The Piedmont Lowland parallels the Piedmont Upland to its northwest. It is actually made of sedimentary rocks into which volcanic rocks are actually intruded. Some volcanic rocks make ridges. The Struggle of Gettysburg was fought there, the Northern army about the substantial ridges acquiring the advantage over the Southern forces https://deantzfjo.worldblogged.com/25003545/5-easy-facts-about-custom-build-entertainment-centers-macungie-described