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Aquia Formation
Stratigraphic range: Late Paleocene
~59.0–55.5Ma
Thecachampsa crocodile coprolite (Aquia Formation, Upper Paleocene; Potomac River shores, King George County, northeastern Virginia, USA).jpg
Thecachampsa crocodile coprolite (Aquia Formation; King George County, Virginia)
Type Geological formation
Unit of Pamunkey Group
Sub-units Paspotansa & Piscataway Members
Underlies Nanjemoy Formation
Overlies Brightseat Formation
Thickness up to 100 feet (30 m)
Lithology
Primary Sandstone
Location
Location Hopewell, Virginia
Coordinates 38°18′N 77°18′W / 38.3°N 77.3°W / 38.3; -77.3
Approximate paleocoordinates 39°00′N 58°54′W / 39.0°N 58.9°W / 39.0; -58.9
Region Maryland, New Jersey, Virginia
Country  United States
Extent Upper Chesapeake Bay-James River
Type section
Named for Aquia Creek

The Aquia Formation is a geologic sandstone formation that extends from the upper Chesapeake Bay to the James River near Hopewell, Virginia. It consists of clayey, silty, very shelly, glauconitic sand. Fossil records indicate that this stratigraphic unit was created during the Paleocene.

The Aquia formation was named for Aquia Creek where it is exposed in cliff faces along the banks.

Geology

Lithology

When uncovered, it appears dark green to gray-green, argillaceous, with well sorted fine- to medium-grained sand and locally indurated shell beds. It occurs between 0 and 100 feet thick. Quartz and phosphatic pebbles and/or very coarse glauconitic quartz sand mark the base of the unit. A few hard streaks of shells or thin "rock" layers are often reported but appear to be more abundant in the sections south of the James River.

Stratigraphy

The Aquia formation is overlain by the Nanjemoy Formation and overlies the Brightseat Formation.

The Aquia formation is broken down into two members: the lower Piscataway member and upper Paspotansa member.

Age

The Aquia Formation is thought to be 59.0-55.5 million years old. The Piscataway member is 59-56.25 million years old, and the Paspotansa member is 56-55.5 million years old.

Fossils

Vertebrates

Bony fish

  • Lepisosteus
  • Ostracion
  • Phyllodus
  • Scomberomorus
  • Wrasse

Chondrichthyes

Sharks
  • Abdounia beaugei
  • Anomotodon novus
  • Carcharias hopei
  • Cretolamna appendiculata
  • Delpitoscyllium africanum
  • Foumtizia abdouni
  • Galeorhinus
  • Ginglymostoma subafricanum
  • Heterodontus lerichei
  • Hypotodus verticalis
  • Isurolamna inflata
  • Megasqualus orpiensis
  • Notidanodon loozi
  • Odontaspisx loozi
  • Orectolobiform
  • Otodus obliquus
  • Pachygaleus lefevrei
  • Palaeogaleus
  • Paleocarcharodon orientalis
  • Paleohypotodus rutoti
  • Paraorthacodus clarkii
  • Physogaleus secundus
  • Premontreia subulidens
  • Scyliorhinus
  • Squalus
  • Squatina prima
  • Striatolamia macrota
  • Striatolamia striata
  • Triakis
Rays
  • Myliobatis
  • Burnhamia
  • Coupatezia soutersi
  • Dasyatis
  • Hypolophodon sylvestris
  • Ischyodusx sylvestris

Reptiles

Crocodylians
  • Eosuchus
  • Hyposaurus
  • Thecachampsa
  • Thoracosaurus
Turtles
  • Trionyx

Mammals

Mammal fossils are extremely rare.

Birds

Bird fossils are extremely rare.

Molluscs

Gastropods

  • Turritella is very common.
  • Pleurotoma potomacensis

Bivalves

  • Crassatelites alaeformis
  • Cucullaea gigantea
  • Dosiniopsis lenticularis
  • Meretrix ovata
  • Modiolus alabamensis
  • Ostrea compressirostra
  • Panopea elongata
  • Venericardia planicosta
  • Volsella alabamensis

Cephalopods

  • Cimomia marylandensis is present but uncommon.
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