大家在查：菲茨莫里斯 sewagehuman 纳金 Vina 伯提简洁起见 jihadism 单源司提 parietal cortex

古阿纳萨齐人

The Anasazi made arrowheads by chipping away at pieces of glassy obsidian (black) and chert (grey and red) until they became sharp .