GEOLEX

Summary of Citation: Hammer Creek

Publication:
Glaeser, J.D., 1963, Lithostratigraphic nomenclature of the
   Triassic Newark-Gettysburg basin: Pennsylvania Academy of
   Science Proceedings, v. 37, p. 179-188

Usage in Publication:
Hammer Creek Formation

Modifications:	Geologic Province:	Dominant Lithology:
Named	Piedmont-Blue Ridge province Gettysburg basin Newark basin	Conglomerate

Summary:
Coarse sandstones and conglomerates which outcrop in the narrow neck of the Newark-Gettysburg basin in PA are here named the Hammer Creek Formation of the Newark Group to avoid extending either the Gettysburg Formation from the west or the Brunswick Formation from the east to include rocks typical of neither unit. The Hammer Creek is defined between two arbitrary cutoffs, the Dauphin-Lebanon Co. line on the west and a line in the vicinity of the Schuylkill River on the east. It is characterized by heterogeneous texture and composition and lateral pinching out of individual beds. It overlies the New Oxford Formation in the west and the Stockton Formation in the east. It includes rocks previously defined as the Brunswick Formation, Robeson Conglomerate, and the Gettysburg Formation and its Furnace Ridge and Elizabeth Furnace Conglomerate Members. Thickness at type section is 9,360 ft. Age is Late Triassic.

Summary of Citation: Hammer Creek

Publication:
Van Houten, F.B., 1969, Late Triassic Newark Group, north central
   New Jersey and adjacent Pennsylvania and New York; Field trip
   4, IN Subitzky, Seymour, ed., Geology of selected areas in
   New Jersey and eastern Pennsylvania and guidebook of excursions:
   Rutgers University Press [Field Trip Guidebook], Geological
   Society of America, [82nd] Annual Meeting, Atlantic City,
   NJ, p. 314-347

Usage in Publication:
Hammer Creek Formation

Modifications:	Geologic Province:	Dominant Lithology:
Revised Areal limits	Piedmont-Blue Ridge province Newark basin

Summary:
The name Hammer Creek Formation is here extended to all the predominantly conglomeratic deposits in the Newark Group concentrated mainly along the northwest margin of the Newark basin in eastern PA, NJ, and Rockland Co., NY. In the central part of the basin it interfingers with the Stockton, Lockatong, and Brunswick Formations. It varies from poorly sorted well rounded conglomerate to angular breccia and consists of Paleozoic quartzite, conglomerate, and gneiss.

Summary of Citation: Hammer Creek

Publication:
Van Houten, F.B., 1980, Late Triassic part of Newark Supergroup,
   Delaware River section, west-central New Jersey, IN Manspeizer,
   Warren, ed., Field studies of New Jersey geology and guide
   to field trips: New York State Geological Association Guidebook,
   no. 52, 52nd Annual Meeting, Newark, NJ, p. 264-275

Usage in Publication:
Hammer Creek Conglomerate

Modifications:	Geologic Province:	Dominant Lithology:
Revised Areal limits	Piedmont-Blue Ridge province Newark basin

Summary:
Coarse fanglomerate along the northwest border of the Newark basin east of the Delaware River, NJ, interfingering with the Stockton, Lockatong, and Brunswick formations, is called the Hammer Creek Conglomerate. The deposits are arranged in lenticular, crudely fining-upward units. Clasts are mostly of Paleozoic quartzite and range in size from 10-20 cm cobbles to blocks 30 cm long.

Summary of Citation: Hammer Creek

Publication:
Wood, C.R., 1980, Groundwater resources of the Gettysburg and
   Hammer Creek Formations, southeastern Pennsylvania: Pennsylvania
   Geological Survey Water Resource Report, 4th series, no. 49,
   87 p., (incl. geologic map, scale 1:50,000)

Usage in Publication:
Hammer Creek Formation*

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Piedmont-Blue Ridge province Gettysburg basin

Summary:
The Hammer Creek Formation of the Newark Group is adopted as defined by Glaeser (1963) in the narrow neck between the Gettysburg and Newark basins.

Summary of Citation: Hammer Creek

Publication:
Lyttle, P.T. and Epstein, J.B., 1987, Bedrock geologic map of
   the Newark 2 degrees quadrangle, New York, New Jersey, and
   Pennsylvania: U.S. Geological Survey Miscellaneous Investigations
   Series Map, I-1715, 1 sheet, scale 1:250,000

Usage in Publication:
Hammer Creek Formation*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	Piedmont-Blue Ridge province Newark basin

Summary:
On the east side of the narrow neck near the Schuylkill River, the Hammer Creek Formation is a partial lateral correlative of and unconformably overlies the Stockton Formation, and interfingers laterally with the lower part of the Brunswick Group.