CONTENTS. 
PAGE 
Introduction, 1 
General stratigraphic relations 2 
The Pre-Cambrian surface • 4 
Structure of the Palseozoic plain 8 
The Laurentian Plateau escarpment 12 
Interpretation of the data 13 
Former extent of the Palaeozoic 19 
Summary 22 
ILLUSTRATIONS. 
Plate I. A. 
B. 
C. 
II. A. 
B. 
Laurentian escarpment south of Kings moun- 
tain, Que Frontispiece 
Lowland plain north of Quyon, Que., with 
Laurentian Plateau escarpment in the 
distance “ 
Laurentian Plateau escarpment north of 
Breckenridge, Que “ 
Contact of granite and Ordovician limestone 
at Kingston Mills, Ont 4 
Granite boulder at base of Trenton limestone 
at Pont Rouge, Que. 4 
Figure 1. Escarpment topography east of Montebello, Que. 2 
2. Outline map of the Ottawa district, showing 
principal faults and lines of cross-sections , . 10 
3. Cross-section from Kings mountain, through 
Aylmer, Que 12 
4. Cross-section to Vars, Ont., from the Laurentian 
plateau near Montebello, Que. 12 
5. Sketch map showing location of Laurentian 
Plateau fault and of Lake Erie and Monte- 
bello section 
12 
