The prehistoric and historic peoples of South Dakota are all around us, and they speak to us in different ways. The most recent of our ancestors have left us their traditions and written histories, and we feel we know them very well. Ancient peoples, though, left us no written history. They are only shadows to us, dim and hard to understand. They have left us a message in the earth, though, in the remains and ruins of their homes, camps, workplaces, and towns.
Archaeology is our way of reading that message and understanding how these peoples lived. Archaeologists take the clues left behind by the people of the past, and, like detectives, work to reconstruct how long ago they lived, what they ate, what their tools and homes were like, and what became of them.
Archaeologists learn these things from the study of what people have thrown out or left behind--stone tools such as arrowheads and scrapers, animal bones, seeds and charcoal, pottery, glassware, and old cans, for instance. Archaeologists also study more complex remains such as fire hearths, storage pits, earthlodges, rockshelters, and root cellars.
Archaeologists would have little to do without knowing where to dig. The place that archaeologists dig is known as a site. It is any place where people have lived or worked in the past and left traces of their activity in the earth. To find a site, you must look for one. The easiest way is to interview the people who live in the area. They are a great source of information. It is a rare farmer or rancher who hasn't picked up arrowheads or other items on his property.
The other method is to march over the country with your eyes glued to the ground, looking for artifacts or any other traces of previous human occupancy. Archaeologists call this a survey.
Once a site has been located, archaeologists record it on a form, measure and map its dimensions, and record other relevant information about it. The site receives a number and is entered into a state database. Each site has a number based on the state and county. This system was developed by the Smithsonian Institution in the 1940s. For example, a site numbered 39BF124 shows that the site is in South Dakota (39), Buffalo County (BF), and it is the 124th site recorded in the county.
Once archaeologists locate a site they wish to dig, the first step is to lay out an excavation grid using surveyor's tools and lots of stakes and string. From above, the site would look as though a sheet of graph paper had been superimposed on it. The map accompanying this section shows the excavations at the Hartford Beach site. The curved lines are elevations, and the grid shows up in the pattern of the excavations. The grid is usually set up on the metric system, since measurement in meters and centimeters is far more practical than feet and inches.
The grid serves to help archaeologists keep horizontal control of the excavation. Each square can be assigned a number by any of several methods. All measurements can then be recorded with reference to the square's location. A grid can cover anywhere from a few to many thousand square meters.
The grid helps archaeologists keep horizontal control. Vertical controls are ensured by the use of excavation levels. If you think of the site as a cake, which has been cut into tidy squares by the grid, then the vertical controls are the cake's layers. The simplest form of excavating by levels is simply to work in evenly spaced, horizontal levels. The usual thickness of an arbitrary level is 10 centimeters (about 4 inches).
The arbitrary level is most useful when the site does not appear to have clearly defined stratigraphy (a word referring to the layering of deposits at the site). In more complex sites, where succeeding occupations have left a more "cluttered" record, the use of excavation by stratigraphic level is employed. One level might consist of a layer of wind-blown sand; the one below it might be a thin deposit of burnt earth mixed with artifacts; below that might be a layer of occasional artifacts embedded in an buried topsoil.
The combination of horizontal and vertical controls allows archaeologists to keep track of the location of every item they find. Most simply, they have a record of the grid square and level of a find; if they wish they can elaborate that with a set of horizontal and vertical measurements within the square.
Such locational record keeping is a necessary part of archaeology. Digging destroys a site as surely as an any bulldozer's blade. By keeping accurate records of where artifacts are found and the location of other features in the site, an archaeologist can ideally reassemble the site back in the lab. This is what distinguishes actual archaeology from Indiana Jones-style treasure hunting.
Anything which has been made by people is known as an artifact. It may be a crude pebble chopping tools used by our most remote ancestors, or the space shuttle Endeavor--both are artifacts. One of the archaeologist's goals is to recover artifacts at a site. The artifacts are one of the primary means by which we can understand past cultures. They represent what is left of a technology. By understanding the technology of a people, we are a step closer to understanding how they met the day-to-day challenges of their environment.
