122 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT.
the center of the stream as be fore. The measurements may then be read f rom the table as before.
"This method is also applicable to measuring the discharges of different pipes when water is distributed about a farm or in a city.
"Pipes which have been cut in the usual way are frequently diminished in diameter by the incurving of the edge of the pipe. This will diminish the flow, but how much can only be roughly estimated. It will be greater than, that of a straight pipe having the exact diameter of the opening as reduced."
THE AREAS OF ARTESIAN FLOW IN FLORIDA
The accompanying map, revised from a similar map published"
inBlei o ,indicates in a general way the flowing and nonflowing areas of the State. In using such general maps it should be borne in mind that artesian \vater. depends primarily upon the structure of the underlying formations, and these are subject to variations of which there may be no surface indications. Moreover a map on a small scale can not indicate local elevations which affect flow. Thus while the map indicates approximately the limits of flow the exact limits can be determined in most cases only by drilling.
The shading on the map indicates those parts of the State in which flowing wells have been obtained., There are, as will be seen three principal. areas of flow as follows: the Atlantic Coast, area, the Southern Gulf Coast area and the Western Gulf Coast area.
The Atlantic Coast area is described' in detail in the subsequent pages of this report. This flowing area includes much of Nassau and Duval Counties, and with the exception of local elevated areas all of St. Johns County; it follows the valley of the St. Johns River almost if not quite to the head waters, while a narrow strip reaches south along the Atlantic Coast for 250 to 300 miles. The artesian water bearing formation dips in passing to the south, being reached at Palm Beach at the depth of about i 000 feet. In addition to its increased depth the water at Palm Beach was found to be too salty to be used for household purposes. Between Palm Beach and Key West no wells have been drilled deep enough to reach this formation. The deep well drilled on Key Vaca by