REPORT OF TEE CHIEF ASTRONOMER xviF 



SESSIONAL PAPER No. 25a 



Page. 



Slesse diorite 532 



Petrography 532 



Contact metamorphism 534 



Chilliwack granodiorite batholith 534 



Petrography 535 



Contact metamorphism 540 



Intrusives cutting the Skagit volcanics 540 



Monzonite stock 541 



Dikes , 541 



Dikes cutting the Chilliwack batholith 542 



Acid dikes cutting the Chilliwack series 543 



Basic dikes and greenstones in the Chilliwack series 543 



Structural relations 544 



Correlation 545 



PAET II 



CHAPTEK XIX. 



Correlation in the Western Geosynclinal belt 547 



Principles used in correlation 547 



Correlation among formations at the Forty-ninth Parallel 550 



Correlation within the Western Geosynclinal belt 555 



General features of the Western Geosynclinal belt 565 



CHAPTEK XX. 



Summary of geological history and note on orogenic theory 567 



Geological history of the Cordillera at the Forty-ninth Parallel 567 



Observations bearing on the theory of mountain-building. . . . # . . . . 572 



CHAPTEK XXI. 



Glaciation of the Cordillera at the Forty-ninth parallel 577 



Introduction 577 



Clarke range 579 



Nature and extent of glacial erosion 580 



Galton-MacDonald mountain group 584 



Purcell mountain system 586 



Selkirk mountain system 588 



Columbia mountain system and the Interior Plateaus 589 



Okanagan range 591 



Hozomeen range 593 



Skagit range 594 



Summary 597 



