NORTHERN OREGON COAST RANGE

The 'Northern Oregon Coast Range' is the northern section of the Oregon Coast Range located in the northwest portion of the state of Oregon, United States. This section of the mountain range, part of the Pacific Coast Ranges, contains peaks as high as 3706 feet (1130 m) for Rogers Peak.^[1] Forests in these mountains are considered to be some of the most productive timber land in the world.Oregon State University: Northern Coast Range Adaptive Management Area; Chapter 2: Physical and Biological Environment The Central Oregon Coast Range is directly south of this section with the Southern Oregon Coast Range beyond the central range.

Contents

Geology

Flora and fauna

Location and climate

Peaks

Other peaks

Rivers

References

External links

Geology

The origins of these mountains began approximately 40 million years ago during the Eocene age. During this time-period, sandstone and siltstone formed in the area. Additionally, igneous rocks and basalt flows combined with basaltic sandstone to create many of the mountainous formations. Other sedimentary rock in the area formed more recently, around 20 million years ago. It is hypothesized that portions of the northern section of the range were islands during parts of the Eocene era.Oregon Department of Forestry: Upper Nehalem Watershed Analysis Other portions of the mountains consist of marine sedimentary rock.An Erosional Classification for the Northern Oregon Coast, Annals of the Association of American Geographers, Vol. 54, No. 3. (Sep., 1964), pp. 329-335. John V. Byrne The entire coast range sits on a convergent tectonic margin interacting with the Juan de Fuca Plate that is subducting beneath North America tectonic plate.^[2] Also, erosion of the region is a major factor in shaping the landscape. Heavy rainfall and landsides have worked to erode the mountains.
The range is part of a broad, plunging structural arch of sedimentary and Tertiary volcanic strata that is being uplifted. Eocene and Miocene sections form the flanks of the uplifted sections. Some of the oldest rocks are submarine tholeiitic basalts from the Eocene era. The basalt came from the basalt flows that covered much of Oregon and originated from volcanoes in the central portion of the state. Other rocks include sandstone, mudstone, and siltstone. It was during the middle Miocene period that the range was uplifted in the broad, northeast-plunging arch.USGS: Geologic Map of the Tillamook Highlands, Northwest Oregon Coast Range

Flora and fauna

Logging in the mountains.

Oregon-grape.

Portions of the range are in the Siuslaw National Forest and Tillamook State Forest, and large sections of the range were burned in forest fires during the 1930s and 1940s as part of the Tillamook Burn. In the forested areas trees include Sitka spruce, western redcedar, Douglas-fir, and western hemlock.Tree Dictionary: From the Forest to the Sea: A Story of Fallen Trees Other plants that grow in the region are huckleberry, salmonberry, salal, vine maple , sword fern, Oregon grape, bracken fern, and thimble-berry to name a few.Biotic Aspection in the Coast Range Mountains of Northwestern Oregon, Ecological Monographs, Vol. 28, No. 1. (Jan., 1958), pp. 21-54. James A. Macnab.
Insects found include millipedes, collembolans, spiders, beetles, slugs, and various centipedes. Animals that inhabit the Northern Coast range are weevils, chipmunks, bears, rabbits, white-footed deer mice, Columbian Black tail deer, and others. Birds include chickadees, red-breasted nuthatches, kinglets, Western pileated woodpeckers, Oregon gray jays, California creepers, and Sitka red crossbills among others.

Location and climate

The range begins at the Columbia River, with some mountainous features on the north side of the river, and continues south roughly 100 miles to the Salmon River where Oregon Route 18 traverses the range from the Willamette Valley to the Oregon Coast. Width of the mountains varies, but are roughly 35 miles wide.
Climate of the range is moderate because of marine influences. Annual precipitation varies from 60 to 180 inches.^[3]

Peaks

All mountains over 3,000 feet in elevation in the Northern Coast Range.^[4]

Mountain Name	Elevation	County
Rogers Peak		Tillamook
South Saddle Mountain		Washington
Larch Mountain		Washington
Trask Mountain		Yamhill
Saddle Mountain		Clatsop
Triangulation Point		Tillamook
Kings Mountain		Tillamook
Mount Hebo		Yamhill
Edwards Butte		Tillamook
Buck Mountain		Tillamook
Sheridan Peak		Yamhill
Woods Point		Tillamook
Gobblers Knob		Tillamook

Other peaks

★ Neahkahnie Mountain (1680 feet)

Rivers

Map of the region with major rivers in blue. Orange line shows divide between watersheds flowing to the east and those flowing north or west.

The following rivers have their headwaters in the Northern Oregon Coast Range:

★ Drains to Columbia River:

★
★ Clatskanie River

★
★ John Day River

★
★ Klaskanine River

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★ Lewis and Clark River

★
★ Skipanon River

★
★ Wallooskee River

★
★ Youngs River

★ Drains to Willamette River:

★
★ Tualatin River

★
★ Yamhill River

★ Drains to Pacific Ocean:

★
★ Kilchis River

★
★ Miami River

★
★ Necanicum River

★
★ Nehalem River

★
★ Nestucca River

★
★ Salmonberry River

★
★ Salmon River

★
★ Tillamook River

★
★ Trask River

★
★ Wilson River

References

1. Peakbagger.com: Rogers Peak
2. Geology of the Luckiamute River Watershed, Upper Willamette Basin, Polk and Benton Counties, Oregon
3. Oregon Department of Forestry: Private Forests
4. USGS: GNIS

External links