As it traverses the marshy Gulf coast lowlands of the Florida panhandle’s Big Bend region, the aquifer-fed Aucilla River would not fit the typical description of a North American river. It flows visibly above the surface in places, like most rivers do, but then disappears in other places into an ancient underground sinkhole system, carved into a vast limestone bedrock foundation over time by geological processes of erosion and collapse. Many thousands of years ago, one might not have recognized it as a river at all. Back then, when sea level was much lower, it was simply a series of sinkholes of various sizes, clearly visible from the surface. Today, the river is an underwater treasure trove of fossilized remains of long-extinct creatures. Needless to say, it has been an important paleontological destination for scientists conducting research on the North American Pleistocene past.
One place along the river, known as the Page-Ladson site, has recently yielded some tantalizing finds — evidence of a very ancient human presence, people who lived here before the Clovis era more than 14,000 years ago.
But few people can actually see this site. It lies submerged under about 30 feet of water and additional layers of sediment within a bedrock limestone sinkhole 60 meters in diameter. It is the exclusive domain of scuba divers. Everyone else, at the surface, only sees the slow-moving river flowing through a thick cypress swampland. During Pleistocene times, however, this sinkhole was essentially dry and easily accessible, and for the animals of the time, it had a particularly attractive feature — a small freshwater pond at its base. We know this because, since the mid-1980’s, scientists have studied the geology and recovered bones and other evidence there that tell a story of giant Ice Age mammals frequenting the pond for its fresh water.
The Aucilla River traverses a marshy Gulf coast lowland area today (see also map below), very different than the drier world that existed here during Ice Age times. Ebyabe, Wikimedia Commons. Below image Karl Musser, Wikimedia Commons
It was in the early 1980’s when Buddy Page, a recreational diver and avocational archaeologist, recovered elephant bones beneath the surface of what is today known as the Half-Mile Run section of the Aucilla River. Thinking that any further investigation would require the services of a professional team of scientists, he reported the site and his finds to Jim Dunbar, then of the Florida Bureau of Archaeological Research, and David Webb, professor of Vertebrate Paleontology at the University of Florida. Together with a team of divers and other experts, Dunbar and Webb proceeded to excavate and study the site beginning in 1983, discovering in the process eight stone artifacts, mostly flakes, in association with butchered mastodon bones within a deposit dated through radiocarbon dating techniques to more than 14,400 years old. Most remarkable was an adult mastodon tusk that exhibited what appeared to be human-made cut-marks.
The findings were not without controversy. The age of the finds based on the dated deposit “was an impossible age for the scientific community to accept at the time,” says Jessi Halligan of Florida State University, a co-author of the most recent study and report on the Page-Ladson site, “because it was well-accepted that the Americas were colonized by the Clovis people who arrived on the continent over the Bering Land Bridge no more than 13,500 years ago at the oldest.”
Part of the difficulty surrounded the nature and difficulty of the location. “As an underwater site, it could not be visited by just any member of the archaeological community, so the discoveries could not be verified by impartial peers,” says Halligan. “And everyone knows that rivers are destructive earth-movers, so it seemed quite possible that even if the layers were as old as the researchers reported, that the material may not be cultural at all.”
Dunbar and Webb published their research on the findings, but for years their findings, enshrouded in dispute, were consigned to near oblivion.
Texas A&M University’s Center for the Study of the First Americans decided to take on the challenge by returning to Page-Ladson to finally resolve the status of the site. “I always thought the site had great potential to help us resolve the issue of whether people were here before Clovis and I always wanted to investigate the site,” said archaeologist Michael Waters, Director of the Center. “I got my chance in 2012 when John Ladson [the owner of the property surrounding the site] invited me to investigate the site.”
Waters, long a well-known name in First American studies, turned to Jessi Halligan to join him as co-director of the new project. Halligan, a veteran of 20 years in North American archaeology and who studied under Waters at Texas A&M, had already been deeply involved in Aucilla River research since 2007. Together, they headed a group composed of scientists and divers that would lend the best expertise to the total research effort. It was a perfect team.
