234 FLORIDA GrOLOGICAL SURVEY-I5TH ANNUAL REPORT

China Clay Corporation's plant, also near Okahumpka, the overburden is removed by hydraulic process.
 The method of mining this clay is very different from any commonly employed in clay-mining. Owing to the slight topographic relief of the region and the proximity of the ground water-table to the surface, ordinary open-cut methods would be unsuccessful, and consequently dredging is resorted to. After the overburden is removed, a pit is dug into the deposit of sand-bearing clay in which, after it is filled with water, a dredge is floated. The clay is then dug by dredging and forced through a pipe to a series of three "sand traps," where the greater part of the sand is eliminated. The clay-bearing wafer then passes through a series of troughs, where it is continuously agitated, to cause the clay substance to remain in suspension and the impurities, which usually have a higher specific gravity, to settle out. From this troughing the clay-bearing water passes into settling vats and the water is later pumped off. The clay is then forced through filter-presses, where the excess water is pressed out. The resulting cakes of damp clay are dried hi either steam or air-heated drying sheds, and, when dry, are ready for shipment. From the time the clay is first dredged until it leaves the filter presses, all water extracted from it, and which necessarily carries some clay, is conducted back to the pit. Some clay is lost, however, in the sand-traps and is carried out with the waste sand.
 The sand washed from the clay is used to some extent in concrete construction. It has been suggested that this sand could be used for glass manufacture, but so far as is known, no practical tests have been made to determine its suitability for this usage.

 DISTRIBUTION BY COUNTIES
 Occurrences sedimentary kaolin have been noted or reported in the following 2c'unties:
 Alacht?'County-A well drilled at the gin in Hawthorne, near the easterri- ob'rder of the county, is reported by W. S. Moore, of that place, to have encountered the clay-bearing sand at a depth of twelve feet. The thickness of the deposit it not known. This place is located only about eight miles west of Edgar. As occurrences of the sedimentary kaolin are known west and southwest of Edgar, similar deposits in the adjoining portions of Alachua County are not at all improbable.