The Haunted Reef

Richard Powers had a very broad brush.  He could illustrate and paint in so many styles (important for illustration work), yet never lost his unique identity -- one could always tell his work.

Here are some early interior illustrations he did for Richard Crisp's "The Haunted Reef", 1952.
You will notice the "woodcut" style of some of the illustrations that are similar to his later work on the Tarzan covers.  Also, the undersea mountains and peaks look very similar to his depictions mountains and spires from "alien worlds" in his early SF work.