The Hanging Rock area of northwestern North Carolina is underlain by three rock types: metabasalt, arkose, and siltstone. Soils developing from metabasalt are fine-textured, moist, and rich in nutrients; northern hardwoods and northern red oak forests predominate. Arkose weathers into a coarse-textured soil that is often dry and poor in nutrients. It supports mostly pine-oak/heath and modified northern hardwoods forests. Soils over siltstone are intermediate in texture and nutrient content. Slopes with northerly aspects support northern hardwoods and cove hardwoods forests, whereas southerly slopes support pine-oak/heath forests. Included in the flora of 355 species are 21 species new to Avery County and 27 new to Watauga County.