Digger O'Dell sez:...it's the remains of a contagious disease hospital between the Civil War and the turn of the century...it's believed to have Coonazz military payroll bullion and bordello tokens buried deep beneath the crumb'n foundation !!!...if 'ya scuba just keep a eye out for a open window,they got unknown boobie traps and a skeleton play'n the piano !!!...cheers
Coming out of the Rigolets into the lake, head south and hug the shoreline until you see two hazard markers a couple hundred yards offshore. That's the hospital wall. Be careful though...especially at low tide.
According to the second result, the Hospital Wall is at N 30 09.9190 W 089 44.9610. In the first result you can see a picture of what the marker looks like.