Ask the Experts
What do archaeologists do?
Archaeologists are scientists who look in the ground for information that can tell us about life in the past. This information can be artifacts—objects made by people—or soil layers and features. A feature can be a wall, a paving or an area of soil that has a different color than the soil around it. For example, a differently colored area might show that a plant or a fence post had been in the soil there at one time.
Archaeologists mark out squares called excavation units (excavate is another word for dig). At Poplar Forest, these units are usually 5 feet long by 5 feet wide. Each unit is given its own number, which will be written on all of the notes about the unit and the bags filled with artifacts that are found in the soil of that unit.
How do you know where to dig?
Archaeologists begin fieldwork by carefully marking the area they want to explore. Sometimes they know where a site is from old maps or documents. Like good detectives, they may be able to find clues on the ground surface. These clues can range from plants that seem out of place to small dips where holes may have been dug in the past.
What do you use to dig?
Usually, archaeologists use flat-ended shovels to remove grass and roots. Shovels also can be used for most of the soil removal. For delicate jobs a sturdy mason's trowel is used. As they dig, archaeologists look for changes in the color or texture (look and feel) of the soil. Each different layer or “stratum” of soil is given a letter and removed by itself. The artifacts found in the different soil layers can show the age of the layer.
Don’t forget to take notes!
Writing down information is a big part of fieldwork. Every time a soil layer or a feature is removed notes need to be taken. Archaeologists record the color and texture of the soil, the top and bottom depths of each layer, the number and kinds of artifacts they find, and whether the soil layer contained any features. Archaeologists will also draw maps and take photos to record what they've found.
All of the soil from excavations is shaken through a screen with ¼ inch holes. Artifacts are found among the rocks and roots (and worms!) that are left behind in the screen. The artifacts are then placed in bags. Each bag is marked with the excavation unit number and the soil layer letter.
When are you done?
Soil layers and features are excavated and recorded until subsoil is reached. Subsoil is the name given to a soil layer that contains no artifacts or features; it can be very close to the ground surface or many feet below it. When an excavation unit is complete, backfilling can begin. Backfilling means shoveling all of the dirt back into the hole. A tractor or backhoe can be used to help backfill a site.
Why do you backfill? And what happens next?
It seems strange to spend all that time digging a nice hole just to fill it in again. But when archaeologists backfill an excavation unit, they have taken all of the information out of it. Backfilling can help keep features (like walls or brick floors) that stay in the ground from getting damaged, and can stop the sides of the hole, that have not yet been excavated, from caving in. A site can only be excavated once, so it’s important to record everything the first time. The information is stored in the form of notes, drawings, photos, soil samples, and artifacts.
The next stop for all of these will be the archaeology lab where other exciting discoveries await!
What happens after excavation?
The artifacts that are found in the field are put in brown paper bags marked with the excavation unit number and then brought into the archaeology laboratory.
Once the artifacts reach the lab, they are washed using water and a toothbrush. Some artifacts are too delicate to be washed in water, so they are just lightly dry brushed.
Want to see an artifact being washed? Click here!
After the cleaned artifacts are dry, they are labeled with their excavation unit number using black ink and clear lacquer. The labels help us to keep track of exactly where each artifact was found.
After the artifacts are labeled, information about them is put in a computer database. The information describes what the artifact looks like, how big it is and how much it weighs.
After the artifacts are processed, most are stored in acid-free boxes until further analysis is needed.
How do Archaeologists Study Artifacts?
Archaeologists at Poplar Forest spend a great deal of time looking at artifacts such as ceramic pieces (that may come from plates, for instance), glass, and objects made from iron. By studying these artifacts, even if they are broken into pieces, archaeologists can tell a great deal about the objects and the people who used them.
It is easy to identify common items, even if only a small piece remains. With some artifacts, however, it is harder to say what they are. We can compare them to objects already identified in our study, or we can compare them to pictures in books, objects in museums, or to information on the internet.
Archaeologists also try to put pieces of artifacts together like a puzzle. This is known as cross mending. Cross mending can help identify an object, or it can help show how different soil layers on a site are related to each other. If an object is made up of pieces that came from similar layers in different excavation units, that means that the layers are from the same time period, and that those portions of the site were being used at the same time.
Once the artifacts have been researched and identified, archaeologists use a computer to make a map (a distribution map) that shows where the artifacts were found within an archaeological site. Distribution maps can tell archaeologists things that they might not have seen while digging. For instance, if the map shows a lot of nails and pieces of brick and window glass in one part of a site, it can mean that a house once stood there.
Some artifacts are sent to experts who do not work at Poplar Forest. These include:
- A conservator, who uses special chemicals and tools to clean and preserve metal, bone, and other fragile artifacts from further decay.
- A faunal analyst who identifies animal bones. This has been especially helpful in finding out what animals slaves hunted and raised at Poplar Forest for food.
- A paleoethnobotanist who identifies and studies seeds and other visible plant remains. This information helps us to determine what types of plants Jefferson and others grew at Poplar Forest, and how these plants might have been used. It also provides information about the environment on the property in the past.
- A soil chemist, who identifies various chemicals that reflect human activity and are preserved in the soil. Chemical studies at the slave quarters helped us understand how people used the yards around their houses.
- A palynologist and a phytolith analyst who study microscopic grains of pollen and tiny plant silicas (phytoliths). These tiny remains help us to identify plants that grew here in the past and give us information about the environment.
What happens with the archaeologists' information?
The archaeologists take what they have learned from their excavations, laboratory analysis, documentary research and work with consultants and write the information in a report. These reports explain the location of the excavation site, describe the artifacts found, and discuss what these findings mean.
Once the reports have been written, the information that is discovered from our research is shared with the public. There are many ways that this can be achieved. Archaeologists at Poplar Forest deliver papers at professional conferences attended by archaeologists from all over the world. Research is written into articles and books for publication. Most importantly, this information is directly seen at Poplar Forest through exhibits and tours shared with our visitors.