Unit is named the Winchester Creek Member of the Tiger Formation (revised) in the Cusick region of northeastern WA. Consists of fine-grained sandstone, siltstone, and shale in 1- to 5-mm-thick fining-upward sequences, and subordinate medium- to coarse-grained sandstone. Base is not exposed but probably unconformably overlies the Sanpoil Volcanics east of the Pend Oreille River and older strata west of the river; is a facies equivalent of, intertongues with, and is separated by a vertical arbitrary boundary from the Gibralter Rock Member (new) of the Tiger; conformably and unconformably underlies the Calispell Lake Member (new) of the Tiger. Thickness is 40 m at the type section; inferred total thickness is 900 m. Age ranges from early middle Eocene, based on inclusions of late early to early middle Eocene volcanic rock clasts, through middle Miocene, based on middle Miocene regional faults that bound the Tiger Formation, although the age determination of middle Miocene is less definite. (B1565)

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