This is an Earthcache – as such, there is no physical cache. Instead you will partake in a geology lesson by making observations and answering 4 questions about the igneous rock at the posted coordinates.
JAMES RUMSEY MEMORIAL
James Rumsey was a successful miller, canal builder, blacksmith, and architect. He was also an inventor and developed innovations in iron mining, smelting, gristmill and sawmill operation, and canal construction. His most significant invention was his development of the steam engine for propelling vessels. It was here in Shepherdstown on December 3, 1787, that he first demonstrated the use of his steam engine on the Potomac River. Interest in building a monument to Rumsey at Shepherdstown, and to the first successful public demonstration of his steam engine, began in the 19th-century. Henry Bedinger, a witness of Rumsey's demonstration and an early proponent of a monument to Rumsey, wrote a letter to the United States Congress in 1836, in which Bedinger said he "would willingly contribute to the erection of a snug little monument." In January 1905, Governor Albert B. White endorsed the monument in a message to the West Virginia Legislature. Finally, in 1916 the Forbes Granite Company of Chambersburg was contracted to erect a 75-foot Woodstock Granite monument for Rumsey. It is situated atop a hill overlooking the Potomac River.
WOODSTOCK GRANITE
Woodstock Granite is a massive biotite-quartz monzonite which intrudes through the Baltimore Gneiss at a single locality surrounding the town of Granite, Maryland. The Woodstock Granite is exposed at the center of the Woodstock Dome. This dome is one of seven large anticlinal domes formations of Baltimore Gneiss that surround Baltimore City. Quarrying for it commenced in 1835 and ceased in the mid-1900s. Many of the quarries where it was found previously are now submerged under water. Rock from the Woodstock Granite was highly desired and was widely used in construction because it is relatively homogenous and did not fracture easily. Woodstock Granite was further described by the Maryland Geological Survey in 1898 as "perhaps the best granite in Maryland for general building purposes."
During the Paleozoic Era (230 to 550 million years ago), Maryland was “rocked” by plate collisions when North America and Africa collided. These collisions caused massive intrusions deep within the Earth's crust and created forces that caused uplifting, warping, folding, and metamorphosing (chemical changes from intense heat and pressure) of the existing rock that created these domes. It was during these collisions that intruding magma formed this Woodstock Granite, which solidified deep within the earth, and formed the core of the dome. The geologic history of the Maryland Piedmont is complex, and evidence exists for over one billion years of Earth’s history. The oldest unit in the region is the Baltimore Gneiss with an age estimated to be 1.1 billion years old. The Baltimore Gneiss formed during high-grade metamorphism roughly 640 million years ago. The Baltimore Gneiss was eventually overlain by transgressional sediments that eventually became part of the Wissahickon Formation. The Baltimore Gneiss crops out as seven anticlinal domes. One of these domes is called the Woodstock Dome and the Woodstock Granite outcrops in its center. An anticline is a structural trap formed by the folding of rock strata into an arch-like shape. The rock layers in an anticlinal trap were originally laid down horizontally and then earth movement caused it to fold into an arch-like shape called an anticline.
Although it is called "granite," Woodstock Granite it is actually a monzonite. You see, both monzonite and granites have a similar chemical makeup. Quartz monzonite is an intrusive and igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. Both of them are igneous intrusive rocks that have a medium-grained texture due to slow cooling magma below the Earth's surface. The difference maker is that granite contains more than 20% quartz, and monzonite has only 5-20% quartz. Quartz is present in significant amounts in the Woodstock Granite. The color of the Woodstock Granite is usually a bright gray, with something of a luster imparted by the quartz and the unaltered feldspars, the latter often giving an additional faint pink tone.
LOGGING REQUIREMENTS:
To log this Earthcache: Read the geology lesson above. Answer all four questions posted below. Answers can be sent via e-mail or messenger contacts on my Geocaching profile. Group answers are fine, please list the members of your group in your message. Please do not post the answers to the questions in your logs.
QUESTION 1: Quartz monzonite has an approximately equal proportion of what two minerals?
QUESTION 2: Examine an area of the Woodstock Granite. Does it appear that the makeup of these minerals is equal?
QUESTION 3: Woodstock granite is mostly bright gray, but sometimes this mineral can give it a faint pink tone. Upon inspection of the Woodstock Granite in this memorial, would you say that it is mostly pink or gray? Why do you think the color make up is like this?
QUESTION 4: As discussed above, the Woodstock Granite is strong, does not damage easily and used for construction. However, this monument has been here for over 100 years but has been subjected to both natural and damage by humans. Please describe what type of natural and/or human induced damage is visible around the monument?
Please include a picture in your log to show that you were here. The picture does not need to include your face but can include your GPS, a thumbs up or other means to prove you were here. The picture as a requirement is allowed by earthcache guidelines.
This earthcache placement was specifically approved by the Sheperdstown Town Council and Corporation of Sheperdstown.
This earthcache has also been approved by Awesnap, which is kinda a big deal!