Digging up petrified forests

"Petrified forests are some of the coolest-looking fossils scientists find and study. They can tell us so much about the past, including what Earth was like before humans walked on it. How do these . . . remains form? Why? Readers can find the answers to these questions within the pages of this book, complete with close-up photographs of petrified wood they might never otherwise see"--Provided by publisher.