Besides artifacts, archaeologists also excavate features. Essentially, a feature is something which cannot be brought physically back to the lab. Features include such things as post holes, storage pits, soil stains, fire hearths, an arrangement of artifacts, a concentration of clam shells, and so forth. Careful attention to the features at a site will reward the archaeologist with a much clearer idea as to how a site was used.
Archaeologists use many tools in their work. An archaeologist on a survey will make heavy use of detailed topographic maps of the survey area, as well as compasses and large measuring tapes. The new GPS (Global Positioning Satellites) technology is becoming common for detailed recording of site information.
As you might expect, the most common excavating tools are the shovel and the mason's trowel. A skilled worker can make effective use of these tools to trim and scrape (not dig!) the soil from the site with virtually no damage to the artifacts and features within it. When a more delicate touch is required, wooden picks (bamboo splinters are popular), spoons, dentist's picks, and brushes are useful. Tape measures are constantly in use for mapping the locations of items and keeping track of depths. An archaeologist who can't keep a floor level and at the right depth and who can't keep a wall vertical is in for severe kidding from his coworkers.
Record keeping is the other half of excavation. Excavation record forms and graph paper are used to keep track of what was found in each level and to map its contents, including artifacts, stains or other marks in the soil, the location of features, and so forth. Photographs (with scales, north indicators, and labels) are taken often during the course of the excavation. Many archaeologists shoot considerable video footage these days, too.
Excavated soil is sifted through screens, usually measuring 1/4" or 1/8". This captures small items which may have been missed by the excavator. Items found in the screen are kept with the rest of the material found in each level of each unit. A smaller screen size can be used effectively if a water hose is used to rinse the soil through the mesh. The technical term for this is, of course, waterscreening. Very often, samples of soil are also floated in water as part of the waterscreening process, which recovers very tiny bits of charcoal, seeds, bone, and such.
Other, more exotic, tools are also used by archaeologists. In recent years nondestructive investigative techniques have been employed successfully at many sites. These remote sensing techniques include magnetometers, resistivity measurements, and ground penetrating radar. All of these can, under good conditions, provide a sense of what features lie under the ground surface. They have proven to be very helpful at locating the lines of buried walls, foundations, earthlodge floors, and many other features.
Stone is the raw material for mankind's oldest durable technology. More than a million years ago, people learned that certain kinds of stone--those related to flints--could be chipped into various sharp-edged forms using hammerstones, bone or hardwood batons, and bone or antler flakers. The byproducts of chipping stone tools include the cores of flint, chert, and other "knappable" stones and flakes. Flakes and cores make up a great part of the items found in many archaeological sites.
In South Dakota, chipped stone tools are divided into several categories. One category includes finely finished tools such as projectile points (both arrow and spear points), bifaces (knives), and drills. Another is comprised of tools chipped on flakes, including various scrapers (endscrapers, sidescrapers, and spokeshaves), engravers, shredders, and miscellaneous cutting edges.
Ancient peoples learned that, while not all types of stone could be chipped, nearly all could be battered, pecked, or ground into shape by other stones.
In South Dakota, ground stone tools appear late in Paleoindian times and are in common use after that time. The earliest included the mano and metate (handstone and milling stone), for grinding seeds and other plant material. Another early ground stone artifact was the atlatl weight, which was used to counterbalance the atlatl or spearthrower.
By late prehistoric times, ground stone tools in this region had come to include axes, celts, mauls and hammers, gaming pieces, and tobacco pipes.
Pottery came into use in the Dakotas in the last few centuries B.C. Pots were made with local clays, usually tempered with crushed granite, sand, or occasionally shell. It was worked into shape using the paddle and anvil technique, where a round, smooth stone was held inside, and the outside was worked with a wood or bone paddle. The paddle was often covered in cord, fabric, or was cut in grooves or checks. Firing was at low temperatures without the use of kilns.
The earliest pottery in South Dakota consisted of thick, conical vessels. The outside surface was usually left roughened by cord or fabric paddle impressions; decorations, when present, usually were confined to the rim area and included punctates (holes pushed partway through the pot), bosses (the other side of the punctate), cord wrapping, and tool marks.
