Croft rock shelter has been the site of extensive arcology work since 1973, after university of pittsburgh students removed layer of layer of sediment, evidence of human activity as long as 19,000 years ago was revealed. We visit to learn the story from james adovasio, who has been leading Archeology Research there for almost 50 years. We are currently 46 kilometers southwest of pittsburgh, pennsylvania, in washington county, on the north bank of cross creek, which is a small tributary of the ohio river. In 1972 there was a vacancy in the Anthropology Department at the university of pittsburgh. I joined the faculty there. One of the parameters of which job was to set up an archeological Training Program that would train not only graduate and undergraduate students in the protocols of modern excavation, but also to train people in ancillary fields, geeolojists. Because i didnt have the opportunity to search for a location for the Field Operation due to research commitments in the eastern mediterranean, i circulated word amongst my colleagues, who directed me to see this particular site, which had actually been discovered in 1955 by the land owner, albert miller. At that particular juncture in time, we thought we understood everything there was to understand about the initial human occupation of the new world. There was a prevalent model about how that event took place, when that event took place, what their lifestyles may have been like that literally everybody believed. And the excavations here and at a series of other locations have profoundly altered our perceptions of the past in such a way that literally everything we thought we knew, we dont know anymore. Cross creek flows into the ohio river directly west of us about 12. 22 kilometers from here, a little more than 6 miles from here. With just a little more water in the stream, you could canoe down to wellsberg, West Virginia on the ohio, with only a couple points necessary where you would have to move to pedestrian traffic. Any human populations moving up or down cross creek, to and from the ohio river prehistorically, whether it was euroamericans, whether it was native americans, late in the day would have seen this rock shelter and stopped here for varying periods of time, sometimes just an overnighter, sometimes for a longer time. What attracted us to the site in 1973 when we first saw it was the size of the overhang, the fact that even during periods of heavy rain and snow, youre protected from the elements inside. The fact that even when the creek floods, as it has several times during the course of the extrications, the rock shelter is always high and dry. There are permanent strings that provide Drinking Water both west and east of the site, as well as the prepolluted state of cross creek itself would have provided Drinking Water. There is an abundance of edible wild plant and animal food in the area, which is a prime attraction. But the protection from the elements is a big deal. It sort of renders this into a kind of prehistoric holiday inn, as it were, and all of the native americans at the time, whether they belonged to a group that had stayed here before or not, would have been aware that this site existed, and would have, by wordofmouth, transmitted that information either to their own kinsfolk or other groups would have found out about it or rediscovered it. So essentially, if youre going to spend the evening anywhere between here and the ohio river or the little town thats nearby, this is where you would stop and this is what attracted us to this location. And its the exact same thing that would have a practitionttr prehistoric people here, too. Back when the initial excavation started, we thought we knew everything there was to know about the first people in the new world. In 1933 there were excavations near a town called clovis, and from that particular location, they recovered a particularly distinctive kind of spear point with two flutes taken from either side. Now, these points had been known previously. In fact, weve known about their existence for several hundred years. Theyve been found all over most of north america, on down into mexico, and south america. And the point is the people who made these points were in fact the first people in the new world. They had come over from siberia, walked across the baring platform at a time when it was exposed, and then basically sprinted all the way down to the tip of south america in less than 500 radio carbon years, killing off 32 genera of ice age animals on their way. It was thought to have been by american and canadian archeologists the worst killing time of the planet. They had material as old as clovis and the u. S. And canadian response was those guys on the other side of the atlantic havent the faintest idea what theyre talking about and the guys in south america dont speak english. Consequently, we ignored all that data and in 1973 when we started to work here, none of us believed that the site would be particularly deep in terms of the sediment pile or particularly old. We were all subscribers, as was everybody, to the clovis first hypothesis. And according to that, the makers of these points crossed the baring straits, again, about 12,000 or 14,000 years ago. They were rapidly moving, big game hunters, and they were critical in the extinction process of most of the ice age animals. And between 1933 and the excavations here, they all claimed to be older than clovis and they all shared a similar trajectory. You would read about them in the local media first or hear about them, and then you would find a scientific publication or two about them, and then some fatal flaw would manifest itself. They either had imperfectly defined strata or layers, they had artifacts that werent of human manufacture or there was some other flaw that rendered them, they had 15 minutes of fame and they disappeared. Each time one of these sites was found to be nont as old as claimed, it reinforced the clovis model, so by the time we started work here in june of 1973, the clovis model was so firmly entrenched that there practically, except in south america, was no one who didnt believe it. Again, we started to work here because a local historian had been a friend of