I am looking for any information regarding rock paintings, artists known for "rubbings" of rock paintings with calligraphic signatures?, and with a round waterseal instead of square. The Chinese writing inside of the waterseal, I was told, says "painting of a rock." I send photographs of the pictures to an Asian rarities appraiser to which she responded I needed to notify a fine arts person or a museum. I would greatly appreciate any information regarding contact information with knowledge in this specific type of art. Thank you.