Pg. 110. Bailey limestone. Argillaceous limestones and shales containing New Scotland Helderbergian faunas at Red Rock landing and above. Overlies Bainbridge limestone and underlies Clear Creek limestone (restricted). Thickness 100+/- feet. Age is Early Devonian (Helderberg).
[Named from exposure at former Bailey's Landing, on Mississippi River, Perry Co., eastern MO, a short distance above present Red Rock Landing. Extends into southwestern IL.]

Source: US geologic names lexicon (USGS Bull. 896, p. 101).

Bailey Limestone in study area consists mainly of siliceous argillaceous limestone and chert beds grading into nodular chert. Unit is at least 200 ft thick and may be as much as 350 ft in southwestern IL. Beds of white microcrystalline silica in the Bailey, along with interbedded chert, siliceous limestone, and clay are exposed in a long roadcut 2 mi southeast of Thebes along IL Rte 3, Alexander Co. Section described in figures 8 and 9. Underlies Grassy Knob Chert. Age is Late Silurian and Early Devonian.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Late Silurian (Cayugan) and Early Devonian Bailey Limestone mapped in IL and MO. Consists of olive-green to light-gray (with reddish tints), thinly bedded argillaceous limestone and chert. Conodont evidence indicates that Silurian-Devonian boundary occurs in lower part of unit (Collinson and others, 1967). Unit grades into underlying Bainbridge Formation. Also mapped undivided with Bainbridge Formation and Sexton Creek Limestone in north-central part of quad where float indicates possible presence of all three formations but outcrops are insufficient to differentiate the units.

Source: GNU records (USGS DDS-6; Reston GNULEX).