Limonite-stained black slate and dark-gray phyllite with subordinate black argillite and banded siltstone in the Skagway quadrangle (Gilbert and others, 1987). As originally described, includes gray bioclastic limestone and marble, but we show those rocks as part of unit |ce herein. The Porcupine slate of Redman and others (1985) intertongues with rocks mapped here as part of the Hyd Group (unit ^hg) and, because of locally intense deformation, in many places workers could not distinguish a difference between the Porcupine slate, older rocks, and the Hyd Group (Green and others, 2003). The Porcupine slate contains Devonian to Triassic fossils and locally overlies marble (unit Pzce, here) that contains Devonian to Mississippian fossils (Gilbert and others, 1987). We suggest, however, that the Triassic fossils are more likely associated with the interleaved Hyd Group. The Porcupine slate has been correlated with the Cannery Formation (unit PDcf) (Karl and others, 2010)