Rock art is generally divided in two categories: carving sites (petroglyphs) and paintings sites (pictographs). Pictographs are paintings that were made by applying red ochre or, less commonly, black, white or yellow dye. Although the majority of the images were traced with the finger, some could be executed with brushes made of animal or vegetal fibres. Petroglyphs are carvings that are incised, abraded or ground by means of stone tools upon cliff walls, boulders and flat bedrock surfaces.

-from The Canadian Encylopedia