Ledger dolomite (new name) described as granular gray to white dolomite, mostly thick-bedded, some siliceous beds, which weather to rust-stained granular cherty layers. Thickness 1,000 +/-ft. Unconformably underlies Elbrook dolomite and overlies Kinzers formation. No fossils found, but Ledger, Kinzers, and underlying Vintage believed equivalent to Tomstown dolomite.

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

Ledger Formation in the West York block of the Conestoga Valley, southeastern PA, is here subdivided into a lower dolomite member, the Willis Run Member (new name), and an upper dolomite member. Unit has not been previously subdivided, but described as approximately 1000 ft of pure dolomite. In area of report, the Willis Run Member is described as predominantly limestone with some dolomite. At Delta Carbonate quarry, this middle limestone is approximately 200 ft thick and contains fossils confirming an Early Cambrian age for the lower Ledger. In Lancaster Co., however, the underlying Longs Parks member (informal) of the Kinzers Formation has been dated as Middle Cambrian. The Conestoga Limestone, which overlies the Ledger, is Middle Cambrian in the report area.

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