Introduction

The North Cascades are a piece of the Cascades that spans the border between British Colombia and Washington. They are predominantly non-volcanic, but include the stratovolcanoes Mount Baker, Glacier Peak and Coquihalla Mountain, which are part of the Cascade Volcanic Arc. (DNR.WA) There are a vast variety of rocks and cladistic material that is prevalent throughout the North Cascades.

The Extent of the Northern Cascade mountains:

The Fraser River and the adjoining lowland on its south bank form the northern and northwestern boundary of the range. On the east, the Okanogan River and the Columbia River bound the range in the United States, while the northeastern boundary of the range departs the Thompson via the Nicoamen River and runs via Lawless Creek, the Tulameen River and Copper Creek to the Similkameen River. On the west, the foothills of the range are separated by a narrow coastal plain from Puget Sound except along Chuckanut Drive between Bellingham and Mount Vernon, where they abut the Sound directly. The southern boundary of the North Cascades is less definite. It leads from U.S. Highway 2, running over Stevens Pass, or equivalently, the Skykomish River, Nason Creek, and the lower Wenatchee River (NPS) Geologically, the rocks of the North Cascades extend south beyond Stevens Pass and west into the San Juan Islands.