Central Oregon Coast Range

The Central Oregon Coast Range is the middle section of the Oregon Coast Range, in the Pacific Coast Ranges physiographic region, and located in the west-central portion of the state of Oregon, United States roughly between the Salmon River and the Umpqua River and the Willamette Valley and the Pacific Ocean. This approximately 90 mile long mountain range contains mountains as high as 4,097 feet (1,226 m) for Marys Peak.

Portions of the range are inside the Siuslaw National Forest and three wilderness areas exist as well: Drift Creek Wilderness, Cummins Creek Wilderness and Rock Creek Wilderness.

Geology

The underlying rock of the Central Coast Range are the igneous rocks from the Siletz River Volcanics of the Paleocene age. These formations consist mainly of pillow basalt, large lava flows, tuff-breccia, and sills. The entire Oregon Coast Range overlies a convergent tectonic margin that interacts with the Juan de Fuca Plate that is being sub-ducted beneath the North America tectonic plate....
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