A red-haired Claude Rains as Professor Challenger claims to have seen live dinosaurs and asks for an expedition to prove that they exist.
Although he's on form enough, this film by Irwin Allen is stodgy and extremely old - fashioned but cut through this, and it is a fun enough adventure.
Michael Rennie, Richard Haydn, David Hedison and Jill St John are the ragbag collection of intrepids who go on the hunt.
The lost world itself is a bit underwhelming, and it seems likely that the welfare of animals was not to of anyone's list when this was made.
In summary, then, this could be a version of Conan Doyle's story - that I'm watching to celebrate his birthday, incidentally - that really is redundant. But if you haven't seen any of the others, it isn't terrible.