Type sedimentary Region Western North America Primary Limestone Underlies Morrison Formation | Other shale, sandstone Country United States Overlies Chugwater Formation | |
-
The Sundance Formation is a western North American sequence of Upper Jurassic age marine shales, sandy shales, and sandstones.
Contents
Geology
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.
Fossils
The Sundance Formation is known for fossils of an extinct species of marine cephalopod, Belemnites densus.
Fossil dinosaur 'footprints' on an ancient ocean shoreline are preserved in the formation and protected at the Red Gulch Dinosaur Tracksite, located in the Bureau of Land Management Red Gulch/Alkali National Back Country Byway, near Shell in Big Horn County, Wyoming.
References
Sundance Formation Wikipedia(Text) CC BY-SA