Type sedimentary Extent Pennsylvania Primary Slate | Country United States Region Appalachian Mountains Named for Need, Pennsylvania | |
Named by Willard and Cleaves, 1939 | ||
The Devonian Needmore Formation or Needmore Shale is a mapped bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.
Contents
Description
The Needmore Formation was originally described by Willard and Cleaves in 1939 as a dark- to medium-gray limy shale, based on exposures in southern Fulton County, Pennsylvania. They considered it part of the Onondaga Group.
DeWitt and Colton (1964) described the Needmore as "soft calcareous medium dark-brownish-gray and greenish-gray shale and mudrock...and soft, slightly calcareous very fissile brownish-black shale" that is not resistant to weathering. They estimated its thickness in their study area as approximately 150 feet.
Fossils
DeWitt and Colton (1964) identified brachiopods (Coelospira acutiplicata, Eodevonaria arcuata), trilobites (Phacops cristata), and ostracods (Favulella favulosa) in the Needmore.
Notable Exposures
Type locality is between Needmore and Warfordsburg in southern Fulton County, Pennsylvania.
Age
Relative age dating places the Needmore in the middle Devonian.