The Karst Topography...of California? There are more than 1,000 wild caves in California. Here's one of them

There is something special about exploring a wild cave, the kind without admission fees, guides, trails, and railings. There are a thousand limestone caves in California (and hundreds of lava tubes), and not even a dozen of them are show caves, i.e. open for business.There are usually reasons the wild caves do not become "tour caves". They may be too short, too inaccessible, maybe even too dangerous.

The wild caves have suffered varying levels of abuse and vandalism. Few of them are protected by any kind of legal authority and are rarely patrolled. They are mostly protected by secrecy, and small groups of serious spelunkers. I've been privileged with the opportunity to explore a couple of them, and as part of my miniseries on the karst terrain of California, I'd like to share one with you.

A nearly empty New Melones Reservoir and the gray marble of the Calaveras Complex.

Karst topography, as described in the previous posts, is a landscape underlain by cavern-filled marble or limestone. Cavern roofs can collapse, forming sinkholes, blind valleys and disappearing streams. The marble, a part of a metamorphic terrane called the Calaveras Complex (late Paleozoic-early Mesozoic), can be seen as gray slopes in the photo above. Many incredible caves were drowned by the waters of the reservoir in the foreground of the picture. Others open out into sheer cliffs above. Few are easily accessible. We had to walk a steep mile to get to the caves we're exploring in the post today.

Oak woodland in the vicinity of the caves

That's what makes these caves special. They are at the end of a pretty stiff hike, but they have accessibility, and are relatively undamaged (this concept is relative; some would call them heavily damaged, but many parts are in good shape). They're not crowded. Months may pass between visits.

When we have a group of newbies who have not explored wild caves before, we do some training on safety, both for the explorers, and for the caves themselves. We stress the importance of exploring in least intrusive way possible, not touching the rocks, and not disturbing any life if possible. We crawl through a short cave with a few narrow passages in preparation for entering the much larger cave to follow.

We finish our spelunking practice at the small cave, and move on towards the larger, more challenging cave. Accessing the cave requires first descending between huge fallen boulders. The cave had grown so large that portions of the roof had collapsed to form a sinkhole. We find a spot with good footholds and climb into the darkness.

The second challenge is getting into the main cave via a narrow passageway at the base of the rockfall. One has to push upwards and twist through the tight little space. Some of the explorers describe it as being "born again".

The entrance merges into a more open room that serves as the "subway" into the largest room in the cave. This passage is where most of the speleothem damage has occurred. It's not exactly the work of vandals, as the breaking of the formations was probably for the purpose of making an easier passageway into the room beyond. This kind of thing happened to many caves discovered in olden days. I don't know anything of the discovery and original exploration of this particular cave.

This passage leads into the main room of the cave, which more than 100 feet long, and 20-30 feet high in places. We come face to face with a spectacular wall of mostly unbroken stalactites (they were protected by being out of reach).

The room is richly decorated with all kinds of dripstone and flowstone features. Some are brown from torches of the early explorers, or from mud seeping through the cracks above. Other features show evidence of recovery from the "dirty early years". The adoption of clean caving techniques in the last few decades shows as some of the cave features are covered with a thin layer of pure white calcite. Some of the caves are being cleaned by volunteers as well. In some cases, people haul gallons of water down difficult trails, set up hoses into the caves, and then spray mud off of damaged speleothems.

There are all kinds of nooks and crannies to explore. There is a false floor in the cave that offers a loop crawl. There is a small passageway called the bedroom and another called the jail room. Openings high on the walls and ceiling hint at other passageways. In a side room, one can view a sinkhole from the underside, looking up at a mass of boulders that had collapsed down into the cave, but have since been cemented together by flowstone to form the ceiling of the room.

What about cave life? We've seen spiders near the entrance, and unusual looking snails. In previous trips we have seen six inch long centipedes, and Ensatina salamanders. There have been a couple of bats. The total darkness of caverns offers little in the way of food, so the biomass quantity of the cave is very low. The creatures that do exist are highly adapted to environment of the caves.

