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Yellowstone's Tower Falls EarthCache

Hidden : 08/20/2007
Difficulty:
4 out of 5
Terrain:
2.5 out of 5

Size: Size:   other (other)

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Geocache Description:

Please read the entire cache description prior to doing this EC. Please do not log this as found if you do not intend on sending your responses within 24 hours of logging! Thank you.


Tucked away in the northeast corner of Yellowstone National Park, Tower Falls may not be as large or as well-known as the park's Lower and Upper Falls, but this waterfall is every bit as spectacular.



A breathtaking creation of natural pinnacles and tumbling water, Tower Falls does not fall directly into Yellowstone River but instead flows a short distance from the bottom of the falls to the river. At one time, the falls were much closer to the river. However, when the water hit the bottom of the falls, some of it sprayed backwards, eroding the soft rock beneath the cascade. Eventually enough rock eroded away, leaving the harder rock layer above without support. The unsupported rock crashed down, causing the waterfall to move further back upstream. Over time, this process has moved the falls away from the Yellowstone River.

Tower Falls was so named in 1870 by Samuel Hauser, a member of the Washburn expedition that was sent to explore the Yellowstone region. Hauser dubbed the waterfall "Tower" because of the "tall spires of rock" at the crest of the waterfall. Hauser reported in 1871 that these towers "are very friable, crumbling under slight pressure; several of them stand like sentinels on the very brink of the fall." Examine the pinnacles that give Tower Falls its name. Next to the falls you will see rock structures of a similar pinnacle shape. As with the Tower Falls pinnacles, these neighboring structures are composed of two separate rock layers: a harder rock at the top and a slightly different color, softer rock underneath. The harder upper layer of rock protects the softer rock beneath it, although the soft rock over time is slowly eroded away by precipitation to create a feature called a hoodoo. Hoodoos are eroded much in the same manner as the softer underlying rock of Tower Falls was eroded away by the backspray of the cascade.

Please note that it is prohibited to climb any part of Tower Falls, its surrounding cliffside, or any of the neighboring hoodoos. Over the years there have been countless times that the Tower Ranger Station has had to come to the rescue of park visitors who attempted to scale the waterfalls' rocks and ended up unable to move. Because of the continuing erosion of the rock here, rock slides and falling rocks occasionally occur. Please keep yourself safe and avoid injuring yourself — and damaging the falls and hoodoos — by staying on the provided park trails.


In order to obtain approval to log this Earthcache, please email us the correct responses to the following questions:


  • 1. Study the brink and walls of the falls. Identify the two rock layers that comprise the Tower Falls structure by name. Please be specific! "Hard rock layer," "rock debris," or "softer rock" are not acceptable answers, while "limestone" or "gneiss" would be, if they were correct. The answers will require some keen observation, on your part, of Tower Falls. NOTE: the geology in the Tower area is very varied. The nearby columnar basalt and the nearby glacial debris flows do NOT come into play at Tower Falls.
  • 2. Which of these two rock layers is the softer, more easily eroded rock? Name another well-known, named geological feature in Yellowstone created by the erosion of this rock (for example, "Old Faithful," versus "the geyser basins."). HINT: that softer rock is the yellow stone that gave the park its name.
  • 3. Take an altimeter reading at the crestline/brink of the falls. How tall do you estimate Tower Falls to be? What is its current height? What causes the height of the falls to change over the course of time? Please be VERY specific. Do NOT just say "erosion" or "the rock erodes." We want to know HOW Tower Falls erodes. HINT: read this Earthcache's description very thoroughly.
  • 4. Count the number of hoodoos visible to the left of the falls. Why might this number vary over time? HINT: the answer to question 3 will help you with the answer to question 4. HINT AGAIN: read the EC description carefully!
  • Optional: Post a photo of you or your GPS with Tower Falls in the background. For extra kudos, post a photo of the Tower Ranger Station, where Team FMA co-leader A was stationed when she was a Yellowstone park ranger.


IMPORTANT! PLEASE READ!
Team FMA maintains this Earthcache to share some of Yellowstone's geology with you, not to share a photo op with you. If you do not plan on submitting your responses within 24 hours of logging this Earthcache as found, then please do not log it as found; use the "write a note" option instead. We will delete any found logs if we do not receive responses within 24 hours of receiving your found log OR if the cacher submitting the found log indicates a refusal to answer the questions -- and yes, we have received a few of these over the years! Submitting a photo is not enough "effort" to gain you a smiley. If you truly believe that just visiting this EC, taking a photo, or answering one or two questions is enough to log this as found, please go to Geocaching.com and reacquaint yourself with logging requirements for Earthcaches. If some (or all) of your responses are incorrect, you have two weeks' time to correct your submissions... and we are happy to give hints, not give the answers away!

Thank you for visiting Tower Falls and Yellowstone!

The above information was compiled from the following sources:

  • NPS Informational Panel
  • The Geologic Story of Yellowstone National Park, William R. Keefer Illustrated by John R. Stacy, GEOLOGICAL SURVEY BULLETIN 1347 1975.
  • The report of Lieutenant Gustavus C. Doane upon the so-called Yellowstone Expedition of 1870, presented to the Secretary of War, February 1871/
  • The Geologic Story of the National Parks and Monuments, David V. Harris and Eugene P. Kiver, John Wiley and Sons, 1985.

Placement approved by
Yellowstone National Park


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Additional Hints (Decrypt)

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Decryption Key

A|B|C|D|E|F|G|H|I|J|K|L|M
-------------------------
N|O|P|Q|R|S|T|U|V|W|X|Y|Z

(letter above equals below, and vice versa)