Point Reyes Station artist Laurie Mahan Sawyer illustrates the small marine worlds that live on shorelines and the bottom of bays. A gnarled ball of kelp. Barnacles on a muscle shell. The skin of an eel. “We’ve all seen how magical that other world is,” she said.

In an exhibit showing through August at the Dance Palace, she uses pen, ink, and watercolor to show the symbiotic life below the surface of San Francisco and…