The story is set in the Cretaceous, but not all the animals are Cretaceous animals. Oviraptors shown stealing eggs. The modern view is that Oviraptors did not steal eggs.
New evidence shows that they actually protected eggs.
The first idea came from only one, partial fossil. Lemurs as seen in the movie didn't really exist for another 40 million years or so. Grass as we know it didn't appear until long after the Cretaceous. The Iguanodonts had lips OVER their beaks. Now that YOU have seen the film please write and tell us what other differences you've found between the characters in the movies and real, paleontologically correct dinosaurs or animals or events in history.