Petroglyph and pictograph

Petroglyph should not be confused with pictograph	Pictograph A pictograph, also called pictogram or pictogramme is an ideogram that conveys its meaning through its pictorial resemblance to a physical object.
	Petroglyphs Petroglyphs also called pictogram (also called rock engravings) are pictogram and logogram images created by removing part of a rock surface by incising, picking, carving, and abrading.	Petroglyphs are found world-wide, and are often associated with prehistoric peoples. Here the Coso Rock Art Complex within the China Lake, Naval Air Weapons Station. Extraordinary numbers of petroglyphs are pecked into the lava flows, canyons, and tablelands.
source text: Wikipedia of course Links Petroglyphs http://en.wikipedia.org/wiki/Petroglyph http://www.desertusa.com/magdec97/cosos/dec_cosos.html http://www.desertusa.com/magdec97/cosos/dec_cosos2.html http://en.wikipedia.org/wiki/Naval_Air_Weapons_Station_China_Lake