But the challenges were considerable. First of all, the site was 30 feet underwater, requiring SCUBA access. Communications between divers during any excavation thus meant using hand signals and notes written on mylar clipboards. Because the river water was stained into a dark red color by tannins, most sunlight could not penetrate the depths to the site, so lights were needed to work. Safety was a premium, so work demanded extensive logistics which required diving in teams of two, redundant SCUBA equipment, a dredge and dredge operator for the dive teams, and additional divers at the surface to manage the divers and air supply. All materials recovered and brought to the surface had to be meticulously dried and conserved, a time-consuming process.
Added to this were the environmental and weather conditions. “We were hot, dirty, and bitten by bugs,” said Waters. “The first year we worked at the site, we were plagued by flooding and hurricanes.”
Reaching their goal of finding new evidence of pre-Clovis occupation proved elusive at first. “The area we excavated yielded no artifacts,” wrote Waters to Popular Archaeology. “We confirmed the stratigraphy and found some bones of extinct animals, but we needed artifacts.”
But for Waters and Halligan, persistence was the name of the game. “We were convinced we needed to give it another try and the next season we had better weather,” said Waters.
Along with the better weather came better results. In 2013, Waters and Halligan hit their ‘pay dirt’. There were multiple dives, but on one dive, a crew that included Morgan Smith, a graduate student of Waters, and John Albertson, went down to clean up an excavation unit and began to excavate a new level. As they dug, Albertson’s trowel met some resistance. Fanning the sediments away, he found what appeared to be an artifact — a biface. Leaving it in place, Smith came up to the surface to announce the new discovery.
“We decided to collect samples from all around the biface and above it and below it for radiocarbon dating so that there would be no confusion about its age,” said Waters. “In the end, 71 samples were radiocarbon dated and confirmed the age of the artifact to 14,550 years ago.”
Finally bringing the artifact up to the surface after the dating samples were taken, they determined upon examination that it was indeed a biface — a reworked knife fragment — lying in the same deposit that contained the remains of extinct mammals — mastodons, camels and bison. This was the same deposit in which Dunbar and Webb had discovered the mastodon tusk that featured cut-marks — the multiple, parallel, deep linear grooves that ran perpendicular to the long axis of the tusk — clear signs of human activity. Other flakes were found within the same or similar deposits, bringing the total artifact finds to six.
“We were all excited,” Waters wrote Popular Archaeology. “I will never forget that day and the feeling of excitement when the artifact came to the surface. It was like a moment when you know you have found something special that will change a long held paradigm.”
Waters was right. It was a moment, like some other moments at other sites, that would change what we know about when and how the first Americans made their debut in the Americas.
Surface setup at the site, showing the floating screen decks with yellow hoses leading to divers underwater, bubbles by buoys are air bubbles from divers. Pictured are John Albertson, Rodrigo Torres, and Jessi Halligan on floating screen decks. Photo by Adam Burke. Provided courtesy of the Center for the Study of the First Americans (CSFA).
Halligan waiting to begin a dive. Photo by Brendan Fenerty. Provided courtesy of the Center for the Study of the First Americans (CSFA).
Halligan and Neil Puckett examining find. This is a juvenile mastodon radius. Photo by Brendan Fenerty. Provided courtesy of the Center for the Study of the First Americans (CSFA).
Puckett bringing subadult mastodon bone to surface for conservation. Photo by Brendan Fenerty. Provided courtesy of the Center for the Study of the First Americans (CSFA).
Halligan excavating underwater during 2015 season. Photo by Shawn Joy. Provided courtesy of the Center for the Study of the First Americans (CSFA).
The pre-Clovis biface in place at the bottom of the 2013 excavation block just after discovery. Photos by Jessi Halligan. Provided courtesy of the Center for the Study of the First Americans (CSFA).
Excavation Schematic Image by Jessi Halligan. Provided courtesy of the Center for the Study of the First Americans (CSFA).
The pre-Clovis biface from the Page-Ladson site. Image by Josh Keen. Provided courtesy of the Center for the Study of the First Americans (CSFA).
Morgan Smith and Michael R. Waters examining biface immediately after its discovery (by Smith and his dive buddy, John Albertson). Photo by Adam Burke. Provided courtesy of the Center for the Study of the First Americans (CSFA).
