....sorry Danny, I had information at one time about the company that was making these, but I can't seem to put my fingers on it at the moment. The date of the cemetary, from the 1870's puts it right on the mark though.
A hole was drilled for the iron stud, and between rust and the chemical breakdown of the marble over the years, many have come loose and are lost. Way back when, my family operated a marble quarry, and there are stones far and wide made from that recognisable marble. During Sunday afternoon drives, we often stop by old cemetaries to look for stones from that quarry and to stroll and read the names and dates from the early days of the community. Sometimes you will see these little ornaments in a pile on a base where a thoughtful person has placed them. Often times, there are just the holes left, indicating where these type ornaments used to be. It's not at all unlikely that someone, possibly a kid picked one of these up after it had come loose and carried it to where you found it.
Hope this helps. Take a wander through that cemetary, and if the stones aren't all toppled and buried, you may find where that ornament came from, possibly some ornaments that are still in place. Be sure to post a pic if you find the place where it goes!
--Steve