Thanks for that idea. I am struggling with the fact that the grave may not be visible anymore. After the Institute moved in the 1930's, the land was sold and developed. It's unclear whether the graves in question still exist, or whether they have been built over by housing developments and possibly the Mandeville post office. Staff at the St. Tammany Parish Library are working with me to try to figure it out. I thought that posting it here might cause any locals who know anything to speak up.