Earth:Aquia Formation

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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
Coordinates [ ⚑ ] : 38°18′N 77°18′W / 38.3°N 77.3°W / 38.3; -77.3
Paleocoordinates [ ⚑ ] 39°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.[1] It consists of clayey, silty, very shelly, glauconitic sand.[1] Fossil records indicate that this stratigraphic unit was created during the Paleocene.[1]

The Aquia formation was named for Aquia Creek where it is exposed in cliff faces along the banks.[2]

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.[3] It is between 0 and 100 feet thick in Maryland.[3] Quartz and phosphatic pebbles and/or very coarse glauconitic quartz sand mark the base of the unit.[4] 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.[4]

Stratigraphy

The Aquia formation is overlain by the Nanjemoy Formation and overlies the Brightseat Formation.[5]

The Aquia formation is broken down into two members: the lower Piscataway member and upper Paspotansa member.[2]

Age

The Aquia Formation is thought to be 59.0-55.5 million years old.[2] The Piscataway member is 59–56.25 million years old, and the Paspotansa member is 56–55.5 million years old.[2] This is the Paleocene period.

Older publications describe the Aquia as being of Eocene age.[6]

Fossils

Vertebrates

Bony fish

Bony fish from the Aquia Formation
Genus Species Material Notes Images
Lepisosteus[2] L.sp. A Gar fish
Ostracion[2] O.sp. An Ostraciid (Boxfish)
Phyllodus[2] P.sp. A bonefish
Scomberomorus[2] S.sp. A mackrel fish
Labridae[2] Labridae indet. A wrasse

Chondrichthyes

Sharks
Sharks from the Aquia Formation
Genus Species Material Notes Images
Abdounia [2][7] A.beaugei A reqium shark
Anomotodon [2][8] A.novus A goblin shark
Carcharias [2][8] C.hopei A sand tiger shark
Cretolamna [2][8] C.appendiculata A megatooth shark
Delpitoscyllium [2] D.africanum
Foumtizia [2] F.abdouni
Galeorhinus[2] G.sp. A houndshark
Ginglymostoma [2] G.subafricanum A nurse shark
Heterodontus [2] H.lerichei A bullhead shark
Hypotodus [2] H.verticalis
Isurolamna [2] I.inflata A mackrel shark
Megasqualus [2] M.orpiensis
Notidanodon [2] N.loozi A cow shark
Odontaspisx[2] O.loozi
Orectolobiform[2] O. Indet.
Otodus [2][9][8] O.obliquus A Megatooth shark
Pachygaleus [2] P.lefevrei
Palaeogaleus[2] P.sp.
Paleocarcharodon [2][9][8] P.orientalis A megatooth shark
Paleohypotodus [2][10] P.rutoti
Paraorthacodus [2] P.clarkii A Paraorthacodontid shark
Physogaleus [11] P.secundus A reqium shark
Premontreia [2] P.subulidens
Scyliorhinus[2] S.sp. A Scyliorhinid shark
Squalus S.sp. A dogfish
Squatina [2] S.prima An Angel shark
Striatolamia [2][8] S.macrota A Sand shark
S.striata
Triakis[2] T.sp. A Houndshark
Rays
Rays from the Aquia Formation
Genus Species Material Notes Images
Myliobatis[12] M.sp. A Mylobatiform ray
Burnhamia[2] B.sp. A devil ray
Coupatezia C. soutersi[2] A dasyatid ray
Dasyatis[2] D.sp
Hypolophodon H.sylvestris[2]
Ischyodusx I. sylvestris[2]

Reptiles

Crocodylomorphs
Crocodylomorphs from the Aquia Formation
Genus Species Material Notes Images
Eosuchus[8] E.sp. A eusuchian crocodylomorph
Hyposaurus[8] H.sp. A dyrosaurid
Thecachampsa[13] T.sp. A gavialoid crocodylian
Thoracosaurus[8] T.sp. A eusuchian crocodylomorph
Turtles
Turtles from the Aquia Formation
Genus Species Material Notes Images
Trionyx[8][14] T.sp. A softshell turtle