The wilderness caverns of the Sierra Nevada are a precious and irreplaceable resource. The breaking of any speleothem destroys the result of thousands, even tens of thousands of years of slow development. They can never be replaced in any kind of human lifetime.

It is a rare privilege to be able to explore this underground wilderness, and it is a privilege for me to introduce my students to this strange new world.

A cave is such a strange and alien world for a human being, at least the deeper parts away from the light. No wonder that some of our first art was scrawled on cavern walls as sort of drug-free hallucination of alternate worlds. Caves were portals to lower worlds, or were the avenues for emergence into our current world. Sitting in the darkness, I can feel a connection to my ancestors.

You have no doubt noted that I have not provided the names of the caves we explored. If you want to get involved in cave exploration, you should contact your local grotto of the National Speleological Society. They provide instruction and training, as well as chances to clean and rehabilitate caves that have been damaged by vandals and overuse. They are great people. And don't forget, the tourist caves in the Mother Lode are wonderful. They are safe and easy to explore. Check them out!

This post is a highly altered version of a post based on our trip in 2014. If you want to see how badly I plagiarized myself, check out the original post here:  http://geotripper.blogspot.com/2014/11/to-explore-wild-cave-underground.html

To Explore a Wild Cave: The Underground Wilderness of the Sierra Nevada

There is a treasure in the Mother Lode of California's Sierra Nevada. It lies hidden beneath the surface, but it's not gold. It is a wilderness, but has no beautiful trees or distant vistas. It is dark and sometimes can be a bit creepy, but it is a place of incredible beauty as well. It is a network of caverns, hundreds of them. A half-dozen are tourist destinations, with lighting, pathways, and guided tours. The rest lie hidden, protected from vandals and abuse only by their secrecy.

I had the pleasant opportunity of introducing some of my students to the Sierra Nevada Underground today, exploring a pair of small caves in the Mother Lode on the slopes above the Stanislaus River. Many of the caves in the Sierra are dangerous, with steep drop-offs, impossibly tight passageways, and even bad air at times. Every cave, like any wilderness, can be dangerous, but the caves we were exploring were less intimidating than most. Falls were possible in these caves, but they would be on the order of six feet instead of forty feet, or a hundred. We headed for the hills above Columbia, stopping in the historical town for a few moments to enjoy the fall colors (and to use the facilities).

A nearly empty New Melones Reservoir and the gray marble of the Calaveras Complex.

We crossed the Stanislaus River and the frighteningly empty New Melones Reservior. The marble, a part of a metamorphic terrane called the Calaveras Complex (late Paleozoic-early Mesozoic), could be seen as gray slopes in the distance upstream. There are over a thousand caverns in the Sierra Nevada, and dozens of them are in the slopes above the Stanislaus River. Many incredible caves were drowned by the waters of the reservoir. Others open out into sheer cliffs above. Few are easily accessible, and many of these have been heavily damaged by vandals and ignorant visitors.

Oak woodland in the vicinity of the caves

That's what makes these caves special. They are at the end of a pretty stiff hike, but they have accessibility, and are relatively undamaged (this concept is relative; some would call them heavily damaged, but many parts are in good shape). One of them is relatively small, but has some good places to practice crawling, and has enough passageways to give a sense of exploring.

Signing the cave register

Most of the caves in the Sierra are monitored by the local speleological society, and they contain a register so visitation levels can be estimated. A party had been in these caves a week previous, but it had been several months since any earlier visits.

The features and "decorations" of caves are called speleothems. The familiar stalactites, stalagmites, and columns are called dripstone speleothems. As the name suggests, these form when calcium carbonate rich water drips from fractures in the ceiling of the cave. A little bit of calcite precipitates out as the water evaporates.

Other speleothems are called flowstone features. These are cave decorations that develop as water flows out the walls of a cavern. These might include draperies, shields, or rimstone pools.

We finished our spelunking practice at the small cave, and moved on towards the larger, more challenging cave. Accessing the cave required first descending between huge fallen boulders. The cave had grown so large that portions of the roof had collapsed to form sinkholes. We found a spot with good footholds and climbed into the darkness.