albert miller, the property owner, who had discovered the site in 1955, and had been looking ever since for somebody to validate his supposition that native americans had camped here. And we were or i was a part of the group that validated that proposition, that in fact this had been a campsite, for the reasons we indicated. There are other attractions here. The rock shelter is south facing, so the daily trajectory of the sun, the sandstone which forms the roof and walls of the rock shelter, provide a micro environment, than it is at the bottom of the creek or up top. So that in conjunction with all the other attributes, a level floor, a high ceiling so that the prevailing wind, which normally blows from west to east across the mouth of the rock shelter, any fires that you ignite in the interior are rapidly and efficiently ventilated. Any insects or pests that might want to bite on you are usually vacated by the prevailing wind. So theres a variety of things that would have drawn you or me, or anyone watching this, to stay here, and clearly that was the case prehistorically. So while we believed for those reasons that people used the site, we had no idea whatsoever how old it would turn out to be. What we wanted to do here was to make sure that in the process of training students the very latest technologies, the very post High Resolution technologies, of which i or any of the staff were aware, were used here. It was always meant to be a methodlogical tour deforce, and how you got the data was more critical to us than whatever we found, at least at the beginning. Later on, as it turned out, as the site proved to be both older and deeper, we recovered indications that we never imagined would be here that caused an enormous controversy at the time, and only when other sites like this, or even older than this, were discovered in various parts of the world, was it clear that the clovis first proposition was in error. When columbus originally got here in 1492, before he was the admiral of the ocean sea, so to speak, he encountered aboriginals wherever he landed, and he or members of his entourage posed a series of questions about these folks that weve been asking ever since. Who are they, where did they come from, via what routes did they employ to get here, and when did they arrive . And a question they didnt ask, but which we obviously have addressed here, is what were they doing, what were their lifestyles like . He thought he knew the answers to all of his own questions because he thought he was in the east, not the west indies, so he called them indios, or indians, a term weve used ever since, and the supposition was, at least within 100 years, that they had arrived here 2,500 years before he did. And that benchmark arrival date has been pushed further and further and further back through the years, but it would take a series of intellectual developments in western europe before we could actually answer any of those questions appropriately. The rock shelter has changed dramatically through time, both in terms of its scale or size. The overhang once went clear out to where you see those lights, and now it is located way back in the vicinity of that rockfall event there. So in the last 15,000 years, the roof has been steadily retreating to the north. The sediment pile that you see here has accumulated in a number of ways, the most common of which when these big rooffall blocks on the west and eastern edge of the site were in place, was by the grainbygrain erosion of sand particles from the roof and walls of the rock shelter, which was a slow and very steady process. That grainbygrain erosion would be punctuated at various points in the past by the detachment of roof blocks, first fist sized and then progressively larger until one of these big blocks came off. Then the whole process would repeat itself again, so that never in any two successive years did this site look exactly the same as it did the year before. And we would learn that later on in the course of the excavation. We began a trench out here where were standing outside the drip line, which proceeded from south to north. The purpose of which was to explore the deposits, the saidments, the layers that had been least disturbed by human activity first before going into the interior where the principal dwelling area would have been, the principal activity area, where the disturbance conceivably would have been much more extensive than out here. So we plumbed these deposits first, moved to the north, and then subsequently expanded to the east and west. Again, the kinds of things we were able to do here in many instances had never, ever been done before on the planet, contrary to most archeological sites this enterprise, from the very beginning, was very heavily funded. We had money from the foundation from the university of pittsburgh and a whole bunch of pittsburghbased corporations, so we always had more than ample money since you could torture students in those days way more than you can do now, labor was never an issue because we mandated four years of field school. And the duration of the project was such that it would usually begin in may or june and run until september. 12 hours a day, six days a week. And so with a captive audience and all the money in the world, so to speak, we were free to explore issues here in particular ways that had never been done before. One of those involved the construction of a series of buildings, of which the one were in now is only the most recent, that prehistorically or historically looked like that portion of the one building that is still adhering to the rockfall event. It let us big basically indoors where we could control not only the temperature and the ventilation, but we could control the hue, intensity and chroma of the lighting system so that the excavators could maximize their ability optically, and then by a series of other attributes, to distinguish one layer from another. Probably at least you or some of your viewing audience have eaten multilevel deserts consisting of layers of cake or icing or nuts or whatever. And the tags that you see here are marking boundaries between layers. Theyre basically devices so that if you wanted to know whether you were eating the nut