Karen Engblom, age 12, Falconers 

Was Niagara Falls always in the same place?

Once in a while; a massive chunk of rock plunges from the rim of the falls into the Niagara river below  This moves the cataract a small distance back up the river, Since 1678, when the falls were discovered, the tumbling waterfall on the American side has receded about 94 feet  The mighty Horseshoe Falls on the Canadian side has receded about a quarter mile,

Slowly, very slowly, the rims at the top of the Niagara Falls seem to be moving back up stream  This is thought to be because the river bad is a layer of hard rock sitting on top of a layer of softer rock, The swirling cataract eats away the lower layer as it tumbles over the cliff, leaving the hard upper layer poking out like a shelf  From time to time, the weight of the water breaks off a piece of the butting shelf