Garrison Rock is a large sandstone outcrop overlooking the Des Moines River Valley. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Sandstone may be any color, but the most common colors are tan, brown, yellow, red, grey, pink, white and black. Sandstone beds often form highly visible cliffs and other topographic features. Certain colors of sandstone have been strongly identified with certain regions. Sandstone is formed from cemented grains that may either be fragments of a pre-existing rock or be mono-minerallic crystals.
A note on what to expect: Though this is not a particularly long hike, the elevation changes are steep. The inclines can be slippery even on dry days. Wear good hiking shoes. You will also be stepping over creeks and muddy areas.
To earn credit for this Earthcache, complete the following tasks:
1. N 40° 59.143 W 092° 21.575 - Stage 1 is the parking area and trailhead for Garrison Rock. At this point, using your GPS, take a reading of your elevation and note it. What is the elevation level here?
2. N 40° 59.225 W 092° 21.618 - Stage 2 is an open ridge top with a scenic view of the Des Moines River. To get there, take the first trail to your left off the main trail. What is the elevation here? Also, make note of the sandstone. What colors are most prominent? What is the texture of the stone?
3. N 40° 59.206 W 092° 21.340 - Return to the main trail. This will take you to Horse Thief Cave which is approximately .20 miles from the trailhead. Note the color and texture of the stone. Does this appear to be the same stone as on the ridge from stage 2? What are the differences? Are there any similarities? Though not mandatory, feel free to take a picture of yourself in front of the cave.
Remember: Email the answers to me. Do not list them in your log. I'm looking for ballpark figures when it comes to elevation levels. Any honest attempt at the other questions will be credited as correct.
Permission granted for this EarthCache by Kurt Baker, Director of Wapello County Conservation.
Congratulations to Tennishoe for the FTF/completing this EarthCache successfully!