Ripley Formation

The Ripley Formation is a geological formation in North America found in the U.S. states of Alabama, Georgia, Mississippi, Missouri,[1] and Tennessee. The lithology is consistent throughout the layer. It consists mainly of glauconitic sandstone. It was formed by sediments deposited during the Maastrichtian stage of the Late Cretaceous. It is a unit of the Selma Group and consists of the Cusseta Sand Member, McNairy Sand Member and an unnamed lower member.[2] It has not been extensively studied by vertebrate paleontologists, due to a lack of accessible exposures. However, fossils have been unearthed including crocodile, hadrosaur, nodosaur, tyrannosaur, ornithomimid, dromaeosaur, and mosasaur remains have been recovered from the Ripley Formation.[2]

Ripley Formation Stratigraphic range: Upper Cretaceous
Rockground exposed in the Ripley Formation near Greenville, Alabama.
Type	Geological formation
Unit of	Selma Group
Sub-units	Cusseta Sand Member, McNairy Sand Member
Underlies	Prairie Bluff Chalk Formation
Overlies	Demopolis Chalk Formation
Thickness	40 m (130 ft) to 175 m (574 ft)
Lithology
Primary	Glauconitic sandstone
Other	Micaceous chalk
Location
Region	Alabama, Georgia, Mississippi, Missouri, Tennessee
Country	United States
Type section
Named for	Ripley, Mississippi