The Cambrian

Cambrian

The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...

 Hardyston Formation or Hardyston Quartzite 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...

 and New Jersey

New Jersey

New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...

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It was originally described by Wolff and Brooks in 1898, where two outcrops in Hardyston Township

Hardyston Township, New Jersey

Hardyston Township is a Township in Sussex County, New Jersey, United States. As of the United States 2000 Census, the township population was 6,171.-Geography:...

, Sussex County, New Jersey

Sussex County, New Jersey

The County of Sussex is the northernmost county in the State of New Jersey. It is part of the New York City Metropolitan Area. As of the 2010 Federal decennial census, 149,265 persons resided in Sussex County...

, were described. They originally named it the Hardistonville quartzite, but the name was later changed by Kummel and Weller in 1901 to Hardiston quartzite, and changed again by the same authors a year later to Hardyston quartzite.

Description

Richard Dalton described the Hardyston Formation in 1989 as having a varying lithology. It is composed of a vitreous, light pink, steel gray or brown, locally arkosic

Arkose

Arkose is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose....

, fine to coarse-grained, resistant quartzite

Quartzite

Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...

. Pebble conglomerate

Conglomerate (geology)

A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...

 is common at the base of the formation. Locally, where the unit is less than 10 ft thick, it is a fine- to medium-grained, gray, pyritic

Pyrite

The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

 quartzite, grading into a dark-gray dolomitic

Dolomite

Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....

 sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

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Stratigraphy

The Hardyston unconformably

Unconformity

An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe...

 overlies Precambrian

Precambrian

The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...

 crystalline basement rocks

Basement (geology)

In geology, the terms basement and crystalline basement are used to define the rocks below a sedimentary platform or cover, or more generally any rock below sedimentary rocks or sedimentary basins that are metamorphic or igneous in origin...

 where it was deposited on an irregular surface and fills only the troughs or depressions. It gradationally underlies the Leithsville Formation of the Kittatinny Supergroup

Kittatinny Formation

The Ordovician Kittatinny Formation or Kittatinny Limestone is a dolomitic limestone formation in New Jersey. The Kittatiny Limestones are located primarily within the long valley running from Picatinny Arsenal in Rockaway Township, southwest toward Chester Township...

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Miller and Myers extended the formation into Pennsylvania in 1939, where it underlies the Tomstown formation.

Notable Outcrops

• Cushion Peak, Berks County, Pennsylvania
  Berks County, Pennsylvania
  -Demographics:As of the census of 2000, there were 373,638 people, 141,570 households, and 98,532 families residing in the county. The population density was 435 people per square mile . There were 150,222 housing units at an average density of 175 per square mile...
  
   - the Hardyston has been thrust faulted over the limestone valley at this site

Fossils

Trilobites have been found in the calcareous sandstone beds of the formation. One genus is Olenellus

Olenellus

Olenellus is a genus of trilobite that lived during the Early Cambrian. It is commonly found in areas of Europe and North America...

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