LATE 18th AND EARLY 19th CENTURY GRANITE MILLSTONE PRODUCTION IN NORTHEASTERN OHIO

Preserved granitic millstones from a number of late 18th and early 19th century gristmills located in northeastern Ohio were examined for mineralogy, grain texture, shape, and furrow patterns. These included millstones associated with a 1799 mill in Newburgh (now part of Cleveland), an (?)1819 mill in North Olmsted, an 1825 mill in Chagrin Falls, and an early 1800s mill in what is now Cleveland's University Circle.

These early millstones were verified as being granitic (containing orthoclase, plagioclase, quartz, and ferromagnesian minerals) in composition. Most show weak to strong foliation and contain distinct felsic bands. The granite millstones are very similar in petrology to certain glacial boulders, suggesting they were carved out of single local boulders as indicated by historical accounts. The glacial boulders found in the area, originating hundreds of kilometers to the north in the Canadian Shield, are also commonly foliated and may contain felsic bands.

The difficulty of transporting large stone blocks in the late 18th and early 19th centuries also makes it likely that these early granitic millstones were fashioned from glacial boulders. Also, the mills that used these granite millstones are all located within a few kilometers of where meter-size glacial boulders can still be found. These are areas mapped as end moraine or kame terraces, and are reported to contain boulders. Teams of oxen could with moderate difficulty haul a one to two megagram (ton) stone to an individual mill site.

These monolithic granite millstones tend to have the same quarter-dressing furrow pattern. This similarity of furrow pattern suggests either that these stones were used for the same grain processing or were crafted by the same tradesman. In Chagrin Falls there are two millstones recovered from the Chagrin River that are now preserved on display at different locations. Based upon the petrology and matching but opposing furrow patterns these two monolithic granite stones are the matching bed and runner stones used in the 1825 mill located here.