Unit is named the Padden Member of the Chuckanut Formation. Is exposed in the Bellingham Bay area on the mainland and is on Lummi and Sucia Islands, in the largest outcrop belt of the Chuckanut Formation, which extends from the San Juan Islands into the North Cascades, WA. Consists of alternating medium- to coarse-grained, cross-bedded sandstone, massive to crudely stratified conglomerate, and mudstone containing minor amounts of coal. Represents braided river and flood-plain deposits. Conformably overlies the Bellingham Bay and Governors Point Members (both new) of the Chuckanut Formation, or unconformably overlies pre-Tertiary rocks in the western part of the outcrop belt; interfingers with the Slide Member and underlies the Maple Falls Member (both new) of the Chuckanut Formation. On Sucia Island strata of the Padden Member, formerly assigned to the Nanaimo Group, are in fault-contact with the Nanaimo Group. Thickness is 680 m at the type section; total thickness may exceed 3,000 m. Age is middle to late Eocene based on radiometric (zircon fission-track) ages and pollen. (B1565)

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