Stetson Mountain Formation of Kossuth Group [new names] subdivided in the Danforth area, ME, into three newly named units: the Tolman Hill, Ironstone, and Public Lot Ridge members. While lower and upper members are composed almost wholly of felsic volcanic rocks, middle member is distinctive in that it contains several unique rock types. Diagnostic lithology is massive, fine grained, dark gray to black rock with abundant euhedral magnetite octahedra. Associated with banded iron-formation consisting of alternating red, hematite-rich layers and black, magnetite-rich layers. Also contains thinly-bedded manganiferous siltstone and pelite and minor ashflow tuffs. Late Ordovician age is based on Caradocian graptolites from the underlying Tolman Hill member.

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