Name Selinsgrove lower limestone introduced in this report for hard light-gray rock, somewhat impure, in layers 1 to 3 in. thick, interstratified with thin gray shales near Selinsgrove Junction. Thickness 65 ft below Selinsgrove, Snyder Co.; 100 ft near southern line of Northumberland Co. Rests on Selinsgrove shale, and is overlain by Marcellus slate. Age is Middle Devonian. [Name Selinsgrove is used for five units.]

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

White (1883) applied Selinsgrove to five members of Middle Devonian age. It is here proposed to drop the name for all but his Selinsgrove lower limestone with adjective lower omitted. Thickness varies: 65 ft at Selinsgrove Junction; 7 ft in Lebanon Co.; 20 ft in Carbon Co; farther east, appears to merge with Buttermilk Falls limestone. Overlies Needmore shale (new) with gradational contact; underlies Marcellus black shales. Needmore shale was Selinsgrove shale of White (1883).

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

Selinsgrove Limestone Member, upper member of Needmore Shale (central PA), is direct equivalent of Onondaga Limestone of western and central NY. Also equivalent to Buttermilk Falls Limestone of eastern PA. Underlying strata of Needmore are therefore equivalent to the older Esopus to Schoharie Formations of NY.

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