Aquia Formation

Aquia Formation
Stratigraphic range: Late Paleocene
~59.0–55.5 Ma
Boulder of Aquia Formation along Chester River. Contains casts of large mollusks. (c. 1917)
TypeGeological formation
Unit ofPamunkey Group
Sub-unitsPaspotansa & Piscataway Members
UnderliesNanjemoy Formation
OverliesBrightseat Formation
Thicknessup to 100 feet (30 m)
Lithology
PrimarySandstone
Location
LocationHopewell, Virginia
Coordinates38°18′N 77°18′W / 38.3°N 77.3°W / 38.3; -77.3
Approximate paleocoordinates39°00′N 58°54′W / 39.0°N 58.9°W / 39.0; -58.9
RegionMaryland, New Jersey, Virginia
CountryUnited States
ExtentUpper Chesapeake Bay-James River
Type section
Named forAquia Creek
Thecachampsa crocodile coprolite from Aquia Formation, King George County, Virginia)

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 is between 0 and 100 feet thick in Maryland. 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. This is the Paleocene period.

Older publications describe the Aquia as being of Eocene age.

Vertebrate paleobiota

Bony fish

Bony fish from the Aquia Formation
GenusSpeciesMaterialNotesImages
Lepisosteus L.sp. A Gar fish
Ostracion O. meretrix An ostraciid (boxfish)
Phyllodus P.sp. A bonefish
Scomberomorus S.sp. A mackrel fish
Labridae Labridae indet. A wrasse

Chondrichthyes

Sharks

Sharks from the Aquia Formation
GenusSpeciesMaterialNotesImages
Abdounia A.beaugei A reqium shark
Anomotodon A.novus A goblin shark
Carcharias C.hopei A sand tiger shark
Cretolamna C.appendiculata A megatooth shark
Delpitoscyllium D.africanum
Foumtizia F.abdouni
Galeorhinus G.sp. A houndshark
Ginglymostoma G.subafricanum A nurse shark
Heterodontus H.lerichei A bullhead shark
Hypotodus H.verticalis
Isurolamna I.inflata A mackrel shark
Megasqualus M.orpiensis
Notidanodon N.loozi A cow shark
Odontaspis O.loozi
Orectolobiform O. Indet.
Otodus O.obliquus A Megatooth shark
Pachygaleus P.lefevrei
Palaeogaleus P.sp.
Paleocarcharodon P.orientalis A megatooth shark
Paleohypotodus P.rutoti
Paraorthacodus P.clarkii A Paraorthacodontid shark
Physogaleus P.secundus A reqium shark
Premontreia P.subulidens
Scyliorhinus S.sp. A Scyliorhinid shark
Squalus S.sp. A dogfish
Squatina S.prima An Angel shark
Striatolamia S.macrota A Sand shark
S.striata
Triakis T.sp. A Houndshark

Rays

Rays from the Aquia Formation
GenusSpeciesMaterialNotesImages
Myliobatis M.sp. A Mylobatiform ray
Burnhamia B.sp. A devil ray
Coupatezia C. soutersi A dasyatid ray
Dasyatis D.sp
Hypolophodon H.sylvestris
Ischyodus I. sylvestris

Birds

Birds from the Aquia Formation
GenusSpeciesMaterialNotesImages
Presbyornis P. isoni Humerus & alar phalanx A giant presbyornithid waterfowl.
?Prophaeton ?P. sp. Distal end of right humerus A potential prophaetontid phaetontiform.

Reptiles

Crocodylomorphs

Crocodylomorphs from the Aquia Formation
GenusSpeciesMaterialNotesImages
Eosuchus E. minor A eusuchian crocodylomorph.
?Hyposaurus H. sp. Teeth A potential dyrosaurid.
Thoracosaurus T. neocesariensis A eusuchian crocodylomorph.

Turtles

Based on Weems (2014):

Turtles from the Aquia Formation
GenusSpeciesMaterialNotesImages
Aspideretoides A. virginianus A softshell turtle. Type locality of species.
Bothremydinae indet. A marine side-necked turtle of uncertain affinities.
Catapleura C. coatesi A pancheloniid sea turtle. Type locality of species.
Eosphargis E. insularis A dermochelyid sea turtle.
Euclastes E. roundsi A pancheloniid sea turtle. Type locality of species.
Kinosternoidea indet. A kinosternoid turtle of uncertain affinities.
Osteopygis O. kranzi A freshwater macrobaenid turtle. Type locality of species.
Planetochelys P. savoiei A planetochelyid trionychian. Type locality of genus and species.
Tasbacka T. ruhoffi A pancheloniid sea turtle. Type locality of species.

Squamates

Squamates from the Aquia Formation
GenusSpeciesMaterialNotesImages
Palaeophis P. virginianus A marine palaeophiid snake. Type locality of species.

Mammals

Based on Rose (2000):

Mammals from the Aquia Formation
GenusSpeciesMaterialNotesImages
Arctocyonidae indet. An arctocyonid of uncertain affinities.
Ectoganus E. cf. gliriformis A taeniodont.
?Phenacodus ?P. sp. A phenacodont.

