Excavating the North Grove

Guided by a ground-penetrating radar survey conducted prior to excavation, the Archaeology team began opening 10-by-10-foot square units in a checkerboard pattern.

Archaeologists use this technique for a couple of reasons. As Mount Vernon Research Archaeologist Jason Boroughs explains, “By alternating these 10-foot squares, if there’s something linear that’s running across them—it could be a fence, a ditch, a former walkway—it will cross those units. By digging the alternating ones, we open up the maximum amount of area, and we can see what’s happening here, there, and everywhere in between. So it’s a way of guiding our discoveries and maintaining control over the area.” 

After digging a checkerboard pattern, the Archaeology team then excavated the remaining squares, thereby excavating the entire area.

Using their variety of tools, Mount Vernon’s archaeologists are able to skillfully excavate the soil around and underneath a tree’s trunk, exposing a portion of its root system. The process can be challenging.

“It comes down to experience—the amount of years an archaeologist has spent doing this,” Boroughs explains. “Think of it like this: Blacksmiths train to create things out of metal. We’re actually in a similar line of work; I would consider ourselves like craftspeople or artisans. It’s just that we’re removing soil in a very specific way.”

Four black locust trees required removal from the North Grove, as they sat in the footprint of the bunker’s eventual construction. Despite their large size, the trees were only about 23 years old, having been planted after the construction of the original bunker in 1998 — a testament to the black locust’s rapid growth, which so attracted Washington to the species.

Unfortunately, none of Washington’s original black locust trees survive in the North Grove.

Notable objects discovered during the excavation of the North Grove included:

• Several lithic concentrations (sites where Native Americans were crafting stone tools), including 5 hearth-like stone scatters.
• Pre-Colombian projectile points (arrowheads and spear points) dating primarily to the Middle Archaic period. At 3,500-5,500 years old, these artifacts are roughly as ancient as the pyramids.
• A variety of 18th-century English, German, Chinese, and American ceramic tablewares and storage vessel fragments, as well as an “air-twist” wine glass stem (high-quality and fashionable tableware used by the Washington family).
• 18th-century lead shot of assorted sizes (ammunition used in hunting or sport).
• Remnants of a former walkway, likely dating from the late 19th and into the 20th centuries. Both ground-penetrating radar scans and historic photos indicate that the walkway led from the north lane to the north cellar entrance of the Mansion.
• Objects associated with tourism, highlighting the importance of Mount Vernon as a touchstone of American identity: modern coins, photographic flash bulbs, children’s toys, and commemorative wine glass fragments were common finds.

John Posey Wine Bottle Seal

John Posey was Washington’s neighbor whose property Washington eventually purchased around 1770, which became part of Union Farm. A fellow veteran of the Virginia Regiment in the 1750s, Posey rode to the hounds with Washington, frequently visited Mount Vernon in the years prior to the Revolution, and was clearly a convivial companion. This is the seventh John Posey seal to be excavated at Mount Vernon, a larger number than the other seals located to date.

Wine bottle seals are one of the very few artifacts types that archaeologists can connect with specific people. They were created by adding a blob of glass to the shoulder or side of a wine bottle and then impressing it with a personalized stamp. These could be initials or coats of arms from individuals, tavernkeepers, or merchants and were used during the 17th and 18th centuries. Because of the extra glass needed for the seal and the custom-made stamp, bottles with seals were more expensive and served as a symbol of wealth.⁣
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The adjacent photo shows a reproduction wine bottle with Augustine Washington’s seal alongside the wine bottle seals excavated on Mount Vernon property to date. Our 19 seals come from George Washington’s neighbor John Posey; Martha Washington’s first husband, Daniel Parke Custis and his father, John Custis; George Washington’s father, Augustine Washington; the Fairfax family, and unidentified seals, including “HEE.”

Mount Vernon’s archaeologists love finding coins because they help assign dates for other artifacts and soil layers found in the same area.

Objects found in layers below generally pre-date, and items above typically post-date the coin’s deposition. Two “large cent” copper coins—dated 1798 and 1817—recovered adjacent to the Mansion’s north gabled end represent multiple generations of Washington households.

The coins were the first series of one-cent pieces issued by the newly chartered United States Mint in Philadelphia.

General fascination with artisanal waters is not a recent phenomenon.⁣

Imported mineral water bottle fragments are found on many historical, archaeological sites, like this example. This fragment likely represents a late 19th-century Cantrell and Cochrane mineral water bottle manufactured in the Cromac area of Belfast, Northern Ireland.

Bottles like this were often sold at ports and apothecaries as they were thought to contain health benefits. Common 19th-century cures encouraged those with certain ailments to bathe in health spas located in natural springs. Such health beliefs may have encouraged individuals to purchase bottled spring water.

Minted between 1942 through 1945, “war nickels” were made from an alloy of copper, silver, and manganese instead of the usual copper and nickel in order to conserve nickel for the war effort during WWII. ⁣
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Along with this nickel, dozens of other artifacts were recovered from the backfill of a modern irrigation line trench. There were 18th-century ceramic and glass fragments, wrought nails, a 1958 wheat penny, a 1972 quarter, and over 80 other modern artifacts, including food and beverage packaging fragments, a dental flosser from 2006, and flashbulbs. ⁣
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While all the soil layers where these artifacts were originally deposited were disturbed by the installation of the irrigation line, we can still learn about the history of the North Grove by studying all these artifacts together.⁣

The modern artifacts we excavate can tell stories just as vivid as the historic artifacts. ⁣
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While cataloging artifacts from a modern planting feature from the North Grove excavation, our archaeologists identified two datable modern artifacts—a crushed Sunkist soda can (c. 1990-1998) and a partial Baby Ruth candy bar wrapper (c. 1988-1997). ⁣
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In the 1990s, Mount Vernon archaeologists monitored over 20 trees and shrubs being planted in the North Grove. Perhaps whoever planted the tree in this particular hole had a snack break and tossed their trash in the hole as they backfilled it.