1. Potentiometric surface of the upper Floridan aquifer in the St. Johns River Water Management District and vicinity, Florida, September 1985 [cartographic material] Yale Public content 1985. 2002-06-01T04:00:00Z. 2023-10-11T03:01:27Z. Geological Survey (U.S.). The Survey ; Open File Services Section [distributor]. English. cartographic image. Public. Florida and Saint Petersburg Region.