In the beginning of the game you wil have some kinds of dinosaurs from this sites

Judith River Group A: Albertosaurus, Pachycephalosaurus and Ankylosaurus.
Hell Creek Formation A: Parasaurolophus, Torosaurus and Acrocanthosaurus.
Morrison Formation A: Ceratosaurus, Dryosaurus and Stegosaurus.

If you have the Morrison or the Judith You have less Tornado's