The Notch Cascade waterfall type is new, and doesn't appear in the Waterfalls of Ontario books. I'm still thinking this one through, and looking for examples.

This type occurs where the river has eroded out a softer vertical or subvertical rock formation. It can also occur where erosion has encountered and widened a significant vertical or subvertical fractures or a fault.

One example is the Montreal River Gorge. Geologists found hard granite walls but a softer rock (diabase) at the river bed. They concluded that the river preferentially eroded a vertical dike of diabase. (Learn more on page 106...").

Remember that all waterfalls erode the bedrock that they pass over. Any waterfall with a deeper channel could be considered to show a "Notch". But for this project, I'm looking for waterfalls where there is evidence that some particular rock structure facilitated the notch. This could be tough!

As discussed earlier, a waterfall can have elements of more than one type. Some Slope Cascades have a notch that dominates the flow during lower flow. See Amii's image of Labrador Falls. Should this be called a "Notched Slope Cascade"? Maybe "Notched" is just an adjective?