The HumunGIS Importance of Mapping Data at Archaeological Sites

Featured Fragment – HumunGIS Importance of GIS

By D. Brad Hatch and Emily Calhoun

Since this past Wednesday (November 13, 2019) was Geographic Information System (GIS) Day, we’ve decided to dedicate this week’s blog to highlighting how archaeologists use GIS as a tool to better understand and interpret archaeological sites. We use GIS (through the computer program ArcGIS) to link archaeological data to specific geographic locations. Once we can link our data geographically across an area, we can begin to tease out patterns in the data that might not have been noticed otherwise. To provide an example of the archaeological application of GIS we will be returning to the Trogdon-Squirrel Creek site in Randolph County, North Carolina, which was the subject of a number of previous blog posts, including posts on eyewear, frog gigs, pottery, and more. On behalf of the North Carolina Department of Transportation (NCDOT), Dovetail Cultural Resource Group conducted data recovery excavations at the site, guided by the data recovery plan authored by NCDOT (Overton 2014).

Archaeologists have demonstrated that plow zone artifact and soil chemical distributions have the potential to reveal important aspects about the use of space on sites (e.g., Fesler 2010; King and Miller 1987; King 1988; Pogue 1988b; Wilkins 2009). Artifact data for spatial analysis at the Trogdon-Squirrel Creek site were collected through the excavation of 80 2 x 2-foot (0.6 x 0.6-m) test units; soil chemical data was collected using the systematic method of taking a sample every 20 feet (6.1 m) on grid across the site. Analysts plotted artifact and soil chemical distributions using ArcGIS, revealing significant patterns for several artifact types and soil chemicals. ArcGIS plots patterns by creating contour maps of distributions. Essentially the computer program takes the raw artifact or soil data and connects locations with similar values to create lines. These lines represent values or counts, which when plotted geographically can show how values change across a site. Where there is little change in value, the lines are spaced farther apart. Where the values rise or fall rapidly, the lines are closer together. The resulting map is similar to a topographic map, which plots changes in elevation.

Dovetail used ArcGIS to plot domestic artifacts across the site. In this case, the most illustrative domestic materials included ceramics and animal bone (Figures 1 and 2). The distribution of ceramics revealed two concentrations of artifacts. The first, and most distinct, occurred off of the southeast corner of the dwelling. This concentration of ceramics is indicative of increased refuse disposal and activity in this portion of the site, which likely stemmed from the traffic between the dwelling and the outbuilding located to the southeast. The second concentration, which is less intense and smaller in size, occurred near the southwest corner of the dwelling. This small peak, which was also noted in the distribution of architectural artifacts, likely represents a disposal area near a window or at the edge of the backyard where refuse was conveniently deposited. Overall, the ceramic distribution matches other historic artifact distributions, indicating that the northern yard was kept relatively free of refuse and that the southern yard functioned as a disposal and work space.

Figure 1: Distribution Map of All Ceramics.

 

Figure 2: Distribution Map of Bone.

Soil chemicals often provide archaeologists with important additional evidence about activity at sites when more traditional artifact types are not present. Different chemicals are associated with different activities. For example, phosphorus is generally interpreted as representing organic refuse, calcium tends to represent bone and shell, and potassium and magnesium are interpreted as representing ash or burning (McCoy 2016:25–26; Pogue 1988a:3; Wilkins 2009:20). At this site the distribution of phosphorus tended to concentrate near the dwelling and an outbuilding (Figure 3). Specifically, the primary area of high phosphorus concentration occurred in a heavily used area between the two buildings. This general pattern coincides with the historic artifact distributions on site, and is almost certainly related to the disposal of domestic refuse. Dovetail archaeologists concluded, based on the high phosphorous signature, that the outbuilding was likely a detached kitchen. Refuse discarded from the outbuilding was also noted down the hill, to the east, as well as between the outbuilding and the dwelling. There are also two small peaks of high phosphorus concentration located to the north of the dwelling. These peaks are associated with the locations of two tree stumps.

Figure 3: Distribution Map of Phosphorus.

