Wills Creek Formation is a mapped Silurian bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.
The Conemaugh Group is a geologic group in West Virginia, Pennsylvania, Ohio, and Maryland. It preserves fossils dating back to the Carboniferous period.
The Monongahela Formation is a geologic formation in West Virginia, Pennsylvania, Ohio, and Maryland. It preserves fossils dating back to the Carboniferous and Permian periods.
The Hinton Formation is a geologic formation in West Virginia. It preserves fossils dating back to the Carboniferous period. It is mainly made up of limestone, sandstone, and shale.
The Hampshire Formation is a geologic formation in West Virginia, USA. It preserves fossils dating back to the Devonian period.
The Oriskany Sandstone is a Middle Devonian age unit of sedimentary rock found in eastern North America. The type locality of the unit is located at Oriskany Falls in New York. The Oriskany Sandstone extends throughout much of the Appalachian Basin.
The Rochester Shale is a geologic formation exposed in New York and West Virginia. It preserves fossils dating back to the Silurian period.
The Williamsport Sandstone is a sandstone geologic formation in West Virginia, Virginia, Pennsylvania, and Maryland. the formation includes the Cedar Creek Limestone member. Near Cumberland, Maryland it includes the Cedar Creek Limestone member. It preserves fossils dating back to the Silurian period.
The Greene Formation is a geologic formation in West Virginia, Ohio, Maryland, Virginia and Pennsylvania. It preserves fossils dating back to the Permian period.
The Waynesburg Formation is a coal, sandstone, and siltstone geologic formation in West Virginia and Pennsylvania. It preserves fossils dating back to the Permian period.
The Washington Formation is a coal, sandstone, and limestone geologic formation in West Virginia. It preserves fossils dating back to the Permian period.
The Chesapeake Group is a geologic group in Maryland, Virginia, Delaware, and North Carolina. It preserves mainly marine fossils dating back to the Miocene and Pliocene epochs of the Neogene period. This group contains one of the best studied fossil record of Neogene oceans in the world. Professional Paleontologists and amateur fossil hunters alike collect from this group intensely. The Calvert Cliffs stretch the length of Calvert County, Maryland and provide the best continuous stretch of the Calvert, Choptank, and St. Marys Formations. Ward (1985) recommended including the Old Church Formation in this group.
The Patapsco Formation is a geologic formation of varigated clays, sandy clays, and sand in Virginia, the District of Columbia, Maryland, Delaware, Pennsylvania, and in the subsurface of New Jersey. It preserves fossils such as plants and molluscs dating back to the Cretaceous period.
The Choptank Formation is a geologic formation in Virginia and Maryland. It preserves fossils dating from the Miocene epoch of the Neogene period.
The Stonehenge Limestone is a geologic formation in Maryland. It preserves fossils dating back to the Ordovician period.
The Helderberg Formation is a geologic formation in Pennsylvania, Maryland and West Virginia. It preserves fossils dating back to the Devonian period.
The Java Formation is a geologic formation in Kentucky, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia. It preserves fossils dating back to the Devonian period. The formation comprises the Pipe Creek Shale, Wiscoy Sandstone Member in New York, and Hanover Shale Member except in Tennessee.
The Tomstown Dolomite or Tomstown Formation is a geologic formation in Maryland, Pennsylvania, Virginia and West Virginia. It preserves fossils dating to the Cambrian Period.
The Maccrady Formation is a geologic formation in West Virginia. It preserves fossils dating back to the Carboniferous period.
The Huntersville Chert or Huntersville Formation is a Devonian geologic formation in the Appalachian region of the United States. It is primarily composed of mottled white, yellow, and dark grey chert, and is separated from the underlying Oriskany Sandstone by an unconformity. The Huntersville Chert is laterally equivalent to the Needmore Shale, which lies north of the New River. It is also laterally equivalent to a sandy limestone unit which is often equated with the Onondaga Limestone. These formations are placed in the Onesquethaw Stage of Appalachian chronostratigraphy, roughly equivalent to the Emsian and Eifelian stages of the broader Devonian system.