Tusk reassembled. Adult mastodon tusk from ARPP excavations at the Page-Ladson site (UF 150701) shown reassembled for Dr. Daniel Fisher’s reexamination of the cut-marks. Jessi Halligan, Cindy Fisher, and FLMNH researcher Jason Bourque shown. Photo by Daniel Fisher.
A Pre-Clovis Episode
The broadly accepted view about when and how people first entered the Americas has revolved in part around the changes in the glacial periods associated with the last glacial period of the Ice Age, a time when the Cordilleran and Laurentide ice sheets covered much of northern North America. However, during the warmer interglacial periods, they retreated to create ice-free corridors along the Pacific coast and areas east of the Rocky Mountains of Canada. Scientists have long suggested that it was through these corridors that humans were likely able to cross Beringia into the Americas (see image below). Beringia was a land bridge as much as 1,000 miles wide that joined present-day Alaska and eastern Siberia at various times 110,000 to 10,000 years ago.
Roblespepe, Wikimedia Commons
The Clovis time refers to a time period (beginning about 13,500 years ago) to which, according to many scholars, the earliest known stone tools and weapons made by early ancestral Native Americans could be assigned. Best known for their medium to large fluted lanceolate projectile points and distinctive bone and ivory objects, these stone artifact finds constitute the evidential basis for the traditional “Clovis First” hypothesis, which suggests that the people associated with the artifacts were the first inhabitants of the Americas. Clovis artifacts have been found in abundance at sites across the North American continent.
Clovis points from the Rummells-Maske Site, Cedar County, Iowa, from the Iowa Office of the State Archaeologist collection. Bill Whittaker, Wikimedia Commons
But new research in genetics and new archaeological finds at a number of sites across the Americas have presented evidence of an earlier occupation, preceding the traditional Clovis culture. “Archaeological evidence shows that people were also present between 14,000 and 15,000 years ago in what are now the states of Texas, Oregon, Washington, Pennsylvania, and Wisconsin,” states Waters. In addition, another well-known site in South America known as Monte Verde near the coast of Chile, thousands of miles south of these sites, has revealed evidence of human occupation dated to pre-Clovis times. Page-Ladson, according to Waters and Halligan, fits well into this emerging new time paradigm because of the compelling evidence it has revealed. “The Gold Standard necessary to demonstrate unequivocally that a site pre-dates Clovis has always been 1) clear evidence of human activity usually in the form of stone tools; 2) artifacts occurring in a solid geologic context, and 3) artifacts dated using a reliable dating technique,” asserts Waters. Page-Ladson, they maintain, meets all of these criteria for several reasons:
- At Page-Ladson, unequivocal lithic artifacts, including a bifacial knife and utilized flakes, are associated with mastodon remains (including a tusk with stone tool marks).
- These artifacts are sealed in undisturbed geological deposits at the base of a 4-m-thick stratified sequence.
- Seventy-one new radiocarbon ages show that the artifacts date to 14,550 years ago and that the stratigraphy at the site is undisturbed.*
Armed with this evidence, Waters and Halligan suggest that the site plays a significant role in informing the ongoing debate about how and when the first peoples of the Americas settled the landscape and what they were doing. They point to the research showing that Page-Ladson is about the same age as the Monte Verde site, indicating that people were living on both American continents at least 14,500 years ago; that there were also people, based on archaeological finds, present at this time in Washington, Oregon, Texas, Wisconsin, and Pennsylvania; that the findings are consistent with the genetic research showing a pre-Clovis presence in the Americas; and that evidence in the form of dung fungus at Page-Ladson indicates that large mammals like mastodons became extinct around 12,600 years ago, showing an overlap of humans and a large extinct mammal presence, suggesting the possibility that human hunting may have had an impact on their extinction.
Most significantly, the Page-Ladson finds feed into an emerging new paradigm. “At the time people were butchering or scavenging a mastodon carcass at 14,550 years ago at Page-Ladson, the Ice Free Corridor or inland route into the Americas would have been closed,” Waters concludes. “The evidence from Page-Ladson provides indirect support for a coastal migration into the Americas. How people made their way to Florida and how long this took, we can only speculate, but this [obviously] hints at an even earlier arrival of people into the Americas.”
