When Jason Gridley got in touch with me recently by radio and told me it was The Year of Our Lord Nineteen Hundred and Thirty-nine on the outer crust, I could scarcely believe him, for it seems scarcely any time at all since Abner Perry and I bored our way through the Earth's crust to the inner world in the great iron mole that Perry had invented for the purpose of prospecting for minerals just beneath the surface of the Earth. It rather floored me to realize that we have been down here in Pellucidar for thirty-six years.