material has been removed. Blocks that have been 

 elevated have become drained of any possible oil, and the folded and 

 crushed areas in consequence rendered of very slight value as oil fields. 

 Where, however, the oil has not migrated to the coarse porous beds or 

 sands, but is retained in the shales, the fracturing may be an aid to their 

 exploration. 



The fracture zones of the continent are, for the Palaeozoic sediments, 

 the limiting boundaries of the oil fields, although within these zones small 

 areas may be found with indications of oil. See Fig. 2. 



Fracture Zones. 



Two main lines of intensive crushing and deformation are indicated. 

 The greatest follows the line of the Cordilleras through the length of the 

 two American Continents. In Cafiada this belt of weakness or deforma- 

 tion, which affected the Palaeozoic sediments, is a broad one, and is 

 represented by the Eastern Belt of the Canadian Cordilleras. In this, 

 the zone in which accumulation of oil might have been looked for, is 

 entirely destroyed, and the blocks that are elevated and exposed in the 

 eastern edges of the Rocky Mountains appear to be already drained. 



Near the Atlantic coast, lines of elevation and fracture show the effect 

 of great lateral pressure exerted at various times. The lines of weakness 

 are not continuous nor essentially parallel, so that the band of deforma- 

 tion contains within it areas not badly crushed and in some of these, small 

 showings of oil have been found. The disturbed measures show large 

 quantities of oil-shales, and the potential value of the Maritime Provinces 

 for the production of oil would seem to lie in these oil-shales. 



Fracture zones are found in the northern or Arctic regions. These 

 represent what appears to be normal faulting and have madte their 



