Jurassic RocksThe throwing rocks used by the Grog tribes are more unique than was once thought. At first observation, the Grog's tendency to settle near caves and volcanically active regions would seem to explain their near-limitless supply of rock projectiles. Upon further study, it was noted that the small stones can be found lying on top of the ground cover in jungle climates, often times in ready-made piles.
Further lithic analysis should determine if they are actually artifacts or merely manuports. In any case, the Grogs are fortunate to have the material at their disposal. Their high density allows Grogs to carry a large number of projectiles in a small space, and their unusual brittleness makes shattering on impact common, which tends to increase the damage inflicted.