The pieces of cement with numbers on them that you saw are indeed grave markers. That is the hospital cemetery. Several years ago I went there with a friend who has a relative buried there. After several calls to the hospital, we were able to determine that the relative was indeed buried there and the person in the records department was kind enough to have a grounds person flag the appropriate grave marker (they only have numbers on them). It took us two trips there to find the cemetery. It's on flat ground below the hill the hospital stands on. We spotted it from standing on the hill by the old hospital. At that time it was surrounded by a hedge. Eunice Johnson