108 FLORIDA GEOLOGICAL SURVEY—THIRD ANNUAL REPORT. 
therefore, a flowing well; and of “artesian water,” water under 
sufficient pressure to cause it to flow. With the extension into 
other areas of the use of deep wells as a source of water supply, 
many instances were found in which the water, although under 
pressure, and rising almost to the surface, would not flow. In 
some cases the water will flow in areas of low surface elevation, 
and yet fail to flow in a slightly elevated area near by. Artesian 
water thus came to mean water under pressure causing it to rise 
in a boring when tapped, regardless of whether or not the pressure 
was sufficient to cause the water to rise above the surface level, 
and hence to flow. In the same way, and for similar reasons, the 
term ‘artesian well’ came to include not only flowing wells, but also, 
wells in which the water rises when the water-bearing stratum is 
tapped, regardless of whether or not the rise is sufficient to cause 
a flow. Occasionally, in popular usage, the term “artesian, well” 
has been applied to any deep boring, and “artesian water,” to water 
fromi such a well. In this report the term artesian is applied to 
water under pressure, and hence rising in a boring when tapped. 
The water may, or may not, rise to or above the surface. An “ar¬ 
tesian well” is any well reaching to and tapping a stratum bearing 
such water; a “flowing well” is an “artesian well” that gives a sur¬ 
face flow. Artesian pressure is the pressure causing the water to 
rise in the boring when tapped. This is essentially the usage of 
these terms as adopted by the Division of Hydrology of the U. S. 
Geological Survey.* 
✓ 
CONDITIONS NECESSARY TO OBTAIN ARTESIAN 
WATER. 
As essentials for artesian water it is necessary to have (i) 
an adequate source of water, and (2) the proper structural con¬ 
ditions to retain the water under hydrostatic or artesian pressure. 
It will be convenient to discuss first the structural conditions. 
ARTESIAN BASIN. 
A variety of conditions in the arrangement and structure of the 
underlying deposits may bring about artesian pressure. The sim¬ 
plest, although probably not the most common, is that of a basin¬ 
like arrangement of successive relatively pervious and impervious 
strata. This typical structure, known as an artesian basin, is shown 
*Water Supply and Irrigation Paper, U. S. Geological Survey No. 160. 
