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Mammoth Cave National Park

2007 Schools Wikipedia Selection. Related subjects: North American Geography

        Mammoth Cave National Park
   IUCN Category II ( National Park)
   Mammoth Cave National Park
   Location:       Kentucky, USA
   Nearest city:   Bowling Green, KY
   Coordinates:    37°11′0″N, 86°6′0″W
   Area:           52,835 acres (214 km²)
   Established:    July 1, 1941
   Visitation:     1,888,126 (in 2004)
   Governing body: National Park Service
   The Rotunda Room at Mammoth Cave.
   Enlarge
   The Rotunda Room at Mammoth Cave.

   Mammoth Cave National Park is a U.S. National Park in central Kentucky,
   encompassing portions of Mammoth Cave, the most extensive cave system
   known in the world. The official name of the system is the Mammoth Cave
   System, though it could be argued that it should be called the
   Flint-Mammoth-Toohey-Eudora-Joppa-Jim Lee Ridge Cave System—to account
   for the ridges under which the cave has formed. The park was
   established as a national park on July 1, 1941. It became a World
   Heritage Site on October 27, 1981, and an international Biosphere
   Reserve on September 26, 1990. The park's 52,830 acres (214 km²) are
   located in Edmonson County, Kentucky, with small areas extending
   eastward into Hart County and Barren County. It is centered around the
   Green River, with a tributary, the Nolin River, feeding into the Green
   just inside the park. The Green River is dammed near the western
   boundary of the park, so that the river only flows freely for a small
   section in the eastern part of the park.

   Almost two million people visit the park every year.

Limestone labyrinth

   Mammoth Cave is developed in thick Mississippian-aged limestone strata
   capped by a layer of sandstone, making the system remarkably stable. It
   is known to include more than 360 miles (579 kilometers) of passageway;
   new discoveries and connections add several miles to this figure each
   year.

   The upper sandstone member is known as the Big Clifty Sandstone: thin,
   sparse layers of limestone interspersed within the sandstones give rise
   to an "epikarstic zone", in which tiny conduits (cave passages too
   small to enter) are dissolved, which concentrate local flows of runoff
   into high-elevation springs which emerge at the edges of ridges. The
   resurgent water from these springs typically flows briefly on the
   surface before sinking for good near the contact elevation between the
   sandstone caprock and the underlying massive limestones. It is in these
   underlying massive limestone layers that the human-explorable caves of
   the region are developed.

   The limestone layers of the stratigraphic column beneath the Big
   Clifty, in increasing order of depth below the ridgetops, are the
   Girkin Formation, the Ste. Genevieve Limestone, and the St. Louis
   Limestone. The large Main Cave passage seen on the Historic Tour is
   located at the bottom of the Girkin and the top of the St. Genevieve.

   Each of the primary layers of limestone are divided further into named
   units and subunits. One area of cave research involves correlating the
   stratigraphy with the cave survey produced by explorers. This makes it
   possible to produce three dimensional approximate maps of the contours
   of the various layer boundaries without the necessity for boring test
   wells and extracting core samples.

   The upper sandstone caprock is relatively hard for water to penetrate:
   the exceptions are where vertical cracks occur. This protective role
   means that many of the older, upper passages of the cave system are
   very dry, with no stalactites, stalagmites, or other formations which
   require flowing or dripping water to develop.

   However, the sandstone caprock layer has been dissolved and eroded at
   many locations within the park, such as the Frozen Niagara room. The
   "contact" between limestone and sandstone can be found by hiking from
   the valley bottoms to the ridgetops: typically, as one approaches the
   top of a ridge, the outcrops of exposed rock seen change in composition
   from limestone to sandstone at a well-defined elevation, neglecting
   slump blocks of sandstone which have broken off the ridgetops and
   tumbled down the limestone slopes below.

   At one valley bottom in the southern region of the park, a massive
   sinkhole has developed, called Cedar Sink, which features a small river
   entering one side and disappearing back underground at the other side.

   Mammoth Cave is home to the endangered Kentucky cave shrimp, a
   sightless albino shrimp.

Visiting

   The National Park Service offers several cave tours to visitors. Many
   of the most-famous features of the cave, such as Grand Avenue, Frozen
   Niagara, and Fat Man's Misery, can be seen on lighted tours ranging
   from one to six hours in length. Two tours, lit only by visitor-carried
   paraffin lamps, are popular alternatives to the electric-lit routes.
   Several "wild" tours venture away from the developed parts of the cave
   into muddy crawls and dusty tunnels.

