Geoloiiy of Fillet Sound Basin. — Kimball. 321 
oiis islands on the east shore of Vancouver island, are, as al- 
ready noted, easily recognized as moderate outlying reliefs 
of the Vancouver range in a state of partial submergence. So, 
too. the bordering islands of British Columbia, like the head- 
lands of the main land, are related to the Coast range of that 
province as lower summits of the same range. In common 
with the subordinate topography of all the coast ranges of 
Washington and British Columbia, profound sculpturing of 
this insular and indented margin is ascribed primarily to flu- 
vial erosion, followed by glacial erosion. Partial submergence 
distinguishes it in particular from the prevailing physiograph- 
ic conditions of these ranges. The same fact also distin- 
guishes the coast north of the strait of Fuca from that to the 
south. The Olympics and the Coast range of Oregon, on the 
other hand, present gradual slopes to the ocean, their distin- 
guishing features being incidental to emergence. 
The Vancouver range which has been onl}^ partly explored, 
is principally made up of crystalline rocks of eruptive type, 
but believed by the Canadian geologists to represent highly al- 
tered sediments of Mesozoic age, the corrugation and pri- 
mary elevation of which are referred to a post-Triassic 
event, succeeded by deformation and reduction, if not b}^ 
subsidence partial or complete.* The probability of par- 
ticipation in the post-Cretaceous elevation of all the coast 
ranges named, and also in the further Pliocene movements of 
the Pacific border has also been indicated by the same geolo- 
gists. Bosses and isolated masses of metamorphic limestone 
occur on Orcas and San Juan islands. More extensive form- 
ations occur as belts on Vancouver, Redonda and Texada 
islands, in close relat on to granitic extrusions — evidentl}' 
continuous, in the case of the two smaller islands, with the 
great granite development of the Coast range, as the lowest 
summits of which these islands have been referred to above. 
Local replacements of the limestone with magnetite on a large 
scale are remarkable occurrences, including certain well- 
known develo])ments on Texada island, hitherto classilled by 
geologists with mineral veins. j- In the spring of 1894, hav- 
* Dawson op. cit. 1890. p. 6; An. Rep. Geol. Surv., Can. 1886— B, p. 
15. 
t An. Rep. Geol. Survey for 1896— B. 36. 
