Aquia Formation

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]

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]

• Lepisosteus[2]
• Ostracion[2]
• Phyllodus[2]
• Scomberomorus[2]
• Labridae (Wrasse)[2]

• Abdounia beaugei[2][7]
• Anomotodon novus[2][8]
• Carcharias hopei[2][8]
• Cretolamna appendiculata[2][8]
• Delpitoscyllium africanum[2]
• Foumtizia abdouni[2]
• Galeorhinus[2]
• Ginglymostoma subafricanum[2]
• Heterodontus lerichei[2]
• Hypotodus verticalis[2]
• Isurolamna inflata[2]
• Megasqualus orpiensis[2]
• Notidanodon loozi[2]
• Odontaspisx loozi[2]
• Orectolobiform[2]
• Otodus obliquus[2][9][8]
• Pachygaleus lefevrei[2]
• Palaeogaleus[2]
• Paleocarcharodon orientalis[2][9][8]
• Paleohypotodus rutoti[2][10]
• Paraorthacodus clarkii[2]
• Physogaleus secundus[11]
• Premontreia subulidens[2]
• Scyliorhinus[2]
• Squalus
• Squatina prima[2]
• Striatolamia macrota[2][8]
• Striatolamia striata[2]
• Triakis[2]

• Myliobatis[12]
• Burnhamia[2]
• Coupatezia soutersi[2]
• Dasyatis[2]
• Hypolophodon sylvestris[2]
• Ischyodusx sylvestris[2]

• Eosuchus[8]
• Hyposaurus[8]
• Thecachampsa[13]
• Thoracosaurus[8]

• Trionyx[8][14]

Mammal fossils are extremely rare.[2]

Bird fossils are extremely rare.[2]

• Turritella is very common.[2][8][15]
• Pleurotoma potomacensis[16]

• Crassatelites alaeformis[16]
• Cucullaea gigantea[17][16][18]
• Dosiniopsis lenticularis[16]
• Meretrix ovata[16]
• Modiolus alabamensis[16]
• Ostrea compressirostra[19][16]
• Panopea elongata[16]
• Venericardia planicosta[16]
• Vulsella alabamensis[19]

• Cimomia marylandensis is present but uncommon.[20]