The Aquia Formation is a geologic
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates ...
formation that extends from the upper
Chesapeake Bay
The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the Eastern Shore of Maryland / ...
to the
James River near
Hopewell, Virginia
Hopewell is an independent city surrounded by Prince George County and the Appomattox River in the Commonwealth of Virginia. At the 2020 census, the population was 23,033. The Bureau of Economic Analysis combines the city of Hopewell with Prin ...
.
It consists of clayey, silty, very shelly,
glauconitic
Glauconite is an iron potassium phyllosilicate (mica group) mineral of characteristic green color which is very friable and has very low weathering resistance.
It crystallizes with a monoclinic geometry. Its name is derived from the Greek () me ...
sand.
[ ]Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
records indicate that this stratigraphic unit
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize ...
was created during the Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...
.[
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
Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces.
Clay minerals ...
, with well sorted fine- to medium-grained sand and locally indurated shell beds.[ ]Quartz
Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...
and phosphatic pebbles and/or very coarse glauconitic quartz sand mark the base of the unit.[
]
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
The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal ...
period.
Older publications describe the Aquia as being of Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
age.
Fossils
Vertebrates
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...
Bony fish
*''Lepisosteus
''Lepisosteus'' is a genus of gars in the family Lepisosteidae.
Distribution
While in the present day, ''Lepisosteus'' is only known across North America, fossil remains show it was much more widespread in the past, with specimens known from ...
''[Phatfossil]
Aquia Formation
in Maryland and Virginia
*'' Ostracion''[
*'' Phyllodus''][
*'']Scomberomorus
''Scomberomorus'' is a genus of ray-finned bony fish in the mackerel family, Scombridae. More specifically, it is a member of the tribe Scomberomorini, commonly known as the Spanish mackerels.
Species
''Scomberomorus'' includes 18 species:
* ...
''[
*''Labridae'' (]Wrasse
The wrasses are a family, Labridae, of marine fish, many of which are brightly colored. The family is large and diverse, with over 600 species in 81 genera, which are divided into 9 subgroups or tribes.
They are typically small, most of them le ...
)[
]
Chondrichthyes
Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue. ...
=
Sharks
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorp ...
=
*'' Abdounia beaugei''[
*'' Anomotodon novus''][
*'' Cretolamna appendiculata''][
*'' Delpitoscyllium africanum''][
*'' Foumtizia abdouni''][
*'']Galeorhinus
The school shark (''Galeorhinus galeus'') is a houndshark of the family Triakidae, and the only member of the genus ''Galeorhinus''. Common names also include tope, tope shark, snapper shark, and soupfin shark. It is found worldwide in temperate ...
''[
*'' Ginglymostoma subafricanum''][
*'' Heterodontus lerichei''][
*'' Hypotodus verticalis''][
*'']Isurolamna
''Isurolamna'' is an extinct genus of mackerel shark from the Paleogene period. It contains at least three species and a fourth is sometimes placed in it. It is thought to be closely related to '' Macrorhizodus'', ''Isurus'', and '' Cosmopolito ...
inflata''[
*'' Megasqualus orpiensis''][
*'' Notidanodon loozi''][
*'' Odontaspisx loozi''][
*'' Orectolobiform''][
*'']Otodus
''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth".
Anatomy
This shark is ...
obliquus''[
*'' Pachygaleus lefevrei''][
*'' Palaeogaleus''][
*'' Paleocarcharodon orientalis''][
*'' Paleohypotodus rutoti''][
*'' Paraorthacodus clarkii''][
*'']Physogaleus
''Physogaleus'' is a small genus of prehistoric shark that lived from the Eocene to Miocene epochs.
Description
''Physogaleus'' are only known from their fossil teeth and isolated vertebra. It has teeth similar to the modern tiger shark, but sma ...
secundus''
*'' Premontreia subulidens''[
*'']Scyliorhinus
''Scyliorhinus'' is a genus of catsharks in the family Scyliorhinidae. This genus is known in the fossil records from the Cretaceous period, late Albian age to the Pliocene epoch.Carrier, J. C.; Musick, J. A. & Heithaus, M. R. (2004)''Biology of ...
''[
*'']Squalus
''Squalus'' is a genus of dogfish sharks in the family Squalidae. Commonly known as spurdogs, these sharks are characterized by smooth dorsal fin spines, teeth in upper and lower jaws similar in size, caudal peduncle with lateral keels; upper ...
''
*'' Squatina prima''[
*'' Striatolamia macrota''][
*'' Striatolamia striata''][
*'' Triakis''][
]
=
Rays
Ray may refer to:
Fish
* Ray (fish), any cartilaginous fish of the superorder Batoidea
* Ray (fish fin anatomy), a bony or horny spine on a fin
Science and mathematics
* Ray (geometry), half of a line proceeding from an initial point
* Ray (gra ...
