Sandstone, chert and interbedded dolomite
Coarse - crystalline cherty dolomite with a basal Gunter Sandstone Member.
Eminence Dolomite - dolomite with some druse - coated chert. Potosi Dolomite - dolomite with abundance of druse - coated chert.
Chiefly alkali rhyolitic ash - flow tuffs, lava flows, and bedded tuffs, with minor trachytes.
Fine crystalline, silty, cherty dolomite, and oolitic chert with local sandstone beds.
St. Francois Mountains intrusive suite (subvolcanic, alkali granitic ring complexes).