The Crescent chert quarries are located in southern St. Louis and northern Jefferson Counties, Missouri. They are situated along several miles of ridges that lie south of the Meramec River (a tributary of the Mississippi River). Native American surface miners extracted chert from several thousand pits and quarry ledges scattered across an area of approximately 104 square kilometers. One estimate of the number of quarry features (pits, ledges and tailings) ranges between 6,000 and 10,000. Dalton points (ca. 8000 BC) manufactured from Crescent chert have been identified in Arkansas. Archaic and Woodland Period artifacts have been identified in Missouri and Illinois that were manufactured by Crescent chert. The distinctive chert appears at Cahokia Mounds and other Mississippian sites in the St. Louis area.

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The central portion of the quarries (23SL115) is protected by the West Tyson County Park. These pits and quarry ledges were probably cut during the Middle Woodland Period (ca. AD 100) based upon diagnostic lithics at an adjacent village site (the Mason Site). The pit and quarry ledge features of 23SL115 are listed on the National Register of Historic Places.

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The chert quarried at 23SK15 was obtained from the Burling-Keokuk formation and residuum that tops the ridges along the Meramec River. The ancient quarry beds are mainly situated at an elevation of 750 ft. above mean sea level in a zone that is only one to two feet in thickness.

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I mapped the quarry pits along 2000 meters (6562 ft) of the North-South and East-West ridges within 23SL115. There does not seem to be a slope preference (63 pits on the west face, 20 on the crest and 70 on the east face).

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