174 
FLORIDA state; geological survey. 
from the profiles of the several railroads crossing this section, 
particularly the Seaboard Air Line from Jacksonville to Maxville, 
the Florida East Coast from Jacksonville to Mayport and the 
Atlantic Coast Fine from Jacksonville to the St. Marys River. 
From Jacksonville westward the rise in elevation, as shown 
by the profile of the Seaboard Air Line Railway, is very gradual, 
to a point three miles west of Jacksonville where an elevation of 
27 feet is reached. From this summit the elevation drops off 
slightly, the elevation of Cedar Creek being 17 feet. Beyond 
Cedar Creek the elevation rises more rapidly. Marietta station 
is approximately GO feet above sea. The summit of this rise is 
reached two miles west of Marietta where the elevation is 94 
feet. White House station is 82 feet above sea Beyond McGirts 
Creek one and one-half miles an elevation of 91 feet is reached. 
From this point there is a very gradual slope to Baldwin, this 
latter place being 86 feet above sea. South from Baldwin the 
contour rises in general, reaching an elevation of 93 feet at Max¬ 
ville and 100 feet one-half mile beyond the county line. 
The line of levels run by United States Engineers extends 
from Trout Creek, passing just to the south of Brandy Branch 
station, or Bryceville postoffice. The summit elevation in Nas¬ 
sau and Duval Counties along this line occurs about four miles 
northeast of Brandy Branch, where an elevation of 90 feet is 
recorded. 
WATER-BEARING FORMATIONS. 
The deeper wells in Duval County reach and terminate in the 
Vicksburg Limestone. This is known to be the case at Jack¬ 
sonville, at which place the Vicksburg is reached at approxi¬ 
mately five hundred feet from the surface. The wells at Jack¬ 
sonville, the deepest of which reach a total depth of something 
over a thousand feet, do not, so far as the records show, pass 
entirely through the Vicksburg. 
The formations lying above the Vicksburg are less charac¬ 
teristic lithologically and are not easily differentiated. The sur¬ 
face deposits include both recent and Pleistocene material. During 
a part of Pleistocene time this section of the State stood at a 
