Geophysical Survey of the Mt. Calvary Cemetery, Vincennes, Indiana

Abstract

At the request of the Vincennes city engineer geophysical surveys were performed at the Vincennes Mt. Calvary Cemetery located at the intersection of 6th and Willow Streets. The surveys were intended to locate unmarked graves in the path of a proposed road expansion. A resistivity survey was initiated by the Glenn A. Black Laboratory based on previous success by this method in the detection of early historic cemeteries. The survey was conducted on Sept. 21, 2001 by Dr. Stephen Ball and two assistants. A Geoscan RM15 resistivity meter in a twin probe array was used for the survey. The results of this survey did not provide firm evidence for the existence of grave shafts in the study area. A Noggin 250MHz ground penetrating radar (GPR) unit was then used for another survey. A GPR survey is far preferable for the detection of subsurface graves. The GPR survey was performed by Ball and Shaffer on Oct. 3, 2001. There appear to be at least 12 graves located in the survey area. The results of the resistivity survey appear to corroborate the GPR survey. Three possible grave shafts were identified in the resistivity survey all of which correspond to locations where the GPR survey indicated graves. In conclusion, there do appear to be unmarked graves in the survey area. Any attempt to widen the road through this area should take the additional expense of grave removal into account. One could minimize the possibility of encountering graves during the road widening by restricting earth moving activities to the area formed by an arc between the metal access cover located on Willow St. to the area already impacted by the previous road building along 61st Street.