Geologic units in Delaware county, New York

Upper Walton Formation (Upper Devonian) at surface, covers 38 % of this area

Shale, sandstone, conglomerate.

Lower Walton Formation (Upper Devonian) at surface, covers 31 % of this area

Shale, sandstone, conglomerate.

Oneonta Formation (Middle - Upper Devonian) at surface, covers 16 % of this area

Shale, sandstone, conglomerate.

Slide Mountain Formation (Upper Devonian) at surface, covers 5 % of this area

Sandstone, shale, conglomerate.

Honesdale Formation (Upper Devonian) at surface, covers 5 % of this area

Sandstone, shale.

Slide Mountain Formation (Upper Devonian) at surface, covers 3 % of this area

Sandstone, shale, conglomerate.

Unadilla, Laurens, New Lisbon, and Gilboa Formations (Middle Devonian) at surface, covers 2 % of this area

Shale, siltstone, sandstone.

Enfield"" and Kattel Formations (Upper Devonian) at surface, covers 0.5 % of this area

Shale, siltstone, sandstone.

Honesdale Formation (Upper Devonian) at surface, covers 0.4 % of this area

Sandstone, shale.

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

In west: Cooperstown and Portland Point shale and sandstone Members; In east: ""Manorkill"" and Portland Point shale and sandstone Members.

Beers Hill, Dunn Hill, Millport, and Moreland Shales (Upper Devonian) at surface, covers < 0.1 % of this area

Beers Hill, Dunn Hill, Millport, and Moreland Shales.

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

Grayish-red sandstone, siltstone, shale, and mudstone; units of gray sandstone occur in upper part; lithologies in upper part arranged in fining-upward cycles. In the Altoona area, the Catskill Formation is mapped as the Duncannon, Sherman Creek, and Irish Valley Members, which are described under "Central and Eastern Pennsylvania" provinces.