“They chipped off a few large flakes”
So they hunted for smooth, round stones that were hard to break.
They wanted other stones for knives, spears, and axes.
So they hunted for stones that broke with a sharp edge.
They struck the sharp edges with hammer stones to see if they crumbled under a heavy blow.
When they found stones that crumbled they threw them away, but they kept the stones that were tough and strong.
When they had chipped off a few large flakes they carried the rough stones to the cave.
“Some handles were long bones that were large at the joint”