Although Alberta is better known for dinosaur and terrestrial fossils, there are actually a large number of marine fossils found as it was once covered by a large body of water called the Western Interior Seaway. It stretched from the Arctic Ocean to the north, all the way down through the Northwest Territories, Alberta, and western US, down to the Gulf of Mexico. It existed during much of the Cretaceous, and is the reason why Alberta is full of marine fossils. Large marine reptiles like plesiosaurs, pliosaurs, and mosasaurs were common fauna during this time, and can be found often in marine deposits in Alberta from this time. The dinosaurs in Alberta are of ages younger than the seaway, in the very Late Cretaceous.
|Image showing the extent of the Western Interior Seaway (from the USGS)|
|Artists impression of Nichollssaura by ArthurWeasley|
1. Druckenmiller, P.S., and Russell, A.P. 2008. Skeletal anatomy of an exceptionally complete specimen of a new genus of plesiosaur from the Early Cretaceous (Early Albian) of northeastern Alberta, Canada. Palaeontographica Abteilung A 283: 1-33.
2. Druckenmiller, P.S., and Russell, A.P. 2009. The new plesiosaurian genus Nichollssaura from Alberta, Canada: replacement name for the preoccupied genus Nichollsia. Journal of Vertebrate Paleontology 29: 276.