Here is an Earthcache exclusive to this natural structure found within McConnell's Mills State Park. You may park at the parking lot for Hell's Hollow, then hike the blue blazed North Country Trail until you encounter this naturally made structure. As always with an EarthCache, there is no container or logbook to sign. You'll be asked to answer some questions about the structure. Please email your answers to us to avoid your found it log being deleted. The posted coords are for a spot just beyond the bridge on the NCT. There are several elevation changes and some muddy spots along this portion of the trail.
A natural bridge is a rare occurrence in nature. Most natural bridges are formed by erosion of water through horizontal layers of rock. The path of a body of water is usually found underneath. Some of these structures are formed from layers of sandstone or limestone, within this park.
Sandstone is a sedimentary rock formed over time by compressed layers of sand. Other minerals such as clay, calcite, and silica are mixed into the sand grains and adhere them together, forming a rock. Here's a link you can use to read some fascinating information on the formation and different types of sandstone: https://en.wikipedia.org/w/index.php?title=Sandstone&oldid=846952907
Limestone is commonly found around the park. Limestone is another form of sedimentary rock, formed by fragments of aquatic organisms. The major component of calcium carbonate in limestone would be the minerals calcite and aragonite. Here's another link for you to copy and paste into your browser's search engine; https://en.wikipedia.org/w/index.php?title=Limestone&oldid=846727754
Here are two more interesting links added that are also filled with PA DCNR information about our state's geology, and especially our Moraine and McConnell's Mills state parks. I highly recomend reading and researching these pages to help you determine some facts about the structure and how it was formed.; http://www.dcnr.pa.gov/Geology. http://www.dcnr.pa.gov/StateParks/FindAPark/MoraineStatePark/Pages/History.aspx
Here's another link to a very exclusive page on how these different types of rocks are formed.; http://volcano.oregonstate.edu/book/export/html/1056.
Some natural bridges are formed by collapse of weaker layers of strata underneath them. The interior of a cave or a natural tunnel may collapse, leaving a bridge-like structure. To get credit for finding this natural bridge and Earthcache, please study the structure and the surrounding area and answer the following questions.
1.) What type of rock is the structure made of? Sandstone or limestone?
2.) Determine whether the bridge was formed by erosion from water passage or collapse of weaker material underneath.
3.)Determine what type of rock lies underneath the structure. Sandstone or limestone?
You may choose to include a photo of you or your GPS in your log. We love pretty pictures of this fascinating structure.
