The Coast Mountains rise out of the Fraser Valley and extend northward along the coast to Alaska. Near Vancouver they consist mainly of granitic and metamorphic rocks more than 100 million years old. Younger sandstones, about 85 to 35 million years old, overlie these rocks and form many of the hills in Vancouver and Burnaby.

The southern Coast Mountains were created by compression, heating, and uplift, stemming from subduction (undersliding) of Pacific Ocean crust beneath North America. Their present form, however, owes much to erosion. Deep U-shaped valleys, such as the Capilano and Seymour, were carved rivers and modified by glaciers. These valleys contain thick fills of Ice Age and modern sediments. Mountain slopes and peaks have only thin, discontinuous veneers of sediment. Slopes below about 1500 m elevation are somewhat smoothed and rounded due to their having been overridden by the Cordilleran ice sheet which covered nearly all of south-coastal British Columbia as recently as 15,000 years ago. The highest peaks projected through this ice sheet and are more jagged.

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	Photo 10 View of Stanley Park and downtown Vancouver from West Vancouver. Stanley Park is underlain by south-tilted layers of sandstone, which are visible along the Stanley Park seawall. Resistant volcanic rock (basalt) forms the steep cliff at Prospect Point near the south end of the Lions Gate Bridge.
	Photo 11 Bedrock slopes of the Coast Mountains rise sharply above North Vancouver, which is built on an upland underlain mainly by Ice Age gravel and sand. View from Stanley Park.
	Photo 12 The bouldery channel of Lynn Creek, a typical North Shore mountain stream. Steep-gradient streams such as this transport gravel, even boulders, during floods.
	Photo 13 Capilano Lake is one of three reservoirs that provide water to Vancouver. The lake fills the lower part of a large, glacier-carved valley. Cleveland Dam, which impounds the lake, straddles the head of a deep, narrow canyon that has been cut into bedrock by the Capilano River.
	Photo 14 Downtown Vancouver is built on a ridge of sandstone tilted gently to the south. To the north, soft mudstone has been more deeply eroded to form Burrard Inlet.
	Photo 15 Burnaby Mountain; view east from the Lions Gate Bridge. This mountain is formed of layers of resistant conglomerate and sandstone tilted about 10o to the south. The tilted layering is responsible for the striking asymmetry of the mountain.
	Photo 17 Delta at the mouth of the Capilano River. Since construction of Cleveland Dam, Capilano Lake has trapped sediment that would otherwise be transported to the river mouth. A new delta is forming where Capilano River flows into Capilano Lake.
	Photo 18 Siwash Rock, a Vancouver landmark. This pillar-like rock was once part of Stanley Park, but became separated from it through erosion by waves and weathering. Siwash Rock remains today because it consists mainly of basalt which is more resistant to erosion than surrounding sandstone.