MAIN CAVE
The “Main Cave” portion of
Mammoth Cave is the large level B passage that starts at the Gothic Avenue
intersection, extends to the southeast & south, and ends at Violet City,
very near a surface sinkhole.
The only current, regular
cave tour that allows examination of the entire stretch of the Main Cave is the
“Violet City tour”, which is conducted using hand-held lanterns. The
stretch from Gothic Avenue to Giant's Coffin can be seen on the “Historic tour”
and the “River Styx tour”. The “Star Chamber tour” includes a walk in the
Main Cave from Gothic Avenue to Star Chamber, just beyond the tuberculosis
cottages.
An interesting illusion was
discovered during early cave tours of the Main Cave. It can be witnessed
between the intersection with Gothic Avenue and the large breakdown block
called Giant's Coffin. When the Main Cave-Gothic Avenue intersection is
illuminated, the sinuosity of the Main Cave's passage, as seen from the east,
creates an irregularly tapering pillar of light. Early visitors perceived
a likeness to Martha Washington, America's first First Lady.
Martha Washington's Statue (from Hovey & Call,
1912; original photograph by Benjamin Hains). Looking in the old downstream
direction of the Main Cave (looking WNW).
The very large breakdown
block called “Giant's Coffin” is a regular stop on many Mammoth Cave
tours. It consists of upper Ste. Genevieve Limestone (upper Middle
Mississippian). Some graffiti is present on Giant's Coffin (&
throughout this portion of Mammoth Cave).
Giant's Coffin (looking ~SW) - large breakdown
block in Mammoth Cave's “Main Cave”.
Giant's Coffin (looking ~WNW) - the
Historic & River Styx cave tours walk through the Main Cave as far as here,
then head down to lower levels (levels C, D, E, and F). A narrow passage
(“Dante's Gateway”) exists behind this large rock (see below), just around the
corner on the left in this picture.
Giant's Coffin (looking ~NNW) (from an old
postcard; original photograph by Nat Wigginton) - Dante's Gateway is the
opening on the left side of the Giant's Coffin breakdown block.
Giant's Coffin (southeastern corner of
block) - Dr. Joseph Nash McDowell's 1839 scratch signature is the most
well-known piece of defacement on Giant's Coffin. McDowell was a famous
1800s physician and surgeon in Midwestern America, despite his eccentric,
outrageous, foul-mouthed, insulting, gun-loving, and grave-robbing
nature. McDowell had been aware that tuberculosis (TB) patients were
experiencing improved symptoms after having spent time in Alpine settings in
Europe. He suggested that cool, subterranean air might have the same
effect. This thinking resulted in a TB curative experiment in Mammoth
Cave in the 1840s.
To the south of the Giant's
Coffin breakdown block is a noticeably sharp left turn in the trend of the Main
Cave. It is a prominent landmark called the Acute Angle (aka Great
Bend). The passage of the ancient underground river suddenly turns at
about a 60 to 70 degree angle.
Acute Angle (from Hovey & Call,
1912; original photograph by Benjamin Hains) - looking ~SE.
Between the Acute Angle and
the Star Chamber are the remnants of an early 1840s experiment in curing
tuberculosis (TB; formerly called consumption). TB patients in
Europe perceived improvements in their symptoms while hanging out in cool, high
Alpine settings or in cool cave settings. Two cottages were set up in the
Main Cave and TB patients were invited to live in this stretch of the
cave. The consumptives’ symptoms did not improve. Deaths occurred
and the experiment ended after 10 months.
Tuberculosis cottage (from an old postcard)
The Star Chamber is located
in the Main Cave just beyond the tuberculosis cottages. This is
absolutely my favourite part of Mammoth Cave (but I've not had access to any features
beyond the modern, regular tourist trails). The walls are principally
limestones of the upper Ste. Genevieve Limestone (Levais Member & Aux Vases
Member).
Star Chamber gets its name
from the presence on the ceiling of numerous spots of whitish material with a
black background. If you lie down on your back on the benches, an amazing
& moving illusion appears. One experiences the feeling of being in a
rock-walled canyon with just stars & space above. I'm sure the
illusion is much more moving in a quiet setting. Incessant talk by NPS
rangers & other people on the tour don't allow for this, of course.
However, I've never been so drawn to any one spot in any other cave.
A large, somewhat rounded
whitish area on the ceiling is often referred to as the Moon. A line of
whitish material near “the Moon” is said to represent a comet or a
meteor. Neither of these features is apparent in the photo shown below.