The second challenge was getting into the main cave via a narrow passageway at the base of the rockfall. One has to push upwards and twist through the tight little space. Some of the students described it as being "born again". Not everyone gets through, but we had a stubborn crew, and they all successfully negotiated the passage.

The entrance merges into a more open room that serves as the "subway" into the largest room in the cave. This passage is where most of the cavern damage has occurred. It's not clear whether this is the work of vandals, or more likely, the breaking of the formations to forge an easier passage into the room beyond. This kind of thing happened to many caves discovered in older days (I don't know the history of these particular caverns though).

I was still helping students get through the entrance when I heard the others exclaiming in delight at the first view of the big room. There is a rather stunning collection of stalactites hanging from the ceiling, the majority of which are unbroken.

The big room is almost 100 feet long and 30-40 feet wide. It is richly decorated with all kinds of dripstone and flowstone features. Some are brown from torches of the early explorers, or from mud seeping through the cracks above. Other features show evidence of recovery from the "dirty early years". The adoption of clean caving techniques in the last few decades shows as some of the cave features are covered with a thin layer of pure white calcite. Some of the caves are being cleaned by volunteers as well. In some cases, people haul gallons of water down difficult trails, set up hoses into the caves, and then spray mud off of damaged speleothems.

There are all kinds of nooks and crannies to explore. There is a false floor in the cave that offers a loop crawl. There is a small passageway called the bedroom and another called the jail room. Openings high on the walls and ceiling hint at other passageways.

What about cave life? We saw spiders near the entrance, and an unusual looking snail. In previous trips we have seen six inch long centipedes, and Ensatina salamanders. There have been a couple of bats. The total darkness of caverns offers little in the way of food, so the biomass quantity of the cave is very low. The creatures that do exist are highly adapted to environment of the caves.

An Ensatina Salamander from a trip to the cave in 2003.

The wilderness caverns of the Sierra Nevada are a precious and irreplaceable resource. The breaking of any speleothem destroys the result of thousands, even tens of thousands of years of slow development. They can never be replaced in any kind of human lifetime. A major part of our preparation for this trip was instruction in the ways of clean caving, conducting ourselves in such a way as to protect the cave to the greatest extent possible (the simple act of exploring has effects).

It was a rare privilege to be able to explore this underground wilderness, and it was a privilege for me to introduce my students to this strange new world. We finished up and started to climb back into the entrance chamber.

I lingered for a few minutes after the others had left. I wanted to hear the silence and just feel the pulse of the cave. A cave is such a strange and alien world for a human being, at least the deeper parts away from the light. No wonder that some of our first art was scrawled on cavern walls as sort of drug-free hallucination of alternate worlds. Caves were portals to lower worlds, or were the avenues for emergence into our current world. Sitting in the darkness, I felt a connection to my ancestors.

And then I looked up, over my head. Oh crap, I'm in a dark cave alone with gigantic spikes just waiting for an earthquake to drop them on me! I quietly excused myself and caught up with the rest of the crew (of course, given the number of earthquakes here over the course of geologic time, the likelihood of these things falling is nil).

We climbed out of the cave and headed back up the long hill. It had been a great day in the Sierra Underground. You have no doubt noted that I have not provided the names of the caves we explored. If you want to get involved in cave exploration, you should contact your local grotto of the National Speleological Society. They provide instruction and training, as well as chances to clean and rehabilitate caves that have been damaged by vandals and overuse. They are great people. And don't forget, the tourist caves in the Mother Lode are wonderful. They are safe and easy to explore. Check them out!

What To Do on a Rainy Day? Explore the Mother Lode Underground!

So what does one do when an atmospheric river storm is barreling towards your region, with an expected 10"-20" of rain in some places? If you are among the intrepid members of the Geology Club at our school, you go caving! It's not that they planned on doing a field trip during one of the heaviest storms of the year, but this was scheduled two months ago. They looked at the weather radar and decided to go anyway. In the end we caught a bit of breathing space between two major storm systems. It was mostly drizzling and misting on us as we hiked the mile or so down the hill to the cave entrances.

