The Collaborative International Dictionary of English v.0.48:

petroglyph \pet"ro*glyph`\ (p[e^]t"r[-o]*gl[i^]f`), n.
   A carving or drawing on rock, especially one made by
   prehistoric humans; called also a petrograph.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

petrograph \pet"ro*graph`\ (p[e^]t"r[-o]*gr[a^]f`), n.
   A carving or drawing on rock, especially one made by
   prehistoric humans; called also a petrograph.
   [PJC] Petrographic