The Amature Paleontolgist"s Guide to
Fossils in and around Maryland
Maryland's Blue Ridge Province
The Blue Ridge in western Frederick County is a large anticlinal fold whose limbs are represented by Catoctin Mountain and South Mountain. The two ridges are composed of Weverton quartzite, which is very resistant to weathering and erosion. The Middeltown Valley, which lies between these two ridges, is composed of the Loudon, Catoctin and Swift Run formations. These formations which are composed of Precambrian gneiss and volcanic rocks, which are harder than the sedimentary rocks of the surrounding s. Consequently, the Middletown Valley of the Blue Ridge is higher than the surrounding Frederick and Hagerstown valleys.
