In the darkness of the 19th unnamed cave, you must crawl. Although the chamber is wide, it is vertically quite small – there is enough space for a squat. You have to lie on your back to look at the ceiling. What you can see in an instant is incredibly limited by these natural restrictions. Still, the extreme nature of the 19th unnamed cave makes the massive ancient artworks etched there all the more amazing.
In a study published Wednesday in the magazine antiquity, researchers detail five incised figures on the mud veneer of the ceiling of the cave, located in an undisclosed location in Alabama. The art was created during what is called the Woodland Period by Native Americans between 600 and 1000 AD Their descendants belong to the Chickasaw Nation, Cherokee Nation, Choctaw Nation, and Muscogee Creek Nation, among others.
These figures, described as mud glyphs, are believed to be the largest known rock art images identified to date in North America. The largest is an 11-foot-long snake resembling an eastern diamondback rattlesnake, a creature sacred to the indigenous peoples of the Southeast. Slightly smaller but more mysterious, three anthropomorphic figures bear no resemblance to characters known from Native American stories of the Southeast. The final figure is six feet of swirling curls; we do not know what it represents.
What is known is that these caves are considered sacred places by the Native Americans of the American Southeast, considered as pathways to the underworld. This is why scholars hypothesize that the anthropomorphic figures could have been spiritually significant.
These massive numbers are also described in the study as “invisible”. The cave is so cramped and the carvings so pale that the artwork was overlooked when researchers entered the chamber more than 20 years ago. To solve this problem, the study team used a technique known as high-resolution 3D photogrammetry to digitally manipulate the chamber space and reveal the artwork.
Photogrammetry involves taking many overlapping photographs from many angles and using them to create a 3D model through software. It’s a method developed in the 19th century as a means of transforming aerial photographs into topographic maps. But later breakthroughs in computing and digital photography allowed the process to become what it is today: a technique for producing photorealistic models that can be digitally manipulated in virtual space.
This new study marks the first time this team has used 3D photogrammetry to analyze an ancient cave like this. They argue that this technology offers “untapped potential” to document and identify other “archaeological phenomena”.
These massive figures have long defied the human eye; the size of the cave also suggests that the artists could not see their work in its entirety as they created it. Instead, they must have entered the cave “with a composition already in mind”, John Simek, the study’s first author, told The Daily Beast. The lines are too well defined and purposely placed to be just doodles.
“It was a remarkable experience because all of a sudden we realized that this cave was much more complicated than we thought.”
— Jan Simek, cave archaeologist, cave archaeologist and professor at the University of Tennessee, Knoxville
Simek is a rock archaeologist and professor at the University of Tennessee in Knoxville. He has known about the 19th unnamed cave since co-author Alan Cressler, a speleologist and independent researcher, stumbled upon the site in 1998 and saw hundreds of much smaller mud glyphs also on the ceiling – carvings of geometric shapes, wasps and birds. What Cressler couldn’t see, however, were those much larger numbers, that is, until the team used 3D photogrammetry years later.
“We’ve been doing this job for 35 years and we’ve seen a lot of very impressive things,” Simek said. “But we didn’t expect to see characters of this size, especially human-like characters. When we did, it was a remarkable experience because all of a sudden we realized that this cave was much more complicated than we thought.
Technology is advancing archeology at a rapid pace, Simek said. Tools like lidar, a remote sensing method, and satellites allow teams around the world to see what was previously hidden. Photogrammetry as a field has also advanced over the past decade, so much so that the co-author Stephane AlvarezNational Geographic photographer and founder of the Ancient Art Archive, asked Simke and Cressler to return to the cave in 2017.
Over the course of two months, the study team took 16,000 photographs, with each shot overlapping by 60-80%. These were used to create three 3D models: two of the etched ceiling and one of another artless bedroom. (The unnamed 19th cave is only part of three miles of underground passageways.) Digital manipulation of the models, in turn, allowed for a clear view of the ceiling.
“The “access” provided by 3D photogrammetry without physically entering the cave cannot be overstated.”
— Julie Reed, associate professor at Penn State
“You can move the floor and you can move the ceiling in ways that you actually can’t,” Simek said. “It gives us a much wider field of vision.” This process, and the perspective it allows, revealed that the faint lines of the ceiling were in fact incisions corresponding to intricate works of art.
“The large number of images collected from the 19th Unnamed Cave and the overlays created allow us to see the big picture, so to speak, and see it in greater detail than before,” Julie Rosean associate professor at Penn State who was not part of the study team, told The Daily Beast.
Reed is also a historian specializing in Southeast Indian and Cherokee history, and a citizen of the Cherokee Nation. Although she did not participate in this project, she visited other caves with members of the study team. So far, Simek and his colleagues have visited about 2,000 caves across Tennessee, Georgia, Kentucky and Alabama. They saw art in 100 of these caves.
Reed observes that the worker-artists of the Woodland period also created the Serpent’s Mound, a 1,000-foot-long effigy and burial site, in present-day Ohio. The artistic imagination and thematic choices seen both there and in the 19th Unnamed Cave remind us “of how our native ancestors spoke similar creative and spiritual languages to each other across time and space. “, said Reed.
The study team was also keen to use 3D photogrammetry because you can, with little effort, turn the data into a VR experience, Simek said. In the paper, the team discusses the potential of bringing these virtual experiences to descendant communities. They have already presented the first results to the eastern band of the Cherokees, although the unnamed 19th cave project did not directly involve the natives.
(The study team is working on another paper on another cave in Alabama with members of the Louisiana Coushatta tribe. They have also partnered with the Chickasaw Nation to document rock art in their home country. .)
“The ‘access’ provided by 3D photogrammetry without physically entering the cave cannot be overstated,” Reed said.
“As someone who has been in caves containing the ancient Cherokee syllabary, I regularly think about how we can bring the documents and the physical space to the ancient Cherokee people who are the expert speakers and readers of the language,” said she added.
Access, as far as the 19th unnamed cave is concerned, is complicated on several levels. It is designated as such to keep its location anonymous: It is unprotected and located on private land. “Security is a real concern,” said Simek, who fears damage and looting.
Nor is it on land legally owned by a tribe. Around 1813, a movement of settlers led by Andrew Jackson led to illegal land sales and squatter claims on Native-owned properties in Alabama. The subsequent passage of the devastating Indian Removal Act of 1830 forcibly removed an estimated 125,000 southeastern tribesmen from their lands.
Today, around two-thirds of the 100 cave sites identified by Simek and his colleagues are located on private land – and they are very difficult to access, both because of their legal status and the simple fact that they are physically difficult to access. Universal access, however, is not necessarily the ultimate goal of these sites. Instead, we should “consult with descendant communities today to avoid the extractive nature of relationships that has long been associated with non-Indigenous interest in Indigenous lands, cultures and histories,” Reed said.
While the issue of access remains unresolved, Simek plans to continue searching for more rock art. There are approximately 25,000 caves in the American Southeast, and only 2,000 have been examined for rock art. He is also eager to re-examine sites with 3D photogrammetry; he thinks it’s very likely that there is art they missed.
“I’m about to retire from my teaching job, but I’m not going to stop doing this,” Simek said. “There is so much work to do.”