Type locality designated as shoreline of Kuiu Island, just west of entrance to Saginaw Bay, southeastern AK. Crops out on southwest shore of Saginaw Bay and on few islets and reefs in Keku Islets. Characteristic and dominant type is brownish-gray dense stylolitic limestone. Lenses of polymict conglomerate occur sporadically throughout unit. Thickness is about 2500 ft on southwest side of Saginaw Bay. Contacts are faults or of equivocal nature. Exact stratigraphic relations are uncertain. Distribution of Silurian System suggests that unit overlies Bay of Pillars Formation (new) and underlies red arkose and volcanic graywacke and argillite. Shown on geologic map of Keku Islets and neighboring parts of Kuiu and Kuprenof Islands. Is considered Late Silurian age based on fossil assemblages identified by C.W. Merriam (unpub. data, 1964). Fossil list included in study.

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