From abstract: The land-pebble phosphate district of Florida is a part of the Gulf Coastal Plain. The geologic formations cropping out in the district are the Miocene Hawthorn, Pliocene Bone Valley, and Pleistocene terrace sands. The Bone Valley formation consists of a lower strongly phosphatic unit and an upper less phosphatic unit. This paper is concerned principally with the lower unit, which contains the bulk of the minable phosphate deposits of the district.

From abstract: Areas of abnormal radioactivity south of Ocala, Marion County, Fla., discovered in 1953 by aerial survey, were investigated by surface examination and by 10 power auger drill holes. Interbedded clay, clayey sand, and uraniferous phosphorite occur in the areas of anomalous radioactivity. Miocene fossils occur at three localities in these beds which are evidently outliers of Miocene sediments on the Ocala limestone of Eocene age. The preserved outliers are southwest of the main belt of Miocene sediments. The principal uraniferous rocks are clayey, sandy, pellet phosphorite that occurs in beds a few feet thick, and very porous, phosphatic sand rock which makes abundant float at many places. Apatite forms the phosphate pellets in the unweathered phosphorite. The very porous, phosphatic sand rock is the highly leached residuum of the pellet phosphorite and is composed mainly of quartz, kaolinite, wavellite, and crandallite ( pseudowavellite2). It closely resembles the aluminum phosphate rock of the "leached zone" of the Bone Valley formation in the land-pebble phosphate district.

From abstract: This report comprises data derived from 53 prospect drill holes drilled by the Davison Chemical Corp. in the eastern part of the Bonny Lake mine, Polk County, Fla.

From abstract: During the month of May 1950, the Davison Chemical Corporation, under contract with the Atomic Energy Commission, drilled 24 phosphate prospecting holes in the western part of the Bonny Lake mine, in the SW NW4 and the NW*SW4 sec. 32, T. 29 S., R. 24 E., Polk County, Fla. The purpose of this drilling was to obtain a comparison between tonnage and grade of uranium in the phosphate as indicated by prospecting, and the tonnage and grade of uranium in the phosphate products recovered in the mill. The results presented in this paper are based upon a study of drill cores, drill logs, gamma-ray logs, and the chemical analyses of drill-core samples.

From abstract: Investigations of the land-pebble phosphate deposits of Florida by the Geological Survey began in November 1947. This report presents the computation of reserves of phosphate rock in the northern part of the district.

Introduction: Deposits of phosphate in Florida, located beyond the limits of known producing areas, have been reported by prospectors and mining companies. Much of the information has been based upon prospecting and exploration which was undertaken many years ago and as a result the published data relating to the occurrence of these deposits are fragmentary, and few details relating to specific locations and extent are available.

From purpose and scope: One of the objectives of the ongoing U.S. Geological Survey investigation of the Loxahatchee River estuary is to provide baseline information on the estuary. This map report was prepared to fulfill part of this objective. It provides information on bathymetry, hydrology, and benthic sediment and biota.

From purpose and scope: The purpose of the investigation was to make a preliminary evaluation of the effects of the Faka Union Canal system on water levels in the Fakahatchee Strand. The evaluation includes more of a data collected specifically for the report as well as other data.

From introduction: This report describes the long-term and short-term trends and fluctuations of the potentiometric surface of the Floridan aquifer. Data shown include: (1) annual rainfall and departure from average rainfall at St. Leo and Arcadia from 1961 through 1980, and hydrographs of selected wells; and (2) maps that show change in the potentiometric surface of the Floridan aquifer from January 1964 to May 1969, from May 1969 to May 1975, from May 1975 to may 1980, from September 1975 to September 1980, and from January 1964 to May 1980.

