REPORT OF THE CHIEF ASTRONOMER ix 



SESSIONAL PAPER No. 25a 



CHAPTEE VI. 



Page. 



Stratigraphy and structure of the Purcell mountain system 119 



Purcell series 119 



Creston formation 120 



General description . 120 



"Western phase 122 



Eastern phase 126 



Kitchener formation 128 



Western phase 129 



Eastern phase 132 



Moyie formation 135 



Gateway formation in the McGillivray range 136 



Structure of the Purcell mountain system 137 



CHAPTEE VII. 



Stratigraphy of the Selkirk mountain system (in part) 141 



Summit series 141 



Irene conglomerate formation 141 



Irene Volcanic formation 144 



Monk formation 147 



Wolf formation 150 



Dewdney formation . . . 153 



Eipple formation 155 



Beehive formation 156 



Lone Star formation 158 



CHAPTEE VIII. 



Correlation of the formations in the Eocky Mountain geosynclinal . . . . . . 161 



Correlation along the Forty -ninth Parallel 161 



Systematic variation in the rock-character of the geosynclinal at the 



Forty-ninth Parallel 166 



Metamorphism of the geosynclinal prism 171 



Specific gravity of the geosynclinal prism 172 



Correlation of the four Boundary series with the Castle Mountain-Bow 



Eiver (Cambrian) group. Summary 174 



Correlation with the Belt terrane 179 



Earlier views on the Belt terrane 179 



Evidence of fossils 183 



Eelative induration and metamorphism of the Belt terrane and 



Flathead formation 185 



Evidence of unconformity 186 



Summary of conclusions 189 



Correlation with Dawson's Selkirk and Adams Lake series 191 



