Older Than Dirt: A Wild but True History of Earth

An extended conversation between a science-savvy groundhog and a new-to-Earth's-history worm features a comprehensive overview of the geological past of our planet. The graphic format, light tone, and amusing repartee keep up the pace over the course of an impressive number of geology topics, from the formation of the planet through the various processes that formed the oceans and continents, Earth materials, and life. Concrete examples and illustrations that combine science and humor (Groundhog: "A nearby planet collided with Earth! THWACK! Some scientists say it was a punch to the gut and others say it was a slap to the shoulder." Worm: "What's a shoulder?") make for an effective presentation of content. It's a whirlwind tour but with clear explanations and a coherent line of reasoning. A feature titled "Deep Time Comix," comprising sepia-toned comic panels, pops up occasionally to introduce important geologists of the past and their contributions to plate tectonic theory. Global warming is addressed in an appendix; back matter also includes source notes, an extensive bibliography, a "24-hour Earth Clock," and a geological-era chart. danielle j. ford