This is "The Wheel"
Cave near the river — A Local caveman named Fred accidentally created a circular shaped rocked with a hole in the middle that he is now calling "The Wheel."
It happened when he was chiseling away at the bedrock in his cave — his daughter wanted a shelf to put her lizards on. At one point he chiseled too deep and a very large portion of the wall fell down. It broke into a rectangular shape, but after using his stone axe, he smoothed the edges and found that the round shape was rather appealing.
After neighboring cave dwellers saw the wheel they were intrigued. Fred decided to trade the wheel for the head of an alligator to his cousin Charles.
"Please, that thing isn't even worth a lizards tail! Charles can keep it, heck, he can even take credit for it!" Fred laughed as he recalled the trade.
As for the name of the round rock Fred says, "I named it "The Wheel" because when I rolled it around my daughter said, 'weee!" Then I added an L sound at the end."