The waterfall will fluctuate with the most recent amount of precipitation. The area that you are in consists of a bedrock primarily of limestone, but also contains some layers of sandstone. The flow of water over a long period of years here have eroded the soil and limestone bedrock that you see, and you should also recognize the ever so gradual recess of the underlying bedrock that cause the waterfall cascade. 
Stillhouse Hollow Falls is a 90-acre state natural area located approximately 21 miles southwest of Columbia and three miles northeast of Summertown off Hwy US 43. The natural area is on the Western Highland Rim in the Duck River watershed. The geology of this region creates scenic natural features such as seeps, flat shale-bottom streams, and waterfalls, both small and large, which help shape the region’s dissected topography. The natural area is named for its most significant feature, Stillhouse Hollow Falls, which can be seen by walking approximately 2/3 of a mile along the Stillhouse Hollow Falls trail. The trail crosses an unnamed tributary that forms small scenic cascades before plunging approximately 75 feet over the falls. A deep hollow is formed below the falls that is surrounded by steep slopes where wet-weather springs emerge contributing to a rich habitat supporting a colorful spring wildflower display of trillium, spiderwort, wild geranium, phlox and many other species.
During periods of heavy rainfall, and years of erosion and mechanical weathering, the waterfall you see here has both receded and became wider. The reason this waterfall is more often than not dry, is because it is located on a hillside, dependent on runoff, instead of being spring fed like many.
In order to log this cache, email me the answers to the following questions.
1. Do you see evidence that this waterfall is receding and/or getting wider? If so please elaborate.
2. Do you see evidence of undercutting at this waterfall?
3. Do you think this waterfall is ever dry, and if so why?
4. Take a photo of yourself or your GPSR with the waterfall in the background
5. At the base of the water fall a plunge pool is formed. How is it formed and how deep would you expect this one to get ?
6.And lastly, how wide would you guess the pool to be?
