Hi Lisa - have you looked at the Youtube video of the cemetery? Some gravestones are legible. I have read that at one time there were 280 stones there - don't know how many remain. From the research I have done to date, my impression is that most of the Americans were buried at the Columbia cemetery. Who were your ancestors? I have familymaterial I will check for you - my ancestor started one of the land companies that sold to Americans beginning about 1900.
There is one person I might ask about walking the cemetery and recording the stones. I will try to track him down and see what he thinks.
I am changing my e-mail address to firstname.lastname@example.org effective tomorrow.