California is not exactly known for her cavern systems, but the state does in fact have around a thousand known caves, and some are world class; one has nearly thirty miles of passageways. Seven or eight of them are operated as tourist attractions (Black Chasm, California, Mercer, Moaning, Boyden, Crystal, and Shasta are the ones that come to mind). Many are on public land and plenty more are on private land (how cool would it be to have your own cave?) but their locations are not widely publicized, because a well-known unprotected cave is quickly dismantled by vandals, and the damage to caverns is permanent. You can't grow stalactites in a human lifetime.

We explore a couple of wild caves in the hills around Columbia. They occur in pods of marble that originated as carbonate reefs and shelf deposits in the Pacific Ocean in late Paleozoic time which were accreted to the edge of the North American plate by the process of subduction. The suite of exotic rocks are called the Calaveras Complex.

We had to pay obeisance to the mystic black cows that guard the cave entrances (well maybe anyway; they certainly like to hang out on the grass-covered plateau where the caves are located).

There were two caves that we explored today. The first was a smaller "practice" cave that provided a few crawling and climbing opportunities and some nice speleothems in a small gallery. The cave had three entrances and several small rooms that angled away from the central area.

Caves are explored these days with flashlights and headlamps, but it hasn't always been that way. The miners used candles, and the native Americans would have used torches. The caverns have a completely different aspect by candlelight. There is literally a primal mystery hidden in the shadows. I developed a greater appreciation for the cave paintings done by our distant ancestors in Europe. Can you imagine being led into the depths, and then have the torchlight suddenly play on paintings of animals and people in the darkest parts of the cavern?

The other cave is a bit more of a challenge. One must first climb down some slippery boulders into the collapsed sinkhole, and then push up through a very narrow passage that is a pretty tight  squeeze...especially for late middle-aged fat professors. But what a payoff! The 150 foot-long main room is festooned with hundreds of unbroken stalactites and columns. The ceiling was high enough to prevent vandals from reaching and breaking them off. And frankly, most vandals are lazy bastards; it's a tough hike and fairly difficult to find unless you know exactly where to look (on my fourth trip to the caves many years ago I got lost in the fog and wandered aimlessly for an hour or so).

If you wonder about cave life, there are certainly creatures living in the darkness. There are usually two or three bats hanging on the highest ceiling (although there is no light, I suspect there is a vertical entrance to the cave somewhere, because I can't imagine bats negotiating the narrow hole we climb through, but maybe they can).

On this particular day we saw half a dozen 5-inch-long millipedes. I'm told they are mainly scavengers and don't bite, but I didn't experiment with the possibility today.

I didn't see any of them today, but a couple of years back we saw a beautiful orange newt deep in the cave (I think it is a Sierra Newt, but as in all things biological I am open to correction).

Wow, Thanksgiving is over and Christmas is coming, but I'm already out of shape and overweight. The climb up out of the cave and the long mud slog back to our vehicle was tougher than it should have been. But what a nice day it turned out to be...

Another Day in the Sierra Foothills: The Sierra Underground

I had another marvelous day exploring the Sierra Nevada foothills, this time a Geology Club journey underground in a series of wild caves in the Stanislaus River Drainage. The host rock was marble of the Calaveras Complex, which originated as carbonate shelf and reef deposits in a late Paleozoic sea off to the west. The caves occurred high above the river and have not been active in a long time, being well above the regional water table. They would have formed when the adjacent canyon was more shallow, and the water table much higher. Minor formation growth can occur in the present day during the rainy season, but most of the formations show little evidence of activity.

Wild caves are one of the precious geological gifts we have in our region, and one of the most fragile of environments. There are developed caves, which I have featured in previous posts, six or so, but around 1,000(!) caves are known in the Sierra, including some that exceed 20 miles in total explored passages. Their locations are kept out of public attention because of the ease with which they can be vandalized (and vandalism is a huge problem). Our trip today was one of education and building an appreciation for these rare environments. Our college students were accompanied by a group of local high school students who joined us in the exploration.

We did an exploration of a small cave that required crawling and scooting through a narrow passageway to prepare them for the adventure of the larger cave a few hundred yards away. All of our explorers wore helmets and carried three lights for safety, but they also wore gloves to preserve surfaces in the caves. Any visit will impact a cave and the life within it (even clothing lint), so our purpose was to teach how to explore with the least amount of impact. They did well, as I saw no gratuitous touching of formations (although that may have had something to do with not one, but three "wrath of God" speeches before entering any of the caves).

