140 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT.
Feet.
Light colored fossiliferous limestone (Vicksburg). Upon
reaching this formation the flow is increased to 200 gallons per minute. At 625 to 635 feet the harder stratum was drilled through which flowed 500 gallons per minute, temperature 74 degrees F. At 68o feet the water pressure measured, as shown by the gauge, 12 pounds....... 510 -680
Limestone prevailing brownish in color, and as a rule harder
than above. Occasional thin layers of marl and shell.
Slight increase of flow at 780, water pressure at 900 feet 15 pounds; flow about 900 gallons per minute; temperature 74 degrees F ..................................... 68o -900
Limestone similar in character to above but as a rule not
so hard. Flow at 980 feet, 1,500 to 2,000 gallons per
m inute ..............................................900 -980
The Vicksburg Limestone was reached in this well at a depth of about 510 feet. The first 170 feet of the Vicksburg is prevailingly light colored or white and fossiliferous. Below 68o feet the limestone is as a rule brownish in color, compact and harder in texture and not so fossiliferous. The amount of flow, the pressure and the temperature increased as the deeper layers of the Vicksburg Limestone were penetrated.
The formations lying above the Vicksburg Limestone can
scarcely be differentiated. The Jacksonville formation, Miocene, is reached at the depth of 33 feet. At about 320 feet some clays resembling fullers earth were obtained. At from 45 to 420 feet light colored clayey limestones were encountered. With these exceptions the interval from 37 feet to 510 feet consists largely of art olive green sandy marl.
An analysis of the water of the public supply at Jacksonville was made in 1898. Analyst, Albert Leeds, Stevens Institute of Technology. The analysis is as follows:
Grains per Parts per
Constituents. U.S. Gallon. million.
Silica and insoluble matter...................0.729 12.497
Alumina ......................................0.047 8.057
Carbonate of lime .............................. 3.866 66.274
Sulphate of lime..............................4.053 69.480
Sulphate of magnesia.............2.927 50.177
Sulphate of soda ............................. 5.843 lOO.166
Chlorides of soda ............................ 4.8I1 82.474
Free ammonia...................................... 0o.143
Alhuminoid ammonia................................ 0o.oo44