The Skunnemunk Conglomerate (also spelled Schunemunk) is a mapped bedrock unit in

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

and New York from the

Middle Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

. It forms the resistant ridge of

Schunemunk Mountain Schunemunk Mountain (also spelled Schunnemunk) is the highest mountain in Orange County, New York. The summit is located in the town of Blooming Grove, with other portions in Cornwall and Woodbury. The community of Mountain Lodge Park is bu ...

in New York and

Bearfort Mountain Bearfort Mountain, historically known as Bear Ford Mountain, is a mountain ridge located near Wawayanda State Park in West Milford, Passaic County, New Jersey. It is a continuation of Bellvale Mountain in New York. The Appalachian Trail crosses a ...

in New Jersey.

Description

The Skunnemunk is a Middle Devonian, grayish-purple to grayish-red, thin to very thick-bedded, locally cross–bedded, conglomerate and

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

containing clasts of white vein

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

, red and green

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

and sandstone, red and gray

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...

, and red shale. It is a classic Puddingstone. Pieces of the conglomerate are easy to recognize and have been found in glacial deposits throughout the lower Hudson Valley region.

References

{{NewYork-geologic-formation-stub Conglomerate formations Geologic formations of New Jersey Geologic formations of New York (state)