PENNSYLVANIA'S FOSSIL FOREST

Some 300 million years ago, near the town of St. Clair, Pennsylvania, the land was covered by lush green forests with a wide variety of plants and trees.

- BY JOSEPH “PALEOJOE” KCHODL

Known as the Llewellen formation, exquisite fossils from this time can be found. This area of Pennsylvania is known for the anthracite coal deposits sandwiched between layers of conglomerate, sandstone, siltstone and shale. The coal fields were closed as the coal ran out, but a treasure trove of ancient plants was left behind.

CARBONIFEROUS FOSSILIZATION

During the Pennsylvanian period (323 to 299 million years ago), the environment was wet, warm, and humid — providing perfect conditions for the growth of large flora. The shallow lagoons and bogs in coastal areas were periodically inundated with water that buried plants and trees. Storms would strip leaves away from the plant trunks. The foliage that fell into the swampy water was covered by layers of mud and sand. The plants were further buried under successive layers of sediment and additional plant material. During this time, they were protected from oxygen, which slowed decay and decomposition.