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.
Fine crystalline, silty, cherty dolomite, and oolitic chert with local sandstone beds.
Chiefly alkali rhyolitic ash - flow tuffs, lava flows, and bedded tuffs, with minor trachytes.