Later pots took on a globular shape with flared rims. Smoothed vessel surfaces and decorations of scrollwork on the pot shoulders were popular among early Plains Village peoples in eastern South Dakota. Their descendants favored a variety of roughened vessel surfaces (often by a grooved paddle) with a variety of cordmarking and toolmarking decorating the rim and lip. Smoothed, shell-tempered vessels with trailing were in use by the Oneota peoples in the middle of the second millennium. Other pottery implements included jars, bowls, and pipes.
One aspect of pottery which archaeologists find very useful is that it is very susceptible to style changes over time. This has been very useful in sorting out different prehistoric cultures and dating them.
Flora and fauna refer to plants and animals. Both were doubly useful in that they provided not only food, but material for tools, clothing, and housing.
The remains of animals and plants at a site give us many clues as to what happened there. They can, first off, provide information on exactly what was being eaten. Sometimes we can also tell how animals were butchered and how food was prepared. Other information can tell us what time of year the site was occupied. An examination of the plant pollen, insect remains, and tiny animals such as snails can provide clues to the ecology of region and its climate in ancient times.
A question archaeologists commonly hear is "how do you know how old it is?" Dating a site or artifact has always been one of the most important elements in archaeological research. There are several ways which have been developed over time.
The oldest method of dating is stratigraphic. As time passes, older layers of earth and artifacts are covered by new ones. Thus it stands to reason that items found in a higher stratigraphic position at a site are younger than those below. By comparing the stratigraphic position of several sites, a picture of the relative ages of various prehistoric cultures could be assembled. This was how dating was primarily done before about 1950.
Archaeological dating was revolutionized in the 1950s by the invention of radiocarbon (also known as carbon-14 or 14C) dating. Basically, all living things absorb carbon during their lives. The carbon absorbed contains regular carbon (12C) and a small percentage of radioactive carbon (14C). Over time, the radioactive isotope in the remains breaks down. Scientists know that it takes about 5500 years for half the carbon to break down. By measuring the remaining radioactive carbon, researchers can thus calculate the age of the item. Modern techniques have allowed dates to within a few years of accuracy. Radiocarbon dating is most effective on items such as wood charcoal. Items up to 30,000 or 40,000 years old can be reliably dated. Carbon dates done these days are often calibrated against known tree ring dates.
Another form of dating which has proven effective is tree ring dating, dendrochronology. Rings form in trees each year, in a pattern dependent on variables such as precipitation, temperature, etc. By comparing a series of trees, researchers in many areas have compiled master tree ring sequences. Wood samples from sites can be compared to these to see where they fit in the sequence, thus dating the site. Tree ring series have also been used to help calibrate radiocarbon dating methods.
Other techniques for dating sites exist. One is paleomagnetic dating. In this method, it is known that the orientation of magnetic north has shifted steadily over time. If an artifact (such as a freshly fired, unmoved pot) or feature (such as a fire hearth with baked soil in it) can be found, the magnetic orientation of particles in them can be measured and an approximate age estimated. Another method, known as thermoluminescence, measures the energy stored in an artifact once heated by fire. The measure of the remaining stored energy is a measure of the age of the item. Yet another researcher has developed a means of dating ancient rock art by measuring the varnish (a form of weathering) which has formed on it. This is still an experimental method, but it shows promise.
Once a prehistoric culture has been dated by any one or more of the above methods, similar groups of artifacts from other sites may be dated by association. So when a collector brings an archaeologist an Agate Basin point, it is relatively easy to say "that point is 10,000 to 10,500 years old" because other Agate Basin sites have been dated both stratigraphically and by radiocarbon.
One of the most exciting aspects of archaeology is taking all the clues provided by artifact analysis, dating, animal remains, and so forth, and attempting to reassemble a past culture.
Technology is the point at which human cultures and their environments come together. Each human society has developed its own technology to allow it to make the best use of its surroundings. Since technology provides the only substantial physical traces of human existence, it is what archaeologists deal with the most.
The tools of everyday life in ancient times provide clues. By studying how they are made we can determine the underlying means of production, or by studying the raw materials we can make deductions about the patterns of movement and exchange of peoples. For example, if an ancient people living in eastern South Dakota made extensive use of obsidian rock, which is found in the Yellowstone area an in the Northwest, we can assume they had firm exchange relationships with peoples living further west. Conversely, if they made little use of a more readily available material such as Knife River flint from North Dakota, we might guess that relations with their northern neighbors were less than cordial.
