This is a cavegirl film with hardly any cavegirls in but leads to the sequel The People that Time Forgot which is more visually interesting (although not such a good film) as we will see.
In the UK in the early seventies, Amicus Films had noted the success of Hammer Films in moving away from pure horror films to the likes of One Million Years BC (1966), When Dinosaurs Ruled the Earth (1970) and Creatures the World Forgot (1971). They decided to bring one of Edgar Rice Burroughs novels, The Land that Time Forgot to the screen.
The novel was written in 1918 and set during World War 1 (or, of course, The Great War as it was then known!). The novel and the film are reasonably close to each other with the script being adapted by lifelong ERB fan, British Science Fiction author, Michael Moorcock and James Cawthorn, better known as an illustrator and reputedly the first man to ever do illustrations to scenes from The Lord of the Rings, back in 1962.
James Cawthorn's Against the Deeping Wall. Not a million miles from Peter Jackson's version of the scene.
Both the novel and the film open with a a man finding a thermos in the sea containing an account of the main part of the story. The author Tyler (played by the matchless Doug McLure in the film) is on board a ship torpedoed by a U-Boat in 1916.
"This film could have been a lot dirtier. Did you see When Dinosaurs Ruled the Earth?"
He and a girl, Lisa Clayton (Susan Penhaligon), and some of the British crew are picked up by the U-Boat that sank them. They capture the submarine but then are overpowered before taking control once more. But the cunning Germans have sabotaged the compass and they end up at the lost island of Caprona. They enter a long tunnel and come out into a river full of prehistoric creatures (cue attack by rather rubbery plesiosaur).
Couldn't afford Harryhausen.
They discover oil and start to refine it to re-fuel the submarine. They also encounter more puppet dinosaurs (the film's $750,00 budget couldn't stretch to stop-motion) and different evolutionary levels of cavemen. There is some unlikely sub-plot about evolution becoming more developed as they go up the river culminating in them finding a giant upturned pudding out of which the river of life is pouring.
This is the only cavegirl bit because using the top of the pudding like a giant jacuzzi are a number of topless cave babes. You really can't see anything as they are too distant and are only on for a few seconds but I remember being quite excited about this when I saw it when I was younger. There are several more scenes in the village with a number of other girls wearing, if not fur bikinis, then fur mini dresses and crop tops. I couldn't get any pictures or screen captures, sadly, but it is the sequel we are really interested in, anyway.
Eventually there is a big volcanic eruption (there always is in these kinds of films) and Trampas (I mean Tyler) and Lisa tramp (sorry!) off across the Island where we see him throwing his thermos into the sea, desperate to be rescued (as the submarine sank - isn't that what they are supposed to do?- leaving them stranded).
So very little cavegirl content and Susan Penhaligon reamins scandalously overdressed for the whole film. It makes you realise that Amicus hadn't really worked out the Hammer recipe yet. I would have definetely inserted a gratuitous bathing in the river scene.
See, she was quite happy to do bathing scenes!
Actually, despite rather ropey special effects (but better than At the Earth's Core which followed) it is a pretty good film, with a better script than usual (as you would expect, given the writer) that can still pass an enjoyable hour and a half even now.
One disappointment is the location. Caprona is realised as a mixture of studio bound jungle, very dodgy matte paintings and a bit of location filming in what looks like Burnham Beeches with a few palms strewn about.
So ropey dinosaurs, cheap locations and very short on cavegirls, but they are there and the sequel The People that Time Forgot makes up for it!