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cous mass of limestone through which water may move with equal ease in any direction, laterally or vertically. Actually its structure is far more complex. The aquifer is composed of layer upon layer of limestones that have different water-transmitting properties. Within some of these layers water moves quite freely, but it moves from one layer to another only very slowly and with considerable loss of pressure head. As a consequence, the artesian pressures vary considerably from one layer to another. Under this condition a single map of the piezometric surface, such as that in figure 17, obviously cannot be truly representative, although it is useful until more complete information is available. Before we can obtain an adequate comprehension of how the artesian water moves from the areas of recharge to areas of discharge, we must map the piezometric surfaces for the individual geologic formations that make up the aquifer. But we cannot do this by measuring water levels in existing supply wells. Such wells generally draw from several layers of limestone, and the water levels in them do not indicate the pressure in any one layer. To do the mapping will require numerous observation wells drilled under the control of trained hydrologists.
REFERENCES
PARKER, GARALD G., 1951, Geologic and hydrologic factors in the perennial yield of the Biscayne aquifer: Am. Water Works Assoc. Jour., vol. 43, no.
10, pp. 817-835.
PARKER, GARALD G., FERGUSON, G. E., LOVE, S. K., and others, 1953, Water resources of southeastern Florida, with special reference to the geology and ground water of the Miami area: U. S. Geol. Survey WaterSupply Paper 1255 (in preparation).
STRINGFIELD, V. T.,, 1936, Artesian water in the Florida peninsula: U. S. Geol. Survey Water-Supply Paper 773, pp. 115-195.
Noic added while in press:
From A. O. Patterson, District Engineer, Surface Water Branch, U. S. Geological Survey, Ocala, the following data was received February 1, 1954: "On January 13, 1954, a discharge measurement was made of Kissengen Springs and it was flowing 3.55 second.feet. This is the first time it has been found flowing since it stopped several years ago".