The petroglyphs are symbolic designs engraved on rocks, made to rough the surface layer. Many were made by our prehistoric ancestors of the Neolithic period. They are the nearest antecedent of the previous writing symbols. Its use as a form of communication is dated to 10,000 b.c. and accessible to modern times in some cultures and places. The word comes from the Greek words petros ( 41 stone; and glyphein ( carve ).
