Horsethief Sandstone
Encyclopedia
The Horsethief Sandstone is a Mesozoic
geologic formation. Dinosaur
remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus
. The southern part of the Two Medicine Formation grades into brackish water siltstone/sandstone series composing Horsethief Formation. The sediments of the Horsethief represent shallower water deposits than the Bearpaw Shale adding further evidence of higher elevation areas existing to the south of the Two Medicine Formation's paleoenvironment.
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
geologic formation. Dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
. The southern part of the Two Medicine Formation grades into brackish water siltstone/sandstone series composing Horsethief Formation. The sediments of the Horsethief represent shallower water deposits than the Bearpaw Shale adding further evidence of higher elevation areas existing to the south of the Two Medicine Formation's paleoenvironment.