Steven Spielberg’s “The Lost World: Jurassic Park,” might not have depicted prehistoric times 100 percent accurately, but the movie title got it right: this world, million and millions of years old, was lost. Until recently, that is. William A. DiMichele from the Smithsonian Institution in Washington and other scientists from around the world have described what we thought was lost: an ancient forest. In the Springfield Mine in southern Illinois, a prehistoric landscape left its mark 250 to 800 feet underground, on the shale ceilings of coal-mining caves. “Forest” is not an understatement: the fossils from hundreds of trees and plants exist for 100 miles in one direction, painting a picture of an extensive wooded area 307 million years old. Flora from this forest lived in the Pennsylvanian Period of the Carboniferous Era, before dinosaurs had come into existence. Most abundant in the caves are the fossils of scale trees: enormous ancient trees with huge tubular roots and bark that looked like reptilian scales. Ferns and fallen leaves can also be seen in the assemblage. A river more than 2 miles wide also left its imprint. The scientists believe that it was the flooding of this river that caused the forest to eventually go under (literally). When temperatures rose, the climate grew drier and silt filled the river, causing water levels to rise and spill over, drowning the plant life and preserving the fossils as it died. Three hundred million years ago, during the time that this prehistoric landscape flourished, the climate was similar to our modern climate. Carbon dioxide levels were about 350 parts per million (ours is now 380 ppm) and the average temperature was about 12 degrees Celsius (54 degrees Farenheit). Knowing that the Carboniferous climate was comparable to ours, scientists hope that studying this ancient forest will provide insight into the effects of changing climates on our world today.

Read more about this ancient forest at New York Times Science.

Read more about Carboniferous climate at