Archaeology at Rock Creek Mortar Shelter, Pickett State Forest

30 Days of Tennessee Archaeology 2015, Day 14

Jay Franklin
East Tennessee State University

Rock Creek Mortar Shelter Study Area.

Rock Creek Mortar Shelter Study Area.

We have now completed three field seasons at Rock Creek Mortar Shelter in Pickett State Forest on the Upper Cumberland Plateau.* The archaeological deposits here are very deep and extend back into the Paleolithic, or the last Ice Age. New radiocarbon dates from just this past winter confirm this to have occurred at least 12,500 years ago. The site was intermittently occupied over the course of the next 11,500 years until about AD 1000.

The Upper Cumberland Plateau was likely a very different environment 12,500 years ago at the end of the Pleistocene during an abortive return to ice age conditions called the Younger Dryas. Still, some early pioneers ventured their way up on the plateau, perhaps up the Wolf River and/or Big South Fork river valleys, the ends of early migration routes as noted by David Anderson. As the climate ameliorates beginning about 11, 600 years ago, hardwood forest communities migrate to higher elevations. People began to exploit the nut mast resources and associated game animals. A seasonal round, a way of doing, was established. This way of doing things in the uplands sets the tone for the next several millennia – indeed up to the arrival of Europeans in some places.

Early Holocene flat, blade-like flake.

Early Holocene flat, blade-like flake.

These early pioneers of Rock Creek Mortar Shelter traveled and stayed in family groups as evidenced by the range of activities that took place here. Microscopic use wear on stone tools indicates meat cutting (butchery), hide scraping, and wood working – a host of activities that go beyond simple short-term hunting camps. Perhaps more telling are the technological studies. Late Paleolithic peoples often practiced a highly skilled blade tool manufacturing process, and we can see some of this in the earliest levels at Rock Creek Mortar Shelter. However, we also see that while the idea was technically sound, the execution of blade production was often poor. Or, stone tools and cores were initially well-thought out and executed but then digressed in technical know-how and execution. This suggests that skilled adult knappers were teaching (probably younger) novices their technological knowhow on site with varying degrees of success.

We can also see a shift in technology. Late Paleolithic blade tool production was a very specific type of production that involved very precise preparation of cores and the production of long, straight blades with regular lateral edges. We see some of this at Rock Creek. However, we also see a shift in the production. Long flakes were still selected, but the manufacturing process changed. Cores were no longer intricately prepared. Flakes are long and flat but without the regular lateral margins. Widely available raw materials may have allowed early inhabitants of the plateau the luxury of spending much less time preparing their cores for stone tool manufacture in favor of more expedient methods for essentially the same end products.

Nutting Stone (top) and Bedrock Mortar Hole (bottom).

Nutting Stone (top) and Bedrock Mortar Hole (bottom).

As the Archaic Period progressed, climate continued to improve, populations grew, and people intensified their subsistence efforts. By 4,000 years ago, people really began to key onto nut mast resources. Perhaps this signifies the beginnings of matrilocal societies in Southern Appalachia given the more reliable nature of nut resources. This intensification is evidenced at Rock Creek Mortar Shelter, and many other sites on the plateau such as Pogue Creek Canyon, by bedrock mortar holes, nutting stones, and prepared, baked clay surfaces. Acorns require significant processing and leaching to be edible. Bedrock mortar holes were ground into the sandstone in order to process acorn meal then leach out the tannic acid. Portable nutting stones were likely used for nuts that require much less processing such as hickory and perhaps chestnut.

The baked clay surfaces involved bringing in clay from outside the shelter (rock shelter sediments on the plateau are sandy given that the parent bedrock is sandstone). The baked clay surfaces were then used to parch nuts. Parching allowed them to be stored for longer periods of time, and also kept insects out of the nut foods. Again, these intensive activities identified at Rock Creek Mortar Shelter suggest entire family groups lived in the shelter for extended periods of time on a seasonal basis. Research farther north on the plateau at Cliff Palace Pond in the Daniel Boone National Forest even suggests that later Archaic peoples managed these hardwood forests by using controlled fire. These burns would have fostered hardwood species and also increased the browse for key game animals like white-tailed deer, wild turkey, black bear, and squirrels.

Baked Clay Surface (hole is from a geologic micromorphology sample).

