The rounded rock is 1,250 cubic feet, weighs 103 tons, and is granitic in composition.  Granite is not indigenous to the regions and geologists have recognized that it has been transported from Proterozoic granites that exist just north of Toronto, Canada, by a huge continental glacier that reached southern Ohio about 23,000 years ago.  These rocks exist in moraines all over the region but large glacial eratics like this are rare.