The Smithsonian has an interesting new article about the petrified forest the was found in an Illinois coal mine a little over a year ago. It's supposed to be the world's largest fossil forest and dates back to 300 million years ago, a time prior to the existence of dinosaurs. And more importantly, immediately before a drastic change in the environment where "earth's atmosphere suddenly acquired a lot more carbon dioxide". The scientists studying the fossilized forest hope to gain valuable information into the natural ebb and flow of our planet's ecosystem. You can check out the Smithsonian article here. And head over to the Illinois State Geological Survey for some additional photos.