I don't think the stories are particularly interesting. They are dragging, and “The Living Death” is constantly interrupted by scientific or pseudo-scientific expositions (a bit like a bad Verne novel), although I suppose this could be because it was published in a popular science magazine. Still, I would consider “The Living Death” to be the best of the three stories. “Drome” feels even more dragging, despite all the monsters introduced by the author at critical junctions in the storyline.
What makes the stories intriguing is their lost world mythos. “The Living Death” and “In Amundsen's Tent” is about the discovery of a lost and quasi-subterranean civilization in Antarctica, threatened by winged monsters. “Drome” is about the discovery of a subterranean civilization inside Mount Rainier, also threatened by a wide assortment of, you guessed it, winged monsters. Presumably, “Drome” is freely based on the tales about Mount Shasta being part of Lemuria. The Golden City of Drome turns out to be ruled by a queen. A Lemurian-Atlantean priestess, perhaps? Also, both lands are likened to paradise. The mythos is never explained in full, however. The publisher of this volume is also into crypto-zoology, and seems to believe in Forteana at some level, which may explain why they brought out this edition of John Martin Leahy's magna opera.