Sundance Formation

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Sundance Formation
Stratigraphic range: Jurassic
Type sedimentary
Underlies Morrison Formation
Overlies Chugwater Formation
Primary limestone
Other shale, sandstone
Region Western North America
Country United States

The Sundance Formation is a western North American sequence of Upper Jurassic age[1] marine shales, sandy shales, and sandstones.

The Sundance Formation underlies the western North American Morrison Formation, the most fertile source of dinosaur fossils in the Americas, and is separated by a disconformity from the underlying Upper Triassic Chugwater Formation red beds. The Sundance Formation is known for fossils of an extinct species of marine cephalopod, Belemnites densus.

Vertebrate paleofauna[edit]


Pterosaurs of the Sundance Formation
Taxa Presence Description Images


  1. P. stokesi[2]
  • Found in Wyoming at the Alcova/Grey Reef Reservoir, Seminoe Reservoir, and Bighorn Canyon National Recreation area.[2]
  1. Found in Wyoming, at the ichnospecies' type locality.[2]
  • Alcova/Grey Reef Reservoir and Seminoe Reservoir housed at University of Wyoming, Laramie.[2] Alcova/Grey Reef Reservoir specimens are also housed at Tate Museum, Casper College.[2]
  1. Specimens housed at University of Wyoming, Laramie.[2]

Invertebrate paleofauna[edit]


Belemnoids of the Sundance Formation
Taxa Presence Description Images


  1. B. densus


  1. ^ Jennings, Debra S.; Stephen T. Hasiotis (2006). "Taphonomic analysis of a dinosaur feeding site using Geographic Information Systems (GIS), Morrison Formation, Southern Bighorn Basin, Wyoming, USA". Palaios (SEPM Society for Sedimentary Geology) 21 (5): 480–492. doi:10.2110/palo.2005.P05-062R. 
  2. ^ a b c d e f g Lockley, M.; Harris, J.D.; and Mitchell, L. 2008. "A global overview of pterosaur ichnology: tracksite distribution in space and time." Zitteliana. B28. p. 187-198. ISSN 1612 - 4138.