Memorial to pastors of the parish. I think the stone is the work of J.B. Verment of Massillon, Ohio. It's virtually identical to one at St. Augustine's in Minster, Ohio: http://www.saintaugustinecemetery.com/about.html
Be sure to check out this exciting project – “The Faithful Traveler.” Their slogan: “Discovering the treasures of the church, one city at a time.” I’ve watched the debut DVD – a documentary and tour of the Miraculous Medal Shrine in Philadelphia. Host Diana von Glahn and her crew do a fine job of bringing together church history, shrine lore, landmarks and music in a fast-paced presentation that makes you want to visit the shrine (and the city) in person. The DVD includes additional features such as a novena service and a slideshow. Two more Philadelphia churches are next on their list. (I’m sure we have a few suggestions if they travel west to Ohio.)
A short biography from Msgr. Houck's "The Church in Northern Ohio":
Toussaint St. Joseph and La Prairie St. Philomena were parishes that served French-Canadian settlements not far from Lake Erie. Perhaps some more on those parishes in the future.