Geologic units in Sullivan county, New York

Upper Walton Formation (Upper Devonian) at surface, covers 34 % of this area

Shale, sandstone, conglomerate.

Honesdale Formation (Upper Devonian) at surface, covers 25 % of this area

Sandstone, shale.

Lower Walton Formation (Upper Devonian) at surface, covers 16 % of this area

Shale, sandstone, conglomerate.

Slide Mountain Formation (Upper Devonian) at surface, covers 11 % of this area

Sandstone, shale, conglomerate.

Oneonta Formation (Middle - Upper Devonian) at surface, covers 6 % of this area

Shale, sandstone, conglomerate.

Slide Mountain Formation (Upper Devonian) at surface, covers 2 % of this area

Sandstone, shale, conglomerate.

Austin Glen Formation (Middle Ordovician) at surface, covers 2 % of this area

Graywacke, shale

Undifferentiated Hamilton Group (Middle Devonian) at surface, covers 1 % of this area

Shale, siltstone. In eastern Orange County: Skunnemunk Formation-sandstone, conglomerate; Bellvale Formation-shale, sandstone; Cornwall Shale.

Bloomsburg Formation (Upper Silurian) at surface, covers 1.0 % of this area

Shale, sandstone; Guymard Quartzite; Otisville Shale; Shawangunk Conglomerate-sandstone, conglomerate.

Rondout Formation (Upper Silurian) at surface, covers 0.3 % of this area

Dolostone, limestone; Binnewater Sandstone; High Falls Shale; Warwarsing Limestone; Decker Limestone; Bossardville Limestone; Poxono Island Formation-shale, dolostone.

Undifferentiated Lower Devonian and Silurian rocks (Lower Devonian - Silurian) at surface, covers 0.2 % of this area

In northern Ulster County: Port Ewen thru Manlius Limestones; Rondout Dolostone; Binnewater Sandstone; High Falls Shale. In Orange County: Kanhouse Sandstone; Woodbury Creek Formation-shale, sandstone; Esopus Shale; Connelly Conglomerate; Central Valley Sandstone; New Scotland Limestone thru Rondout Dolostone; Decker Limestone; Poxono Island Formation-shale, dolostone; Longwood Shale; Green Pond Conglomerate.

Onondaga Limestone (Lower to Middle Devonian) at surface, covers 0.2 % of this area

Seneca, Morehouse (cherty), and Nedrow Limestone Members, Edgecliff cherty Limestone Member, local bioherms, Buttermilk Falls Limestone Member; Schoharie Formation-shale, limestone; Carlisle Center Siltstone; Esopus Shale.

Helderberg Group (Lower Devonian) at surface, covers 0.1 % of this area

Alsen, Becraft, New Scotland, Kalkberg, Coeymans, and Manlius Limestones.

Long Run and Walcksville Members of Catskill Formation, undivided (Devonian) at surface, covers < 0.1 % of this area

Includes, in descending order, the Long Run (Dclr) and Walcksville (Dcw) Members of the Catskill Formation, which are described separately below.

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.

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

Shale, sandstone, conglomerate.

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

Dominantly gray sandstone and some siltstone and shale; freshwater fossils.