The type section of the Bainbridge formation of southeastern Missouri is about one mile south of Moccasin Springs. The Bainbridge includes some red, strongly mottled, argillaceous limestones; some poorly bedded, greenish gray earthy limestones; and a conspicuous unit of finely laminated dark brown shale in which Cyrtograptus ulrichi Ruedemann is the conspicuous fossil. The section is more than 100 feet thick, but its base is below water level and a railroad embankment is against the foot of the bluff. The formation has been traced by many geologists in discontinuous exposures from Ste. Genevieve County into Cape Girardeau County, Missouri. It has been observed, also, in Alexander County, Illinois, and has been reported from other localities within that state. Lithological y it seems to be identical with parts of the Henryhouse formation of Oklahoma, the Lafferty of Arkansas, and with certain beds in the Silurian of western Tennessee. More exact correlations with these formations possibly may be accomplished by further faunal studies.