The Land That Time Forgot – Edgar Rice Burroughs (1918)
The author’s explanation for how this manuscript got into his hands is that it was stuffed into a vacuum flask by the original author and ended up on the shores of North America.
The journal is written by one ‘Bowen’, a man who is inadvertently captured by a German submarine during World War I. His fellow captives eventually manage to overpower the Germans but find that they can dock nowhere, and are fired on by ships. Lost, they find themselves at a land mass surrounded by cliffs, one which has a subterranean river leading to the interior.
This is standard fare for Burroughs. ‘The Lost World’ in essence, since there are plenty of dinosaurs. The central mystery however and what distinguishes it from Conan-Doyle is that there are men on the island who seem to range from pre-human ape-like creatures at one end of the land to the level of modern man at the other. It is suggested that these humans are moving through various stages of evolution during their lives and moving across the island to live in the various communities as they develop.
It’s an interesting concept which Burroughs puts aside to examine further in the remaining volumes of the trilogy.