Abstract: The three lakes investigated gain water- from adjoining water-table aquifer and lose water to Floridan aquifer by downward leakage. Net seepage (net exchange of water between lake and aquifers) can be estimated by equation S = AX + BY, where S is net seepage, X represents hydraulic gradient between lake and water-table aquifer, A is lumped parameter representing effect of hydaulic conductivity and cross-sectional area of materials in flow section of water-table aquifer, Y is head difference between lake level and potentiometric surface of Floridan aquifer, and B is lumped parameter representing effect of hydraulic conductivity, area, and thickness of materials between lake bottom and Floridan aquifer. If values of S, X, and Y are available for two contrasting water-level conditions, coefficients A and B are determinable by solution of two simultaneous equations. If the relation between lake- and ground-water level is same on all sides of the lake with regard to each aquifer and if X and Y are truly representative of these relations, then X and Y terms of equation provide valid estimates of inflow to lake from water-table aquifer and outflow from lake to Floridan aquifer.

From introduction: The purpose of this study is to define causes of sinkhole development in an area north of Tampa (Florida) (fig. 1), particularly the relation of geology, hydrology, and hydrologic changes to the type and severity of subsidence or collapse.

This report evaluates a cavity-riddled zone of an aquifer near Riviera Beach, Florida. It includes maps, graphs, and other figures.

This report presents an assessment of water resources and data-network of the Manasota Basin located in Manatee and Sarasota counties in Florida.

From introduction: This report presents some borehole data-collection methods that can be used during the drilling of ROMP or other wells where data collection is a prime objective. Hydraulic, water-quality, and geophysical data-collection methods applicable to the hydrogeology of west-central Florida are emphasized.

From purpose and scope: In 1980, the U.S. Geological Survey, in cooperation with the Southwest Florida Water Management District, initiated an investigation to appraise the ground-water resources of coastal parts of Citrus, Hernando, and Levy Counties that are within the Southwest Florida Water Management District and to provide information necessary for the use and protection of the resource.

From abstract: "An aquifer test conducted in the Green Swamp area December 15-16, 1975 was designed to stress the uppermost part of the Flordian aquifer so that the leakage characteristics of the overlying confining bed could determined." This report includes those results.

From purpose and scope: The purpose of this investigation is to evaluate, through electrical analog model simulation, the effects of two specific water-management proposals in Dade County. Proposal one is the installation of a secondary control on Snake Creek Canal and proposal two is the forward pumping scheme.

From introduction: This report describes some basic principles of hydrology as they apply to Martin County. The major land features of the county are described first, then the hydrologic cycle and the county's surface-water and ground-water resource. Specific problems associated with population growth and the county's development, such as saltwater intrusion and water use, are sited and sections have been included in the report to deal with these problems.

From purpose and scope: The purpose of this report is to describe the development and calibration of a regional digital model of the Floridian aquifer in the Tampa Bay area. This model can be used to provide regional analyses of the effects of present and proposed pumping from the Floridian aquifer.

From analysis: "Data on streamflow, tide stage, specific conductance, and chloride concentrations were collected in the Alafia River and Bullfrog Creek to describe the salinity and physical characteristics of the saltwater wedge." It contains maps, graphs, and tables.

Report and geological survey. This report is on the effects of the domestic secondary-treated effluent used for irrigation of pastures near Lakeland, Florida. Includes a number of maps, tables, and other figures.

From purpose and scope: The purpose of this investigation was to evaluate the effects of certain land uses on ground-water quality in the East Everglades.

From introduction: For the purpose of this evaluation, which is qualitative, and which is based on an arbitrary numerical ranking of the thickness and hydraulic conductivity of the different materials involved, the intent was to include only the relatively pure sand beds, which would most readily store and transmit appreciable quantities of water and the clay beds, which would most effectively retard the downward movement of water to the Floridian aquifer.

From introduction: This report documents the results of the 1980 Florida water assessment made by personnel of the five Water Management Districts in a joint effort with U.S. Geological Survey personnel. The study was made as part of a statewide cooperative program with the Florida Department of Environmental Regulation, Northwest Florida Water Management District, St. Johns River Water Management District, South Florida Water Management District, Southwest Florida Water Management District, and the Suwannee River Management District.