2 GEORGE V. SESSIONAL PAPER No. 25a A. 1912 



TABLE OF CONTENTS. 



PART I. 



CHAPTER I. 



Page. 



Introduction 1 



Area covered 1 



Conditions of work in the field 1 



Acknowledgments 2 



Collections 3 



Previous publications by the writer on the Forty-ninth Parallel geology 3 



Earlier work on the geology of the Forty -ninth Parallel 5 



Continuation of the Forty-ninth Parallel section 5 



General sketch of the subject matter 5 



CHAPTER II. 



Synopsis of the report 9 



CHAPTER III. 



Nomenclature of the mountain ranges crossed by the Forty-ninth 



Parallel 17 



Introduction and outline 17 



Different nomenclatures in use .* 18 



Diverse naming of the western mountain region as a whole . 18 



Diverse naming of ranges crossed by the Forty-ninth Parallel 22 



Adopted principle of nomenclature for the Boundary mountains. ... 23 



Trenches and greater valleys 25 



Subdivision of Rocky Mountain system 27 



Purcell mountain system and its subdivision 30 



Selkirk mountain system and its subdivision 34 



Columbia mountain system and its subdivision 37 



Belt of Interior Plateaus 40 



Cascade mountain system and its subdivision 40 



Summary 42 



. Leading references 43 



CHAPTER IV. 



Stratigraphy and structure of the Clarke range 47 



Rocky Mountain geosynclinal prism 47 



Lewis series 49 



7 



