Clementine Chapel has a granite monument.
Clementine Chapel . Open today for pilgrims , the site venerates the original pavonazzo marble monument placed there by Emperor Constantine , and was used in early medieval times to house the skull of St. Peter The Groton Monument , sometimes called the Fort Griswold Monument , is a granite monument in Groton , Connecticut . The Groton Monument is located in Fort Griswold Battlefield State Park , which includes Fort Griswold , in Groton , Connecticut , United States .