Name credited to J.W. Wells who suggested it as geographic name for conodont bed of Hinde at base of Genesee Group along Eighteen Mile Creek in Eden 15-min quad, west-central NY. Underlies Genundewa Limestone. Interfingers with Penn Yan Shale and Geneseo Shale. Type locality and derivation of name not stated. Age is Late Devonian.

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

Unit reduced in rank to North Evans Member of Genesee Formation of Seneca Group. Described as a bone bed with a matrix of black and gray limestone and shale. Overlies Windom Shale Member of Moscow Formation (Hamilton Group). Age given as Middle Devonian.

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

The North Evans Limestone Member of the Genesee Formation at Eighteenmile Creek in westernmost NY is the type stratum of the lectotype of ANCYRODELLA ROTUNDILOBA (Bryant). The diachronous North Evans represents a mix of several Middle and Upper Devonian conodont zones. At Eighteenmile Creek, the unit is 3 cm thick and is composed of dark-gray to brownish, coarse-grained limestone with irregular upper and lower contacts. Weathers rusty along its base. Contains conodonts, stylolines, crinoid debris, and fish debris visible with a hand lens. Base of measured section; underlies Penn Yan Shale Member(?).

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