Invertebrate paleobiota

Molluscs

Gastropods

Gastropods from the Aquia Formation
GenusSpeciesMaterialNotesImages
Turritella T.sp. very commonly found in the formation
Pleurotoma P.potomacensis

Bivalves

Bivalves from the Aquia Formation
GenusSpeciesMaterialNotesImages
Crassatelites C.alaeformis
Cucullaea C.gigantea
Dosiniopsis D.lenticularis
Meretrix (bivalve) M.ovata
Modiolus (bivalve) M.alabamensis
Ostrea O.compressirostra
Panopea P.elongata
Venericardia V.planicosta
Vulsella V.alabamensis

Cephalopods

Sharks from the Aquia Formation
GenusSpeciesMaterialNotesImages
Cimomia C.marylandensis Uncommonly found

Mammal and bird fossils are also uncommonly found in the formation.

See also

References

  1. 1 2 3 Geology of the National Capital Region - Field Trip Guidebook. Reston, Virginia: U.S. Geological Survey, Department of the Interior. 2004. p. 270.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 Phatfossils Aquia Formation in Maryland and Virginia
  3. 1 2 "Coastal Plain Rocks and Sediments". Geological Maps of Maryland. Maryland Geological Survey. 1968. Retrieved 21 January 2015.
  4. 1 2 Powars, D.S.; Bruce, T.S. (2000). The Effects Of The Chesapeake Bay Impact Crater On The Geological Framework And Correlation Of Hydrogeologic Units Of The Lower York-James Peninsula, Virginia. United States Geological Survey. Retrieved 22 January 2015.
  5. ↑ Page, Richard A (1959). "The Questionable Age of the Aquia Formation". Journal of Paleontology. 33 (2): 347–350. JSTOR 1300764.
  6. ↑ Tolchester folio, Maryland, Folios of the Geologic Atlas 204, by B. L. Miller, E. B. Mathews, A. B. Bibbins, and H. P. Little, 1917.
  7. 1 2 3 Weems, R. E. (1993). Stratigraphic distribution and bibliography of fossil fish, amphibians, and reptiles from Virginia (Report). U.S. Dept. of the Interior, Geological Survey.
  8. ↑ Elasmo.com, The Life and Times of Long Dead Sharks, Abdounia, Jim Bourdon, author.
  9. 1 2 3 4 5 6 7 8 "Fossil Identification for the Potomac River".
  10. 1 2 "Potomac - Aquia Formation 3/15/18".
  11. ↑ "Paleohypotodus?".
  12. ↑ "Physogaleus secundus".
  13. ↑ "Myliobatis".
  14. 1 2 Olson, Storrs L.; Olson, Storrs L. (1994). "A Giant Presbyornis (Aves, Anseriformes) And Other Birds From The Paleocene Aquia Formation Of Maryland And Virginia". Proceedings of the Biological Society of Washington. 107: 429––435.
  15. ↑ Brochu, Christopher A. (2006). "OSTEOLOGY AND PHYLOGENETIC SIGNIFICANCE OF EOSUCHUS MINOR (MARSH, 1870) NEW COMBINATION, A LONGIROSTRINE CROCODYLIAN FROM THE LATE PALEOCENE OF NORTH AMERICA". Journal of Paleontology. 80 (1): 162–186. doi:10.1666/0022-3360(2006)080[0162:OAPSOE]2.0.CO;2. ISSN 0022-3360.
  16. ↑ "The Marine Crocodilian Hyposaurus in North America", Ancient Marine Reptiles, Academic Press, pp. 375–397, 1997-01-01, doi:10.1016/B978-012155210-7/50020-X, retrieved 2026-02-15
  17. ↑ Weems, Robert E. (2014-05-27). "Paleogene chelonians from Maryland and Virginia". PaleoBios. 31 (1). doi:10.5070/P9311022744. ISSN 0031-0298.
  18. 1 2 Weems, Robert E. (2014-05-27). "Paleogene chelonians from Maryland and Virginia". PaleoBios. 31 (1). doi:10.5070/P9311022744. ISSN 0031-0298.
  19. ↑ Gentry, Andrew D.; Kiernan, Caitlín R.; Parham, James F. (2022-08-19). "A large non‐marine turtle from the Upper Cretaceous of Alabama and a review of North American "Macrobaenids"". The Anatomical Record. 306 (6): 1411–1430. doi:10.1002/ar.25054. ISSN 1932-8486. Archived from the original on 2022-08-19.
  20. ↑ Rose, K. D. (2000). "Land-mammals from the late Paleocene Aquia formation: The first early Cenozoic mammals from Maryland". Proceedings of the Biological Society of Washington. 113 (4): 855–863. ISSN 0006-324X.
  21. ↑ "Turritella sp".
  22. 1 2 3 4 5 6 7 8 9 Virginia Division of Mineral Resources (1912). Bulletin. p. 200. fossils of the aquia formation.
  23. ↑ "Cucullaea Gigantea". 15 May 2010.
  24. ↑ "Views of the Mahantango: Cucullaea gigantea pelecypod from the Aquia Formation". 11 August 2014.
  25. 1 2 "Ostrea compressirostra".
  26. ↑ "Sanity check: It's a Nautilus, right?".