Star Chamber (from an old postcard) -
explanations accounting for the origin of the Star Chamber's ceiling
vary. First of all, it is not a natural feature. That
doesn't ruin the awesomeness of it for me, however. The ceiling in the
Main Cave is, in many areas, coated with a crust of gypsum (CaSO4·2H2O).
The original, natural color of the gypsum ceiling crust was white. It is
now black in color from centuries of torch smoke from prehistoric Indians and
countless cave tours.
The “stars” have been
explained by some as being spots where new ceiling crystals have grown
downward, pushing away the black crust. That phenomenon has occurred in
Mammoth Cave, and likely occurred here. But I'm pretty sure that's not
the origin of many of the stars in the Star Chamber.
OK - look at the stars in
the above photo. Note that they are not randomly distributed on the black
ceiling. They're concentrated near the center. There are few to no
stars near the ceiling-wall intersections. It would be expected that new
ceiling crystal growth pushing away old black gypsum crust results in a
randomly distributed “star field”.
It is known that during some
early cave tours, guides and visitors threw rocks at the ceiling here to create
new stars. The rock impacts knocked away blackened gypsum crusts.
The pale color seen at each star is either whitish gypsum or whitish limestone.
During the 1930s, in the
southeastern stretches of the Main Cave, cave guides discovered the desiccated
corpse of an American Indian that had been crushed under a limestone
block. It had been known that prehistoric Indians entered & used
Mammoth Cave - the oldest known evidence dates to about 2170 B.C. Indian
artifacts have been found as far as 12 miles in. Their known activities
included the collection of gypsum crystals from the walls of the historic
section of Mamoth Cave.
In the case of this Indian
mummy, nicknamed “Lost John”, he had been digging for gypsum under a moderately
heavy piece of limestone breakdown. The block of rock shifted and trapped
him. Examination of the corpse while under the rock revealed that he had
time to get his head and arm out from under the rock, but not the rest of
him. Autopsy of the corpse provided some diet information - hickory nuts
and sunflower seeds were in his stomach. Intestinal tissue from this
mummy has been isotopically dated to about 15 B.C. Cloth associated with
the body has been dated to about 445 B.C.
The original limestone block
is still viewable on the “Violet City tour”. It's along the eastern side
of the Main Cave, on a slab-covered ledge. It has some metal straps
wrapped around it, which were used in lifting the rock during recovery of the
mummy.
Indian Mummy (from an old postcard) - “Lost
John” was on long-term public display at the discovery site & then at
Giant's Coffin. A couple other mummies found much nearer to the mouth of
the cave were discovered in the 1800s and reburied somewhere in Houchins
Narrows. Indian mummies from other Kentucky caves were sometimes put on
display at Mammoth Cave, including near the entrance to Gothic Avenue (see
photo below). Stories about these mummies usually gave the incorrect
impression that they, too, were found in Mammoth Cave. Most of them were
not found here.
Sadly, this interesting part
of Mammoth Cave history is now inaccessible. The mummy was reburied in
the 1970s in a spot near the discovery site. The exact site is known only
to the Mammoth Cave superintendent (& a few other people). I detest
censorship of visual information. So, I present the old postcard photo
shown above so that everyone can better appreciate a small, but fascinating,
part of American history.
“Mammoth Cave Mummy”
(from Hovey & Call, 1912) - this specimen was discovered in nearby Salts
Cave back in the 1800s. It was put on long-term public display near the
mouth of Gothic Avenue (in the “Mummy's Niche”). It eventually ended up
at the United States National Museum (USNM; aka the Smithsonian Museum)
in Washington D.C. Published isotopic dates on this mummy range from
about 10 B.C. to A.D. 130.
Enormous piles of breakdown
occur in places in the Main Cave. The piles of large rocks reminded early
visitors of the flood-ravaged ruins of ancient cities. Each major breakdown
pile was thus called a “City” (“First City”, “Second City”, etc.). Those
early names are retained for two of the largest breakdown piles in the Main
Cave - Chief City and Violet City. Chief City is the larger of the two
rock piles. Violet City is a rock pile at the southernmost end of the
Main Cave, which is directly below a surface sinkhole. Downward
percolating water from the sinkhole has resulted in some nice speleothem in the
upper parts of the Violet City breakdown pile (see below).
Violet City (from an old postcard) -
nice travertine speleothem covering a portion of the Violet City breakdown pile
(loose rocks visible at bottom of photo). The speleothem consists of
dripstone (stalactites, stalagmites, columns) and flowstone. The surface
sinkhole is uphill to the left. Violet City is the southernmost and
upstream-most portion of Mammoth Cave's Main Cave.
Violet City (from an old postcard) -
dripstone & flowstone covering part of the upper Violet City breakdown
pile.