layer in your desert, you might mark its boundary. Thats what all the tags are for. They mark boundaries between levels, which there are 11 at this site. The deepest level, stratum one, is the birmingham shale, which is a much softer rock than the sandstone which makes up the bulk of this particular phenomenon. The most recent level, 11, is the stratum that you see there gradually slanting down toward the creek, minus, of course, the vegetation that would have grown upon it, and minus the remnants of the living tree, the stump of which you can see over there. So that is the original 1973 Ground Surface. The surface that you see down here represents a much earlier Ground Surface at the site. Its about 13,500 years old, and all of that sediment has accumulated since 13,500 years ago. When we got down to the area where you can see a step, we were essentially at a timeframe that would have been equivalent to clovis. We decided to remove the rocks from there, not because we expected to find earlier material, because none of us did, but we wanted to get to the birmingham shale to understand the geology of the site. And as soon as those rocks were peeled off and we began to find earlier material, we began to appreciate that the site may be far older than we imagined and might have represented a very different kind of lifestyle than what the current wisdom was in 1973, 4, 5, 6, 7 and 8. Specifically i think we can demonstrate that man was here by at least 14,000 bc, if not a few thousand years earlier, and that, in turn, relates to the whole problem into the new world, because clearly if hes down here in southwestern pennsylvania by 14,000, then he must have come across the baring straits land bridge perhaps 25,000 or 30,000 years ago. And so during the course of the excavations here, signs of a human presence took many forms. There were obviously artifacts of indisputable human manufacture, made of various kinds of raw materials, usually highgrade flint, as theyre popularly called, or jasper from a wide array of quarries. Some of this raw material came from flint ridge in ohio, some of it came from the outcrops in new york, some of it came from the pennsylvania jasper quarries in eastern pennsylvania. In any case, we dont think that the populations that were using stone from these farflung areas were, in fact, visiting all of those places, and that their territory would have been thousands of square miles. Instead, we think theyre exchanging it, along with other things, back and forth with other groups that lived in a widely distributed situation like that. Of course because the site is relatively wet, the most durable items that are recovered from here are usually made of stone, like they are at most archeological sites. Its worth stressing that when you only get stone or ceramics later in time, youre only getting about 5 or less of what they actually made or used. When a site is very, very dry, like some of the caves and rock shelters in the west and elsewhere, you get a full representation of what these huntergatherers made and used, in the form of plant fiber objects, bone, wood objects, which are far more common than stone. Nonetheless, here we only have a hint of those nondurable technologies. We have some burn basketry, we have bits and pieces of cortage and bone and wooden artifacts to give you an idea of what on ter si the other side of what the technology looked like. But most of the artifacts are stone and most of it was used either in the procurement, transport or preparation for consumption of wild plant and animal foods. However, unlike the clovis model, its clear that the earliest people who came to this site were in fact what we called broadspectrum s broadspectrum folk. Like college guys, they would eat anything in the refrigerator, they were eating elk and mousesized animals and an incredible assortment of plants. Weve got 1. 4 million plant remains from here, 956,000 animal bones, representing over 105 different species, and theyre clearly doing things here all the way through time, all the way up to a. D. 1775, which is within striking distance of the Miller Family taking possession of this property as the Virginia Land grant. So theres a juncture here between history and prehistory thats very real. In fact, one of the very first things we encountered when we started to excavate was a large stone line historic fire pit at the very top of which were aluminum fliptop beer cans and as you worked your way down, you encountered beer cans without flip tops, steel cans, early beer bottles, and at the very bottom, glass that had been flaked by native americans into tools. So the juncture of history and prehistory is very vivid here, and all of the stages of prehistory that are represented in Eastern North America are known from here, beginning with the paleoindian, which is whenever people first got to the new world up to about 10,500 years ago, and during which time the environment was rather different than it is presently, not dramatically so, but different enough that you would notice, and ice age animals were still around. And then about 10,500 years ago, most of them go extinct, not due to human predation in many instances, but because of the stresses of environmental change, and you start a very long archaic. Now, theres a peculiarity to the english language and we like to divide things into threes. So theres an early, middle and a late archaic, and if youre particularly anal, theres an early, middle early, late early and so on and so forth. But whatever is the case, during the archaic, you have native americans gradually increasing in numbers in this area, late in the archaic theyre actually going to be settling for several months at a time at various open sites in the area. Throughout the sequence of the archaic and paleoindian, the populations are principale noma. Tracking human beingings across the land scape is a hard proposition. Were it not for the invasion of the mongels and huns in europe, its practically nonexistent, so that we arent really sure where these people are when they arent here. We have studied the drainage more fully to try and ascertain how many other kinds and representations of how many kinds and the representations that there might be