Geographic Center of the Contiguous United States.
A little history and cultural references of the Center:
The geographic center of the contiguous United States as located in a 1918 survey is located at 39°50′N 98°35′W, about 2.6 miles (4.2 km) northwest of the center of Lebanon, Kansas, approximately 12 miles (19 km) south of the Kansas–Nebraska border.
While any measurement of the exact center of a land mass will always be imprecise due to changing shorelines and other factors, the NGS coordinates are recognized in a historical marker in a small park at the intersection of AA Road and K-191. It is accessible by a turn-off from U.S. Route 281.
It is distinct from the geographic center of the United States, which reflects the 1959 additions of the states of Alaska and Hawaii, which is located at a point northeast of Belle Fourche, South Dakota.
In a technical glitch, a farmstead northeast of Potwin, Kansas, became the default geolocation of 600 million IP addresses (due to a lack of fine granularity) when the Massachusetts-based digital mapping company MaxMind changed the putative geographic center of the contiguous United States from 39.8333333,−98.585522 to 38.0000,−97.0000.
The Marker
The marker located near Lebanon, Kansas
In order to protect the privacy of the private land owner where the point identified by the 1918 survey falls, a proxy marker was erected in 1940 about half a mile away.
Its Inscription Reads:
The GEOGRAPHIC CENTER of the UNITED STATES
LAT. 39°50' LONG. −98°35'
NE 1/4 – SE 1/4 – S32 – T2S – R11W
Located by L.T. Hagadorn of Paulette & Wilson – Engineers and L.A. Beardslee – County Engineer. From data furnished by U.S. Coast and Geodetic Survey.
Sponsored by Lebanon Hub Club. Lebanon, Kansas. April 25, 1940
An American flag usually flies atop a pole placed on the monument. A covered picnic area and the U.S. Center Chapel, a small eight-pew chapel, are nearby.
Method Of Measurement:
In 1918, the Coast and Geodetic Survey found this location by balancing on a point a cardboard cutout shaped like the U.S. This method was accurate to within 20 miles, but while the Geodetic Survey no longer endorses any location as the center of the U.S., the identification of Lebanon, Kansas, has remained.
Cultural References
The geographic center of the contiguous United States is mentioned in Neil Gaiman's American Gods as a neutral ground where the modern and the old gods can meet despite the war between them.
In the 1969 Disney movie The Computer Wore Tennis Shoes, the final question of the college knowledge program is 'A small Midwest city is located exactly on an area designated as the 'geographic center of the United States.' For ten points and $100,000, can you tell us the name of that city?' The answer of Lebanon, Kansas is accepted as correct.
A 2021 Jeep Super Bowl commercial, The Middle, with Bruce Springsteen features the U.S. Center Chapel in Lebanon, Kansas.
Geology Of The Area:
The Geology of Kansas encompasses the geologic history of the US state of Kansas and the present-day rock and soil that is exposed there. Rock that crops out in Kansas was formed during the Phanerozoic eon, which consists of three geologic eras: the Paleozoic, Mesozoic and Cenozoic. Paleozoic rocks at the surface in Kansas are primarily from the Mississippian, Pennsylvanian and Permian periods.
Paleozoic Era
The oldest rocks at the surface in Kansas are Mississippian rocks that consist of limestones, shale, dolomite, chert, sandstones and siltstones. The Mississippian consisted of an environment similar to what we see today. Fast moving streams and rivers cutting into the limestone bedrock and in places creating caverns and sinkholes. Pennsylvanian rocks consist predominantly of alternating marine and non-marine shales and limestones with some sandstone, coal, chert and conglomerate. The Pennsylvanian was a time that the region that is now eastern Kansas stayed nearly at sea level. Between the transgression and regression of the seas, swamps and bogs formed, depositing dead vegetation and later, after burial under younger sediments, this dead vegetation formed into coal. Permian rocks predominantly consist of limestones, shales and evaporites. The Permian in Kansas began as an environment consisting of warm, shallow seas. As the Permian progressed, the climate became very dry and the seas began to subside, creating bodies of water shut off from the open seas, in turn creating areas for the generation of dark shales and evaporite minerals such as halite and gypsum as the waters evaporated. The end of the Permian marks the largest extinction period in Earth's history; over 90% of all life disappeared.
Mesozoic Era
Mesozoic rocks at the surface in Kansas consist predominantly of rocks from the Cretaceous. A relatively small outcrop of Jurassic sediments are exposed in the southwest corner of the state. Cretaceous age rocks consist of limestone, chalk, shale and sandstone. The Cretaceous in Kansas was an open ocean or sea environment dominated by microscopic marine plants and animals that floated or swam near the surface of this ancient water body. As these microscopic creatures died they sank to the bottom, formed a soft, limy ooze and would preserve any larger creatures that would die and sink into it.
Cenozoic Era
Cenozoic rocks at the surface were formed during the Paleogene, Neogene and Quaternary periods. Paleogene to Neogene rocks in Kansas consist of river silt, sand, freshwater limestones and some volcanic ash derived from eruptions in the western United States. Near the beginning of the Paleogene, the Rocky Mountains were born, as were the streams and rivers heading eastward out from the mountains into Kansas. Over 60 million years of erosion, the Rocky Mountains created a wedge of material extending to the Flint Hills of eastern Kansas. Quaternary rocks in Kansas consist of glacial drift; river silt, sand and gravel; dune sand and wind blown silt. The Quaternary Period in western Kansas was very similar to the Neogene, continual erosion of the Rocky Mountains deposited additional sediments.
Subsurface geology
The subsurface geology of Kansas consists of several sequences of sedimentary strata deposited on the Pre-Cambrian basement of the North American Craton.
Several regional subsurface structures including five sedimentary basins exist under Kansas. These structures are important in controlling the vast deposits of petroleum and natural gas in the state. The Central Kansas Uplift is a broad arch in the rocks of west central Kansas. The rock units within this arch have been major oil producers. The Anadarko Basin of southwest Kansas contains significant natural gas. The Sedgwick Basin, the Cherokee Basin and the Forest City Basin of south and east Kansas also produce petroleum and natural gas.
To Claim This Earthcache you will need to send the answers to these questions to me in a text on geiocaching site.
1. The posted cords take you to a Kansas Historical Marker labeled “The Geographic Center”. At this location you will need to examine the soil in the area and tell me if it is:
-Sand – granular material composed of finally divided rock and mineral particles.
-Loam – Fertile soil of clay and sand containing humus
-Clay – A type of fine-grained natural soil material containing clay minerals.
-Mixture of sand and gravel – Sand and a loose aggregation of rock fragments
****Before moving on to the next waypoint take an elevation reading (In Feet) standing near the Historic Marker.***
2. At the (Waypoint #2) “The Geographic Center of the United States” monument:
Take an elevation reading standing in front of the monument and tell me the difference between the “Kansas Historical Marker” and “The Geographic Center Marker”.
3. Using the list provided with question one. What is the make up of the soil around (Waypoint #2) “The Geographic Center of the United States Marker”? Are they the same?
4. At waypoints #3 and #4 you will find two completely different markers:
Which one of these markers is made from a material native to this area, waypoint #3 or #4?
5. When you determine which marker (Waypoint #3 or #4) is made of material native to the area, Using the “Geology of the Area” section in the write up for this cache. Tell me what Era you think the rock was formed in and what type of rock listed below that you think the monument is made of.
-Limestone
-Shale
-Dolomite
-Chert
-Sandstone
-Siltstone