Popular Archaeology asked Halligan if she, based on the findings, could reconstruct the scene that existed at this place so long ago in prehistory:
What we have evidence for is the following: 14,500 years ago, people were within this steep-walled sinkhole butchering a mastodon at the edge (and possibly partially within) a shallow pond. They expended a great deal of effort to extract a tusk that they later left behind, either because they were only interested in the fatty meat within the tusk cavity, or because they wanted to leave it preserved in the shallow pond for later, but never returned for it. The evidence from this site is sparse, but its location and contents can tell us some important things: this site shows people were well-familiar with the landscape, and knew where to get stone for toolmaking, knew how to extract a tusk, and knew when, where, and how to access freshwater. In other words, they were very capable and competent hunter-gatherers who probably were pretty familiar with this landscape.
Pushing Back the Clock on the First Americans
Page-Ladson joins a short list of sites across North and South America that have revealed a pre-Clovis human occupation of the Americas. Depicted to the right is a view of the interior of the Meadowcroft rockshelter, located in Pennsylvania. Meadowcroft is now widely thought to have yielded evidence of one of the earliest known examples of a human presence in North America, along with the longest sequence of continuous human occupation. It was first systematically excavated by Dr. James M. Adovasio, currently the Dean of the Zurn School of Natural Sciences and Director of the Mercyhurst Archaeological Institute at Mercyhurst University. His efforts included a team of colleagues and field school students in the early 1970’s. All together, they uncovered evidence of a human presence they suggested dated thousands of years before the time of the advent of the first broadly recognized human culture in the Americas—the Clovis—and its implied first peopling of the North American continent. Their dating at this site pushed the clock back on human occupation of North America to as much as 16,000 years ago.
But this stature and acceptance didn’t come quickly and easily for Meadowcroft and its chief archaeologist. It challenged the prevailing paradigm, radically pushing back the dates on human occupation of the continent. From the very beginning, the validity of his findings related to the earliest human modified stone objects and other features of human habitation found at the site were marked with controversy. Decades later, however, the story of the Meadowcroft controversy has evolved to one of broad acceptance. Partly due to the mounting evidence from other sites with pre-Clovis artifacts across the Americas, and in no small measure to the meticulous and scientifically rigorous methods used in the Meadowcroft research, the site has arguably become a kingpin in a new mainstream of scientific inquiry that has increasingly legitimized the ‘pre-Clovis’ way of thinking. Today, Meadowcroft is designated as a National Historic Landmark, drawing thousands of visitors yearly.
Image: Sue Roth, Wikimedia Commons
For now, neither Waters nor Halligan have any immediate plans to return to the field at Page-Ladson. It doesn’t mean, however, that work is over. Project staff is busy documenting the findings from the younger strata at the site, including pollen and spore analysis and special studies on core and sediment samples, and Waters and Halligan are also continuing their search for other sites that may bear on the earliest Americans.
In the end, whether or not scientists return to Page-Ladson for further excavation and survey, the site is already well on its way to leaving a legacy.
“The record of human habitation in the Americas between 14,000 and 15,000 years ago is sparse, but it is real,” concludes Waters. “The few stone tools and the other evidence left behind by hunter-gatherers at the bottom of the Page-Ladson sinkhole 14,550 years ago will have a long lasting and profound impact on our understanding of the earliest pioneers and explorers of the Americas.”
Diving crew lined up for survey work. These divers are waiting to conduct a survey, looking for new sites. Photo by Jessi Halligan. Provided courtesy of the Center for the Study of the First Americans (CSFA).
*Michael Waters, response to Popular Archaeology inquiry, January 2017.
Information for this article was obtained from a variety of sources, including written interviews with Michael Waters and Jessi Halligan, as well as the detailed study report cited below.
Halligan et al., Pre-Clovis occupation 14,550 years ago at the Page-Ladson site, Florida, and the peopling of the Americas, Science Advances 13 May 2016;2:e1600375
Cover image, top left: SCUBA diver Ivy Owens collecting micromorphology samples during 2015 season. Photo by Shawn Joy. Provided courtesy of the Center for the Study of the First Americans (CSFA).