Questions:
1-About how many 'potholes' do you see from GZ
2-What circular sizes are these 'potholes'? Choose: basketball, vollyball, softball, baseball--Choose average size.
3-The water is usually shallow, so if possible go out to a pothole and measure the depth of one of them.
4-What is the height of the falls above the plunge pool? What effect do you think the height had on the formation of the potholes?
5-This is such a scenic area, so submit a pic if you please. There is a beautiful red covered bridge about 300 ft upstream.
Please submit the answers to these questions to my profile before YOU SUBMIT YOUR 'FIND'--Thanks!
What Is a Pothole?
What is a pothole? Of course not the kind that damage our tires! Let us call them geological potholes.
Geological potholes are commonly found in plunge pools below cataract style water falls. They are circular pits found in the rocky channel of a turbulent stream of water. They are formed by the abrasive action of water bearing stones and gravel in swirling water currents especially in fast moving cataract waters.
The pebbles fall into small cavities and swirl around making the cavity wider and deeper. The action of these rocks swirling around literally "drills" down into the bedrock.
Geological Past of this location:
After the last glacier retreated, a creek carved its channel at this location, and exposed the bedrock of the Mississippi Blue River group. Now the Upper and Lower Cataract Falls cascade across these rocks as Mill Creek drops some 80 feet in less than a mile. Now many potholes appear especially at low water-- evidence of the swirling eddies that stirred this stream in the ancient past.
Information source:
Camp, Mark J., and Graham T. Richardson. Roadside Geology of Indiana. Missoula, Mt.: Mountain, 1999. Print.
This is my 40th of 45 published earthcaches