Park Archives: Carlsbad Caverns National Park

Your encounter with Carlsbad Caverns National Parle begins in the Chihuahuan Desert of the Guadalupe Mountains. But beyond the somewhat familiar surroundings of rugged mountains and broad plains is another world. Away from sunlight, away from the flowering cactus, away from the songs of the desert birds and the howl of the coyote, lies the celebrated underground world of Carlsbad Cavern. It is an incomparable realm of gigantic subterranean chambers, fantastic cave formations, and extraordinary features. The first adventurers entering Carlsbad Cavern had no idea what to expect as they walked, crawled, and climbed down into the darkness. Today many of the wonders of Carlsbad Cavern are well known, yet the experience of exploring its chambers is every bit as exciting.

The story of Carlsbad Cavern begins 250 million years ago with the creation of a 400-mile-long reef in an inland sea that covered this region. This horseshoe-shaped reef formed from the remains of sponges, algae, and seashells and from calcite that precipitated directly from the water. Cracks developed in the reef as it rose. Eventually the sea evaporated, and the reef was buried under deposits of salts and gypsum.

Then, a few million years ago, uplift and erosion of the area began to uncover the buried rock reef. During the uplift that would become the Guadalupe Mountains, rainwater seeped downward through cracks and faults in the limestone. At the same time, hydrogen sulfide-rich water migrated upward from vast oil and gas fields to the south and east. These two waters mixed, forming sulfuric acid, which dissolved the limestone and opened up the fractures and faults into the large chambers we see today. As the mountains were pushed up, the level where the rooms and passages in the cave were being formed moved lower into the ancient reef rock. This process created nearly horizontal levels connected by steep passages. In Carlsbad Cavern, the older Bat Cave level and the younger Big Room level are connected by the steeply descending trail from the natural entrance.

The decoration of Carlsbad Cavern with stalactites, stalagmites, and an incredible variety of other formations began over 500,000 years ago after much of the cavern had been carved out. It happened slowly—drop by drop—at a time when a wetter, cooler climate prevailed. Creation of each formation depended on water that dripped or seeped down into the limestone bedrock and into the cave. As a raindrop fell to the ground and percolated downward, it absorbed carbon dioxide gas from the air and soil, and a weak acid was formed. As it continued to move down, the drop dissolved a little limestone, absorbing some of the basic ingredient needed to build most cave formations—the mineral calcite. Once the drop finally emerged in the cave, the carbon dioxide escaped into the cave air. No longer able to hold the dissolved calcite, the drop deposited its tiny mineral load as a crystal of calcite. Billions and billions of drops later, thousands of cave formations had taken shape. Oh, the shapes they took!

Where water dripped slowly from the ceiling, soda straws and larger stalactites appeared. Water falling onto the floor created stalagmites. Sometimes a stalactite and stalagmite met and merged into a column. Draperies were hung where water ran down a slanted ceiling. Flowstone was created by water flowing over the surface of a wall or floor while depositing layers of calcite. Cave pearls, lily pads, and rimstone dams appeared where pools of water occurred in the cave. Like pearls from oysters, cave pearls developed as layer upon layer of calcite built up around a grain of sand or other tiny object. Lily pads formed on the surface of pools, while dams formed where water flowed slowly on the floor.

Another type of cave formation that decorated cave walls and even other formations was popcorn, which formed when water evaporated and left behind aragonite. Aragonite is a mineral chemically identical to calcite but with a different crystal structure. These crystals tend to be small, delicate, and shaped like needles.

Some of the more unusual formations that occur in Carlsbad Cavern are helictites. They grow seemingly without regard to gravity, their twisting shapes governed by crystal shapes, impurities, and the force of water under pressure.

Carlsbad Cavern is a sanctuary for hundreds of thousands of Mexican free-tailed bats (also .known as Brazilian free-tailed bats). During the day they crowd together on the ceiling of Bat Cave; a passageway near the natural entrance of Carlsbad Cavern. In this darkened home they are seen only by scientific researchers. At nightfall the bats leave the cave in gigantic swarms. Silhouetted against the night sky like a dark, swift-moving could, the bats make their most dramatic display. Other extraordinary characteristics of bats—their natural sonar system and their ability to fly—make these creatures of darkness of great interest.

