Dennis Formation
The Dennis Formation is a geologic formation in Missouri. It preserves fossils dating back to the late Carboniferous period. The formation is part of the Kansas [City Group], Missourian Stage, Pennsylvanian subperiod of the Carboniferous period.
The formation members, from bottom to top, are Canville Limestone, Stark Shale, and Winterset Limestone.
The three members form the major part of a cyclothem, created as sea water rise quickly and then gradually fall again over millions of years.