   The park's tours are notable for the quality of the interpretive
   program, with occasional graphics accompanying artifacts on display at
   certain points in the cave. The lectures delivered by the National Park
   Service cave guides are varied by tour, so that in taking several tours
   the visitor learns about different facets of the cave's formation, or
   of the cave's human history and prehistory. Most guides are quite
   knowledgeable and open to visitor's questions. Many guides include a
   "theatrical" component, making their presentations entertaining with
   gentle humor. The guide traditions at Mammoth Cave date back to the
   period just after the War of 1812, and to guides such as Stephen
   Bishop. The style of this humor itself is part of the living tradition
   of the cave guides, and is duly a part of the interpretive program.

   The Echo River Tour, one of the cave's most famous attractions, used to
   take visitors on a boat ride along an underground river. The tour was
   discontinued for logistic and environmental reasons in the early 1990s.

   Interested members of the public can join an Earthwatch.org sponsored
   field survey of the history of Mammoth Cave. However, due to Mammoth
   Cave park regulations, participation on this project is restricted to
   US citizens only.

Park superintendents

   List is incomplete..
     * Robert P. Holland; September 2, 1936 – June 21, 1938; acting
     * R. Taylor Hoskins; June 22, 1938 – June 30, 1941; acting
     * R. Taylor Hoskins; July 1, 1941 – March 31, 1951
     * Thomas C. Miller; April 1, 1951 – June 30, 1954
     * Perry E. Brown; July 1, 1954 – September 14, 1963
     * Paul McG. Miller; September 15, 1963 – December 30, 1965
     * John A. Aubuchon; January 2, 1966 – September 7, 1968
     * Robert H. Bendt; September 8, 1968 – January 23, 1971; assigned
       line supervision of Abraham Lincoln Birthplace National Historic
       Site, September 2, 1970 – April 27, 1975
     * Joseph Kulesza; February 21, 1971 – May 31, 1976
     * Albert A. Hawkins; July 4, 1976 – August 11, 1979
     * Robert L. Deskins; August 12, 1979 – September 1, 1984
     * Richard N. Strange; September 2, 1984 – December 8, 1984; acting
     * Franklin D. Pridemore; December 9, 1984 – January 2, 1988
     * David A. Mihalic; January 3, 1988 – July 1994
     * Ronald R. Switzer; March 1995 – January 2005
     * Bruce Powell; January 2005 – January 2006; acting
     * Patrick Reed; January 2006 –

History

   The story of human beings in relation to Mammoth Cave is a long one,
   spanning six thousand years. It is also a complex story, involving not
   only themes of human exploration and exploitation of the cave, but the
   lifeways of the cultures which have lived in the surrounding region.
   The relation between people and their environment is always
   bidirectional, and this is exemplified in the history of the Mammoth
   Cave region.

Prehistory

   Several sets of Native American remains have been recovered from
   Mammoth Cave, or other nearby caves in the region, in both the 19th and
   20th centuries, by 1813 on the early side (the "Short Cave Mummy.")
   Most mummies found present examples of intentional burial, with ample
   evidence of pre-Columbian funerary practice.

   An exception to purposeful burial was discovered when in 1935 (not
   1835) the remains of an accidentally deceased adult male were
   discovered by Grover Campbell and Lyman Cutliff under a huge boulder.
   The boulder had shifted and settled onto the victim, a pre-Columbian
   miner, who had disturbed the rubble supporting it. The remains of the
   ancient victim were named "Lost John" and exhibited to the public into
   the 1970s, when they were interred in a secret location in Mammoth Cave
   for reasons of preservation as well as emerging political sensitivies
   with respect to the public display of Native American remains.

   Research beginning in the late 1950s led by Dr. Patty Jo Watson of
   Washington University in St. Louis, Missouri has done much to
   illuminate the lives of the late Archaic and early Woodland peoples who
   explored and exploited caves in the region. Preserved by the constant
   cave environment, dietary evidence yielded carbon dates enabling Dr.
   Watson and others to determine the age of the specimens, and an
   analysis of their content, also pioneered by Dr. Watson, allows
   determination of the relative content of plant and meat in the diet of
   either culture over a period spanning several thousand years. This
   analysis indicates a timed transition from a hunter-gatherer culture to
   plant domestication and agriculture.

