The Appalachian Mountains were formed in the remote past by collision of two continental crusts. During such mountain building, huge sheets of rock are pushed over each other. A rock layer called the Blue Ridge Thrust Sheet was moved over 60 miles to cover what is now Grandfather Mountain.
These mountains were once much higher (10 times as high!) than they are today. Erosion over hundreds of millions of years has carried away most of the rocks to form thick layers of sediment all across the Piedmont, Coastal Plain, and in the Atlantic Ocean. At Grandfather mountain, erosion has worn away the Blue Ridge Thrust Sheet from over top of the underlying older rock, allowing us to study them. Geologists call this a "window" in time.
These rocks are likely linked to mountain erosion.
OBTW, I was up that way last summer and saw those rocks. Although interesting in a geologic sense, that's about it. Beautiful scenery up in the Carolina High Country, however!
They used to grow cheap dope in Foscoe. You’d be able to get a bag of Foscoe Gold for about $15. Then they went all touron on us.