What is Battlefield Archaeology?
Battlefields present unique archaeological challenges. Here is a look at how battlefield archaeology differs from standard archaeology, and how this relatively new approach has allowed us to discover history's secrets.
Battlefields were considered unapproachable by archaeologists, their buried secrets doomed to either remain hidden or to be looted by relic hunters, thereby losing all historical context. Their unique problems included the fact that battles were fluid, covering hundreds - or even thousands - of acres. Also, many times battles were fought in open farmland, and this soil has been plowed and its artifact locations have been disturbed hundreds of times since the actual battles were fought. But in 1984, archaeologists Dr. Douglas Scott and Richard Fox found a way to reveal the clues of Little Bighorn Battlefield by turning a foe into a friend - the metal detectorist.
Because metal detectors were the implement of choice used by site looters, they were shunned by archaeologists. Scott and Fox proved that decades of painstaking archaeological work could be completed in a fraction of the time with systematic metal detecting surveys. Scott calculated that of the 5,000 artifacts excavated by metal detectorists at Little Bighorn, only about 10 artifacts would have been found using traditional 5'x5' squares. And battlefield archaeology was born.
In 1987, Dan Sivilich, not knowing of the work at Little Bighorn, began developing his own similar techniques at a farm in Freehold, NJ that turned out to be the area of heaviest fighting at the Battle of Monmouth. Since then a lot of new technology has been used both to excavate battlefields and to correctly interpret the information these artifacts reveal. At Monmouth Battlefield BRAVO utilizes metal detectors, a total station laser transit, and Geographical Information Software (GIS) donated by ESRI, Inc. to rewrite the history of the Battle of Monmouth. Here's a quick look at what we do and what we've found.
The three square miles of property at Monmouth Battlefield State Park, if excavated with traditional 5'x5' squares, require about 3.3 MILLION squares and would take about 3,000 years to excavate. Call us impatient, but we didn't want to wait that long, so we're utilizing modern technology to get the job done quicker.
With so much area to cover and over 230 years of disturbance to contend with, we began by attempting to "see" beneath the surface without actually breaking ground. This is done with the use of very sophisticated electronic metal detectors. These are not your typical toy metal detectors, but professional grade tools that are used with detectorists having decades of experience.
BRAVO also conducts systematic metal detecting surveys of specific areas, utilizing our "Bag, Tag, and Flag" system. Each artifact we discover is put into a bag, given a a unique field identification number, and put back into the open hole with a flag to mark the spot. Once all of the metal detecting work is completed, these flagged artifact locations are very accurately pinpointed and recorded using a Trimble 5600 total station laser transit with a TDS Ranger 500 data collector. Finally the artifacts are collected, identified and the holes refilled.
The next step is to plot the artifact locations into an ARCView GIS system, which reveals important information such as patterns of fire. Once we have the artifact locations plotted into ARCView, we can go one step further and create layers of artifact types within ARCView. By doing this, we can choose to bring up a screen of only one specific type of artifact, such as chewed musket balls, in order to clearly determine where a field hospital might have been located. Think of layered GIS images like computerized transparencies where the viewer can add or take away layers of images in order to focus on one specific thing.
Using GIS analysis of case shot at the Parsonage site to identify the original cannon locations of 4 French guns under the command of General Nathaniel Green
We have excavated thousands of musket balls at Monmouth Battlefield, Valley Forge, West Point, Ft. Montgomery, NY and numerous other Rev War sites. Years of analysis by BRAVO President and founder, Dan Sivilich, has been able to determine many bits of information from the lead balls, such as type of musket used, impacted vs dropped musket balls, mutilated shot, and even musket balls chewed by soldiers, possibly to help bear the pain of field surgery. (Revolutionary War Musket Ball Typology, pages 7-20).
A new problem arose when finding these musket balls: while it was easy enough to measure the diameter of dropped musket balls, how can we determine the diameter of an impacted or chewed musket ball, which can be so misshapen that it may resemble a flattened piece of chewed gum more than a ball? That's where Dan Sivilich's engineering background blended with his knowledge of archaeology to develop a formula that has given battlefield archaeologists a way to answer this crucial question.
It's called the Sivilich Formula, which was published by the Society of Historical Archaeology in 1995. The formula is a combination of physics and chemistry that calculates the original diameter of any nonspherical musket ball. It is based on the density of 18th-century impure lead that has been in the ground for over 200 years developing a lead carbonate/oxide patena. The resulting data of knowing the diameter of a flattened musket ball can be used to show clusters of gun calibers that represent concentrations of enemy fire, among other things.
The accuracy of the Sivilich Formula proved itself when it correlated with an account left by Joseph Plumb Martin, one of the soldiers who fought in the Battle of Monmouth. Martin's narrative account of his experiences in the battle are presented in a book called "Private Yankee Doodle". In the book, Martin speaks of British and American artillery placement and troop movements in relation to topographical features. When Sivilich identified the sizes of the musket balls excavated at the site and compared this account to his GIS images, he was amazed at how accurate the images were. Not only with regard to movement of troops and location of artillery, but even where the orchard was located that the 42nd Regiment of Foot, 2nd Brigade of Royal Highlanders got trapped in. The reverse was discovered on the other side of the Park where Anthony Wayne and his Pennsylvania troops were pinned down in the Parsonage orchard by the British Grenadiers. These two orchards have been lost to time, but the GIS analysis of impacted musket balls, grape shot and canister shot clearly identifies the orchard locations.
Now that we're able to correctly interpret history, Monmouth Battlefield's past will become its future. The site will be rehabilitated to its 18th century plantings, which will help us interpret the battle even further as it educates visitors in the history of their community. Musket ball analysis has identified numerous 18th century landscape features that are already being used to change the current park landscape. In addition, it is an official goal of the New Jersey State Division of Parks and Forestry to turn the battlefield into a world class park, complete with tour roads and wayside exhibits.