Tyhe SUmerians actually were here way before Columbus, before the Vikings and way before the Chinese fleet off the West coast.
So why were they purchasing sheep and goats from each other in America? It means the Sumerians were here,had settled and had trade among each other?
Interesting questions, or did native AMericans join with the Sumerians to learn cuniform in an ancient colony in America, established by Sumerians?
Unless all the goats and sheep died out after the Sumerians left or that that the Sumerians used the term goat or sheep for an indigenous native American animal like a deer or buffalo then the receipt makes no sense.