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The Rocks Of Bulson Creek: Eocene-Oligocene Sedimentation And Tectonics In The Lake Mcmurray Area, Washington, Kim Lance Marcus

WWU Graduate School Collection

Upper Eocene to lower Oligocene sedimentary rocks in the Lake McMurray area of Skagit County, Washington, consist of approximately 1500 m of conglomerate, sandstone, shale, and siltstone which were deposited in fluvial and marine environments along the continental margin. These rocks are known as the rocks of Bulson Creek.

Two main lithofacies can be recognized within the sequence: the lowest is nonmarine and consists of poorly sorted, thick, and structureless conglomerate with interbedded sandstone, siltstone, shale, and minor coal lenses; the upper lithofacies grades from a transitional nonmarine facies to a shallow water marine facies that consists of well sorted, …