Like most species of bats, Mexican free-tailed bats navigate and locate their prey by emitting ultra-high frequency sounds. Known as echolocation, this natural sonar system is similar to that used by dolphins and whales. When a bat's signals strike an object, they are reflected back and heard by the bat. The bat then takes whatever action is appropriate, whether it be zeroing in on a moth and other flying insects or swerving to avoid a tree limb.

As many as seven types of bats may roost in Carlsbad Cavern, but none is as prevalent as the Mexican free-tailed. This dark brown to gray bat is distinguished by its long, narrow wings and a free-dangling, skinny tail. Only a part-time resident of Carlsbad Cavern this migratory bat stays here and in other Southwest caves from early spring through October. It flies to tropical Mexico and further south for the winter.

Bat Cave serves as a summer home, a daytime refuge, and, perhaps most importantly, as a maternity roost for Mexican free-tailed bats. The bats, which are mammals, migrate from Mexico to Carlsbad Cavern each year to give birth and raise their young. Young are born in June, under the cover of darkness and away from predators or disturbances. A female usually has just one offspring. Each birth occurs on the ceiling as the mother hangs by her toes and thumbs. The baby (called a pup) clings to its mother or to the ceiling. For the next four to five weeks, the youngster stays on the ceiling. During the day, mothers and pups hang in clusters on the ceiling, resting and nursing. As many as 300 bats may crowd into one square foot. At night the young are left in the cave while the adults leave to feed. How does a mother ever find her own baby in the teeming mass of pups? She remembers her pup's location, its scent, and the sound of its cry. In July or August each young bat takes its first flight, joining the adults on nightly forays. In Bat Cave, bats share their quarters with only a few insects and spiders. In late October or early November the adults and young leave for Mexico—and return again next year.

The spectacular flight of the Mexican free-tailed bat begins with a few bats fluttering out of the natural entrance of Carlsbad Cavern. Then in a matter of minutes a thick bat whirlwind spirals out of the cave up into the darkening night sky. The exodus can last from 20 minutes to 2½ hours. Once out of the cave the mass of thousands of bats undulates, serpentine fashion, toward the southeast to feed in the Pecos and Black river valleys. Once there, they gorge on moths and other night-flying insects. Using echolocation, its sonar system, each bat may catch and eat more than half their body weight in insects in a single night. With the coming of dawn, the bats begin flying back to the cave individually or in small groups. They reenter the cave in a fashion almost as remarkable as their departure. Each bat positions itself high above the cave entrance. It then folds its wings close to its body and plummets like a hailstone into the blackness of Carlsbad Cavern, making strange buzzing sounds as it does. One by one, the bats return to the safety of Bat Cave, where they sleep until dusk the next evening.

Over 1,000 years ago American Indians ventured into the entrance of Carlsbad Cavern. They left no record of entering the dark zone of the cave, but they did leave mysterious drawings on cave walls near the natural entrance. In the 1800s settlers discovered the cavern, drawn to it by the spectacle of hundreds of thousands of bats rising up out of the natural entrance in the evening. Some stayed on to mine the huge deposits of bat guano in the cave and sell it as a natural fertilizer. A cowboy named Jim White became fascinated by the cave and spent hours exploring it. White was eager to show the natural wonders of this extraordinary place to others, but few believed his improbable tales of a huge underground wilderness full of unusual formations. It took photographs to convince skeptics that Carlsbad Cavern was everything it was said to be.

In 1915 black-and-white pictures taken by Ray V. Davis, who accompanied White on a cave trip, were displayed in the town of Carlsbad, N.M. They created a sensation. People clamored to see the marvelous cave. White took them on tours that began with a 170-foot descent in a bucket once used to haul bat guano from the cave.

Word of the cave spread, finally reaching Washington, D.C. Again, there were nonbelievers. In 1923 the U.S. Department of the Interior sent Inspector Robert Holley to see whether Carlsbad Cavern was truly an outstanding natural scenic wonder. Originally a skeptic, Holley wrote in his final report: "I am wholly conscious of the feebleness of my efforts to convey in words the deep conflicting emotions, the feeling of fear and awe, and the desire for an inspired understanding of the Divine Creator's work which presents to the human eye such a complex aggregate of natural wonders."

