Alpha Falls Site 3 Kildoo Falls (Site 4) Breakneck Falls (Site 5)
Waterfalls of two origins are common features along the Gorge. More spectacular high falls occur on the east side of the Gorge. At Alpha, Kildoo, and Breakneck Falls (Sites 3, 4, and 5, respectively) tributaries to Slippery Rock Creek flow across resistant Homewood Sandstone and plunge into the much deeper Slippery Rock Gorge.
Hells Hollow Falls
Small, low falls, such as Hells Hollow Falls, form where a stream in its normal course flows across hard rock layers (sandstone and limestone) that do not erode as easily as weaker layers (shale and siltstone). This type of falls is the most common and can be found on almost every tributary to Slippery Rock Creek.
The rapids in Slippery Rock Creek are not formed by hard rock layers, but are situated on reaches of the stream where resistant sandstone blocks are particularly large and numerous in the rubble that fills the Gorge.
Muddy Creek Falls
Because the small streams at the rim could not erode downward as fast as the main stream, they were left as "hanging waterfalls." In the case of Alpha and Muddy Creek Falls (I), the streams which form the cascades were outlets for Lake Watts as the ice retreated northward and progressively exposed low spots along the western side of the glacial lake. For a short time all the flow from Lake Watts poured past these points into the gorge, flushing glacial debris and undercutting the sandstone rim downstream on each occasion.