Several evergreen wood ferns (Dryopteris intermedia) grow on a mossy rock outcropping near the Minister Valley in the Allegheny National Forest in Warren County, Pennsylvania. The Allegheny Front was once part of a vast delta and layers of a hard, sandstone congolomerate were deposited. Between 250 and 320 million years ago, the Allegheny Front was lifted, forming hills and mountains. Over time, erosion exposed, split, or dislodged and moved the former sedimentary rock, resulting in large rock outcroppings.
Add to Cart Add to Lightbox Download