Changes in The Course of Continental Rivers
As the ice sheets moved into the central portion of North America, the rivers that used to flow from the Rocky Mountains to the northeast into the Arctic Ocean found their valleys choked with ice. The rivers had to divert around the farthest extensions of the ice. When the ice retreated, the new valleys eroded into the landscape kept the rivers from moving back to their old positions.
Read more about this topic: Glacial History Of Minnesota
Famous quotes containing the word rivers:
“I remember once dreaming of pushing a canoe up the rivers of Maine, and that, when I had got so high that the channels were dry, I kept on through the ravines and gorges, nearly as well as before, by pushing a little harder, and now it seemed to me that my dream was partially realized.”
—Henry David Thoreau (1817–1862)