Baked Clay Surface (hole is from a geologic micromorphology sample).

By the end of the Archaic Period on the Upper Cumberland Plateau sometime after 2,700 years ago, use of Rock Creek Mortar Shelter became less intensive. This may because the shelter itself changed. We see a lot of roof fall in the form of large boulders that essentially divide the Archaic layers at the site from the later Woodland layers. Elsewhere in Southern Appalachia, a cold spell during this time has been documented, and this cooling event may have caused freezing and thawing that led to the roof fall. In short, the ground surface in the shelter may have been less stable and safe during this time. It may also have been less attractive for longer stays in the shelter due to much decreased floor space. Nonetheless, Woodland peoples occasionally used the shelter for the next two thousand years as evidenced by recovered pottery and hearth features, although this use may have been much less frequent and intensive than during the Archaic. All in all, though, population was highest during the Woodland Period on the Upper Cumberland Plateau. We will continue our work at Rock Creek in Summer 2016. Artifact analysis is ongoing at our archaeology labs at ETSU Valleybrook.

Large Breakdown Blocks on Surface of Shelter (note how some extend underneath the current ground surface and protrude from our profile walls). Photo: Cayla Cannon.

Large Breakdown Blocks on Surface of Shelter (note how some extend underneath the current ground surface and protrude from our profile walls). Photo: Cayla Cannon.

* Editor’s Note: You can find Jay Franklin’s 2014 post about work at the Rock Creek Mortar Shelter here.

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30 Days of Tennessee Archaeology, Day 6

Paleoindian Pioneers of the Upper Cumberland Plateau of Tennessee

Jay Franklin
Associate Professor of Anthropology
East Tennessee State University

Upland areas do not typically fit into conventional models of human exploitation, except in cases where they are invoked as marginal areas used for hunting and gathering forays by ancient peoples who then returned to their lowland homes. However, work on the Upper Cumberland Plateau (UCP) of Tennessee has demonstrated this is not the case, and we can add the earliest Tennesseans to the list.

East Tennessee State University students excavate a rockshelter site on the Upper Cumberland Plateau. Photo by Alan Cressler.

East Tennessee State University excavations at the Rock Creek Mortar Shelter site on the Upper Cumberland Plateau. Photo by Alan Cressler.

At Rock Creek Mortar Shelter on the UCP, we have recorded a more or less continuous record of human occupation from at least the end of the Pleistocene (around 11,500 years ago) to about AD 1000. In the late Pleistocene and early Holocene deposits about 1.25 – 2 meters below surface, we recovered more than a dozen blades from a restricted area under the drip line of the shelter. Most of the blades were made/prepared from unipolar cores using a mix of hard hammer and soft hammer percussion.

There also seems to be a mix of skill level and/or execution in producing the blades. A few of the well made examples would be at home in European Late & Epi-Paleolithic assemblages, while a others are poorly executed. This potentially suggests the site was occupied by a family group as opposed to simply a group of hunters. It may have been that older, skilled knappers were teaching younger novices to make blades on site. It may also be that these earliest inhabitants of the UCP were coping with the constraints of using the locally available small rounded cobbles of Monteagle Chert for blade production (as opposed to large tabular cherts encountered in the lower Tennessee River drainage). Our excavations also recovered numerous core edge flakes and crested blade fragments that were removed to prepare cores for blade production. We have some evidence for over shot biface thinning flaking at the site, which is a technique common in Paleoindian assemblages.

The entire range of lithic reduction is present in these early levels, indicating chert cobbles were brought to the shelter for core reduction and tool production. Like later Holocene assemblages all over the UCP, there is evidence of biface production at Rock Creek Mortar Shelter. However, unlike the myriad other shelters we have excavated, we have already recovered far more unifacial tools at this site than any other on the UCP. So far, 50 tools/pieces have been analyzed for microscopic use wear. Activities represented in the late Pleistocene/early Holocene levels include early stage hide and meat processing and scraping wood. In addition, two tools possess some sort of residue which we think may be blood.

We are excited to continue our work at this important site. We hope to recover blade cores in the coming field season so that we may reconstruct the entire blade production sequence. More generally, we will continue to explore why these early people ventured onto this rugged, upland landscape far removed from a major stream and tens of kilometers from primary raw material sources.