InGen Database Description
The Lance Formation is named after Lance Creek in Wyoming. The formation sits above the Meeteetse Formation and underneath the Fort Union Formation. It dates to the Maastrichtian age of the Late Cretaceous, 69 million years ago. It occurs above the ammonite marine zone in Wyoming, dated to 69 million years ago. The formation extends up to the K-Pg extinction event boundary.
The formation is comprised mainly of sandstone. The presence of some marine fossils indicate that it was a coastal plain along the Western Interior Seaway. Its climate was likely to have been subtropical with no indications of a cold season.
Many thousands of fossils have been recovered from this site, and amphibians, turtles, crocodiles, fish, mammals, and turtles are present as well as dinosaurs.