The Appalachian Mountains are primarily composed of schist and shale.

The Appalachian Mountains are known for their complex geological history, with layers of rock formed from ancient tectonic activity. Schist and shale are common sedimentary and metamorphic rocks found in this region, reflecting the age and the dynamic forces that shaped the mountains over hundreds of millions of years. These rocks often form the foundation for the characteristic ridges and valleys of the Appalachian range.