Is not used in the Kiernan quad, eastern Iron Co, MI (Lake Superior region). Clements and Smyth (1899) correlated sericite slate west of center of sec 32, T44N, R31W, with the "Mansfield slate" at Mansfield south of the quad and considered it a facies equivalent to the volcanic unit of the Hemlock. However, this slate is either an upper member of the Randville dolomite or a distinct unit above the dolomite. In the southwestern part of the quad, slate occurs in narrow belts interbedded with greenstone of the Hemlock formation; the zone of slate extends south into Lake Mary quad and evidently grades southward into locally iron-rich slate (the "Mansfield slate") that was formerly mined for iron at Mansfield. The iron-rich part of the slate probably thins northward and has not been observed in the Kiernan quad.

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

Pg. 30 (table 1), 36. Mansfield iron-bearing slate member of Hemlock formation of Baraga group (new) of Animikie series. Consists in part of chert-siderite iron-formation and in part of slate, with a maximum thickness of about 500 feet. Occurs within lower third of formation; thus is stratigraphically below newly defined Bird iron-bearing member. Present in Iron County, northwestern Michigan (Lake Superior region). Age is middle Precambrian (Animikie Series). Report includes stratigraphic sequence chart.

Source: US geologic names lexicon (USGS Bull. 1200, p. 2364); supplemental information from GNU records (USGS DDS-6; Reston GNULEX).