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VANCOUVER ISLAND. 



BY 



Charles H. Clapp. 



INTRODUCTION. 



The Vancouver Island excursions afford an opportunity 

 to study the geology of a readily accessible area which is 

 fairly representative of the whole Pacific Coast region of 

 North America, and to examine the most important coal 

 field of that region. Features of wide geological interest 

 to be seen, are: — (i) Ancient volcanism, including flows 

 and fragmental rocks, denuded volcanoes, fossiliferous 

 tuffs, columnar jointing, and pillow structure. (2) Dyna- 

 mic and contact metamorphism of basic volcanics and 

 associated limestones producing marbles, amphibolites, 

 and garnet-diopside-epidote rocks. (3) Batholithic and 

 dyke intrusives, illustrating contact shatter-breccias, 

 differentiation, sequence of the different phases of igneous 

 activity, and origin of primary gneisses. (4) Sedimenta- 

 tion, illustrating unconformity, rapid lateral and vertical 

 gradation, calcarenites, sandstone dykes, and coal. (5) 

 Glaciation, grooves, striations, roches moutonnees, glacial 

 and interglacial deposits, such as deltas with terraces 

 and kettles. (6) Physiographic features, peneplain and 

 monadnocks, glacial lakes and fiords, and various types 

 of shore-lines. (7) Economic geology, contact deposits, 

 coal and other non-metallic materials. 



GENERAL GEOLOGY AND PHYSIOGRAPHY. 



Vancouver island (4) is one of the border ranges of 

 North America and is separated from the mainland by the 

 submerged northern portion of the great marginal de- 

 pression of North America, known as the Pacific Coast 

 downfold (17). This depression is flanked on either side 

 by great mountain ranges; in British Columbia by the 

 Coast range to the east and the ranges of Vancouver 

 island and Queen Charlotte islands to the west. The 

 Vancouver range, which virtually constitutes Vancouver 