The largest cave we explored had a challenging squeeze through a very narrow passageway into a large room about 70 feet long (I tried not to think about the fact that it was the ONLY way out; what if someone got stuck? I have phobias...). It is festooned with some glorious stalactites and columns that hang in thick masses from the high ceiling (click on both pictures above for a better view).

In some sections, water flowing from cracks in the wall has formed flowstone and rimstone pools (above). The cave formations (collectively they are called speleothems) are mostly composed of crystalline calcite (calcium carbonate), which is the reason the formation is sparkling.

Although not quite so spectacular as those at Black Chasm Cave, there are helictites that have formed on the ceiling of the big room. Helictites are basically stalactites on LSD, paying no attention to gravity as they grow.

Living organisms have a tough time of it in caves, with a general lack of food sources, but there is a surprisingly rich collection of creatures that live there, and which are adapted to life in total darkness. We saw quite a few spiders on this trip, but I was especially watching for salamanders, as I have seen them in this cave twice on previous trips. I didn't see any this time, but I've never had a good excuse to show a picture of one of them, so here it is. Anyone want to tell me the species?

Update: Helena Heliotrope provides an example of the horrific damage that can occur in caves when morons and idiots find them. This sort of thing has ruined many caves in the Sierra, and elsewhere across the country. Cave vandalism is a serious problem, and the perpetrators deserve stiff fines and imprisonment. Hopefully education can overcome the tendencies people can have towards this sort of crime. Certainly a great deal of damage occurs through simple ignorance, too (not to mention injuries; I took a hard hit on the head this last weekend that made me see stars, and put a gash in my helmet).

Cave Bacon and Stalactites on Drugs: The Mother Lode Underground

During our field trip outdoors last weekend, we spent a lot of time underground. One of our stops included a tour of Black Chasm Cavern near the town of Volcano in the Mother Lode of the Sierra Nevada. It is a strikingly beautiful cave in a region that is not really known for its cave systems, but they are there and they are a truly unique place to learn about geological processes in the Sierra Nevada.

Most people, if they ever think of it all, will associate the Sierra Nevada with granite, an igneous rock that forms from the slow cooling of magma miles beneath the surface. As a point of fact, only about three-quarters of the Sierra is composed of granitic rocks, and only a small percentage of that is technically granite (mostly it is granodiorite). The remainder of the range is covered by volcanic rocks, or is composed of older metamorphic rocks, including a significant amount of marble. Marble is derived from the heating and deformation of limestone, which formed on the floors of Mesozoic and Paleozoic tropical seas, possibly as coral reefs or carbonate shelf deposits. The rocks were lifted from the ocean floor and added to the edge of the North American continent when the terranes collided with the Cordilleran subduction zone in Mesozoic time.

Marble, like the limestone from which it was derived, is composed of the mineral calcite. Weak acids in the soil and groundwater react with the calcite, carrying it away in solution, forming the openings that eventually become the caverns. As the Sierra Nevada rose and deep canyons were eroded across the range, the groundwater table dropped, exposing the caverns to the atmosphere. Water dripping or seeping into the cavern evaporates, leaving behind the mineral deposits that hang from the ceiling of the cave or rise from the floor (dripstone deposits), or which cover the walls of the cave (flowstone deposits). Collectively these cave decorations are called speleothems.

More than 1,000 caverns grace the Sierra Nevada foothills. Some of the caves are world-class in their intricacy and decoration. One cave in Kings Canyon National Park has more than 2o miles of passageways. Many of the caves are also extremely dangerous: most are developed in vertical passageways with deep unexpected dropoffs, and these serve as sinks for "bad" air (carbon dioxide is a heavier gas). On the other hand, some of the very nice caves are open for guided tours: Crystal Cave in Sequoia National Park, Boyden Cave near Kings Canyon, Moaning Cave north of Columbia, Mercer Cavern at Murphys, California Cavern up the hill from San Andreas, and Black Chasm, site of our exploration last week. A trail near New Melones Reservoir leads to the Natural Bridges, where Coyote Creek flows through a cavern.

