Uncle Scrooge Bargain Book: Walt Disney's Comics in Color #4

Scrooge buys up all the 1916 quarters ever minted and sinks all but one deep in the Atlantic, with the aim of making that one coin the most valuable in the world. But the last quarter is flattened by a steamroller and so Scrooge must dive into the Atlantic to get another. There, the ducks find Atlantis, a sunken city populated by fish-men who breathe under water.