Later that year Carlsbad Cavern was proclaimed a national monument. White, who continued cave explorations for most of his life, became its first chief ranger. In 1930 Congress created Carlsbad Caverns National Park. Through illustrated articles in magazines like National Geographic and by word of mouth, Carlsbad Caverns became one of the world's most celebrated cave systems and was designated a World Heritage Site in 1995. The park has expanded and now includes 46,766 acres and over 100 other caves.

Experienced underground explorers, or cavers, and cave scientists are the Christopher Columbuses of today—journeying beyond what is known into the unknown. For many years cavers felt a strong breeze blowing from the floor of a small cave known as Misery Hole. In 1986 they received permission to explore and break through this level. Their discoveries opened Lechuguilla Cave.

Lechuquilla Cave extends over 112 miles and holds a spectacular but fragile ecosystem. To protect this system, entry into Lechuguilla is restricted to exploration and scientific groups. Lechuguilla Cave will probably not be opened to the public. Within, cave scientists have discovered microbes that produce enzymes capable of destroying cancer cells. Scientific discoveries continue to give us clues about the complex creation of the area's caves, about bats and other members of the cave community, and how human activities affect these fragile underground worlds.

The evening flight of the bats of Carlsbad Cavern is a natural phenomenon as fascinating as the cave itself. In a mass exodus at dusk, thousands of Mexican free-tailed bats (also known as Brazilian free-tailed bats) fly from the cave for a night of feasting on insects. You can view this exciting spectacle from the outdoor amphitheater at the cave's natural entrance. Before each flight a park ranger gives a short talk on bats. Because the bats winter in Mexico, the flights occur only from early spring through October. Check at the visitor center for the scheduled time. To protect the bats, cameras and camcorders are not allowed at the bat flight program.

Protection and preservation of Carlsbad Cavern is the mission of the National Park Service. It's your responsibility, too. Unfortunately, over the years careless people have damaged many of the cave's smaller and more delicate formations.

Experimental techniques, like those that enable rangers to match pieces of broken stalactites and painstakingly glue them back together, are sometimes successful, but in practically all cases damage is irreversible.

Cave Regulations
Please help preserve Carlsbad Cavern and other park caves by observing park regulations.

Touching any cave formation is prohibited. Formations are easily broken, and the oil from your skin permanently discolors the rock.

Smoking or any use of tobacco is not permitted. Eating and drinking are not permitted except in the underground rest area and lunchroom.

Throwing coins, food, or other objects in cave pools is forbidden. Foreign objects ruin the natural appearance of the pools and are difficult to remove. Also, the chemical reaction among the foreign objects, the water, and the rock can leave permanent stains.

Photography is permitted on most cavern tours. Photographers should not step off the trails or rest tripods or other camera equipment on formations.

You may choose from three main cave tour options depending on your time, interest, and physical ability. Two are self-guiding; the third is a ranger-guided tour.

Your first stop for any cave tour is the visitor center information desk, where rangers can answer your questions about tours, and you may purchase tickets. The basic entry fee allows you to take either, or both, self-guiding tours. Rangers at the information desk can provide information on special ranger activities. They can tell you about wild cave tours that may be available.

Big Room Route
The basic tour through Carlsbad Cavern is the Big Room Route, a one-mile, self-guiding, underground stroll around the perimeter of the largest room in the cave. Taking approximately 1½ hours, this circular route passes many large and famous features, including Bottomless Pit, Giant Dome, Rock of Ages, and Painted Grotto. Highly decorated and immense, the 8.2-acre Big Room is a must-see tour for all visitors to the park. You can get to the Big Room by elevators located in the visitor center. The relatively level and well-lit trails make this the ideal tour for visitors with limited time or walking difficulties. Portions of the Big Room are accessible to visitors in wheelchairs; a map is available at the visitor center information desk. Visitors in wheelchairs should only go into the Big Room with assistance.

Natural Entrance Route
The Natural Entrance route is a self-guiding tour available to visitors with plenty of time and in good physical condition. This one-mile tour follows the traditional explorers' route, entering the cavern through the large historic natural entrance. The Natural Entrance route descends over 750 feet into the Earth following steep and narrow trails through a tall and spacious trunk passage called the Main Corridor. The route culminates in the lunchroom and underground rest area, near the elevators and the Big Room route starting point. Visitors in good health who plan to take both self-guiding tours may enjoy starting with the Natural Entrance route. Highlights along this route include Bat Cave, Devil's Spring, Green Lake Overlook, and the Boneyard, a complex maze of highly dissolved limestone rock reminiscent of Swiss cheese. Watch for Iceberg Rock, a single 200,000-ton boulder that fell from the cave ceiling thousands of years ago.

