The Pinnacles EarthCache
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The Pinnacles
Hidden within the rolling hills of Boone County lie the Pinnacles. These Sirens beckon the visitor to take heed of the wonderful geologic formations nestled within the boundaries of the Pinnacles Youth Park. Access to this treasure is found easily off U.S. 63, about 12 miles north of Columbia.
This slim ridge lies between two streams, Silver Fork and Kelley Branch. It was formed when Silver Fork doubled back on itself and met the parallel Kelley Branch. These streams crowded each other so closely that what remains is a precariously thin, approximately 1,000-foot ridge as an erosional remnant. One of the probable influences in this action are parallel vertical rock fracture planes that caused the streams to take the paths that they did.
All in all, the ridge itself doesn't have much time left, geologically-speaking, as it's only several feet wide at some points and has already been perforated a few times, leaving windows through the formation. At some point, probably in a few thousand years, either one of the streams will breach the ridge or it will collapse.
The Pinnacles are composed of the Burlington Limestone, which is approximately 300 million years old. In many areas, this is an exceptionally pure limestone and is quarried at a number of points in eastern and central Missouri and as far southwest as Springfield, Missouri. This particular kind is famous for possessing many kinds of marine fossils, particularly crinoids. This limestone is the source material for the columns of the University of Missouri-Columbia's Red Campus and Boone County's Old Courthouse.
SOURCE: Geologic Wonders and Curiosities by Thomas R. Beveridge,
Second Edition, revised by Jerry D. Vineyard, 392 p., 163 figs., app., 1991.
The Pinnacles Youth Park is administered by a board of directors and is patrolled by the Boone County Sheriff's Department. The park is open from 8 a.m. until dark. The gates close an hour before dark.
Please do not put yourself and geocaching in danger by violating the hours that have been established for this park..
Do NOT attempt this EarthCache if it's been snowing or if it's icy. The terrain on top of the ridge can become quite treacherous in such conditions and people have been seriously injured from falling. I cannot stress this enough; take your time as you make your way up and be safe! We want to see you again on the caching trail.
Depending on the river conditions you might be able to cross the stream on stepping stones or using rubber boots...all else failing, you just might get your feet wet.
This particular EarthCache will require you to do some work with your GPSr as you explore this treasure. First, at the posted coordinates above, take an elevation reading and record it for later. Make your way to the top of the ridge, and stop at these coordinates: N 39º 08.025 W 092º 19.352. Take an elevation reading here and record the information.
Now carefully make your way back down the path from which you came and stop at these coordinates: N 39º 08.022 W 092º 19.378. These coordinates should put you in front of what I like to call the Picture Rock because it's a great spot for a quick snapshot. It's completely optional, but if you'd like to do just that, feel free to do so and post it here with your log.
To get credit for this EarthCache, please answer the following questions and email them to me through my profile.
Any logs that do not follow these requirements will be deleted.
1. What is one possible influence that caused the two streams to flow so close together?
2. Using your two elevation readings you took, subtract the first from the second. What is the approximate height of the Pinnacles?
3. Approximately how wide is the rock window at the second waypoint?
4. How wide and long is the top of the Picture Rock?
5. While completely optional and not required, it would be nice to post a photo of yourself on top of the Pinnacles or with Picture Rock behind you.
Additional Hints
(No hints available.)