Rahul Sharma (Editor)

Patuxent Formation

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Type
  
Sedimentary

Overlies
  
basement rocks

Country
  
U.S.A.

Named for
  
Patuxent River

Unit of
  
Potomac Group

Primary
  
sand, clay

Region
  
Atlantic coastal plain

Underlies
  
Arundel Formation

Extent
  
Maryland, Washington D. C., Delaware, Virginia

The Patuxent Formation is a Cretaceous geologic formation of the Atlantic coastal plain.

Contents

Description

The Patuxent formation was first described by W. B. Clark in 1897. The formation is primarily unconsolidated sand and clay. The sand often contains kaolinized feldspar, making it an arkose. Clay lumps are common, and sand beds gradually transition to clay. Sandy beds may be crossbedded, which is evidence of shallow water origin.

The Patuxent is the basal unit of the Coastal Plain sedimentary formations and unconformably overlies the crystalline basement rocks. This underlying unconformity is the subsurface equivalent of the Atlantic Seaboard Fall line.

Fossils

Propanoplosaurus, a nodosaurid known from a single natural cast and mold of a hatchling, was found recovered from rocks belonging to the Patuxent Formation in Maryland.

Fossil stegosaur tracks have been reported from the formation.

E. Dorf (1952) compared the flora identified in the Patuxent to that of the Wealden Flora in England studied by Albert Charles Seward.

Pollen spores have been identified in the formation by G. J. Brenner (1963).

Notable exposures

The type locality is the upper and lower valleys of the Little Patuxent River and Big Patuxent River in Maryland.

Economic value

The Patuxent is a notable aquifer in southern Maryland.

Age

Biostratigraphic dating by Dorf (1952) confirmed Early Cretaceous (Neocomian) age.

References

Patuxent Formation Wikipedia