[3] These formations consist mainly of pillow basalt, large lava flows, tuff breccia, and sills.

[5] Currently it is part of a large forearc basin that extends for much of the entire Coast Range on a north-south alignment.

[3] Parts of the upper portions of the range contain continental margin deposits from the early Eocene to Paleocene age.

[5] The Oregon Coast Range is home to over 50 mammals, 100 species of birds, and nearly 30 reptiles or amphibians that spent a significant portion of their life cycle in the mountains.

[7] These include winter wrens, chestnut-backed chickadees, red-breasted nuthatches, varied thrushes, several swallow species, red crossbills, evening grosbeaks, brown creepers, olive-sided flycatchers, Hammond's flycatchers, gray jays, western wood-pewees, and western tanagers.

[7][8] Birds in lower numbers include Vaux's swifts, the endangered spotted owl, bald eagles, the downy woodpecker, hairy woodpeckers, the pine siskin, the hermit warbler, Pacific-slope flycatchers, golden-crowned kinglets, and ruffed grouse.

[9] The central coast range is also home to some larger animals such as deer, elk, bobcat, and bear.

[8][11] Other mammals living in the central range include beavers, creeping voles, long-tailed voles, vagrant shrews, deer mice, Pacific jumping mice, western pocket gopher, marsh shrew, shrew-mole, coast-mole, ermine, northern flying squirrel, and Townsend's chipmunk among others.

[14] The understory of the forest areas contain vine maple, Oregon grape, salmonberry, huckleberry, and sword fern to name a few.

[8][14][15] Additionally, various grass, sedge, and moss species are some of the other plant life growing in the mountain range.