   Another technique employed in archaeological research at Mammoth Cave
   was "experimental archaeology," also an innovation of Dr. Watson's, in
   which modern explorers were sent into the cave using the same
   technology as that employed by the ancient cultures whose leftover
   implements lie discarded in many parts of the cave. The goal was to
   gain insight into the problems faced by the ancient people who explored
   the cave, by placing the researchers in a similar physical situation.

   Ancient human remains and artifacts within the caves are protected by
   various federal and state laws. One of the most basic facts to be
   determined about a newly discovered artifact is its precise location
   and situation. Even slightly moving a prehistoric artifact contaminates
   it from a research perspective. Explorers are properly trained not to
   disturb archaeological evidence, and some areas of the cave remain
   out-of-bounds for even seasoned explorers, unless the subject of the
   trip is archaeological research on that area.

Earliest known history

   Map of Mammoth Cave from 1842, penned by Stephen Bishop: unusual for a
   slave, he was given complete credit.
   Enlarge
   Map of Mammoth Cave from 1842, penned by Stephen Bishop: unusual for a
   slave, he was given complete credit.

   Legend has it that the first European to discover Mammoth Cave was John
   Houchins, in 1797. While hunting, Houchin pursued a wounded bear to the
   cave's large entrance opening near the Green River. Countervailing
   against this story is Brucker and Watson's The Longest Cave, which
   asserts that the cave was "certainly known before that time."

   The land containing this Historic Entrance was first surveyed and
   registered in 1798 under the name of Valentine Simons. Simons began
   exploiting Mammoth Cave for its saltpeter reserves. Calcium nitrate
   (Ca( NO[3])[2]) deposited as bat guano was leached from cave soils and
   converted via double replacement reaction with potash ( potassium
   carbonate, empirical formula K[2] CO[3]) to produce Potassium nitrate
   (KNO[3]) or saltpeter, an ingredient of gunpowder.

19th century

   In partnership with Valentine Simon, various other individuals would
   own the land through the War of 1812, when Mammoth Cave's saltpeter
   reserves became significant due to the British blockade of United
   States's ports. The blockade starved the American military of saltpeter
   and therefore gunpowder. As a result, the domestic price of saltpeter
   rose and production based on nitrates extracted from caves such as
   Mammoth Cave became more lucrative.

   In July 1812, the cave was purchased from Simon and other owners by
   Charles Wilkins and an investor from Philadelphia named Hyman Gratz.
   Soon the cave was being mined for calcium nitrate on an industrial
   scale.

   A half-interest in the cave changed hands for ten thousand dollars (a
   huge sum at the time). After the war when prices fell, the workings
   were abandoned and it became a minor tourist attraction centering on a
   Native American mummy discovered nearby.

   When Wilkins died his estate's executors sold his interest in the cave
   to Gratz. In the spring of 1838, the cave was sold by the Gratz
   brothers to Franklin Gorin, who intended to operate Mammoth Cave purely
   as a tourist attraction, the bottom long having since fallen out of the
   saltpetre market. Gorin was a slave owner, and used his slaves as tour
   guides. One of these slaves would make a number of important
   contributions to human knowledge of the cave, and become one of Mammoth
   Cave's most celebrated historical figures.

   Stephen Bishop, an African-American slave and a guide to the cave
   during the 1840s and 1850s, was one of the first persons to make
   extensive maps of the cave, and named many of the cave's features.

   Stephen Bishop was introduced to Mammoth Cave in 1838 by Franklin
   Gorin. Gorin wrote, after Bishop's death: "I placed a guide in the cave
   --- the celebrated and great Stephen, and he aided in making the
   discoveries. He was the first person who ever crossed the Bottomless
   Pit, and he, myself and another person whose name I have forgotten were
   the only persons ever at the bottom of Gorin's Dome to my knowledge.

   "After Stephen crossed the Bottomless Pit, we discovered all that part
   of the cave now known beyond that point. Previous to those discoveries,
   all interest centered in what is known as the "Old Cave" . . . but now
   many of the points are but little known, although as Stephen was wont
   to say, they were 'grand, gloomy and peculiar.'

   In 1839, Dr. John Croghan of Louisville bought the Mammoth Cave Estate,
   including Bishop and its other slaves from their previous owner,
   Franklin Gorin. Croghan briefly ran an ill-fated tuberculosis hospital
   in the cave, the vapors of which he believed would cure his patients. A
   widespread epidemic of the period, tuberculosis would ultimately claim
   the lives of both Bishop and Croghan.

