THE LA URENTIAN PENEPLAIN 



633 



it were, a sag in the surface of the peneplain between these two 

 locations. The margin of the plain parallel and close to the St. 

 Lawrence River, in the vicinity of the outlet of the Saguenay 

 River, reaches an elevation of over 1,500 feet, and there is a well- 

 defined gentle swell, whose height approximates to this elevation 



Fig. 6. — Looking across Lake St. John from the discharge of the Saguenay, the 

 margin of the upland makes the even sky-line in the background. 



{Photograph by Dr. F. D. Adams, 1884.) 



extending from southwest of the Saguenay in the neighborhood 

 of Quebec, for a considerable distance along the southeast 

 margin of the plain to below the St. John River. Between this 

 swell and the interior main divide is a gentle depression. The 

 lowest part of this depression forms the well-defined basin of 



Fig. 7. — Central Ontario. The upland shows the less even sky-line of one of the 



pre-Paleozoic facets. 



{Photograph by Dr. A. E. Barlow, iSgS.) 



(This photograph will accompany a detailed report on the geology of this area by 

 Dr. F. D. Adams and Dr. A. E. Barlow.) 



Lake St, John (314'), in this particular case probably located on 

 a graben block. The majority of the streams rising near the 

 interior divide are found to cross this marginal swell in the 

 peneplain through deeply cut, steep sided gorges or canyons. 



