Add to ORKGAt a horizon of some hundred feet above the base of the Coal Measures in Fairfield Township in Jefferson County is a seam of a concretionary limestone varying from two to five feet in thickness. It crops out on the hillside in a creek that follows the south side of the abandoned embankment of the Chicago, Burlington & Quincy railroad, where this leaves the new line, about a mile and a half west of the city of Fairfield. The ledge has been quarried in several places close to the line of the old road, where some pits are still seen. On this limestone lies a black, fissile bituminous shale, lumps of which are seen in the old pits. Last summer the writer found in one of these lumps a bone which he thought might be a phalanx of some early batrac...