Long walks in the woods and well maintained maps

I have spent the majority of my life wandering in the woods, but only the last 8 years professionally. In CRM the majority of the jobs that we do is confirm the presence or absence of cultural resources or archaeological sites. How do we go about doing that? Simple, dig a lot of holes. I’m going to explain the process below and will use some of the terms we do,

Archaeology in CRM takes place in three phases;

  1. Reconnaissance or survey
  2. Evaluation
  3. Mitigation or data collection

About 90% of the work that CRM companies get are phase I projects. These are usually triggered by regulations relating to land use permits and can be over project areas that are under an acre to hundreds of acres, or for road improvements and pipelines hundreds of miles long in a corridor a couple hundred feet wide. But what does the work actually look like?

One of thousands of STPs I have dug, this one is about 3 feet deep

Survey work is usually completed according to your State Historic Preservation Office’s (SHPO’s) standards. In Virginia, where I work the most, that agency is the Virginia Department of Historic Resources (VDHR). In general one hole every 50 feet (~15 m) in a grid across the property is required. The size of the hole and the interval can vary from state to state and if you’re on federal land. For example on National Park Service property the holes need to be 50cm squares every 10 meters (~30 feet). Other federal agencies have their own requirements, as can different local municipalities, but the goal is the same; sort through a statistical sample of the dirt on a property to look for cool stuff (i.e. significant cultural resources).

We keep a record of all of the information we gather doing these reconnaissance surveys through photos, maps, and written notes about every hole we dig.

Example of a USGS topographical map, this is a little south of Leesburg, VA

To record the location of all the shovel test pits (STPs) we use either a paper topographical maps or GPS. I prefer to use paper maps because there are less bits that can fail or create errors. To do this we pick a landmark or location on the map that’s easy to identify on the landscape, line up our grid (also against land marks on the map that are easy to identify on the landscape), and note on the map everywhere we dig an STP and which of those had artifacts in them.

Each STP record includes what layers of soils were observed (stratigraphy) including their color and textures, the depth of each layer (stratum), if there were any artifacts, and which layer of soil they came from. The field director or crew chief also take photos of what the landscape looks like and if there are any areas where the soils are disturbed, or otherwise untestable.

USDA soil texture triangle: used to described the textures of the soil we excavate.
Note: No such thing as sandy silt or silty sand. Fight me.

To find the artifacts in the dirt we push or shake all of it through wire mesh. The artifacts are bagged and labeled with their contextual information (Which STP and stratum). This information regarding the type, number, and location of artifacts that we find in the field is taken back to the lab and analyzed to figure out where there are concentrations of artifacts that could represent sites, and if those sites need further evaluation.

Screening action shot from a survey at Mount Vernon

This adds up to the archaeologists taking part in these surveys spending days, weeks, or even months (depending on the size of the project) taking long walks in the woods, or through other landscapes. The more often you do this type of work the more easily you can identify land forms where sites are more likely to be found.

Some surveys result in no artifacts being recovered. Though often disappointing, it is important to remember that the absence of artifacts is still useful information. Knowing where artifacts aren’t helps us to focus our energy and budgets on locations that can give us more information.

This is probably going to be the first in a line of posts about the different basic types of projects that CRM archaeologists do. Look for them in the coming weeks.

-Tom

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AITC’s 10th birthday is coming up in the beginning of March. We are having a fundraising push leading up to the date, March 9. Donations to this fundraiser help fund our educational programming for youths as well as paid internships for students entering the field. You can donate here.

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