Natural Bridge Waterfall EC EarthCache
Natural Bridge Waterfall EC
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The Natural Bridge Waterfall is located about 30 miles South of Big Timber, Montana on the main Boulder River. When you come off of I-90 head into the center of Big Timber at take McLeod Street and head South East, this will turn into Highway 298. You can find the parking lot for Natural Bridge at: 45 33.010N 110 12.474W, which is just off Hwy 298. It is just a short walk to the Natural Bridge Waterfall. This should be wheel chair accessible in the summer
This is a beautiful drive down the valley and an awesome natural geological site. I had been here several times before I was a geo-cacher and fell in love with the jagged canyon walls and raw power of the waterfall.
First, I want to acknowledge my gratitude to the Yellowstone Ranger District, U.S. Forest Service. They have graciously granted permission to list this earth cache and I am pleased to have the privilege of placing this Earth Cache at such a unique geological location.
GENERAL WARNING, there are HIGH CLIFFS so hike carefully and don't get to close to the edge. Please stay on designated trails, adhere to park rules and please haul out your refuse.
Erosion and the Power of Water: Some 340 millions years ago, most all of the area of what is now Montana as well as many other interior states were covered by a shallow inland sea; called the “Western Interior Seaway”. This was during the late Cretaceous period.
This inland sea extended through the middle of the North American continent from the Gulf of Mexico, extending Northward through Canada and meeting the Artic Ocean. During this period, a certain type of bedrock was formed. This sedimentary type rock was composed of different skeletal fragments of marine organisms. Most cave systems are found in this type of bedrock.
This type of bedrock is high in calcium carbonate content, and is thus easily dissolved in the acids produced by organic materials. This bedrock stone is quite soluble and can be easily dissolved by the weak solution of carbonic acid found in underground water.... thus creating underground fissures or channels.
NATURAL BRIDGE WATERFALL: Over long periods of time, erosion from the main Boulder River carved out a huge canyon in this bedrock. At one time there was a land bridge across the canyon above the main part of the waterfall. Sadly, the natural bridge has collapsed. The waterfalls and water cascades over a sheer drop during the spring run off of melting snow from the mountains. This precipice and waterfall can best be seen during the spring months (high water periods).
As the spring run off waters subside, the Boulder River goes underground through fissures in the bedrock. Over many years of erosion, subterranean fissures were formed and enlarged over time. These fissures were formed by the slow process of water erosion and the chemical dissolving of the bedrock, which in turn created underground channels that allowed the water to disappear underground during low water. During low water, one can see the water pouring out of these subterranean channels at the base of the Boulder River canyon.
Please, DO NOT POST PICTURES OF THE SIGNs. If sign pictures are posted the log will be deleted. Certainly you may re-log the EC as long as the signs are not posted and you have the correct answers.
Although pictures are NOT required it would be great to "post a memory". Smile and hold up your GPS or snap a couple of pictures of the beautiful area that makes this a memorable caching experience.
Following are five (5) questions to answer. Some information is available on signs at the Natural Bridge Waterfalls at the following co-ordinates. Please list the earth cache name and GC number when you e-mail the answers. Please e-mail answers at the same time you post your find.
Sign # 1 at: 45 32.984N and 110 12.483 W
Sign # 2 at: 45 32.955N and 110 12.501 W (Sign on the middle of bridge)
1) Question #1: The Canyon formed by the Boulder River is made up of a type of bedrock which is sedimentary in nature. This type of stone had been formed many years ago and was composed of skeletal fragments of marine organisms. Most cave systems are found in this type of bedrock. What is the name of this sedimentary bedrock type stone?
2) Question # 2: Underground fissures have been eroded by water and chemicals over the years. As these fissures have enlarged over many centuries, they have created underground channels. At low water, the Boulder River goes subterranean and comes out at the base of the falls. What are these underground channels called?
3) Question # 3: When the Boulder River is at high water stage, how tall is the waterfall precipice in feet? What 3 months would have the most water run off?
4) Question # 4: There are two types of erosion, which over time may have caused the bridge to collapse. What are these two types of erosion?
5) Question # 5: What other natural earth phenomenon or event might have been a contributing factor in weaking the natural bridge and thus perhaps being another factor in causing the natural bridge collapse? This could also have been a partial causal factor in the creation of the underground fissures. What is this natural earth event?
I hope everyone enjoys this natural geological waterfalls in their own "personal Gestalt experience". Remember, "The whole is greater than the sum of the parts"
Arliecon ~ Ron
******* CONGRATS TO SCLINGER FOR FTF *******
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