The Meramecian or Maramec stage is a sequence of

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago *Mississippian culture, a culture of Native American mound-builders from 900 to 1500 AD ...

rocks in the

Mississippi River Valley The Mississippi embayment is a physiographic feature in the south-central United States, part of the Mississippi Alluvial Plain. It is essentially a northward continuation of the fluvial sediments of the Mississippi River Delta to its confl ...

. It is named for the

Meramec River The Meramec River (), sometimes spelled Maramec River, is one of the longest free-flowing waterways in the U.S. state of Missouri, draining Blanc, Caldwell, and Hawk. "Location" while wandering Blanc, Caldwell, and Hawk. "Executive Summary" f ...

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

Members

Included are the

St. Louis Limestone The St. Louis Limestone is a large geologic formation covering a wide area of the midwest of the United States. It is named after an exposure at St. Louis, Missouri. It consists of sedimentary limestone with scattered chert beds, including th ...

, Ste. Genevieve Limestone,

Salem Limestone The Salem Formation is a geologic formation in Illinois, Indiana, Kentucky, and Missouri. It preserves fossils dating back to the Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period ...

, and the Harrodsburg Limestone. All of these rocks are generally thick bedded

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms wh ...

s with

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and dr ...

, and dolomite. Some beds consist of

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, ...

. Mississippian Series Carboniferous geochronology Mississippian United States * {{US-geologic-formation-stub