here. In hectares, there is more than 330 other archaeological sites. They represent the meanderings of these populations all of the way through time. It is not until about 3500 calendar years ago that you begin to see the large seasonal camps. And even later, the equivalent of the kinds of villages that would have existed when the europeans arrived. When you have centrramics and domesticated plants, cornbe, beans, and squash. The woodland has an early, middle, and late and we put an end to it by driving the native americans off. All of those statements are represented here by varying con vig ration heres. We have a series of early overnight fireplace remnants. From the very first folk that were here. Later on in time you get more elaborate pits that may have been reused that are lined with clay and so forth. But all of the way through that long sequence of a human presence that is known to be in excess of 16d,000 carbon years or 19,000 calendar years, the people are using the site the same way. To collect wild plant and animal food. Even after the appearance of settled villages, it is still a place to supplement their domestic diet. Im dave scholfield. On the east face of the excavation there is an interesting profile here that has evidence of campfires. All of these reddish stains here, you would also see bits of charcoal and ash. That indicates were campfires were build. In that roughly six foot profile there are literally nows of years of campfires represented. In that fire pit, that was what i like to refer to as the tweet shot of the collapse of the new roof fall. When that collapsed, it changed the dynamics in the site. So subsequent activity took place, but for thousands of years that was the center of activity here at the site. There is another fire pit location here. In the center of this fire pit, right there, is a fresh water mollusk. It would have been in the ohio river, requiring a deeper and faster river, and that is where that was uncovered in the center of that fire pit. So roughly 4,000 years ago that mollusk was presumably eaten here, and the remainer left in the fire pit. Further to the east, right here, is a rib from a white tailed deer. Right around the corner is the end of a long bone from that same deer poking out. That would have been beautifutc here 400 years ago, so that is just two of the 956,000 remains. All of these damages you see indicate the it strata of the sight. So the f number is the top surface layer. Each of those ind cays a particular layer as it is encountered. There is also a few tags, this one reads 1875. So that line at that level it indicates the 13th to 18th centuries. So all of the areas excavated as you see, has been excavated over the course of many years. A number of field schools, but with nothing loarger than a trowel. This was done very slowly. And in a painstaking manner that really illustrated the care and the precision of this site. And the area remains is about a third of the site. So there is still more to excavate, but that was left intentionally. Archaeology is a destructive science. In the process of studying the site, you destroy it so that is why documentation is so important but also some of the site has been left for future excavations. There are portions of the rock shelter where different activities were conducted. Theyre called activity areas. We have places in the site where they would burn off of the trash that had accumulated here from previous visits. Those are called fire floor areas. It is either accidental or intentional. Smarts from a cam fire could have ignited it or they could have done it on purpose. Many of the layers represent a discreet activity. And it is thiper than a trowel blade. And they would remove those layers with single edged razor blades. And the purpose was to be as precise as we could so so that we could study in micro detail 16 thousand years of environmental change and the human adjustments to those changes that the site turned out to be old was kind of a bonus. It was icing on a cake that we never intended to bake. Part of the emphasis of the program here, the material culture, was that were fortunate in having a relatively large number of student thats have been trained in various courses for the analysis of different kinds of artificial interior. And no matter the size we think we can get the most, so to speak, that the class material has to offer and in turn we learned a great about the makers and the materials. When the excavations come down, as much as six hours of Laboratory Study is requires. Unfortunately because of the favorable conditions of preservation they recovered some of the older material that is kind of recovering east of the mississippi river. And what they possibly use these for. The art facts themselves are by which they are articulated or interacting with their environment. As long as most organize in additions are feet, there is an isotope of carbon in the at most fear. Which breaks down at the rate of onehalf of its mass every 5730 years. So when you or a plant croak by measuring the amount of carbon left in your car discuss. It could take a few years. So when the first dates began to come back from those early fire pits, and we started to realize the site was probably older than we imagined it to be, there was great kept similar among us and the crew. That is not supposed to be that way. We became convinced, ourselves, that we were on this location, and it became a very controversial place because there werent any other ones for the longest time. As with any field, when you channel t challenge the perceived wisconsin dome, how to produce a documentary, how to excavate a site. It is is contrary to what you knew, it must be wrong. Often times a person, whatever his field or her field did you want want to change their mind but in so doing we somehow think that we are about abnigating ourselves or repudiating our mentors and we dont want to go there. We dont want to say theyre dumber than a brick. The information that you receive from these kinds of locations, in fact they undermine previously existing models. And so as a result, had we been filming this in 1973, the vast majority of the field would have reacted very negatively from what seemed to be