Unknown Island (1948)
Unknown Island is a 1948 adventure film directed by Jack Bernhard and shot in Cinecolor. The film features monsters such as dinosaurs and a giant sloth and stars Virginia Grey, Phillip Reed, Richard Denning and Barton MacLane. Ray Corrigan also appears in this film, playing a Giant sloth. It is a rare example of a 1940s film that was shot in Cinecolor. It also has the giant sloth fight and kill a Ceratosaurus identified as a Tyrannosaurus rex in the movie. A deleted extended scene shows a Brontosaurus watch as the dinosaur and sloth fight in a lake nearby it can be found on the BBC Motion Gallery but the footage is in black and white.
More at Wikipedia.