Jeffrey wanted badly to belong to the Explorers Club. They took wonderful trips, had secret meetings and even had a shack all their own to have their meetings in. The trouble was that to join the club you had to discover something very unusual like a meteorite or a fossil, and Jeff hadn't discovered anything -- yet!
This story is another one of Mary Adrian's exciting mysteries based on scientific facts. In this one she weaves into the plot a good deal of geologic information on stalactites and stalagmites and other interesting things encountered by spelunkers. -- And if you don't think that is a real word, wait until you have read the book. It probably will make you want to be a spelunker yourself, or to start your own Explorers Club. Or both!