556 BEPARTMENT OF TEE INTERIOR 



2 GEORGE V., A. 1912 



the west (e.g. Ogden quartzite of Fortieth Parallel section) were laid down 

 in the Eastern Belt. If the Western Belt were generally submerged beneath 

 the sea during the Mississippian time, we should expect that few beds other than 

 limestone and volcanics would be laid down in that belt, unless we postulate the 

 contemporary existence of a large land-mass to furnish clastic material, neces- 

 sarily situated on the present site of the eastern Pacific. The notably few 

 suggestions as to the presence of pre-Cambrian terranes in the Western Geo- 

 synclinal Belt correspond to the difficulty of identifying them in a region whicb 

 bears few or no traces of Cambrian sedimentation and but few of Ordovician 

 Silurian, or Devonian sedimentation. At the same time, it is reasonably 

 certain that pre-Cambrian rocks have been so deeply buried under the Car- 

 boniferous and later sediments and so much replaced by intrusive, batholithic 

 material, that the areas of pre-Cambrian rocks can rarely be extensive in any 

 part of the Western Belt. Much of the granite and gneissic rock mapped as be- 

 longing to the ( Archean) Shuswap series of southern British Columbia, may be 

 really intrusive and post- Carboniferous in age. No other large area of rocks in 

 the Western Belt has been definitely referred to the pre-Cambrian. 



The detailed discussion of these various correlations would itself fill a 

 considerable volume and must be omitted in the present report. For further 

 considerations the reader is referred to the works already noted. 



As an aid to the understanding of the correlation from the viewpoint of 

 physical geology, the preceding table has been recast in the form of Table 

 XXXVI, in which the chief processes leading to the present composition and 

 structure of the Western Geosynclinal Belt at the seven standard sections, are 

 enumerated. A final summary is offered in the form of Table XXXVII, which 

 is a composite of the seven columns of the last-mentioned table. 



