Archeologists have found the remains of a 19th-century quarantine hospital and cemetery on a submerged island in the Florida Keys, the National Park Service said.Video released by the Dry Tortugas National Park shows underwater excavations, which began in August 2022, during a survey of the Fort Jefferson Post Cemetery near Garden Key.The research was carried out by park cultural resources staff, the National Park Service’s Submerged Resources Center, the Southeast Archeological Center, and a University of Miami graduate student, the park said.Records indicate dozens of people may have been buried at the site, the park service said.One grave was identified as that of John Greer, a laborer who died in1861. Officials said not much was known about Greer, but his grave was prominently marked with a large slab of greywacke, the same material used to construct the first floor of Fort Jefferson. Efforts to learn more about Greer and other individuals interred on the now submerged island are continuing.Fort Jefferson was a military prison during the American Civil War, and the surrounding islands became a naval outpost, a lighthouse station, naval hospital, quarantine facility and a site for military training, according to the park’s website. Credit: Dry Tortugas National Park via Storyful