OTTAWA

PRINTED BY C. H. PARMELEE, PRINTER TO THE KING’S MOST

EXCELLENT MAJESTY

1909

No. 1075

13739-1

CONTENTS

Page.
[I. Introduction.]
[1. Location and area]5
[2. Statement of work]5
[3. History of development]6
[II. Summary and Conclusions]8
[III. General Character of District]10
[1. Means of access]10
[2. Topography]11
[3. Drainage]14
[4. Flora and fauna]15
[IV. General Geology]16
[1. Outline of Geological history]16
[2. Table of formations]18
[3. Keewatin]18
[General features]18
[Obushkong area]18
[Duncan Lake area]20
[Pigeon lake area]21
[Unfinished areas]22
[4. Laurentian]23
[General features]23
[Relations to other formations]24
[5. Huronian]25
[General features]25
[Basal conglomerate]26
[Greywacke slate and quartzite]27
[Upper conglomerate]27
[Arkose]28
[Structural features and disturbances]28
[Relations to other formations]29
[Origin and correlation]31
[6. Post-Huronian eruptives]32
[Quartz diabase]32
[Character of intrusion and distribution relative to older systems]32
[Macroscopic character]33
[Microscopic character]34
[Local description]36
[Age]37
[Olivine diabase]38
[7. Pleistocene]38
[V. Economic Geology]40
[1. Silver]40
[Distribution]40
[Surface indications]40
[Structure of veins]41
[Composition of veins]41
[Local description]42
[Future possibilities]44
[2. Copper]45
[3. Iron ores]45
[Hematite]45
[Magnetite]46
[4. Asbestos]46
[Distribution]46
[Origin]47
ILLUSTRATIONS.
[1. Frontispiece—View at Foot of Duncan Lake]5
[2. Diagram illustrating the structure of large hills]12
[3. Diagram illustrating geological relationships]16
[4. View looking north from middle of Duncan Lake, 550 ft. hill in distance]20
[5. West Branch Montreal River, near Mosher Lake]22
[6. Fifth portage on West Branch of Montreal River, showing Huronian slate]30
[7. Inclined Huronian Beds, Duncan Lake]32

R. W. Brock, Esq.,

Director Geological Survey Branch,