Taped to Wheaties cereal boxes. Part of a promotion with 3 other comics: Flash Comics, Funny Stuff, and Whiz Comics. First newspaper ad appears 11 May 1947 mentioning their current availability.
Captain Marvel encounters a geologist who has discovered the one stone that holds the rest of the earth in place, and who uses it to cause earthquakes.
Indexer Notes
This story matches the cover illustration for Captain Marvel Adventures #60. (e-mail from Ed Buchman, October 31, 2006).