rhychydwr1
Active member
Discovered in 1964, but new to me. Will add it to the book.
http://www.shurdington.org/gharmirdum/index.html
http://www.shurdington.org/gharmirdum/CaveComplex.htm
http://www.shurdington.org/gharmirdum/index.html
http://www.shurdington.org/gharmirdum/CaveComplex.htm