As you can see, the application of GIS-based mapping of artifact and soil chemical distributions at the Trogdon-Squirrel Creek site was vital to our interpretation of the site. In this case the computation tools within the ArcGIS program helped to reveal activity areas. These GIS-generated maps even helped to define the location of an outbuilding, likely a kitchen. Without this analytical tool archaeologists may have overlooked the kitchen, because no foundation or obvious architectural feature marked its location. Archaeologists have many analytical tools in their toolbelts, but GIS is definitely one of the most powerful for analyzing past landscapes!

Any distributions of blog content, including text or images, should reference this blog in full citation. Data contained herein is the property of Dovetail Cultural Resource Group and its affiliates.

References:
Fesler, Garrett
2010     Excavation the Spaces and Interpreting the Places of Enslaved Africans and Their Descendants. In Cabin, Quarter, Plantation: Architecture and Landscapes of North American Slavery, edited by Clifton Ellis and Rebecca Ginsburg, pp. 27–49. Yale University Press, New Haven, Connecticut.

King, Julia A.
1988     A Comparative Midden Analysis of a Household and inn in St. Mary’s City, Maryland. Historical Archaeology 22(2):17−39.

King, Julia A., and Henry M. Miller
1987     The View from the Midden: An Analysis of Midden Distribution and Composition at the van Sweringen Site, St. Mary’s City, Maryland. Historical Archaeology 21(2):37−59.

McCoy, Curtis A.
2016     Colluvial Deposition of Anthropogenic Soils at the Ripley Site, Ripley, NY. Master’s Thesis, Department of Anthropology/Archaeology, Mercyhurst University, Erie, Pennsylvania.

Overton, Brian
2014     Archaeological Data Recovery Plan: Site 31Rd1426, Randolph County, North Carolina. North Carolina Department of Transportation Human Environment Section, Raleigh, North Carolina.

Pogue, Dennis J.
1988a     Anthrosols and the Analysis of Archaeological Sites in a Plowed Context: The King’s Reach Site. Northeast Historical Archaeology 17:1–15.

1988b     Spatial Analysis of the King’s Reach Plantation Homelot, Ca. 1690−1715. Historical Archaeology 22(2):40–56.

Wilkins, Andrew P.
2009     Identifying 18th Century Hidden Landscapes at Stratford Hall Plantation Using Portable X-Ray Fluorescence Phosphorus Readings on Plowzone Samples. Master’s Thesis, Department of Anthropology/Historical Archaeology, University of Massachusetts, Boston, Massachusetts.

Hindsite is 20/20: A Look at Historic Eyewear

Featured Fragment – Historic Eyewear

By Kerry S. González

We’ve decided to continue our series highlighting the artifacts recovered from the Trogdon-Squirrel Creek site in Randolph County, North Carolina for the month of September. On behalf of the North Carolina Department of Transportation (NCDOT), Dovetail Cultural Resource Group conducted data recovery excavations at the site, guided by the data recovery plan authored by NCDOT (Overton 2014).

The artifacts pictured below are eye glass lens fragments dating to the early-twentieth century (Photo 1). Both lenses are round as opposed to earlier styles that were more ovoid. The lens on the right is made of crown glass with a diamond-beveled edge and was concavo-convex in design, placing it in the 1900–1930-time period (John Tull, personal communication 2017). Furthermore, the lens was tested with a Topcon Lensmeter, a machine that determines the strength of a prescription. This particular lens gave a reading of +4 indicating that the owner of the glasses was moderately farsighted. The second lens was too scratched to provide a prescription reading but given its shape it likely dates from 1900–1930 as well.

 

Photo 1: Eye Glass Lenses Recovered From Trogdon-Squirrel Creek Site.


 

According to several sources, the Romans are credited with using a form of magnified glass to see small items at a larger scale (allabouteyes.com 2019). However, it wasn’t until the 1200s that we see the first evidence of wearable glasses (allabouteyes.com 2019). The first written reference to eyeglasses is in a book titled De iride (“On the Rainbow”) by Robert Grosseteste (circa 1235) (OpticianU 2018). The book mentions using a lens to “read the smallest letters at incredible distances” (OpticianU 2018). Reportedly, these “primitive glass-blown lenses were set into wooden or leather frames (or occasionally, frames made from animal horn) and then held before the face or perched on the nose” and were primarily used by monks for reading, as cited in Archives of Ophthalmology (2002) (Figure 1).

