116 FLORIDA STATL GEOLOGICAL SURVEY. 
obtained, the Vicksburg is believed from well records to occur 
at a depth of from 325 to 400 feet. 
Passing to the south the Vicksburg lies nearer the surface. 
Samples of drillings from wells at St. Augustine and at Hastings 
in St. Johns County and at Orange Mills in Putnam County show 
that the Vicksburg in this section lies at a depth of 130 to 225 
feet, the greater depth being at St. Augustine and the minimum 
depth at Orange Mills. Passing to the south the Vicksburg lies, 
so far as well records indicate, at a fairly uniform level for a dis¬ 
tance of 150 miles. At Sanford, 75 miles south of Orange Mills, 
the Vicksburg is reached at a depth of from 113 to 125 feet. 
At Daytona, although samples are lacking, the depth of this form¬ 
ation is believed, judging from well records, not to exceed 150 
feet. At Cocoa the Vicksburg is reached at a depth not exceed¬ 
ing 190 feet, while at Melbourne Beach, 150 miles south of St. 
Augustine, its depth in one well was found to be 221 feet. 
Passing to the south from this point the Vicksburg dips rap¬ 
idly. At Palm Beach, 100 miles farther south, this limestone 
was reached at a depth of approximately 1,000 feet, *a dip of 
about 750 feet in 100 miles or 7J4 feet per mile. The-Vicksburg 
was not reached in a well 700 feet deep drilled by the Florida 
East Coast Railway Company at Marathon Key, 175 miles south 
of Palm Beach.f At Key West, however, the formation is be¬ 
lieved to have been reached at a depth of 700 feet.J 
It is thus seen that the Vicksburg forms a broad arch extend¬ 
ing from central Florida to the Atlantic Ocean. St. Augustine 
lies near the north slope of this arch, while Melbourne, as nearly 
as can be determined, lies near -the south slope. On either side 
of the arch the limestone dips at a moderate rate. On the north 
side of the arch the maximum depth recorded in Florida is 500 
feet. Passing to the south the maximum of approximately 1,000 
feet is recorded at Palm Beach. 
In view of the importance of the Vicksburg as an artesian 
water reservoir, the depth at which it is to be expected is a matter 
*Darton, N. H.; Amer. Journ. Sci. (3) XLI, pp. 105-6, 1891. 
•{Florida Geol. Survey. Second Annual Report, p. 206, 1909. 
IHovey, E. O.; Mus. Comp. Zool. Bull. XXVIII, pp. 65-91, 1896. 
