You can park at the posted coordinates, but please pull as far off the road (north or southbound) as possible.
This area along FM-965 is known as Bear Mountain, and is the sife of an old rock quarry. Bear Mountain got its name when John Burg, an early Fredericksburg settler, killed a bear near the summit of a large granite dome four miles north of Fredericksburg. People have called that hill Baeren Berg or, in English, "Bear Mountain", ever since.
"Bear Mountain is a monadnock, an isolated erosional remnant of leucogranite about 10 km south of the main exposures of igneous rocks in the Llano Uplift." - Geology of the Western Llano Uplift, Fredericksburg to Mason, Texas
Geologists have described it as a compositionally unique granite that recrystallized at lower temperatures than other Llano area granites such as those around Enchanted Rock.
The Llano Uplift is a hallmark of the Texas Hill Country’s geology. This feature literally stands out from the surrounding area as its granite rises higher than other parts of the Hill Country. The rocks of the Llano Uplift come from the Precambrian era, which predates even the oldest dinosaurs. Most geologic time fits into the extended Precambrian, which lasted from 4.6 billion years ago to 541 million years ago. But the Llano Uplift does not extend throughout this time. The oldest parts of the area only date to 1.5 billion years ago. Though its name suggests the land pushed upward, the exact opposite happened to expose the Llano Uplift. When the surrounding area of younger sedimentary rocks eroded away, it left behind granite at the heart of the uplift. Along with the rest of the Texas Hill Country, the Llano Uplift also rose in elevation during the Cenozoic when the Balcones Fault shifted, lifting the area to the west. - Llano Uplift: A Geological Wonder in the Texas Hill Country
Granite is an igneous rock. Igneous rock is formed when hot magma or lava cools. This type of rock can occur in one of two forms: intrusive or extrusive. Volcanic rocks (rocks that exit volcanoes in a liquid state and cool to solidify at the Earth’s surface) are extrusive rocks. These rocks come out of the Earth--they are extruded from the earth. Granite is an intrusive rock; it forms far beneath the earth’s surface. Beneath the surface, magma is slowly pushed up and fills any crack or space it can find, sometimes pushing other rocks out of its way on the subsurface. This process can take millions of years to complete. During this time, the rock slowly cools and solidifies into a hard rock. Many mountain ranges throughout the world are formed by this kind of intrusive rock.
Granite is made of crystals. These crystals can easily be seen with the naked eye, unlike lava rocks. Even though lava rocks and granite are made essentially through the same process, speed is the important factor here. In lava rocks, the crystals are too tiny to be seen with the naked eye because the rock cooled too quickly for the crystals to grow very large. Granite, on the other hand, cooled slowly underground. The rock surrounding it shielded the granite and allowed the heat to escape slowly. This gave the crystals time to grow. Granite is generally comprised of feldspar, quartz, and small traces of other minerals. The feldspar and quartz give granite its texture. The distinct pink color of the granite is due to the alkali feldspar.
Bear Mountain covers a little over 80 acres at its base. This pluton may have been emplaced into the Coal Creek Domain and, if it is younger than other granites, the intrusion may have occurred after the main Llano Orogeny. The rock at this location is a medium grained, equigranular, porphyritic granite with traces of fluorite and cataclastic features. In some areas the pluton is extensively jointed. Spheroidal weathering along the joints allowed development of rounded hoodoos. - Geology of the Western Llano Uplift, Fredericksburg to Mason, Texas.
Quarry operations started in the 19th century after the founding of Fredericksburg in 1846. The property was originally owned by Ludwig Jung, who later sold it to the Nagel brothers. Willie and Emil Nagel were sons of German immigrants who settled on a stock farm near Comfort. They were sculptors and stone cutters who operated a granite yard in San Antonio. They cut and polished granite in Llano and California before buying an interest in Bear Mountain. Willie and Emil, along with brothers Rudolph and Otto, eventually bought out the other landowners and acquired complete ownership of Bear Mountain. Members of the Nagel family quarried Bear Mountain granite for much of the 20th century. The remnants of this quarrying is very evident here. The granite makes an excellent building stone because it retains it high luster. Bear Mountain Granite has been used in building projects across the state. In the 1880's, the San Antonio National Bank and the San Antonio City Hall were constructed using this granite, as is the base of the 1939 Gillespie County Courthouse in Fredericksburg. One of the largest blocks of granite quarried at Bear Mountain sits in downtown Dallas. It forms the base holding the bronze statue of legendary newsman George Bannerman Dealey, in Dealey Plaza.
Dealy Statue with Bear Mountain Granite Base
A number of years ago part of this location was known as Balanced Rock because of a unique large pinnacle rock produced by differential erosion. In 1986 Balanced Rock fell, an event that some locals attributed to foul play and the use of explosives.
To log this Earthcache as a find, please complete the following tasks and email or message the answers to me. There is no need to cross any fences or go on private property, just make observations at a distance:
1. Describe the area east of the coordinates.
2. Describe the color and luster of the granite. What component gives it it's distinctive pink color?
3.There is an old piece of quarrying equipment installed here with cables stretching in all directions.. What do you think it's purpose was?
NOT A LOGGING REQUIREMENT: Feel free to post pictures of you or your group at the area. Please don't include any spoilers in you pictures!
One set of answers sent in per group is fine, just indicate in the message all of the geocachers in your group.
PLEASE DON'T INCLUDE ANY ANSWERS IN YOUR ONLINE LOG!
Sources:
Geology of the Western Llano Uplift, Fredericksburg to Mason, Texas
Llano Uplift: A Geological Wonder in the Texas Hill Country
U.S. Geological Survey, Mineral resources on-line spatial data, 2015.
Frederickburg Standard Radio Post, July 25, 2018
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