Kings Palace Guided Tour
A third option is the Kings Palace tour, a 1½-hour ranger-guided tour through four highly decorated scenic chambers. Departing from the underground rest area, the Kings Palace tour descends to the deepest portion of the cavern with paved trails, 830 feet beneath the desert surface. Although not as difficult as the Natural Entrance route, this one-mile tour does require you to descend—and later climb—an eight-story-high hill. Look for speleothems or cave decorations including helictites, draperies, columns, and soda straws. Rangers often conduct blackout programs during this tour, briefly turning off all artificial lights to reveal the permanent inky blackness of the natural cave environment. Reservations are suggested; contact the park or see our website. A separate fee is charged for this tour.

All trails in the cave are paved and well lit. You should wear comfortable, closed-toe shoes with rubber soles for maximum safety and traction. The cave temperature varies little from the annual 56°F average, making a sweater or light jacket appropriate year-round. You may want to bring a camera and a flashlight. Strollers are not allowed in any underground cave area, but infant backpacks are permitted on the self-guiding tours.

A pre-tour restroom stop is advisable because restrooms are only available in the visitor center and at the underground rest area and lunchroom. All tours are preceded by a mandatory cavern orientation briefing to promote resource protection and cavern safety. All tours exit the cave by elevator.

Rangers are available throughout the cave to protect park resources and to help you with information and questions. On both self-guiding tours, audio guides are available to provide you with in-depth information about ecology, history, and cave formation. To enjoy the natural quiet of the cave, please speak quietly.

The cavern is open daily except December 25 and operates on summer and non-summer hourly schedules. For current hours and information contact the park at www.nps.gov/cave.

To ensure that your tour of Carlsbad Cavern is comfortable, enjoyable, and safe, please follow these important rules and recommendations.

• Wear low-heeled, non-skid shoes for walking on the paved cave trails, which can be steep and slippery. • Use handrails where available. • Take a jacket or sweater; the cave's temperature is a constant 56°F. • Stay on trails. Beyond the trails are steep drop-offs where you could fall and injure yourself, and there are unlighted passages where you could get lost. Also, fragile formations on the floor, walls, and ceilings can be damaged by anyone straying from the trails. • Do not leave pets unattended in vehicles during the summer months. Kennel services are available at the visitor center.

Visitor Center
The visitor center has information about the park's underground, mountains, and desert. Publications, topographic maps, a schedule of activities, and exhibits are available. Rangers can help you plan your visit. A restaurant, gift shop, bookstore, and kennel are available at the visitor center. Services are available year-round except December 25.

Scenic Drive
The 9½-mile Walnut Canyon Desert Drive is a gravel, one-way loop through dramatic desert mountain scenery. Passenger vehicles can travel the road easily—but the narrow, twisting route is not recommended for trailers or motor homes. The visitor center has guide booklets.

Trails
The park's trail system includes a short nature trail and, for experienced hikers, over 50 miles of primitive backcountry trails. Trailheads are located along each of the park roads. Backcountry hikers should carry an ample supply of water and a topographic map. Overnight hikers must register at the visitor center.

Camping and Picnicking
There is no developed campground in the park, but the nearby towns of Whites City and Carlsbad have several. These towns have lodging, restaurants, gasoline stations, and other services. Camping in the backcountry requires a permit, available free at the visitor center. Picnic tables are near the visitor center and in Walnut Canyon. Rattlesnake Springs has a picnic area with tables, grills, drinking water, and restrooms.

Climate
Expect warm summers and mild winters. Average summer highs are in the 90s°F; winter highs are in the 50s and 60s°F. Thunderstorms occur in summer, posing the danger of lightning in higher areas and of floods in low-lying areas.

Slaughter Canyon Cave
Ranger-guided tours of Slaughter Canyon Cave take you into an underground wilderness without electricity, paved walkways, or modern conveniences. In this wild cave, darkness is penetrated only by the light of flashlights carried by tour members. Highlights of the two-hour tour are the sparkling, crystal-decorated Christmas Tree column and the Chinese Wall, a delicate, ankle-high rimstone dam. Old bat guano mining excavations can be seen. You must hike a strenuous ½-mile trail to the cave entrance where the tour begins. Sturdy walking shoes, flashlights, and water are required. Tours are given daily in the summer season and weekends the rest of the year. A fee is charged; reservations are required. For details contact the park or check our website.

