The Windsor Township Formation, here named, is predominantly a graywacke-shale unit that locally contains boulder conglomerate and slivers of limestone, chert, and variegated shale and mudstone. It is an allochthonous unit in the Greenwich slice of the Hamburg klippe, and underlies the Virginville Formation in the tectonically overlying, but older, Richmond slice of the Hamburg klippe in Berks Co., PA. It is divided into the Weisenberg Member, a shale, siltstone, and mudstone unit, and the Switzer Creek and Dreibelbis Members, graywacke-shale units. Minimum thickness is 6,215 m. Age of the graywacke-shale units is Middle Ordovician, based on graptolites; age of the limestone, chert, and variegated shale units may be Early and Middle Ordovician, based on graptolites and conodonts, suggesting that these units, which occur throughout the formation, may be allochthonous with respect to the Middle Ordovician graywacke-shale units.

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