 

Figure 1: La Mer des Histoires (Letocha and Dreyfus 2002).


 

It wasn’t until the 1700s that eyewear began to improve and from this point on eyeglasses evolved at a rapid pace (allabouteyes.com 2019). While Benjamin Franklin is often credited for inventing bifocals in 1784 when he glued his distance glasses and reading glasses on top of each other, some historians believe he is unduly credited with this invention due to his historic importance (OpticianU 2018). By the late-nineteenth century glasses were being mass produced and advertised in places like the Sears & Roebuck catalog where one could even give themselves an eye exam to determine the strength of glasses needed (Figure 2).

 

Figure 2: Sears & Roebuck Eyeglass Advertisement (Sears, Roebuck and Catalogue Company 1897).


 

It is artifacts like these eyeglass fragments that really speak to the occupants of a site. They are tangible and relatable to the young and old, especially when you hold up a lens and see through the eyes of its owner 100 years ago.

 

Any distributions of blog content, including text or images, should reference this blog in full citation. Data contained herein is the property of Dovetail Cultural Resource Group and its affiliates.

References: 

Allabouteyes.com
2019 See Into The Past: The Fascinating History of Eyeglasses. Electronic document, https://allabouteyes.com/see-past-fascinating-history-eyeglasses, accessed September 2019.

Letocha, J., and M. Dreyfus
2002 Archives of ophthalmology 2002. Early Prints Depicting Eyeglasses (Figure 4). Electronic document, https://www.semanticscholar.org/paper/Early-prints-depicting-eyeglasses.-Letocha-Dreyfus/f952e6a9a6509a4da61e6e48b1e61a6d91331818, accessed September 2019.

OpticianU
2018 Eyeglass History – Seeing Through the Ages. Electronic document, https://www.op
ticiantraining.com/eyeglass-history-vision-through-the-ages/, accessed, September 2019.

Overton, Brian
2014 Archaeological Data Recovery Plan: Site 31Rd1426, Randolph County, North Carolina. North Carolina Department of Transportation Human Environment Section, Raleigh, North Carolina.

Sears, Roebuck and Company Catalogue
1897 The Sears, Roebuck Catalogue. Sears, Roebuck and Company. Skyhorse Publishing, Inc., New York, New York.

The “Clear” Benefit of Bottle Glass. And Wire Nails. And Sewer Pipes….

Featured Fragment – One Person’s Trash

By Kerry S. González

One of the questions we get asked most often with our work revolves around artifact ownership. In many states, all artifacts recovered from private land during Section 106 review rightfully belong to the person who owned the property at the time they are excavated (ACHP 2009). As such, coordination with landowners is essential. Dovetail works with the landowners to assure that their artifacts are returned to them, but what is retrieved often isn’t what they expect.

The conversation with property owners usually begins like this:

Archaeologist: “Would you like to keep the artifacts found on your property or would you like to donate them to the state repository?”

Landowner: “Yes, I would like to keep them. How many whole bottles did you find? What is the collection worth?”

Archaeologist: “Actually we only found small fragments of clear glass and while the collection has research potential it does not have any monetary value.”

Landowner: “I would like to donate the collection.”

A large percentage of the population believes that during an archaeological excavation only complete objects of monetary worth are recovered. The reality is, we find and collect broken stuff. We dig up people’s trash from the past, most of which is not desirable to anyone but an archaeologist who has spent days/weeks/months digging in the dirt to find it. But as the saying goes, “one person’s trash is another person’s treasure.” As archaeologists we love the broken bits and use these fragments of dishes, bottles, smoking pipes, jewelry, etc. to piece together information on the people that lived in a particular area.

Many of the artifacts we typically find date to the late-nineteenth to early-twentieth century, when large-scale commercial manufacturing allowed for faster production of items like glass, nails, and plastics. Faster and easier production meant that they were more affordable. This, in turn, made those items more readily available to consumers and thus seen as more disposable.

Typically, for this blog we like to highlight a particularly interesting object or collection of artifacts. However, in an effort to show what standard finds are during survey work, please enjoy the pictures below showing the types of artifacts we most commonly see. Are they worth a fortune? No. But are they invaluable to our understanding of our past? Absolutely….

