Pottsville Group over Maxville Limestone (Black 17 Mine, White Cottage, Ohio, USA) 19
The Maxville Limestone is the only Middle to Late Mississippian-aged stratigraphic unit in Ohio. Its outcrop belt is not extensive - it principally occurs in Muskingum County and Perry County in eastern and southeastern Ohio. The Maxville Formation can also be found as cobbles and pebbles in the basal Sharon Formation (Lower Pennsylvanian), which disconformably overlies Ohio's Mississippian rocks. Paleohills, or erosional outliers, of Maxville Limestone have also been identified.
Shown here is an active underground limestone mine in Muskingum County. The mine targets Maxville Limestone and crushes it for use as road gravel, fill, rip-rap, and erosion-control blocks. Most limestone or dolostone mining operations are open-pit mines - quarries. This is an unusual example of subsurface quarrying - it started in 2010; this photo depicts the status of the site in September 2011. Available satellite imagery shows the area flooded from 2014 to the present.
The dark-colored sedimentary rocks in the upper part of the photo are the Pottsville Group, an upper Lower Pennsylvanian to lower Middle Pennsylvanian succession of marine and nonmarine rocks dominated by mixed siliciclastics. The Pottsville also includes fossiliferous limestones, coals, and chert/flint horizons.
A series of adits are present in a light-colored unit at the base of the quarry's high wall. This is the Maxville Limestone. The Pottsville-Maxville contact is a significant disconformity. Only diesel engines were allowed underground. At the time of this visit, the underground limestone mining went back 800 to 900 feet. There are 40'x60'-sized rooms back there, forming a checkerboard pattern.
Stratigraphy: lower Pottsville Group (upper Lower Pennsylvanian) over Maxville Limestone (Middle to Upper Mississippian)
Locality: Black 17 Mine (owned by Sidwell Materials, Incorporated), south of Route 22, just east of the town of White Cottage, central Newton Township, southwestern Muskingum County, eastern Ohio, USA (39° 52' 21.35" North latitude, 82° 04' 38.38" West longitude)