Archeological lithic resources - National Parks Gallery

Figure 13. Photographs of lithic resources.
In the upper photograph, a bird sits on a metate
made of Early Proterozoic granitic rock, which is a
specimen of the oldest rock unit in the monument.
In the lower photograph, obsidian comprises the
spearhead, arrowheads, and scraper. Obsidian is
volcanic glass most commonly found in lava flows
or domes of rhyolitic composition.