A petroglyph is any carved and/or painted image made by humans, usually on large stone boulders or outcroppings. As discussed below, "workstones" may sometimes fall into this category, though workstones have clear functional purposes as well. The meaning of petroglyphs (the world over) have always been debated. The short answer is that we don’t know exactly what they meant, though most appear to have spiritual connotations. In the Caribbean, they almost always occur near water and the images range from abstract geometric designs, to simple "smiley faces", to elaborate anthropomorphic (human-like) and zoomorphic (animal-like) figures. These variations imply that they may have been drawn at different times, by different groups, perhaps for different reasons.

Amerindians were animists (everything had a soul -- rocks, trees, animals, etc.), and they called on the spirits of their ancestors to help them navigate and understand the world. One of the dominant interpretations in archaeology, therefore, is that petroglyphs signify places where spirits would gather (perhaps hinting at the significance of water). Petroglyph artists were also likely shamans (religious leaders) and their visions may have inspired the content of the glyphs, perhaps induced by concoctions ground on the nearby workstones.

Workstones are large, enigmatic boulders that appear to have functioned as mortars and anvils for pre-Columbian Amerindians. The linear slits on some stones are likely the result of repeated sharpening of stone (and shell) blades. The circular “cupules” may also have been used for smoothing and polishing groundstone tools, but some may have been used for food as well (as a mortar), among other uses. All of Grenada's petroglyph sites (n=6) have workstones, but not all of the workstone sites have petroglyphs (n=11)-- see the map above. Aside from their functional uses, workstones likely held ritual significance as well, such as in preparing large communal meals (feasts) or grinding narcotic substances taken by shamans and chiefs. The recent discovery of the Montreuil workstone (pictured above) suggests hitherto unknown artistic aspects, perhaps bridging a rock art continuum, from mortars to petroglyphs.

Unfortunately, little research has been conducted on workstones, in part because they only appear in the southern Lesser Antilles. Given this, and their association with ceramics of the Suazan-Troumassoid period, they all probably date between AD 800-1600.