   Throughout the 19th century, the fame of Mammoth Cave would grow so
   that the cave became an international sensation.

   At the same time, the cave attracted the attention of 19th century
   writers such as Dr. Robert Montgomery Bird, the Rev. Robert Davidson,
   the Rev. Horace Martin, Alexander Clark Bullitt, Nathaniel Parker
   Willis (who visited in June 1852), Bayard Taylor (in May, 1855), Dr.
   William Stump Forwood (in Spring 1867), the naturalist John Muir (early
   September, 1867), the Rev. Horace Carter Hovey, and others.

   As a result of the growing renown of Mammoth Cave, the cave boasted
   famous visitors such as actor Edwin Booth, singer Jenny Lind (who
   visited the cave on April 5, 1851), and violinist Ole Bull.

Early 20th century: The Kentucky Cave Wars

   The difficulties of farming life in the hardscrabble, poor soil of the
   cave country influenced local owners of smaller nearby caves to see
   opportunities for commercial exploitation, particularly given the
   success of Mammoth Cave as a tourist attraction. The "Kentucky Cave
   Wars" were a period of bitter competition between local cave owners for
   tourist money. Broad tactics of deception were used to lure visitors
   away from their intended destination to these private show caves.
   Misleading signs were placed along the roads leading to the Mammoth
   Cave. A typical strategy during the early days of automobile travel
   involved a representative of a private show cave hopping aboard a
   tourist's car's running board, to "explain" to the passengers that
   Mammoth Cave was closed, quarantined, caved in or otherwise
   inaccessible.

   In 1906, Mammoth Cave became accessible by steamboat with the
   construction of a lock and dam at Brownsville, Kentucky. The
   construction of this dam has had a long-term impact on the biota of the
   cave. The dam's construction would also prove to have implications for
   the story of the cave's exploration.

   In 1908, Max Kaemper, a young German mining engineer arrived at the
   cave by way of New York. Kaemper had just graduated from technical
   college and his family had sent him on a trip abroad as a graduation
   present. Originally intending to spend two weeks at Mammoth Cave,
   Kamper spent several months. With the assistant of African-American
   slave descendant Ed Bishop, Kaemper produced a remarkably accurate
   instrumental survey of many kilometers of Mammoth Cave, including many
   new discoveries. Reportedly, Kaemper also produced a corresponding
   survey of the land surface overlying the cave: this information would
   have been useful in the opening of other entrances to the cave, as soon
   happened with the Violet City entrance.

   The Crogan family suppressed the topographic element of Kaempers map,
   and it is not known to survive today, although the cave map portion of
   Kaemper's work stands as a triumph of accurate cave cartography: not
   until the early 1960s and the advent of the modern exploration period
   would these passages be surveyed and mapped with greater accuracy.
   Kaemper returned to Berlin, and from the point of view of the Mammoth
   Cave country, disappeared entirely. It was not until the turn of the
   21st Century that a group of German tourists, after visiting the cave,
   researched Kaemper's family and determined his sad fate: the young
   Kaemper was killed in trench warfare in World War I at the Battle of
   the Somme (1916) just eight years later.

   Famed French cave explorer Édouard-Alfred Martel visited the cave for
   three days in October 1912. Without access to the closely held survey
   data, Martel was permitted to make barometric observations in the cave
   for the purpose of determining the relative elevation of different
   locations in the cave. He identified different levels of the cave, and
   correctly noted that the level of Echo River within the cave was
   controlled by that of the Green River on the surface. Martel lamented
   the 1906 construction of the dam at Brownsville, pointing out that this
   made a full hydrologic study of the cave impossible. Among his precise
   descriptions of the hydrogeologic setting of Mammoth Cave, Martel
   offered the speculative conclusion that Mammoth Cave was connected to
   Salts and Colossal Caves: this would not be proven correct until 60
   years after Martel's visit.

   In the early 1920s, George Morrison blasted a number of entrances to
   Mammoth Cave on land not owned by the Croghan Estate. Absent the data
   from the Croghan's secretive surveys, performed by Kaemper, Bishop, and
   others, which had not been published in a form suitable for determining
   the geographic extent of the cave, it was now conclusively shown that
   the Croghans had been for years exhibiting portions of Mammoth Cave
   which were not under land they owned. Lawsuits were filed and for a
   time, different entrances to the cave were operated in direct
   competition with each other.

