Two Thousand Miles Below

Dean Rawson is searching for a way of mining power from a dead volcano, but ends up discovering more than he bargained for. He learns the life-spark of a fabled race glows in the black heart of a dead, Western volcano.
Charles Willard Diffin was an engineer, airplane salesman and writer. He authored hundreds of science fiction stories many for pulp magazines during the 1930s and '40s.