like the site. Now we have a whole bunch of places that indicate the old model is it is a different story. But early on, claes we were skeptical as our audience was. And we were certainly not contemplating that the people here were here long before the points were made or theyre lifestyles were different. Other sites ban to afear, and now there are sites from both north and south american so what we discovered here in all of these deposits is camping debris from thousands of sprawl visits in areas horizontally, theyre not goming every year, theyre not staying very long. We know from the lowering period of the plapts that are available that theyre coming from late august to at most early november 37 it is a time when the local animal populations would have been the densest. They would have supported white tail deer, elk, and other forms. May may have also been coming here in the spring. We get bird eggs from the site. But in any case, we know the major use of the site is in the fall. And it is by groups that are purely migratory either in the course of a season round where they go from place to place to place, and this is one of their stops or from fillages that they would foray out from to collect wild plant and animal foods. If you and i were familiar with the vegetation. We couldly here comfortably. For at most, a couple of weeks. Then we would exhaust the resources and move on. And that is probably a refor example of climate and micro climate changes at this location. Sometimes it is colder than it is today. It is drier than it is today. Sometimes it is warmer than it is today or wetter that it is today, and smoes changes have subtle adjustments that the people have to make. The excavations were done in such a way that we could, in fact, maximize the retrieval of data over however long the site was lived in, to address questions about the past that may have been addressed imperfectly at other places what are the things that cant wait to forget is that the about rigsales are essentially just like us, theyre homosapians. They are us, theyre dealing with problems and issues, perhaps different in degree than we do, but how they resolve tho those, whether they are sea level change. Is instructive for us to apre h apprecia appreciate. Because they are usz, it is easier to identify with their lives and their trajectories here and other places like this than perhaps if you just read about it in a book. If we had a gifted staff, but the stage, the geological stage that they wonderfuled on, and knew what they wanted to learn, and that we could buy or get you can pose questions, you can ask things as you might imagine that you cant do in other bases. We had a telephone that was connected by modem to the mainframe. We could computerize data instantaneously. The codirector of the project designed the computer methodology that shows information from other every area. I take the raw data and generally use a technique called factor analysis. And it is what data reduction process is. It looks things that behave together. People at one time were eating a lot of fish, and because they are down they picked up a lot of crabs. Also fish scales in the site. And in other times when they didnt favor marine things like that, they would have gone to hunting dear. So there was a drop off in fill scales. That is known as a correlation. Things come out about their hunting patterns. They tell about how they will add to an evergrowing array of information about how people behave when they came to visit the shelters through 16,000 years bort of time. What we tried to do through the years is to incorporate since 1973 any new technologies in a might possibly yield data about the site that we had not currently collected in the recent past, we collected soil samples for those focussing on what kinds of plants and animals may have been here on either side of the socalled ice age modern time period boundary. Is there any human dna preserved in these sentiments . And when we initially excavated here, dna research was in its infancy. It wasnt used. So just as you try to employ the latest generations of cameras and sound equipment, we have tried to incorporate the latest techniques often times from other fields so ask questions that had never been asked before about the past. So from 1973 and the initial stages, we have invited the public to visit the site. Since the foundation conjoined, they have more formalized the public viewing process so that tours are offered here in the seasons that the area is open for visitation. And four times a year i give tours of the site insider tours where i explain what split right transpired here. They have a responsibility especially if youre spending public money, to translate the worthy to the audience. If we dont do that and many of my colleagues dont like to do that, then were failing on some level. If i spend your tax money to excan vat here. The but it addresses the scope and the sweep of the past in ways that you can understand. And unfortunately in so many excavations whether or not it is a roman site around the mediterranean or an early site here or a later site, the archaeologists dont do that and the history sen tir exists to dell a variety of stories. They has exhibits. This is one of many stories they try to tell the public, and that we, as participants in the collection of the stories, attempt to translate for the public. Winston churchill, the late prime minister, and a more than casual historian observed on one occasion that a society that doesnt value its history or by extension doesnt have one. A society that has no past has no presence. Or present. And sure as hell doesnt have a fuel. So by understanding where we, as a species, have been in the past, we are understanding how we got to be this way and where were going. Thats why we do this besides the fact that it is fun to take bits and pieces of information, put them together, and our scenes are 10,000 or 12,000. Not ten or 12 days old. Their generations old or millions of years old in some cases. Were doing the same thing. Were taking evidence about the past to try to figure out where we have been. You can learn more by visiting the heinz scenter. Org. 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