   In the early 20th century, Floyd Collins spent ten years exploring the
   Flint Ridge Cave System before dying at Sand Cave, Kentucky, in 1925.
   While exploring Sand Cave, he dislodged a rock onto his leg while in a
   tight crawlway and was unable to free himself . Attempts for Collins'
   rescue created a media sensation.

The National Park Movement (1926–1941)

   As the last of the Croghan heirs died, advocacy momentum grew among
   wealthy citizens of Kentucky for the establishment of Mammoth Cave
   National Park. Private citizens formed the Mammoth Cave National Park
   Association in 1926. The Park was authorized May 25, 1926.

   Donated funds were used to purchase some farmsteads in the region,
   while other tracts within the proposed National Park boundary were
   acquired by right of eminent domain. In contrast to the formation of
   other National Parks in the sparsely populated American West, thousands
   of people would be forcibly relocated in the process of forming Mammoth
   Cave National Park. Often eminent domain proceedings were bitter, with
   landowners paid what was considered to be inadequate sums. The
   resulting acrimony still resonates within the region.

   For legal reasons, the federal government was prohibited from restoring
   or developing the cleared farmsteads while the private Association held
   the land: this regulation was evaded by the operation of "a maximum of
   four" CCC camps from May 22, 1933 to July 1942.

   According to the National Park Service , "On May 14, 1934 the minimum
   park area was provided. On May 22, 1936, the minimum area was accepted
   for administration and protection."

   Superintendent Hoskins later wrote of a summer tanager named Pete who
   arrived at the guide house on or around every April 20th, starting in
   1938. The bird ate from food held in the hands of the guides, to the
   delight of visitors, and provided food to his less-tame mate.

Birth of the National Park (1941)

   Mammoth Cave National Park was officially dedicated on July 1, 1941. By
   coincidence, the same year saw the incorporation of the National
   Speleological Society. R. Taylor Hoskins, the second Acting
   Superintendent under the old Association, became the first official
   Superintendent, a position he held until 1951.

   The New Entrance, closed to visitors since 1941, was reopened on
   December 26, 1951, becoming the entrance used for the beginning of the
   Frozen Niagara tour.

"The Longest Cave" (1954–1972)

   By 1954, Mammoth Cave National Park's land holdings encompassed all
   lands within its outer boundary with the exception of two privately
   held tracts. One of these, the old Lee Collins farm, had been sold to
   Harry Thomas of Horse Cave Kentucky, whose grandson, William "Bill"
   Austin, operated Collins Crystal Cave as a show cave in direct
   competition with the National Park, which was forced to maintain roads
   leading to the property. Condemnation and purchase of the Crystal Cave
   property seemed only a matter of time.

   In February 1954, a two-week expedition under the auspices of the
   National Speleological Society was organized at the invitation of
   Austin: this expedition became known as C-3, or the "Collins Crystal
   Cave" expedition.

   The C-3 expedition drew public interest, first from a photo essay
   published by Robert Halmi (in either Sports Illustrated or Look
   magazine) and later from the publication of a double first-person
   account of the expedition, The Caves Beyond: The Story of the Collins
   Crystal Cave Expedition by Joe Lawrence, Jr. (then president of the
   National Speleological Society) and Roger W. Brucker. The expedition
   proved conclusively that passages in Crystal Cave extended toward
   Mammoth Cave proper, at least exceeding the Crystal Cave property
   boundaries. However, this information was closely held by the
   explorers: it was feared that the National Park Service might forbid
   exploration were this known.

   Some of the participants in the C3 expedition wished to continue their
   explorations past the conclusion of the C-3 Expedition, and organized
   as the Flint Ridge Reconnaissance under the guidance of Austin, Jim
   Dyer, John J. Lehrberger and Dr. E. Robert Pohl. This organization was
   incorporated in 1957 as the Cave Research Foundation, Inc. The
   organization sought to legitimize the cave explorers' activity through
   the support of original academic and scientific research. Notable
   scientists who studied Mammoth Cave during this period include Patty Jo
   Watson (see section on prehistory.)

   In March 1961, the Crystal Cave property was eventually sold to the
   National Park Service for a sum of USD $285,000. At the same time, the
   Great Onyx Cave property, the only other remaining private inholding,
   was purchased for USD $365,000. The Cave Research Foundation was
   permitted to continue their exploration through a Memorandum of
   Understanding with the National Park Service.

