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These coordinates bring you outside the Sweetwater County Historical Museum, the former location of "The Old Post Office" and is on the national Register of Historic Places. Admission is free and it is open 10 am-6 pm Mon-Sat. I highly recommend it.
The geology of the earth is divided into four distinct lengths of time. These time zones are called the Precambrian (before life), the Paleozoic (early life), the Mesozoic (middle life) and the Cenozoic (late life). These divisions of time are designated according to the fossils found within the rocks. For example: Precambrian bacteria, Paleozoic fish, Mesozoic dinosaurs, and Cenozoic mammals.
The rocks may be relatively defined in keeping with the time zones as follows: Cenozoic rocks are the youngest, Mesozoic are middle-aged, Paleozoic are the old rocks, and Precambrian are the most ancient of rocks.
Over time, rivers and wind have eroded portions of these layers of earth. Some parts of the formations are more impervious to the forces of nature and remain standing alone, such as Castle Rock. In other places you will observe areas where rivers have cut deep canyons into these layers of rock.
Cenozoic rocks are mostly deposits formed in large, continental fresh water lakes. These rocks erode into buttresses and castle-like towers. Castle Rock is an example of one of these pillar structures.
Mesozoic rocks are mostly terrestrial rocks comprised of soft, colorful sandstones and shales that erode into slopes, mounds, ledges, and very pronounced escarpments. These rocks are exposed in areas along the Green River.
Paleozoic rocks are usually hard limestones formed in marine environments. They erode into sharp, hard and resistant ledges and cliffs. These rocks are not visible in this area.
Precambrian rock is the basement rock is very old-1.8 billion years old-and very thick-25 miles thick. They consist of hard, black metamorphic rocks called gneiss and schist that were intruded by veins of molten rock (igneous materials). These rocks are relatively rare and not found in this area.
CASTLE ROCK SPECIFIC INFORMATION:
Standing at the posted coordinates, you will be able to observe this best-known pillar rock formation. Walk up the steps from this area for a full, clear view of the rock.
For years large signs, flags were found on top of the pillar and illuminated at night. In 1960, the remnant of the sign, the flagpole and deteriorated steps were removed from the rock by workers.
The multi-colored striations of the pillar are the result of layers of sediment deposited by Lake Goshuite, a huge prehistoric lake. It eventually filled in and became a large mud flat. At that point, what would eventually become the Green River began to carve a channel, exposing the colorful bands of rock below and forming Castle Rock among many other rock formations.
In 1871 fossils were first discovered in this area while making a cut for a railroad bed. The fossils in the shale layers included fish, insects, and reeds. In 1868 oil shale deposits were first discovered when another cut for the railroad bed was being made. This oil shale caught on fire and burned for days, allowing construction to continue at night.
TO LOG THIS CACHE:
Send your answers to me and then write your log at the same time. If I am traveling, my response to your answers may be delayed. Please log your find as soon as you send answers - don't wait for permission.
1. Estimate how high Castle Rock towers above where you are standing.
2. How many different colors of shale can you see in Castle Rock?
3. What do you think caused the different colors?
4. What is the title of the figure at the given coordinates? Use your GPS so that you get the correct structure!!! (Please DO NOT post a photo of it.)
5. For kids only - how do you think the Green River got its name?
(No hints available.)
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Coordinates are in the WGS84 datum