Bunduki

They called James Allenvale Gunn ‘Bunduki', the Swahili word for firearm of any kind. He and Dawn Drummond-Clayton should have been killed when their Land Rover plunged into the Gambuti Gorge. Instead, Bunduki woke to find himself in a primeval jungle and armed with primitive weapons. Dawn came to her senses on a game-haunted plain. Guided by subconscious suggestion, they set out to find each other. To do so, they had to transverse terrain populated by many kinds of wild animals and savage people. Before they were reunited, both had to face danger and death many times.
Fortunately for Dawn and Bunduki, they were respectively the adoptive great-granddaughter and son of Lord Greystoke—who is better known as Tarzan of the Apes ...