Unit is named the Slide Member of the Chuckanut Formation for exposures in the eastern part of the largest outcrop belt of the Chuckanut, which extends from the San Juan Islands into the foothills of the North Cascades, WA. Consists of fining-upward cycles of lower coarse-grained units of arkosic sandstone and upper fine-grained units of mudstone and minor amounts of coal and sandstone, that are interpreted as meandering river and adjacent flood-plain deposits. Overlies the Bellingham Bay Member (new); interfingers with the Padden Member (new) to the west and is in fault contact with pre-Tertiary rocks to the east; underlies the Warnick and Maple Falls Members (new), all of the Chuckanut Formation. Thickness is 1960 m at the type section. Age is middle Eocene based on radiometric age (Zr fission-track) of the Bellingham Bay and Padden Members. (B1565)

Source: GNU records (USGS DDS-6; Menlo GNULEX).