The arrangement of tools at sites is also important. Certain combinations of artifacts might indicate that plant foods were being gathered and processed. Other tool kits might suggest hunting and butchering, clothing manufacture, hide or wood working, and so forth. A pattern of different tool kits in use by the same people at different places might aid archaeologists in reconstructing resource use patterns and annual migrations.
Environment is critical to human cultures both ancient and modern. Data provided by pollen, seeds and other plant remains, and animals sensitive to environmental conditions is vital in reconstructing past climates. Understanding ancient climates is vital to determining what conditions faced early inhabitants. For instance, mild winters and summers with ample precipitation would be a great help to people who depend on farming or gardening.
Likewise, periods of great heat and/or droughts can profoundly affect what use people can make of the land, forcing shifts to lower population density and more efficient use of a broadened resource base. People in Paleoindian times were able to depend to a great extent on buffalo as a food source; their successors in the drier Early Archaic times lived in more dispersed bands, living on not only buffalo but deer, rabbits, rodents, reptiles, and a much greater reliance on plant foods.
Besides the overall reconstruction of past climates, archaeologists are also interested in the local environment at the time a site was occupied. Studies of the plant remains at a site can reveal information on whether a site was situated on the edge of a marsh, a streambank, open prairie, forest, and so forth. Soils also aid in this work; different types of soils are typical of different environments. The study of the geology at a site provides additional information on the shape of the ancient landscape.
The above examples are part of the process used by archaeologists to reassemble the jigsaw puzzle of the past. As the work at one site is compared to other sites, or new information is gathered, a picture slowly emerges and becomes refined about the lives of ancient people. Understanding the technology, resources, climate, and surroundings allows an insight into the life of a people, season by season and day by day over a long time period. Cultural anthropologists have documented the amazing diversity of human life on earth; archaeology expands on that by providing the vital dimension of time.
At one level, anybody can enjoy archaeology. They can read about it in magazines and books, visit museums, join clubs and societies, and participate in volunteer programs at various excavations and labs.
Many people enjoy collecting arrowheads and artifacts as a hobby. Professional archaeologists often frown on this practice as being somewhat destructive, since, once an artifact has been collected, its information value with respect to the rest of the site diminishes greatly. Many collectors, though, enjoy their hobby on a more sophisticated level, recording their finds on maps and cataloging them. This information can then be shared with others. Those who collect in an ethical manner are also careful to limit their efforts to land where they have permission. Government land, whether city, county, state, or federal, is generally off limits to any sort of nonprofessional collection. Private land is just that: private. No one should collect there without the owner's permission.
Unauthorized excavation is not considered ethical, and it is illegal in many instances. Private citizens generally are discouraged from independent excavations because of need for elaborate record keeping, lab work, write up, and proper storage. It is simply beyond the ability of most people to devote enough time and resources to carry out such a project.
Becoming a professional archaeologist requires both education and training. Most archaeologists in the United States and Canada begin by studying anthropology in college, although many also come from a background in history. A thorough understanding of how existing human cultures behave lays the groundwork for learning how to interpret the cultures of the past. Besides anthropology and/or history, archaeology students are encouraged to take classes in a variety of other disciplines. Archaeology is, if nothing else, a multidisciplinary field of study, and a basic understanding of fields such as chemistry, math, geology, soils, geography, and biology is useful. Besides the sciences, knowledge of techniques in photography, art, drafting, surveying, and computers is also advantageous. Good grammar, spelling, and writing skills are also of value. One of the reasons archaeology is such a fun field to work in is that it attracts people with such diverse interests.
Besides the classroom work, archaeology students also attend field schools to learn the basics of setting up and running an excavation, recording data, and interpreting their finds. Additional experience must be gained in lab techniques during the school year.
A four-year bachelor's degree in anthropology/archaeology is the first step in becoming an archaeologist. At this level, a graduate might be able to find employment at a technician's level, moving from project to project as work is available (hence the term shovel bum).
Those who have gone on to earn a graduate degree, either master's or PhD are able to find more senior-level positions. Many universities require the PhD degree as a prerequisite to a teaching position. A master's degree can take one or two years beyond the bachelor's degree, and the PhD another two or three years.