 

Top row from left: White clay pipe stem, clear lead-glazed redware, two whiteware plate fragments. Bottom row from left, ungalvanized wire nail, machine cut nail, collection of window glass.

 

From left: Red automobile tail light fragments, clear vessel glass, and collection of clear bottle glass.

 

 

Any distributions of blog content, including text or images, should reference this blog in full citation. Data contained herein is the property of Dovetail Cultural Resource Group and its affiliates.

References: 

ACHP.gov
2017 ACHP 2009,  http://www.achp.gov/docs/ACHP%20ARCHAEOLOGY%20GUIDANCE.pdf, accessed September 2017.

History Buttoned Up

Featured Fragment – Huntley House Button

By Kerry S. González

In 2016 Dovetail conducted an archaeological excavation at the Historic Huntley House in Fairfax County, Virginia. This work was completed at the request of the Fairfax County Park Authority as part of their Huntley Tenant House Rehabilitation Project. Dovetail surveyed portions of the property surrounding the tenant house as well as the interior of the building. This was a unique case where the floorboards of the tenant house had been removed prior to the installation of new flooring, revealing the soils below the dwelling and allowing archaeological access to an often-hidden living surface. Dovetail’s excavations inside the house primarily focused on the builder’s trench (an excavated trench for the placement of a brick or stone foundation) in the southwest room of the building. Of the numerous artifacts recovered during this excavation, one was instrumental in determining a possible construction date for the building.

View of the Huntley Tenant House.

 

View of Southwestern Room of the Huntley Tenant House.

 

A copper-alloy U.S. great coat button (pictured below) was recovered from the builder’s trench within the southwest room. This coat button dates to the 1830s and 1840s and was potentially dropped by someone involved in the construction of the home. This date proved extremely useful for interpretation as the previous estimated date of construction was circa 1880.

 

1830s–1840s Great Coat Button with Inset Showing 1830s Great Coat (USHistory.com 2017).

 

The presence of this button and other artifacts suggested an antebellum construction date for the dwelling. Also key to dating the structure was the lack of Civil War-era material within the builder’s trench. The Huntley House property “was the scene of a large encampment of Union troops during the Civil War” (Bierce 2002:6; cf. also John Miner and Associates 2003:67–75). Earlier excavation near the tenant house recovered many Civil War-specific artifacts and post-1860 materials across the yard. If the tenant house were constructed after 1880, some artifacts dating to the 1860–1880 period likely would have been dug up during the building’s construction and thus end up in the builder’s trench. The builder’s trench, though, only contained artifacts that predate this period. The tenant house, therefore, potentially dates to the circa 1825–1862 Mason family ownership of the Huntley House property, rather than having been built after the Civil War, as previously thought (National Park Service 1972). This excavation, along with other studies on the property, highlights Fairfax County Park Authority’s dedication to history and the importance of having professionals present during renovations on historic properties.

 

Any distributions of blog content, including text or images, should reference this blog in full citation. Data contained herein is the property of Dovetail Cultural Resource Group and its affiliates.

References: 

Bierce, C. Richard
2002   Historic Structure Report. Schaffer, Wilson, Sarver, and Gray, Reston, Virginia.

John Milner and Associates, Inc. (JMA)
2003   Historic Huntley: Cultural Landscape Report. JMA, Charlottesville, Virginia.

National Park Service (NPS)
1972   National Register of Historic Places Nomination Form. United States Department of the Interior. Electronic document, http://www.dhr.virginia.gov/registers/Counties/Fairfax/029-   0117_Huntley_1972_Final_Nomination.pdf, accessed June 2016.

USHistory.com
2017   M1832 Enlisted Greatcoat, http://www.ushist.com/mexican_war/us_military/uniforms/qm-3350_greatcoat_m1832_mexican-war-us.shtml, accessed August 2017.

What’s in the Attic?

Featured Fragment – Archaeology in historic Salubria’s attic

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Historic Salubria

On August 23, 2011, 5.8-magnitude earthquake struck central Virginia with its epicenter in Louisa County. The earthquake caused massive damage to eighteenth-century Salubria, a Georgian home located in Culpeper County, Virginia and owned by The Memorial Foundation of the Germanna Colonies In Virginia, Inc. (The Foundation).