Molluscs

Gastropods

Gastropods from the Aquia Formation
Genus Species Material Notes Images
Turritella [2][8][15] T.sp. very commonly found in the formation
Pleurotoma [16] P.potomacensis

Bivalves

Bivalves from the Aquia Formation
Genus Species Material Notes Images
Crassatelites [16] C.alaeformis
Cucullaea[17][16][18] C.gigantea
Dosiniopsis [16] D.lenticularis
Meretrix (bivalve)[16] M.ovata
Modiolus (bivalve)[16] M.alabamensis
Ostrea[19][16] O.compressirostra
Panopea[16] P.elongata
Venericardia[16] V.planicosta
Vulsella[19] V.alabamensis

Cephalopods

Sharks from the Aquia Formation
Genus Species Material Notes Images
Cimomia[20] C.marylandensis Uncommonly found

Mammal and bird fossils are also uncommonly found in the formation.[2]

See also

  • List of fossiliferous stratigraphic units in Virginia
  • Paleontology in Virginia
  • Aquia Creek sandstone
  • Public Quarry at Government Island

References

  1. ↑ 1.0 1.1 1.2 Geology of the National Capital Region - Field Trip Guidebook. Reston, Virginia: U.S. Geological Survey, Department of the Interior. 2004. p. 270. 
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 2.20 2.21 2.22 2.23 2.24 2.25 2.26 2.27 2.28 2.29 2.30 2.31 2.32 2.33 2.34 2.35 2.36 2.37 2.38 2.39 2.40 2.41 Phatfossils Aquia Formation in Maryland and Virginia
  3. ↑ 3.0 3.1 "Coastal Plain Rocks and Sediments". Maryland Geological Survey. 1968. http://www.mgs.md.gov/esic/geo/lgcp.html. Retrieved 21 January 2015. 
  4. ↑ 4.0 4.1 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. https://pubs.usgs.gov/pp/p1612/powars.html. Retrieved 22 January 2015. 
  5. ↑ Page, Richard A (1959). "The Questionable Age of the Aquia Formation". Journal of Paleontology 33 (2): 347–350. 
  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. ↑ Elasmo.com, The Life and Times of Long Dead Sharks, Abdounia, Jim Bourdon, author.
  8. ↑ 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 8.10 "Fossil Identification for the Potomac River". http://www.fossilguy.com/sites/potomac/liv_col.htm. 
  9. ↑ 9.0 9.1 "Potomac - Aquia Formation 3/15/18". http://www.thefossilforum.com/index.php?/topic/82854-potomac-aquia-formation-31518/. 
  10. ↑ "Paleohypotodus?". http://www.thefossilforum.com/index.php?/topic/83055-paleohypotodus/. 
  11. ↑ "Physogaleus secundus". http://www.itano.net/fossils/marylan2/galeo1s.htm. 
  12. ↑ "Myliobatis". http://www.itano.net/fossils/marylan2/mylio1s.htm. 
  13. ↑ "Thecachampsa". http://www.itano.net/fossils/marylan2/theca1s.htm. 
  14. ↑ "Trionyx". http://www.itano.net/fossils/marylan2/trion1s.htm. 
  15. ↑ "Turritella sp". http://www.itano.net/fossils/marylan2/turr1s.htm. 
  16. ↑ 16.0 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 Virginia Division of Mineral Resources (1912). Bulletin. p. 200. https://archive.org/details/bulletin04virggoog. "fossils of the aquia formation." 
  17. ↑ "Cucullaea Gigantea". 15 May 2010. https://iapetancaptain.wordpress.com/2010/05/15/cucullaea-gigantea/. 
  18. ↑ "Views of the Mahantango: Cucullaea gigantea pelecypod from the Aquia Formation". 11 August 2014. http://viewsofthemahantango.blogspot.com/2014/08/cucullaea-gigantea-pelecypod-from-aquia.html. 
  19. ↑ 19.0 19.1 "Ostrea compressirostra". http://www.itano.net/fossils/marylan2/ostre1s.htm. 
  20. ↑ "Sanity check: It's a Nautilus, right?". http://www.thefossilforum.com/index.php?/topic/84977-sanity-check-its-a-nautilus-right/. 



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