New York: Metropolitan, 1929. Frontispiece and Original Dust Jacket illustrated by Paul F. Berdanier. Original blue publisher’s cloth, black lettering. 312 pages. Third book of the Pellucidar series.
“From David Innes and Abner Perry build a giant mechanical prospector with which they hope to uncover vast mineral deposits far beneath the surface. On the “Iron Mole’s” first trip, however, they discover that their vehicle can’t be steered. Death seems certain, for doesn’t everyone know that the center of the Earth is a molten mass of white-hot magma? Instead what Innes and Perry discover is that the earth’s crust is only 500 miles thick and that the inner surface is inhabited. This is the land of PELLUCIDAR, a place where dinosaurs roam through the jungles, and where saber-toothed tigers hunt the mastodon and mammoth. The struggle of David Innes and Abner Perry to free humanity from the Mahar tyranny is only the beginning of their adventures in Pellucidar. There are a total of seven books in this exciting series, in which Edgar Rice Burroughs takes you on journeys across savage seas infested with plesiosaurs and other hungry creatures, to mountains where pterodactyls roost, and to lands where every waking moment is a struggle to survive. Even Tarzan visits Pellucidar, taking a ride on a dirigible through “Symmes Hole” at the North Pole.” — from the Edgar Rice Burroughs site