Mystery #2Tier 2waterfalls and erosion
Why does a waterfall very slowly creep upstream, year after year?
Some famous waterfalls have moved. Not overnight, but over hundreds and thousands of years the edge has crept slowly upstream, leaving a long gorge trailing behind it. The water keeps pouring over the same drop, yet the drop itself is on the move. Why does a waterfall very slowly creep upstream, year after year?
Your guess
The waterfall's edge keeps shifting upstream, little by little. What do you think is wearing it back?
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