This is an earthcache. There is no container at the posted coordinates. To claim this earthcache as found, you must send your answers to the questions below to the cache owner.
Karst is a landscape formed from the dissolution of soluble rocks including limestone, dolomite, and gypsum. It is characterized by sinkholes, caves, and underground drainage systems. Nearly all surface karst features are formed by internal drainage, subsidence, and collapse triggered by the development of underlying caves. Rainwater becomes acidic as it comes in contact with carbon dioxide in the atmosphere and the soil. As it drains into fractures in the rock, the water begins to dissolve away the rock creating a network of passages. Over time, water flowing through the network continues to erode and enlarge the passages; this allows the plumbing system to transport increasingly larger amounts of water. This process of dissolution leads to the development of the caves, sinkholes, springs, and sinking streams typical of a karst landscape. (information from http://www.esi.utexas.edu/outreach/caves/karst.php) Sinking Valley contains many of these features, such as Arch Spring, Tytoona Cave, sinking streams, and sinkholes. Learn about some of these features while vising the Fort Roberdeau grounds.
Cache is located at the Fort Roberdeau Historic Site and Natural Area. The park is open from 8AM to sunset, is located on 230 acres of land, and includes trails, picnic areas, and a reconstructed Revolutionary War fort. Admission is only charged to those wishing to tour the fort (which is not needed to find this cache) and during the annual reenactment. If you do wish to tour the fort, hours and prices can be found on their website.
This cache is placed with permission and collaboration with the fort staff.
The posted coordinates will take you between the fort’s garden and farmhouse to a bridge into the woods.
1. As you cross the bridge located behind the farmhouse, describe the water amount in the stream bed. (ex. dry, a trickle, flowing, deep, flooding, etc)
After crossing the bridge, turn right on the path and follow the trail until you see post 1.
2. Based on the information sign (waypoint 1) along the path to the sinkhole platform:
a. What is the depression left on top of the ground called?
b. What kind of bedrock lies beneath at this site?
c. How do you think this valley became known as Sinking Spring Valley?
d. What year did the lead miners dig looking for lead ore?
Go down the steps to the platform.
3. As you stand on the platform at the sinkhole, describe the water amount in the stream bed at this location.
4. If there is a difference in the water amount at the 2 locations, why do you think there is a difference? If there is not a difference in the water amount at the 2 locations, why do you think there is not a difference?