Landforms of British Columbia 1976 - Department of Geography

materials. Along the west coast of Vancouver Island, sea cliffs occur in bays on
the Tertiary sediments, between headlands of more resistant crystalline rocks, or
where the coastal plain is being attacked and cut into by erosion, producing low cliffs
in the more resistant sandstone and conglomerate beds of Oligocene age. Along the
east coast of Vancouver Island south of Campbell River, there are occurrences of
relatively soft Upper Cretaccous formations and of unconsolidated glacial materials
which are susceptible to marine erosion. Wave attack on such materials produces
sea cliffs, and in so doing provides detritus for beaches, bars, spits, and similar
shoreline features.
Sea cliffs on the Queen Charlotte Islands present a striking contrast to those
on Vancouver Island. On the west coast of Moresby Island even the most resistant
rocks may be facetted to heights of 500 feet by steep sea cliffs, product of fierce wave
attack upon the fully exposed coast (see Plate XLVA). However, the submarine
slopes are far tw steep for the detritus to accumulate as beaches.
In general it can be stated that, except for the relatively few places where
erosion of weaker materials is taking place, the coastline of British Columbia is
rugged and resistant, and drops off rapidly into deep water with only minor
accumulations of beach materials (see Plate XLVIA).
The outstanding features of the British Columbia coast are its numerous fiord
inlets (see Plate IIIA, XLVIB, and XLVIII). The mainland from Howe Sound
to Portland Canal is indented by fiords, as are the west coast of Vancouver Island
and the coasts of the Queen Charlotte Islands, except for the northeast corner of
Graham Island.
The fiords on the mainland rank in size and scenic grandeur with the worldfamous
fiord coastlines of Norway, Patagonia, and the South Island of New Zealand.
The fiords are half a mile to 2 miles wide and have steep glaciated sides that rise
from the water’s edge in long unbroken slopes to summits at 6,000 to 8,000 feet.
Along their length, water cascades over falls and down rock faces, and landslides
on steep slopes frequently have bared the granitic rocks of all vegetation. On clear
days when the all too prevalent low clouds are swept away, the scenery along the
many lonely fiords is majestic.
Some of the inlets are unusually long. Burke Channel extends 56 miles into
the heart of the Coast Mountains, Dean Channel is 60 miles long, and the head of
Gardner Canal is about 120 miles from the outer coast at Otter Pass.
“
. on a map the simplest fiords are seen to be straight, narrow waterways.
A few of the fiords are smoothly and gently curved, but in the majority of
cases changes of course occur by abrupt deflections through high angles, giving a
cranked plan in which the several reaches of the fiord conform to two dominant
directions that are usually, but not invariably, inclined at nearly a right angle.
‘C
. . the fiord pattern of the coastland . . two simple two-component
patterns can be distinguished: a dominant pattern consisting of elements arranged
longitudinally [northwesterly] and transversely [northeasterly] to the trend of the
coastland, giving a rudely rectangular network of varying orientation; and a subordinate
pattern composed of linear elements forming a second roughly rectangular
pattern oriented obliquely to the tist [that is, northerly and easterly]. Since one
direction of the dominant pattern runs with the grain of the coastland, the pattern
may be described as concordant. . . “*
Soundings along the fiords almost invariably indicate a shoaling near their
mouths produced by a threshold which may be of bedrock or of unconsolidated
’ Peacock, M. A., Geol. sot.. Am.. Bun. “0,. 4.5 1935, p. 655.
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