Black Chasm is named for the deep cleft not far from the cavern entrance that drops 90 feet or so into a small lake. The lake extends at least another 60 feet downwards into the mountain. The chasm prevented the miners and other early explorers from exploring (and vandalizing) the more remote passages of the cave. As a consequence, the owners were able to develop the cave with a mind towards preserving the most pristine parts of the cave. They constructed stairwells and pathways across the chasm, with handrails preventing visitors from accessing and breaking the most fragile speleothems. The cave was opened for tours about 2001, and it quickly became my favorite choice for our geology field trips.

Besides the well-placed lighting system that highlights some beautiful draperies (cave bacon) and stalactites (see the second picture), the cavern offers some of the best developed helictites to be found anywhere (top picture). Helictites are essentially stalactites that have forgotten to follow the law of gravity. The precise details of the their origin are enigmatic, but water pressure clearly plays a greater role than gravity does. They are exceedingly fragile and are usually the first things to be vandalized in unprotected caves. Black Chasm has a spectacular wall covered with them (my photo is of a small corner of the entire panel).

The operators of Black Chasm offer a group discount, and the guides enjoy speaking to geology groups when they get the opportunity. It is well worth a visit!

If you are interested in exploring wild caves, preservation and protection is the highest priority. As such, you should get in touch with the local grotto of the National Speleological Society if you want to be involved in protecting this special resource. If you have followed my blog for any period of time, you will know that I think that cave vandals are one of the lowest and most moronic forms of humanity in existence.

Of Rat Pee and Uranium and Scavengers...The Underground Story of the Ice Ages on the Colorado Plateau

Two essentially unrelated events were happening underground in Grand Canyon National Park in 1976. A precious paleontological resource was burning away in the newly established western part of the park, and in the eastern part of the park, a gawky teenager emerged from a cave with an intense desire to become a geologist.

Caverns are one of the most scenic and most valuable research resources in the Grand Canyon and other parts of the plateau, and one of the least known. Only two caves, Grand Canyon Caverns near Peach Springs, and Timpanogos Cave National Monument offer guided tours. Only one cave within the Grand Canyon, the Cave of the Domes (pictured above), is authorized for entry by inner canyon hikers. It is the one I explored in 1976 as that gawky soon-to-be geology major. The cave is exposed on the brink of a huge cliff on the side of Horseshoe Mesa (look at the drop-off to the right of the people in the top picture). Access was provided many years ago by miners who blasted a trail to the cave entrance, which is great for those who want to see a cavern in the canyon (wasn't there a song like that?), but also made it easier for vandals to reach the cave as well. The outer, easily accessible parts were pretty beat up last time I visited in the late 1990's.

What information can be offered up by the exploration of these caverns?

One of the ongoing mysteries of the Grand Canyon is the precise timing of the final carving of the canyon. The caves form while below the regional water table: the slightly acidic groundwater eats away at the limestone, forming the underground cavities. The familiar speleothems (stalactites, stalagmites and the like) don't form until the water table drops below the level of the cavern (many of these features from from dripping water). The main cause of a massive drop in the groundwater table was the carving of the canyon itself. So...the age of the oldest dripstone speleothems in a cave provides a date for when the carving of the canyon had reached near the level of the cave. Dating is provided by small amounts of uranium trapped in the calcium carbonate formations or isotopes of other radioactive elements. Examples of preliminary results can be found here and here.

Packrat middens, mentioned in the previous post, are another rich (and pungent) source of information about the past. They gather all manner of objects from their environment, and urinate on the pile. The viscous liquid binds the materials and protects them from decay in the dry cave environment. The rats may use the same location for thousands of years, so carbon dating and analysis of pollen and plant fragments allows researchers to reconstruct the biota over a significant period of time. And research shows that since the last ice age ended about 12,000 years ago, the changes were significant.

