The Scarecrow of Oz by L. Frank Baum - Ozathon24

Trot, a serious little girl, and her devoted friend, Cap’n Bill, are exploring the California coast when their boat hits a whirlpool. They are brought down, down, down into the depths of the ocean and eventually resurface in a cave where they are temporarily safe (if you are like Alec Ramsey and can survive on seaweed).