This gorge has always been a popular destination for geology class field trips because of a variety of interesting features. The fossils in the strata above the streambed below the large falls are diverse, abundant and among the more interesting in the region. In this same stretch, the streambed makes some near-right-angle bends where it follows joints (vertical cracks) in the shale bedrock.
Due to lateral compression, the Tully limestone formation is two times as thick as what was originally laid down. One layer is stacked on top of another. This stratum forms the top of the lake cliffs and the ledge or cap rock for the grandest of several waterfalls. And it is even more clearly revealed where a number of small streams come down the slope and over the top of the lake cliff. As you might imagine, the soils are very calcareous.