106 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT.
The oxidizing processes are the most rapid near the surface, especially above the underground water level, and H2S derived from this source probably supplies relatively shallow, rather than deep waters.
The formation of H2S by steam passing over sulphur which occurs in connection with volcanoes, may be dismissed in considering the sulphur waters of Florida, since Florida has no volcanoes and no indications of volcanic activity.
SULPHUR WATER NOT EVIDENCE OF BEDS OF SULPHUR.
There is a widespread belief that the presence of sulphur water must necessarily indicate the existence of beds of the mineral sulphur. This conclusion does not follow, '1lie probable sources of the sulphur in sulphur waters as indicated above is organic matter toget'>.2r-- with metallic sulphates and sulphides scattered trliough sedimentary rocks.
SULPHUR DEPOSITS FORMED FROM HYDROGEN SULPHIDE.
As stated in the last paragraph, sulphur waters are not to be regarded as resulting from beds of pure sulphur. On the contrary, it is probably true that these waters may, in some instances, result in the formation of such deposits. Hydrogen sulphide when acted upon in the water by oxygen breaks up, forming water and sulphur, the reaction being .T2S+O-H20+S. It is thus possible that H2S in the underground water, or escaping from the underground water, may become disassociated, forming deposits of pure sulphur. Such deposits of economic value have not been, reported in Florida. It is a noteworthy fact, however, that one large mass of sulphur has been found underneath phosphate beds, in Citrus County.* The formation of this mass of sulphur is probably due to hydrogen sulphide. A flocculent white coating of sulphur or a sulphur compound invariably forms around sulphur springs and flowing sulphur wells.
ABSENCE OF HYDROGEN SULPHIDE FROM CERTAIN WATERS IN FLORIDA.
The absence of hydrogen sulphide from the first water obtained' from areas in which the open porous limestone is the surface forma'ion, has already been stated. It is a well-known fact that if sulphur water is allowed to stand in the open air the gas will escape.
*Florida Geological Survey, First Annual Report, p. 44, I908.