Out of Time's Abyss is a science fiction novel, the third of Edgar Rice Burroughs' Caspak trilogy. In this conclusion, the mysteries of the lost world's unique biological system are revealed. (Adapted from Wikipedia)
Link to The Land that Time Forgot [http://librivox.org/the-land-that-time-forgot-by-edgar-rice-burroughs/] (Caspak series #1)
Link to The People that Time Forgot [http://librivox.org/the-people-that-time-forgot-by-edgar-rice-burroughs/] (Caspak series #2)