• "the finer grained, less fossiliferous parts of the Clays Ferry Formation were deposited in quiet water at least 80 ft deep, similar to the depositional environments of the Logana and Brannon Members of the Lexington Limestone. The more fossiliferous parts of the formation probably were deposited at shallower depths, but currents were never strong enough to remove fine clastics or to break up the skeletal material effectively."

• "This 120 to 220 ft of interbedded limestone and shale straddles the Middle-Upper Ordovician boundary. To the south it intertongues with the upper members of the Lexington Limestone, but to the north it becomes younger and intertongues with the shales of the Kope Formation in north-central Kentucky.

•Limestone makes up 30 to 60 percent of the Clays Ferry Formation. Beds are even and 1 to 6 in thick. The limestone varies from medium- to dark-gray, argillaceous calcisiltite to medium-gray brachiopodal limestone to medium-gray crinoidal calcarenite. The calcisiltite is sparsely fossiliferous and contains mainly crinoidal fragments and some gastropods. The brachiopoal limestone is characterized by abundant Rafinesquina, some of which are shingled, as well as by Sowerbyella and Dalmanella, all packed in a mud matrix. Bryozoans are also common.

•Shale makes up 30 to 60 percent of the formation. It is generally greenish to olive gray, and is present in distinctly laminated sets 1 to 12 in thick. Fossils generally are sparse in these shales, though bryozoans are common at some locations.

•Siltstone makes up 5 to 10 percent of the unit, occurring mainly in the upper part. It is present mostly in 1- to 3-in even beds in which fossils are sparse. This lithology resembles the Garrard Siltstone, which overlies the Clays Ferry in south-central Kentucky."