Sundance Formation
| Sundance Formation | |
|---|---|
Ma | |
| Type | Gypsum Springs Formation |
| Thickness | Up to 100 m |
| Lithology | |
| Primary | shale |
| Other | limestone, sandstone |
| Location | |
| Region | Western North America |
| Country |  United States |
| Type section | |
| Named for | Sundance, Wyoming |
| Named by | Darton |
| Year defined | 1904 |
The Sundance Formation is a western
inland sea
that covered large parts of western North America during the Middle and early Late Jurassic.
Geology
The Sundance Formation underlies the western North American
Gypsum Springs Formation
.
Fossils
The Sundance Formation is known for fossils of an extinct species of marine
belemnite Pachyteuthis densus, as well as several extinct species of oyster, including Deltoideum, Liostrea, and Gryphaea nebrascensis. Other common invertebrates include crinoids, echinoids, gastropods, insects, ostracods, and foraminifera.[3]
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.[4]
Paleobiota
Vertebrates
| Genus | Species | Member | Material | Notes |
|---|---|---|---|---|
|
|
Trace fossils |
A Pteraichnid belonging to the Pterodactyloidea. | |
|
|
A Cryptoclidid Plesiosaur .
| ||
|
|
A Cryptoclidid Plesiosaur .
| ||
|
|
A Pliosaur .
| ||
|
|
An Ichthyosaur .
| ||
|
Material now lost.[6] |
Possibly a Plesiosaur .
|
Invertebrates
| Genus | Species | Member | Material | Notes |
|---|---|---|---|---|
|
A Belemnoid. |
Fish
| Genus | Species | Member | Material | Notes |
|---|---|---|---|---|
|
An ichthyodectiform
|
References
- S2CID 55369947.
- S2CID 210290670.
- S2CID 126843460.
- ^ BLM−Bureau of Land Management, Wyoming Office: "Red Gulch Dinosaur Tracksite" website, info, maps, photo gallery, accessed 8.21.2015
- ^ ISSN 1612-4138.
- ^ W. R. O'Keete, F. R. and Wahl Current taxonomic status of the plesiosaur Pantosaurus striatus from the Upper Jurassic Sundance Formation, Wyoming, article on pages 37-47 of the complete issue, 2003, Paludicola, 4 (2) : 27-68. Paperback – January 1, 2003
44°15′24″N 105°40′57″W / 44.2568°N 105.6824°W