146 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT.
level. The principal supply is obtained at a depth of two hundred feet.
Feet.
Record incomplete, said to consist largely of clays, bluish in color
except where oxidized yellow at the surface............. o I28
A sample from the depth of 128 feet consists of fragments of darkcolored rock more or less water worn, including small sharks' teeth, fragments of bones, occasional shining black phosphatic pebbles ......................................... 128 to 130
Yellowish sandy clays ..................................... 130 to 145
Dark fossiliferous rock. Fragments of this rock are of grayish
color and contain inclusions of a dark colored mineral similar in character to rock found at St. Augustine at a depth of 178 feet. Sharks' teeth and black phosphatic
pebbles also occur as well as numerous shell fragments.... 145 to i6o
A mixed sample contained material similar to above with addition of gray sandy clay. ..........................16o to 168
Buff colored sandy clay ..................................... I68 to 18o
White granular fossiliferous limestone.....................8o to 225
This-well probably reaches the Vicksburg group of limestones as indicated by sample from the depth of I8o to 225 feet. The material obtained between the depth of 168 and 18o feet may represent the Upper Oligocene as it has certain lithological resemblences to parts of the Alum Bluff formation. The conglomerate
material from I45 to 16o feet together with a part of the overlying clays probably represents ithe Jacksonville formation of the Miocene.
HASTINGS.
Hastings is in the western part of St. Johns County, and is located on Deep Creek, a tributary to the St. Johns River. The town site is inland about three miles from the river. The elevation at Hastings, at the residence of T. H. Hastings is according to the U. S. Coast'and Geodetic Survey 8 feet above sea.
A considerable number of artesian wells have been put down at and in the vicinity of Hastings. Record has been obtained
of fifty-one wells within a radius of three miles of the town.
Wells at Hastings are largely used for irrigating purposes.
The" average depth of the wells now in use is 148 to 272 feet althogh omereach a greater depth. Most of the wells are to 6 inches in diameter. The length of casing used in the wells i variable ranging from 65 to 170 feet.