The contents of brochures, site bulletins and trading cards (denoted with a colored caption) can be viewed by clicking on the cover. Most modern-day brochures, however, are cover only (denoted by a white caption) due to photograph copyrights. These items are historical in scope and are intended for educational purposes only; they are not meant as an aid for travel planning. The dates under each brochure do not reflect the complete range of years that a particular brochure was issued.

1933		cover only 1935		1936 (HTML)
1937		1938		1939
1940 (HTML)		1941 (HTML)		1942
1946		1948		1949
cover only 1950		1951		1952
1953		1954		cover only 1955
1956		1958		1961	cover only 1962
1963	1966	1967	1968	cover only 1968 (Spanish edition)	cover only 1970
1972	1973	cover only 1973 (Spanish edition)	cover only 1975	1975 (Spanish edition)	1977
1978	1977	cover only 1980	1982 (Spanish edition)	1983	1985
cover only 1986-1991		cover only 1995-2001		cover only 2002-2019
cover only Date Unknown (Spanish Edition)		cover only 2016 (Spanish Edition)

Accessibility Guide Date Unknown		Accessibility Guide 02/2019		Area Attractions 12/2019
Backcountry Caves 10/1998		Backcountry Caves 08/28/2003		Backcountry Caves 2017
Backcountry Caves 04/2021		Backcountry — Be prepared for rugged beauty Date Unknown		Bat Research Date Unknown
Cave Exploration Milestones 02/2021		Cave Geology Date Unknown		Caverns' Chronology Date Unknown
Cavern Information 01/1979		Guided Tours 04/1998		Cavern Trails and Tours 01/2019
The Famous Bats of Carlsbad Cavern 05/1999		Frequently Asked Questions Date Unknown		Interesting Facts 04/2021
Native Plants of the Chihuahuan Desert Date Unknown		Native Plants of the Chihuahuan Desert 12/2017		An Historical Perspective 02/1997
The Permian Period Date Unknown		Surface Geology Date Unknown		Area Information Date Unknown
Large Print Brochure Date Unknown		The Bat Flight Date Unknown		The Bat Flight Date Unknown
Cavern Information Date Unknown		Cavern Information Date Unknown		New Cave — A Guided Flashlight Trip Through An Undeveloped Cave Date Unknown
Checklist of Amphibians and Reptiles of Carlsbad Caverns National Park January 2007		Checklist of the Birds of Carlsbad Caverns National Park January 2007		Preliminary List of Known Insects of Carlsbad Caverns National Park Through 2006 January 2007
Checklist of the Mammals of Carlsbad Caverns National Park January 2007		Checklist of the Vascular Plants of Carlsbad Caverns National Park January 2007		Bird Checklist April 2021
Carlsbad, New Mexico: The Cavern City Date Unknown	Carlsbad Caverns Nat'l Park Date Unknown	Carlsbad Caverns Information Date Unknown	Carlsbad Caverns National Park Date Unknown	Carlsbad Caverns National Park, New Mexico 1959
Hungry Bats and Buggy Nights Date Unknown
Trading Cards
(©Jefferson National Parks Association)

Geology of the Guadalupe Mountains National Park (John P. Brand and Alonzo D. Jacka)

Late Pleistocene Plant Communities in the Guadalupe Mountains, Culberson County, Texas (Thomas R. Van Devender, W. Geoffrey Spaulding, and Arthur M. Phillips, III)

Preliminary Report of the Ecology of Fire Study, Guadalupe Mountains and Carlsbad Caverns National Parks (Gary M. Ahlstrand)

The Guadalupe Mountains—A Chink in the Mosaic of the Chihuahuan Desert? (Marshall C. Johnston)

Summary of the Vegetative Zones of the Guaoalupe Mountains National Park, Texas (David K. Northington and Tony L. Burgess)

Status of Rare and Endangered Plant Species of the Guadalupe Mountains National Park, Texas (David K. Northington and Tony L. Burgess)

Agave—Complex of the Guadalupe Mountains National Park: Putative Hybridization Between Members of Different Subgenera (Tony L. Burgess)

The Land and Freshwater Mollusca of the Guadalupe Mountains National Park, Texas (Richard W. Fullington)

