The Devonian

Devonian

The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...

 Needmore Formation or Needmore Shale is a mapped bedrock

Bedrock

In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

 unit in Pennsylvania

Pennsylvania

The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...

, Maryland

Maryland

Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

, Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

, and West Virginia

West Virginia

West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...

.

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

Fulton County, Pennsylvania

Fulton County is a county located in the U.S. state of Pennsylvania. As of 2010, the population was 14,845.Fulton County was created on April 19, 1850, from part of Bedford County and named for inventor Robert Fulton.Its county seat is McConnellsburg....

, 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

Phacops

Phacops is a genus of trilobite in the order Phacopida, family Phacopidae that lived in Europe and North American in the Silurian and Devonian periods. It was a rounded animal, with a globosa head and large eyes, and probably fed on detritus...

 cristata), and ostracods (Favulella favulosa) in the Needmore.

Notable Exposures

Type locality is between Needmore

Needmore, Pennsylvania

Needmore is a populated place in southern Fulton County, Pennsylvania. It lies at the intersection of U.S. Route 522 and Route 655 .-Geology:...

 and Warfordsburg

Warfordsburg, Pennsylvania

In December 1776, Joseph Warford was deeded of land on which he laid out a village that was to become known as Warfordsburg. A large stone structure that served as the Warford home and tavern was built, though the building was destroyed by fire in 1947....

 in southern Fulton County

Fulton County, Pennsylvania

Fulton County is a county located in the U.S. state of Pennsylvania. As of 2010, the population was 14,845.Fulton County was created on April 19, 1850, from part of Bedford County and named for inventor Robert Fulton.Its county seat is McConnellsburg....

, Pennsylvania.