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National Geologic Map Database
Geologic Unit: West York
Map showing publication footprint
  • Usage in publication:
    • West York Member
  • Modifications:
    • Overview
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Taylor, J.F., and Durika, N.J., 1990, Lithofacies, trilobite faunas, and correlation of the Kinzers, Ledger, and Conestoga Formations in the Conestoga Valley [Chapter IX], IN Carbonates, schists, and geomorphology in the vicinity of the lower reaches of the Susquehanna River; 55th annual field conference of Pennsylvania geologists: Field Conference of Pennsylvania Geologists, no. 55, p. 136-160.


Summary:

Conestoga Limestone in report area is divided into three members. Most spectacular lithofacies of the Conestoga is the polymictic megaconglomerate or megabreccia at the base. These debris flow deposits include clasts ranging upward to 30 ft or more and are referred to as the West York Member. This member is replaced to the southeast by the Kreutz Creek Member which consists of dark lime mudstones and phyllite. The Wrightsville Member overlies both the West York and the Kreutz Creek and shows a general increase in the percentage of argillaceous lithologies and a decrease in peloidal and lithoclastic limestones toward the southeast and a change from slope or proximal submarine fan deposition in the northwest to mid-fan environments to the southeast. [Because members were named by G. Gohn (1976) in a Ph.D dissertation they are considered informal by the GNU.]

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


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

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