The Grand Canyon today is dominated by pinyon pine, with ponderosa at the highest elevation. Research conducted with middens has demonstrated that the pinyon and ponderosa are recent arrivals (pinyon, 11,000 years ago, and ponderosa around 7,000-8,000 years), and that during the ice ages, another conifer dominated, the limber pine. Limber pines occur in the west today, but nowhere near the Grand Canyon. These changes of flora indicate not just dryer and warmer conditions, but a change in the pattern of precipitation over the course of the seasons. The summer 'monsoons' have not always been the norm for the region.

Finally, as we saw in the previous post, at times the caves have served as a shelter for animals, or a final repository for their bones after scavengers like condors carried them in. A full listing of some of these wonderful creatures will be the subject of the next post. One other creature sheltered in these caves, but unlike the other animals, left relatively few bones behind. It did however make things, and some of their creations, made of willow twigs, survived in the dry cave environment (their creations of rock could be preserved almost anywhere). About 12,000 years ago, the first humans seem to have entered the Grand Canyon and the Colorado Plateau to take up residence.

Holy Crap, Batman! The Bat Cave is Full of it!

"It was the best of times, it was the worst of times..."

"A Tale of Two Caverns" was my alternate working title for today's blog entry, but my lower levels of sophomoric humor prevailed. This is a tale of two caves, both of which are found in the lower reaches of the Grand Canyon, and this is a continuation of a geological exploration of the Colorado Plateau that has been going on for well over a year now. The fact is, there really is a Bat Cave in Grand Canyon, and another called Rampart Cave. And they were both full of crap, as it were.

As noted in the most recent post of the series, there are hundreds of limestone caverns in the Grand Canyon region, very few of which are well-known, or even accessible. Most of them occur in a particularly difficult position, in alcoves at the top of a 400-500 foot high cliff in the Redwall Limestone. Others, including the Bat Cave, occur in the older Muav Limestone.

Bat Cave was discovered in the 1930's by a river rafter. When large amounts of bat guano were found inside, efforts began to find a way to mine the nitrogen-rich fertilizer. The cave was high on a cliff, and efforts to float a barge or to fly the product out were unsuccessful. In 1957, when a geologist estimated that the cave contained 100,000 tons of guano (worth about $10 million, in 1957 dollars), a mining corporation got serious, and invested more than $3 million constructing a tramway that crossed 7,500 feet of canyon, and climbed 2,500 feet to the south rim. The one ore cart could carry 2,500 lbs of guano and six people. It was an incredible engineering feat, although it was beset by problems. The cable failed soon after completion, and had to be completely re-hung. Worst of all, the estimates of the quantity of guano turned out to be wildly optimistic: literally 100 times more optimistic (can you imagine being the one who had to deliver this news to the boss?). Only 1,000 tons was ever produced. The venture closed down within a few months.

The cable remained hanging across the canyon. In 1960, an Air Force jet was flying far below what regulations allowed, and clipped the cable. The plane somehow remained airborne, but the cable snapped and fell to the canyon floor. The corporation was able to sue for damages, despite being shut down, and they recouped some of their losses.

The area around Bat Cave was added to Grand Canyon National Park in 1975, and for a time the NPS considered tearing down the metal frameworks of the mine, but the idea was abandoned. The cave is once again inhabited by hundreds or thousands of bats (see the Billingsley link below for a fascinating account of a 1995 exploration of the cave).

The details of the story of Bat Cave are quite fascinating. An account by one of the steelworkers who helped construct the cable system can be found in this American Heritage article. Many details of the Bat Cave mining venture and pictures of the mine developments can be found in a chapter of Billingsley et al., 1997, Quest for the Pillar of Gold: The Mines and Miners of the Grand Canyon, Grand Canyon Association, ISBN 0938216562. This book is available online; the Bat Cave article may be found in http://www.grandcanyon.org/booksmore/epubs/pillar/pdfs/chapter3_part1.pdf and http://www.grandcanyon.org/booksmore/epubs/pillar/pdfs/chapter3_part2.pdf (thanks to Wikipedia for the links).

Well, it's late, and I haven't been able to get to the story of Rampart Cave, and the photo of the strange-looking creature above, so I guess it now must be called a "Tale of One Cavern". I'll just promise to get to it in the next post!