Geologic units in Yates county, New York

Genesee Group (Upper Devonian) at surface, covers 36 % of this area

West River Shale; Genundewa Limestone; Penn Yan and Geneseo Shales; all except Geneseo replaced eastwardly by Ithaca Formation-shale, siltstone and Sherburne Siltstone.

Sonyea Group (Upper Devonian) at surface, covers 32 % of this area

In west: Cashaqua and Middlesex Shales. In east: Rye Point Shale; Rock Stream ("Enfield") Siltstone; Pulteney, Sawmill Creek, Johns Creek, and Montour Shales.

Beers Hill, Dunn Hill, Millport, and Moreland Shales; Grimes Siltstone (Upper Devonian) at surface, covers 11 % of this area

Beers Hill, Dunn Hill, Millport, and Moreland Shales; Grimes Siltstone.

West Hill and Gardeau Formations (Upper Devonian) at surface, covers 11 % of this area

Shale, siltstone; Roricks Glen Shale; upper Beers Hill Shale; Grimes Siltstone.

Lower Beers Hill Shale (Upper Devonian) at surface, covers 4 % of this area

Dunn Hill, Millport, and Moreland Shales.

Moscow Formation (Middle Devonian) at surface, covers 2 % of this area

In west: Windom and Kashong Shales, Menteth Limestone Members; In east: Cooperstown Shale Member, Portland Point Limestone Member.

Tully Limestone (Middle Devonian) at surface, covers 2 % of this area

Tully Limestone

West Hill and Gardeau Formations (Upper Devonian) at surface, covers 1 % of this area

Shale, siltstone; Roricks Glen Shale; upper Beers Hill Shale; Grimes Siltstone.

Nunda Formation (Upper Devonian) at surface, covers 0.9 % of this area

Sandstone, shale.

Ludlowville Formation (Middle Devonian) at surface, covers 0.3 % of this area

In west: Deep Run Shale, Tichenor Limestone, Wanakah and Ledyard Shales, Centerfield Limestone Members. In east: King Ferry Shale and other members, Stone Mill Sandstone Member.

Skaneateles Formation (Middle Devonian) at surface, covers < 0.1 % of this area

Levanna Shale, Stafford Limestone Members.