THE 



JOURNAL OF GEOLOGY 



OCTOBER-NOVEMBER, 1903 



THE LAURENTIAN PENEPLAIN. 



TABLE OF CONTENTS. 



Introduction. 



The Canadian Oldland. 



Exploration and Surveys. 



Physiographic Controls. 



The Date of the Emergence of the Canadian Shield. 



Features of the Planation Surface. 



1. Character of the sky-line. 



2. Departures from the normal peneplain type. 



3. Detailed descriptions of characteristic portions of the plain. 



4. Drainage features. 



5. Topographic depressiotts. 



a) Upland depressions. 



b) Depressions containing sedimentary deposits. 



c) Gorge and canyon valleys. 



6. Monadnocks. 



7. Lakes. 



The Peneplain Facets. 



Summary. 



Some Problems of General Interest. 



1. The former extent of the Paleozoic cover. 



2. The subaerial origin of the peneplain and the date of origifi of the 

 principal plain. 



3. The origin of the basins, valleys, and gorges. 



4. The origin of the smooth, fresh surface of the Archo'an rocks. 

 Literature. 



INTRODUCTION. 



The late director of the Geological Survey of Canada, Dr. 

 George M. Dawson, in his address before the Geological Section 



Vol. XI, No. 7. 615 



