Message From the Eocene, St. Clair, Vintage Paperback Book, Ace #M-105, Science Fiction

Vintage Paperback Book, "Message From the Eocene" and "Three Worlds of Futurity", Margaret St. Clair, 1964, Ace Double #605. Paperback original (PBO). Cover art by Gaughan. Grades GD. Some cover wear, some corner wear, some creasing, pages and inside covers beginning to brown somewhat, name written in ink inside both covers.