The rock could have been put in by the Biblical Flood.
Mt. St. Helens demonstrate rapid stratification (rock does not need Millions of years to be placed).
Living Index Fossils shows the mainstream methods of dating rocks as Millions of Years old to be erroneous.
Sea fossils are found on the tops of high mountains, and fossil formation requires flood conditions.
The Ice Age started the formation of Niagara Falls (which was triggered by the Biblical Flood).
The Flood solves many problems surrounding what started the Ice Age. Especially the evaporation problem. Where did the water vapor/snow that caused the Ice Age evaporate from to produce the massive amounts of snow deposited during the Ice Age?
Carbon-14 dating errors make it seem like Niagara Falls is older than it actually is.
A glacial lake rapidly cut out 2.8 miles of the Niagara Gorge. Making the Falls much younger that many of the conventional geologists believe.
Large chunks of rock have fallen into the Gorge (and can be seen strewn throughout it). This indicates the rate of erosion of the Gorge is much faster than the standard estimates. Which would make the Gorge much younger.
There are may other ways for rapid erosion to take place, which would put the start of Niagara Falls within Biblical timing.