James Leslie Mitchell
Three Go Back
from the dustjacket of the 1986 Greenhall edition:

"The three survivors saw — just for a moment — a bunched, barred, gigantic body, a coughing, snarling, malignant face. Then a rushing patter filled the cafe. 'What is it?' Sir John drew a long breath; 'A tiger.'
"Sinclair spoke very quietly. 'Like one, but it wasn't. It was a Machaerodus.' 'A what?'
"There fell a moment's silence — of stupefaction — on the part of all three. Clair, ill, closed her eyes and opened them again. She must be dreaming. But — it can't be. They're extinct."

The three are Clair Stranlay, aged thirty-three, writer of spicy novels; Sir John Mullaghan, head of an armament combine; and Keith Sinclair, an American, president of the League of Militaristic Pacifists. When the luxury airship on which they are travelling across the Atlantic breaks in half and crashes, they find themselves on a beach near black basalt mountains.

Gradually in their wandering south, it is revealed to them that they have been transferred back in time twenty-five thousand years, that they are on the lost continent of Atlantis; that the great beasts they glimpse are mammoths and sabre-toothed tigers. And that the Cro-Magnards who take them in are not savages, but clean and kindly children whose unspoiled ways are worth adoption — a noble savage leading an idyllic existence.

Three Go Back is one of the classic novels of prehistoric life, along with such work as Jack London's Before Adam and William Golding's The Inheritors.

Three Go Back is a lyrical idealization celebrating the possibility of a free, fulfilling and uncomplicated existence.