Named for Glenn Creek. Type section designated along banks and bed of Washington Creek, north-flowing tributary of Yukon River, 2 to 4 mi northwest of bench mark 2452 (Glenn) from NW/4 sec.24 T5N R26E to NW/4 sec.12 T5N R26E, Charley River B-3 (1:63,360) quad, AK. Recognized over area more than 2000 sq mi. Consists predominantly of grayish-black fissile carbonaceous shale which grades upward into grayish-black massive argillite and siltstone, and dark-gray fossiliferous limestone. Is about 5000 ft thick. Unconformably overlies Tahkandit Limestone or Step Conglomerate (new); Conformably underlies Keenan Quartzite (new); locally, unconformably underlies Cretaceous or Tertiary sedimentary rocks. Fossils identified by N.J. Silberling (listed in table) indicate unit ranges in age from Middle Triassic (Ladinian) to Early Cretaceous (probably Valanginian).

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