Flint–Mammoth Connection (1972)

   On September 9, 1972, a Cave Research Foundation mapping team led by
   Dr. John P. Wilcox, Patricia Crowther, Richard B. Zopf, Dr. P. Gary
   Eller, Stephen G. Wells, and Cleveland F. Pinnix (a National Park
   Service Ranger) managed to find a low, wet passage that linked two of
   the area's long cave systems—Flint Ridge Cave to Mammoth Cave. This
   connection made the combined Flint–Mammoth Cave System the world's
   longest. (Flint Ridge had itself recently surpassed Hölloch Cave, in
   Switzerland, as the world's longest cave.)

   On a previous trip deep in the Flint Ridge Cave System, Patricia
   Crowther—with her slight frame of 115 pounds (52 kilograms)—crawled
   through a narrow canyon later dubbed the "Tight Spot", which acted as a
   filter for larger cavers.

   A subsequent trip fielded past the Tight Spot by Crowther, Wilcox,
   Richard Zopf, and Tom Brucker found the name "Pete H" inscribed on the
   wall with an arrow pointing in the direction of Mammoth Cave. The name
   is believed to have been carved by Pete Hanson, who was active in
   exploring the cave in the 1930s. Hanson was killed in World War II. The
   passage was named Hanson's Lost River.

   On a yet later trip, following Hanson's Lost River led the six-person
   team to Cascade Hall in Mammoth Cave. John Wilcox emerged in neck-deep
   water to see a regular horizontal line across his field of vision,
   which proved to be a tourist handrail: the "One small step for a man"
   quote for "conquering the Everest of speleology" was his exclamation to
   the others "I see a tourist trail!" Of all of the many miles of Mammoth
   Cave, only a small fraction is developed with trails and lighting, so
   it was remarkable that the moment of connection took place in an
   utterly familiar setting.

Recent discoveries

   Further connections between Mammoth Cave and smaller caves or cave
   systems have followed, notably to Proctor/Morrison Cave beneath nearby
   Joppa Ridge in 1979. This connection pushed the frontier of Mammoth
   exploration southeastward.

   At the same time, discoveries made outside the Park by an independent
   group called the Central Kentucky Karst Coalition or CKKC resulted in
   the survey of tens of miles in Roppel Cave east of the Park. On
   September 10, 1983, a connection was made between the
   Proctor/Morrison's section of the Mammoth Cave system and Roppel Cave.
   The connection was made by two mixed parties of CRF and CKKC explorers.
   Each party entered through a separate entrance and met in the middle
   before continuing in the same direction to exit at the opposite
   entrance. The resulting total surveyed length was near 300 miles.
   Incremental discoveries since then have pushed the total to more than
   360 miles.

   In early 2005 a connection into the Roppel Cave portion of the system
   was surveyed from a small cave under Eudora Ridge (originally
   discovered and entered in 2003 by CRF/CKKC personnel.)

   It is accepted with certainty that many more miles of cave passages
   await discovery in the region. Scientists believe that there are
   thousands of species of animals yet undiscovered in the cave system.

Common misconceptions

   The superlatives which are justly applied to Mammoth Cave often lead to
   exaggeration of the cave's extent and reach. One such misconception is
   that the cave extends far beyond its geographical boundaries, even to
   other states in the United States. This misconception is easily
   debunked. Caves of Mammoth's type form as water from the surface seeks
   the level of the surface streams which drain them: in Mammoth Cave's
   case, the Green River to the north. It is a virtual certainty that no
   cave passages connecting to Mammoth will ever be found north of the
   Green River, or substantially east of the Sinkhole Plain which is the
   primary recharge area (the place where water enters) for the cave. More
   tantalizing is the prospect of ancient passages to the south which
   might bridge the current drainage divide between the Green River basin
   and the Barren River basin south of it, but in that case, the maximum
   expected southerly extent of Mammoth Cave would be the Barren River.

   It is true, however, that the layers of sedimentary rock in which
   Mammoth Cave has formed do extend many miles (kilometers) in almost any
   direction from Mammoth Cave. These rocks were all laid down over the
   same period. The similarity of the rocks of the broader region to those
   in the immediate vicinity of Mammoth Cave means that conditions are
   right for cave formation; however, the absolute boundaries of the
   Mammoth Cave system are known, so it is expected that these other caves
   will not be found to connect to Mammoth Cave.

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