Stone Inventory

Mason and Dixon Stone Inventory

By Eric Gladhill, PLS

In the year of our Lord 1730 there was a property line boundary dispute happening in the American Colonies. This was not the typical boundary dispute we might think of today with a disagreement over a foot or two of property; this conflict was between the heirs of William Penn and George Calvert, 1 st Baron Baltimore, (aka Lord Calvert), which held about 4,000 square miles of territory in the balance. There were many battles over where taxes were to be paid and where individual property boundaries were located; even to the point where the violence erupted into a small war (The Cresap’s War).

The Mason and Dixon survey was conducted in the years between November 15, 1763 and September 11, 1768. The astronomers were sent over from the Greenwich Royal Observatory in England to perform the world’s first geodetic survey and set stones along the agreed-upon line of demarcation between the land grants from King Charles II to the Penns and Calverts. These five-feet tall limestones were quarried and carved in England and brought to the “new world” to be set along the north latitude that was agreed upon. The stones were carved with a “P” to face north on the side of Pennsylvania and an “M” to face the south on the side of Maryland, and place at one-mile intervals. At each five-mile interval and “crownstone” was set, featuring the coat of arms for the respective families carved into the stone.

Over the years since that line was established, the stones have held up surprisingly well. There have been various resurveys, reconnaissance and inventories of the stones. In 1990 group called the Mason and Dixon Line Preservation Partnership (MDLPP) was started by Todd Babcock and involved a number of concerned surveyors who, using accurate survey-grade GPS, obtained coordinates on every Mason and Dixon stone found. They also documented the conditions of the stones and directions to find the stones. This established some valuable data for surveyors to find these stones when performing a boundary survey of a property that adjoined or crossed the state border between Pennsylvania and Maryland. This group eventually became somewhat defunct and financially solvent, but they still maintain an active Facebook page and website with lots of information.

In February of 2018, a joint meeting was held in Gettysburg between the Appalachian Chapter of the Maryland Society of Surveyors (MSS) and the South Central Chapter of the Pennsylvania Society of Land Surveyors (PSLS).

Richard Ortt, Director and State Geologist of the Maryland Geological Survey, (MGS) spoke to the 30- something surveyors gathered there to tell them of the Maryland State mandate which requires his department to inventory and maintain the state boundaries. He was looking for help with a large undertaking. Continued on page 14

He wanted to have an inventory performed and documented in order to submit the data to the Maryland Historic Trust, who would then send this information along to the National Park Service to have the stones placed on the National Historic Registry. This would ensure the preservation of these important monuments in perpetuity. Patrick Simon, Professional Land Surveyor and Past-President of MSS, being somewhat of a Mason and Dixon expert, and having worked with MDLPP on past inventories and surveys, presented some history on the original survey and subsequent resurveys of the line.

After several more meetings and lots of work behind the scenes, including a special mobile application being developed by Chris Connallon, a Geologist from MGS, to collect the data using a smart phone, tablet or other mobile device. The app was beta-tested by several surveyors and found to be user-friendly. Connallon also created an on-line sign-up sheet so that volunteers could assign themselves to be responsible for the inventory of certain stones. A soft launch was made to start the inventory in February, 2020 with the actual kick-off started this week in recognition of National Surveyor’s Week.

At this time, inventory has been completed on about 50 of the stones and about 100 or more have been claimed by volunteers who will be responsible for the inventory of those stones. This is not a true resurvey because the accuracy of the coordinates for the monuments is only required to be within 30 feet of the true values. This will not change anything about the location of the state boundary but will assure that the location will remain unchanged.