Potsdam Sandstone

Potsdam Sandstone Stratigraphic range: Latest Guzhangian–Furongian PreЄ Є O S D C P T J K Pg N
Old Snell Hall at Clarkson University was built with Potsdam Sandstone.
Type	Geological formation
Sub-units	Cairnside Formation, Nepean Formation (Upper Cambrian) Covey Hill Formation (?Middle Cambrian) Mount Simon Sandstone
Area	Western North America
Lithology
Primary	Orthoquartzite
Other	Conglomerates, local siltsone lenses

The Potsdam Sandstone, more formally known as the Potsdam Group, is a geologic unit of mid-to-late Cambrian age found in Northern New York and northern Vermont and Quebec and Ontario. A well-cemented sandstone of nearly pure quartz, in the 19th century it was widely used in construction and in refractory linings for iron furnaces.

The Potsdam Sandstone is named for its type locality in Potsdam, New York, where in 1838 Ebenezer Emmons described it in outcrops along the Raquette River.

The Potsdam Sandstone lies unconformably on a surface of Precambrian metamorphic rock. It is the earliest unit in the marine-transgressive sedimentary rock sequence deposited during the early Paleozoic as sea level rose to gradually inundate the craton of the paleocontinent of Laurentia. The rock, which is formed from sediments eroded off unvegetated terrestrial landscapes and deposited in near-shore coastal environments, consists almost entirely of sand-size quartz grains held together by quartz cement. It ranges in color from gray to tan, yellow, and red, with the colors imparted by small amounts of the red iron oxide mineral hematite, Fe₂O₃, and the yellow iron oxide mineral goethite, FeO(OH).