Beginning in the 1870s, metal headstones cast in Zinc began showing up in Montgomery County Cemeteries. I've been to ninety cemeteries in Montgomery County and I've seen around a dozen of these. Even though they've been exposed to the weather for more than 125 years most that I've seen are in great condition. All you have to do is tap on these and you know it's made of metal and that it's hollow. Granite stones don't start showing up in county cemeteries until 1910. Prior to 1910 most stones were white marble and they haven't aged well. The Blackman monument dates back to 1901 and is at Oak Grove in Hillsboro. This is the only example of a zinc monument in Hillsboro township.
Blackman Monument at Oak Grove Cemetery Hillsboro
Side View - Blackman Monument at Oak Grove Cemetery Hillsboro
Small Zinc Metal Marker - Blackman Monument at Oak Grove Cemetery Hillsboro