THE ARTESIAN WATER SUPPLY OF EASTERN FLORIDA. 
127 
Water is reported to flow from this depth. Below this stratum 
of rock 100 feet of blue marl with inclusions of several thin strata 
of shells is reported. In a sample from this stratum the sand was 
gray in color and the grains were round in outline. The black 
pebbles, smaller than those in the above stratum, occur also at 
this depth but may have dropped down from above. At 
a depth of from 355 to 364 feet a very hard rock is reported, but 
no further notes were made of this and no samples kept. From 
364 to 418 feet indurated gray sand and blue marl is reported and 
immediately below this is encountered a rock, apparently limestone, 
in which the water is reported to increase in head and in volume 
of flow as each hard layer is penetrated. From all information 
that could be gathered it seems probable that this limestone is the 
Vicksburg. 
Exposures of clayey impure limestones are found along the 
St. Marys River at High Bluff about six miles and at Saw Pit 
Bluff about two miles above the Atlantic Coast Line Railroad 
bridge; also at Chalk Bluff and at Orange Bluff near King’s 
Ferry. 
The section at Saw Pit Bluff (PI. 14, Fig. 3). is as follows: 
Sticky blue clay with some soil ... 5 feet 
Impure limestone ..... 5 feet 
At Chalk Bluff about two miles above King’s Ferry the follow¬ 
ing section was observed: 
Sticky blue clay with some soil at top.,. .. 2 feet 
Calcareous clay resembling fullers earth .. •. 2 feet 
White chalky material .... 1 foot 
Clay resembling fullers earth .... 2 feet 
Going down the river from King’s Ferry no rock or shell expo¬ 
sures are seen until Reed’s Bluff near Crandall is reached. This 
bluff, which lies on the Florida side of the St. Marys River, is 
semi-circular in shape and is about three-fourths of a mile long. 
The following section was made near the middle of this bluff: 
Incoherent pale yellow sands .20 to 40 feet 
Oyster shell reef imbedded in fine sandy clay .10 to 15 feet 
Blue sands and sandy clays oxidizing yellow.10 to 20 feet 
The oyster reef in this section rests irregularly upon the un- 
dei lying sands, the base of the reef being 10 to 20 feet above low 