=
*''Myliobatis
''Myliobatis'' is a genus of eagle rays in the family Myliobatidae.
Description
''Myliobatis'' species can reach a width up to about . Their bodies consist of a rhomboidal disc, wider than long, with one dorsal fin. The head is broad and short, ...
''
*'' Burnhamia''[
*'' Coupatezia soutersi''][
*'']Dasyatis
''Dasyatis'' (Greek δασύς ''dasýs'' meaning rough or dense and βατίς ''batís'' meaning skate) is a genus of stingray in the family Dasyatidae that is native to the Atlantic, including the Mediterranean. In a 2016 taxonomic revisi ...
''[
*'' Hypolophodon sylvestris''][
*'' Ischyodusx sylvestris''][
]
Reptiles
=
Crocodylians
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...
=
*''Eosuchus
''Eosuchus'' ("dawn crocodile") is an extinct genus of eusuchian crocodylomorph, traditionally regarded as a gavialoid crocodilian. It might have been among the most basal of all gavialoids, lying crownward of all other known members of the ...
''[
*'']Hyposaurus
''Hyposaurus'' is a genus of extinct marine dyrosaurid crocodyliform. Fossils have been found in Paleocene aged rocks of the Iullemmeden Basin in West Africa, Campanian–Maastrichtian (Late Cretaceous) Shendi Formation of Sudan and Maastrichtia ...
''[
*'']Thecachampsa
''Thecachampsa'' is an extinct genus of gavialoid crocodylian, traditionally regarded as a member of the subfamily Tomistominae. Fossils have been found from the eastern United States in deposits of Miocene age. Those named in the 19th century we ...
''
*'' Thoracosaurus''[
]
=
Turtles
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tur ...
=
*''Trionyx
''Trionyx'' is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today '' T. triunguis'', the African or Nile softshell turtle, is the only extant softshe ...
''[
]
Mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...
Mammal fossils are extremely rare.[
]
Birds
Bird fossils are extremely rare.[
]
Molluscs
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...
Gastropods
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. The ...
*''Turritella
''Turritella'' is a genus of medium-sized sea snails with an operculum, marine gastropod mollusks in the family Turritellidae.Vos, C.; Gofas, S. (2013). Turritella Lamarck, 1799. Accessed through: World Register of Marine Species at http://www.m ...
'' is very common.[
*''Pleurotoma potomacensis'']
Bivalves
*'' Crassatelites alaeformis''[
*'' Cucullaea gigantea''][
*'' Dosiniopsis lenticularis''][
*'']Meretrix
Prostitution in ancient Rome was legal and licensed. In ancient Rome, even Roman men of the highest social status were free to engage prostitutes of either sex without incurring moral disapproval, as long as they demonstrated self-control and m ...
ovata''[
*'' Modiolus alabamensis''][
* ''Ostrea'' compressirostra][
*'']Panopea
In Greek mythology, Panopea (Ancient Greek: Πανόπεια ''Panopeia'') or Panope (Πανόπη) may refer to various characters. The names mean 'panorama' or means 'of the beautiful husband'.
* Panope or Poenope,Hyginus, ''Fabulae'' Preface ( ...
elongata''[
*'' Venericardia planicosta''][
*'' Vulsella alabamensis''][
]
Cephalopods
*'' Cimomia marylandensis'' is present but uncommon.
See also
* List of fossiliferous stratigraphic units in Virginia
This article contains a list of fossil-bearing stratigraphic units in the state of Virginia, U.S.
Sites
See also
* Paleontology in Virginia
References
*
{{DEFAULTSORT:Fossiliferous stratigraphic units in Virginia
Virginia
Stratigraph ...
* Paleontology in Virginia
Paleontology in Virginia refers to paleontological research occurring within or conducted by people from the U.S. state of Virginia. The geologic column in Virginia spans from the Cambrian to the Quaternary. During the early part of the Paleozoic ...
* Aquia Creek sandstone
Aquia Creek sandstone is a brown to light-gray freestone used extensively in building construction in Washington, D.C. in the late 18th and early 19th centuries. Quarried at Aquia Creek in Stafford County, Virginia, the stone was valuable for it ...
* Public Quarry at Government Island
The Public Quarry at Government Island in Stafford County, Virginia is the principal source of Aquia Creek sandstone, a building stone used in many of the early government buildings in Washington, D.C., including the U.S. Capitol and the White Hou ...
References
{{reflist
Geologic formations of Maryland
Geologic formations of New Jersey
Geologic formations of Virginia
Paleocene Series of North America
Paleogene Maryland
Paleogene geology of New Jersey
Paleogene geology of Virginia
Thanetian Stage
Sandstone formations of the United States