Cary, Marty,
These formations are geologically karsts and according to Wikipedia....
"Karst topography is a geologic formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite........
Mature karst landscapes, where more bedrock has been removed than remains, may result in karst towers."
and I guess the remaining "towers" are the equivalent of good old (very old?) Aberdeen granite.
Cheers Colin