THE GREAT FLOOD (A fragment)
Reading edition
Mandan
THE earth is a large tortoise. It moves very slowly and carries a great deal of earth on its back. Long ago there was a tribe which is now dead. They used to dig deep down in the earth for badgers. They dug with knives. One day they stuck a knife far down into the earth. It cut through the shell of Tortoise.
Therefore Tortoise at once began to sink into the water. The water rose through the knife cut until it covered all the ground. All the people were drowned except one man.
But some of the old people say it was this way. They say there were four Tortoises, one in the East, one in the West, one in the South, and another in the North. Each Tortoise made it rain for ten days. Therefore the water covered the earth and all the people were drowned.

From Report of the Bureau of American Ethnology.
Early Indian Pottery.