Researchers uncovered nearly 600 stone tools, almost exclusively made of obsidian, in one section of the cliff side. The artifacts were over 1.2 million years old, the study said.

Inside the box sat three blocks of copal tree resin, 59 pocket knives and seven obsidian stone knives, all between 4 and 6 inches in length, the institute said. Photos show these weapons.

However, during the course of their excavations, the team came across an ancient layer of sediment containing a cache of 578 stone tools, all but three of which were sculpted from obsidian.

A new analysis of hundreds of obsidian artifacts from the Aztec Empire has revealed the vast trade networks that supplied obsidian, sometimes even from rivals. CNN values your feedback 1.

Stone Age Shipwreck Carrying Obsidian Cores Discovered Off Italian Coast An increasing amount of evidence suggests ancient humans were skilled sailors (except these guys, who sank).