550 Reviews — The Geology of Vancouver and Vicinity. 



meation, but the figures given will be very valuable to those 

 interested in the study of fuels. 



VIII. — The Geology of Vancoxtver and Yicinity. By E. M. J. 

 Btjewash. pp. 106, with 23 figures and 2 maps. Chicago, 111. : 

 The University of Chicago Press. 1918. 



r nHE area covered by this report may be divided into two parts : 

 J_ the southern portion, which extends from the international 

 boundary to Burrard Inlet, is part of the floor of the great structural 

 valley in which lie Puget Sound and the Gulf of Georgia ; the 

 northern area forms part of the southern margin of the coast range 

 of British Columbia. In the latter the relief of the land is high and 

 yields a definite record of a succession of physiographic cycles. Five 

 such stages can be recognized and correlated with those already 

 worked out in the Cascades of Washington State ; they are as 

 follows : the Methow peneplain, represented by accordant summits 

 and terraces, the Entiat stage when mature valleys were developed 

 in this older surface, the Twisp stage when the Entiat valleys were 

 over-deepened by canyons cut in their floors, after uplift, the Chelan 

 stage of glacial modification, and the Stehekin stage of post-Glacial 

 stream-denudation and deposit. 



The rocks found in the region include Devono-Carboniferous 

 (Texada and Britannia series), the first wholly volcanic, the second 

 including slate and sandstone as well as lavas, some porphyrite 

 intrusions assigned to the Trias, the Upper Jurassic coast-batholith, 

 Eocene conglomerate, sandstone, shale, and clay, post-Eocene eruptives 

 (Black Tusk basalts), the Garibaldi volcanic formation, and a variety 

 of Quaternary deposits. Of each of these detailed descriptions are 

 given, together with a very complete discussion of the sti'uctural and 

 physiographic features attending the formation of each. 



The coast-batholith forms part of the immense series of pre- 

 dominantly dioritic batholiths extending from the Frazer River into the 

 Yukon territory. This particular igneous complex includes varieties 

 ranging in composition from biotite-granite through granodiorite, 

 diorite, and gabbro to hornblendite. There is clear evidence of 

 differentiation with mai'ginal basic facies, the latter being in some 

 places intruded by more acid apophyses. Near the contacts gneissoid 

 texture, due to flow, is in evidence, and orbicular types are also known. 

 The Black Tusk basalts form the summits of certain conspicuous 

 mountains, these being probably remnants of flows that filled 

 a Miocene valley, while similar rock-types occur elsewhere as dj-kes. 

 The Garibaldi volcanics form three cones which are clearly later than 

 some of the Pleistocene glacial deposits : they are mainly basaltic in 

 composition. 



Among Quaternary deposits the moraines and various forms of 

 drift are the most noteworthy, since they indicate several stages 

 of glaciation of the region. There are also numerous examples 

 of deltaic and other alluvial deposits, as well"': 

 author considers to have been formed by glacial lakes. 



