Co-author David B. Williams will discuss the new book “Spirit Whales & Sloth Tales: Fossils of Washington State” at 6:30 p.m. on Nov. 12 at the Mercer Island Library. He partnered with Elizabeth A. Nesbitt to write the book.

Friends of the Mercer Island Library are co-sponsoring the event.

“No matter where you wander in Washington, you are never very far from the past with evidence of the plants and animals that came before,” reads an event description.

Williams is an author, naturalist and tour guide. “I write about natural history, primarily focusing on geology and how it impacts our lives in myriad ways, from earthquakes to the stone we use in buildings to the hills that make riding a bike more challenging. I write about geology because it is such a fascinating and cool subject, whether out on the trail or in your own backyard,” he said in the event notes.

His award-winning books include, “Homewaters: A Human and Natural History of Puget Sound,” “Too High and Too Steep: Reshaping Seattle’s Topography and Seattle Walks: Discovering History” and “Nature in the City.” Books will be available for purchase and signing. Williams also writes a free weekly newsletter, the “Street Smart Naturalist.”