Plusiotis woodi and Plusiotis gloriosa (Scarabaeidae): First Report of the Guadalupe Mountains National Park (Richard W. Fullington and Don Harrington)

Notes on the Bionomics and Nest Structure of Pogonomyrmex maricopa Hymenoptera: Formicidae) (James V. Moody and David E. Foster)

Limnology of McKittrick Creek, Guadalupe Mountains National Park, Texas (Owen T. Lind)

The Quaternary Vertebrate Fauna of Upper Sloth Cave, Guadalupe Mountains National Park, Texas (Lloyd E. Logan and Craig C. Black)

Environmental Implications of Herpetofaunal Remains From Archeological Sites West of Carlsbad, New Mexico (John S. Applegarth)

The Biogeographical Relationships of the Amphjbians and Reptiles of the Guadalupe Mountains (John S. Mecham)

Compositional Aspects of Breeding Avifaunas in Selected Woodlands of the Southern Guadalupe Mountains, Texas (George A. Newman)

Post-Pleistocene Mammals From Pratt Cave and Their Environmental Significance (Ernest L. Lundelius, Jr.)

Ground Sloth Dung of the Guadalupe Mountains (W. Geoffrey Spaulding and Paul S. Martin)

Mammals of the Guadalupe Mountains National Park, Texas (Hugh H. Genoways, Robert J. Baker and John E. Cornely)

Demographic Patterns of Small Mammals, a Possible Use in Impact Assessment (Peter V. August, John W. Clarke, M. Houston McGaugh, and Robert L. Packard)

Population Size of Tadarida brasiliensis at Carlsbad Caverns in 1973 (J. Scott Altenbach, Kenneth N. Geluso, and Don £: Wilson)

Coexistence of Two Species of Kangaroo Rats (Genus Dipodomys) in the Guadalupe Mountains National Park, Texas (Margaret A. O'Connell)

Ecological Distribution of Woodrats (Genus Neotoma) in Guadalupe Mountains National Park, Texas (John E. Cornely)

Status of the Guadalupe Mountains Vole, Microtus mexicanus guadalupensis (Dallas E. Wilhelm, Jr.)

Food Habits of Mule Deer on Foothills of Carlsbad Caverns National Park (Walter H. Kittams, Stanley L. Evans, and Derrick C. Cooke)

Biomes of the Guadalupe Escarpment: Vegetation, Lizards, and Human Impact (Frederick R. Gehlbach)

Canyons & Caves: A Newsletter from the Natural Resources Office, Carlsbad Caverns National Park (Issue #)

CAVE History Update: A Newsletter from Carlsbad Caverns National Park's Cultural Resources Office in the Resources Stewardship and Science Division

Issue: 5 (August 29, 2003) • 6 (September 16, 2003) • 7 (October 30, 2003) • 8 (December 15, 2003) • 9 (February 25, 2004) • 10 (August 31, 2004) • 11 (April 27, 2005)

Familia Mormoopidae (Sergio Ticul Alvarez-Castañeda, extract from Mamíferos del noroeste de México, 1999)

Western Texas and Carlsbad Caverns International Geological Congress XVI Session Guidebook 13: Excursion C-1 (N.H. Darton and P.B. King, 1932)

The following visual bibliography is just a sampling of the handbooks and books which have been published for this park. NPSHistory.com does not endorse these, but are merely presenting them for informational purposes only. As most are copyrighted, we are only able to provide the covers, and not contents, of these publications.

The Carlsbad Caverns of New Mexico: Its History and Geology A.W. Anderson 1939	cover only The Discovery and History of Carlsbad Caverns, New Mexico Jim White c1946	cover only The Indians of Carlsbad Caverns National Park 1956	A Guide Book to Carlsbad Caverns National Park Paul F. Spangle, ed. 1960
cover only Carlsbad Caverns National Park, New Mexico John Barnett 1979	cover only Carlsbad Caverns: Silent Chambers, Timeless Beauty John Barnett 1981	cover only Bats of Carlsbad Caverns National Park Kenneth N. Geluso, J. Scott Altenbach and Ronal C. Kerbo 1987	cover only Carlsbad Caverns: The Early Years Robert Nymeyer and William R. Halliday 1991
cover only Carlsbad Caverns National Park: Worlds of Wonder Candace Crane 2000