When is a rock also an artifact?

/ ferryfarmandkenmore

As archaeologists, we focus on studying the past by examining the items previous humans have left behind. Anything that has been made or changed by someone in the past is therefore considered to be an artifact.

When you think of stone artifacts, the first thing that usually comes to mind are arrowheads. Arrowheads and spearheads are referred to by archaeologists as projectile points. In addition to projectile points, archaeologists also find a wide variety of other stone tools, including awls, scrapers, knives, axe heads, grinding stones, and fishing weights. All of these tools, and others, were used to procure and process food and for preparing items of clothing, storage, and shelter.

Complete tools, however, are not the only evidence Native Americans left behind. Stone artifacts called flakes, shatter, and cores are evidence of the production of stone tools and are found in abundance on prehistoric Native American sites. A core is the first stage of lithic reduction, where the rock is considered an artifact. Typically a natural rock is broken into one or more lithic cores, which will be reduced to usable flakes and tools. Flakes are relatively thin shards of stone precisely removed from a stone core. Shatter consists of chunks of stone that come off the core in unintended or less predictable ways. To make a stone tool, flakes are removed from a core by striking them off with a hammerstone or antler baton. This is called percussion flaking. Each core would then be reduced through percussion flaking to a rough preform of the intended tool. Once that is complete, a lithic tool will be reduced to a finished shape and then sharpened. This is done through a process called pressure flaking. While percussion flaking makes bigger lithic flakes, pressure flaking makes very small flakes. Instead of hitting the stone, a narrow piece of bone or antler is firmly pressed against the side of the stone, breaking off a small flake and leaving a sharp and more robust edge.The best lithic tools are made from stones that break in predictable patterns. This quality is found in rocks that have a cryptocrystalline structure. Some examples of rock types we find lithic tools made from are: chert, flint, jasper, and quartz.

Three methods of lithic reduction.
Examples of lithics found at Ferry Farm, a core on the left and on the right a projectile point surrounded by flakes and shatter.

While archaeologists can learn much from artifacts such as projectile points and tools, we are also interested in a category of stone artifacts called fire-cracked rock. Fire cracked rock, commonly abbreviated to FCR, is a byproduct of cooking at a time primarily before the creation and widespread use of ceramics more than 3000 years ago. In order to boil water for cooking, they would heat rocks in a fire and drop them into pots of water made from animal hides or wood. After doing this multiple times, the rocks would permanently turn red from the heat of the fire and shatter into small pieces from the rapid cooling and heating. By finding FCR here at Ferry Farm, we can deduce that people were cooking meals here before ceramic technology was widespread.

Fire Cracked Rock found at Ferry Farm. Note the red color on the exterior caused by the heat of a fire.

When lithic flakes and shatter are found, we know that at some point, someone made a stone tool there. By examining the type of stone, it is possible to determine where that material came from. Sometimes the local material available isn’t the best for making tools, and people would travel or trade for better materials. This is the case at Ferry Farm, where most of the lithics we find are made of quartz, but sometimes we find jasper or chert flakes that indicate travel or trade.

There’s even more, we can learn from projectile points and some tools. Projectile points changed in shape, size, and form over time. These changes could be due to a change in purpose of the point or a change in maker. Archaeologists have grouped points together to create types that were made in a certain region during a given date range. We can use these groups to match points we find in our excavations and determine where it came from and when it could have been made.

Native Peoples lived in the Rappahannock area, including what would become Ferry Farm, for thousands of years before Europeans arrived. The projectile points, tools, FCR, and lithic debris they left behind are some of the only artifacts that were able to survive until today. Being able to tell the difference between them and a natural rock becomes an important skill for archaeologists. Have you ever found a lithic?[1][2][3]

Top and Bottom images: Examples of different types of points and the various materials they can be made from. All excavated at Ferry Farm.

Mason Schultz

Co-Field Director and Staff Archaeologist

[1] “Diagnostic Artifacts in Maryland, Projectile Point Typology.” Jefferson Patterson Park and Museum, Maryland Archaeological Conservation Lab, 2002, https://apps.jefpat.maryland.gov/diagnostic/ProjectilePoints/AboutProjectilePoints/ProjectilePointTypology.html. Accessed 9 Aug. 2022.

[2] “Diagnostic Artifacts in Maryland, How Are Points Made?” Jefferson Patterson Park and Museum, Maryland Archaeological Conservation Lab, 2002, https://apps.jefpat.maryland.gov/diagnostic/ProjectilePoints/AboutProjectilePoints/HowArePointsMade.html. Accessed 9 Aug. 2022.

[3] Cullen, Darcy. “Methods of Flaking Stone.” Quizlet, https://quizlet.com/250350464/methods-of-flaking-stone-diagram /. Accessed 9 Aug. 2022.