The damage caused by the 2011 earthquake required extensive repairs to the original roof truss system, roof cladding, and chimneys. Prior to installation of associated new attic flooring, Dovetail Cultural Resource Group, at the request of The Foundation, was hired to remove the detritus that had accumulated on the attic “floor” over the years. Because the process involved hand removal of soil, dust, and other materials through careful, controlled digging, the project was termed an “archaeological excavation” despite its location two stories above the ground surface.

Using the building’s structural system, Dovetail laid in a “grid” to divide the attic into 12 sections. All artifacts were bagged by section to examine the deposition of the artifacts. More than 12,000 artifacts were recovered from the attic, including over 350 pieces of cloth of varying size and material, nails, personal items, and paper.

Dovetail archaeologist hard at work!

Dovetail archaeologist hard at work!

The thousands of pieces of paper found in the attic are a direct reflection of both the humans who lived at Salubria and the animals who carried the goods to the attic. One of the most remarkable intact paper fragments was a personal letter from 1862! This haunting letter speaks of the first student death at Farmville Female College (Longwood University) and speaks of the demise and death of Molly Priott (see transcription below the letter).

Front of letter from the Farmville Female College.

Front of letter from the Farmville Female College.

back

Back of letter from the Farmville Female College.

 

The death of our dear Mollie is as great a shock to us as it can possibly be to you my precious friend – we did not know the poor child was sick until Sunday when we all thought she had neuralgia, at a late hour last night the Dr. pronounced her disease congestion of the brain – her mother at 10 o’clock last night, no later when I left her, did not seem to apprehend any danger – at five this morning word came to me that she was dying. I went hastily up…[unreadable]

the children, half conscious, half unconscious, of their loss. – I have just left her, little May and I being the last to look upon the loved face of mine the last kiss upon her brow. The coffin is closed and we can not see her more until we all go home where you and we will live again with our beloved.

We have service in the chapel this evening at six, and Mr. Preot goes with the corpse to Petersburg to-night. Write to Mrs. P or come to see her to-morrow. – I feel so obliged to you for your sympathy, it is the first death in our school and keenly felt by Mr. [La chonde] and myself.

I hope to see you soon. – God bless you, my dear, dear friend and be to you all He has promised. Love to you mother and the children –

Tuesday 14th Jan, 1862, Truly and fondly your friend

R…

The 12,000-plus artifacts found during the excavation shed light on the lives of the residents of Salubria. Because this type of “excavation” is rare, these fragile, perishable artifacts are typically lost. This was truly a unique and amazing, albeit filthy, experience for Dovetail!

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Dr. Kerri Barile, Dovetail’s president, after a day in the attic!

Any distributions of blog content, including text or images, should reference this blog in full citation. Data contained herein is the property of Dovetail Cultural Resource Group and its affiliates.

To learn more about Salubria, or Germanna Castle, visit http://germanna.org/.

Glowing Glass Discovery

Featured Fragment—Vaseline Glass

In a recent excavation Dovetail Cultural Resource group found several fragments of what is known as Vaseline glass. This glass ranges in color from yellow to green and was manufactured from the 1840s to 1940. What is interesting about this type of glass is it was made with Uranium, which is the reason for its distinctive color. This type of glass was produced until WWII at which time the shortage of Uranium put an end to its production. What is the best way to identify Vaseline glass? If put under a black light, the glass will light up. The Uranium makes the glass emit radiation and glow, or a Geiger counter can be used to determine whether it is radioactive. The vessel found by Dovetail registered at 0.15 milliroentgens per hour. Is this a dangerous level? No, the amount put out by this type of glass is small and not harmful.

Image of Vaseline Glass. On left: yellow tumbler base and body fragment. One right: tumbler under black light.

Image of Vaseline Glass. On left: yellow tumbler base and body fragment. One right: tumbler under black light.

 

Joe Blondino using Geiger counter on Vaseline glass.

Joe Blondino using Geiger counter on Vaseline glass.

Any distributions of blog content, including text or images, should reference this blog in full citation. Data contained herein is the property of Dovetail Cultural Resource Group and its affiliates.

Informative links:

http://www.vaselineglass.org/?page_id=56