Western Interior Seaway Fossils

Elizabeth nicholls from pink mountain in british columbia.

Western interior seaway fossils. The western interior seaway also called the cretaceous seaway the niobraran sea and the north american inland sea was a huge inland sea that split the continent of north america into two halves during most of the mid and late cretaceous period. Ichthyosaur fossils are also found in the dried up western interior seaway basin. The western interior seaway formed about 100 million years ago when the mountains that now define western north america lifted up as a result of tectonic forces.

Numerous species of invertebrate and vertebrate animals inhabited the wis and left behind fossils in the sedimentary rocks that were deposited during the time of the wis. It was a shallow sea with diverse marine life including predatory marine reptiles such as mosasaurs growing up to 18 meters long ichthyosaurs and plesiosaurs. Paleogeographic reconstruction of the western interior seaway during the cretaceous.

In badlands national park mosasaur fossils have been found in the pierre shale a rock unit laid down in the western interior seaway roughly 75 69 million years ago. Ichthyosaurs are marine reptiles that superficially resemble fish or dolphins. The seaway was created when the pacific and north american tectonic plates collided causing the uplifting of the rocky mountains.

At tanis north dakota university of kansas phd student robert depalma has. The western interior seaway was a shallow inland sea that stretched from the gulf of mexico all the way to the arctic ocean cutting the north american continent in two. The western interior seaway was a large inland sea that existed during the mid to late cretaceous period as well as the very early paleogene splitting the continent of north america into two landmasses laramidia to the west and appalachia to the east.

The ancient sea stretched from the gulf of mexico and through the middle of the modern day countries of the united states and canada meeting with the arctic ocean to the north. They ve also dug up the remains of huge sharks turtles the size of cars and clams six feet in diameter the largest to ever exist. Some 100 million years ago much of what is now north america was underwater.

The world s largest ichthyosaur fossil to date was dug up by canadian paleontologist dr. Many of these fossils can be viewed on this cretaceous atlas of ancient life page. The body of water scientists call the western interior seaway covered a swath of land that stretched over the entire.