The Beachcomber's Companion Guide to Collecting and Identifying Beach Treasures written by Anna Marlis Burgard features over 50 watercolor illustrations. This was such a fun project and collaboration. I was able to work largely from specimens that Anna sent from her collection. It's a great read, here's a quick synopsis from Chronicle's website below:
Breezy, inviting, and delightful—just like a day at the beach— The Beachcomber's Companion is a charming illustrated guide to collecting and identifying shells and other coastal treasures. Each of the entries includes fascinating descriptions, fun tidbits, and detailed artwork that makes it easy for readers to identify their own beach discoveries. A handy resource section offers tips on how to prepare before setting out on a shoreline adventure: from the beachcomber's commandments to must-have items for every beachcombing toolkit and advice on preserving shells. Awash with information and gorgeous watercolor illustrations, this is an essential companion for all who love the ocean's shore.