Scientists discovered a collection of stone tools that dated back 3.3 million years near a dry riverbed in Kenya. This is the oldest trove of tools to ever be discovered, and it pushes back the record of known stone tools 700,000 years.

This means that the tools are half a million years older than any trace of human beings. Until now, it was thought that stone tool culture appeared 2.6 million years ago alongside the earliest member of the human genus family Homo habilis or “handy man,” as reported by Irish Examiner.  The oldest tools were called “Oldowan” Homo habilis tools.

And it was thought that only members of designated “Homo”–like Homo sapiens–constructed and used sharp-edged stone tools, according to Brisbane Times. These new findings are strengthening the argument that tool-making may have started with smaller-brained forerunners.

Jason Lewis and Sonia Harmand of Stony Brook University in New York reported the discovery in the scientific journal Nature Wednesday. The paper states that scientists found 149 stones and stone flakes near Lake Turkana in Kenya in 2011.

The collection included hammer stones, worked cobbles, anvils and cores used for making sharp edges (for cutting). The creators of these Lomekwi tools are said to have had good coordination and a strong grip, but they were not quite human.

Experts are not exactly sure of the purpose of the Kenyan tools. However, the markings on the stones indicate that some may have been used to pound items.

Harmand said that she thought the purpose of the tools was to create sharp-edged flakes for cutting, but she is unsure as to precisely how the tools were used. “The technological features of flakes and flake fragments are clear, unequivocal and seen repeatedly,” Harmand said.

Generally, ancient human tools were thought to have been used for tasks such as skinning animals or hammering. But scientists believe that the hand and arm motions involved were more similar to those of chimpanzees cracking nuts than to human actions.