Ripley Formation

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Ripley Formation
Stratigraphic range: Upper Cretaceous
Maastrichtian Ripley Formation rockground near Greenville, Alabama.JPG
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)
Primary Glauconitic sandstone
Other Micaceous chalk
Region Alabama, Georgia, Mississippi, Missouri, Tennessee
Country  United States
Type section
Named for Ripley, Mississippi

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 quite 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. Crocodile, dinosaur, and mosasaur fossil remains have been recovered from the Ripley Formation.[2]


See also[edit]


  1. ^ "Hypsibema missouriensis". DinoData. DinoData. 2011. Archived from the original on February 4, 2011. Retrieved January 12, 2011. 
  2. ^ a b Kiernan, Caitlin R. (2002). "Stratigraphic distribution and habitat segregation of mosasaurs in the Upper Cretaceous of western and central Alabama, with an historical review of Alabama mosasaur discoveries". Journal of Vertebrate Paleontology 22 (1): 91–103. doi:10.1671/0272-4634(2002)022[0091:SDAHSO]2.0.CO;2. Retrieved 2009-02-02. 
  3. ^ "Table 20.1," in Weishampel, et al. (2004). Page 443.