THE ARTESIAN WATER SUPPLY OF EASTERN FLORIDA.

PLEISTOCENE.
The marine Pleistocene deposits have been recognized at several localities in eastern Florida. Messrs. Matson and Clapp obtained collections from Eau Gallie, Titusville and Mims in Brevard County. It is probable that marine Pleistocene shell deposits are somewhat widely distributed along the east coast and perhaps in the St. Johns River valley. Here again satisfactory determination can be made only from large and carefully kept samples obtained in well drilling. The coquina rock which occurs extensively at St. Augustine and extends along the coast to the south for 250 miles, is also to. be placed with the Pleistocene. Some of the older sand dunes of the east coast also probably belong to the Pleistocene.
EARTH MOVEMENTS DURING THE PLEISTOCENE.
Changes in the relation of land and water have occurred recently along the east coast, probably during Pleistocene time. The best evidence of these changes is that offered by the sand dunes and the coquina rock bordering the east coast. The line of sand dunes a long the coast is well developed !and largely continuous. From, Daytona south these dunes occur, not on the present beach, but backfrom the beach a variable distance depending upon the configuration of -the country. At Daytona the sand dune lies back from the, Halifax River about two miles. From Daytona to Titusville the dunes are to be seen lying mostly to the west of the East Coast Railroad at a distance of one or two miles from the coast. At Titusville the dunes lie back from the Indian River two to two and one-half miles. At Rockledge the dunes approach closer to the coast. They recede again, however, to the south and at no place directly face the ocean. The dunes are now quiescent and are covered with a thick growth of trees indicating that they have been undisturbed for a long time. In the same way the coquina rock, found facing the ocean at Anastasia Island in St
Johns County, falls back from the coast to the south extending at places a few miles inland. The presence of this ledge of coquina rock bordering the coast together with the sand dunes lying back clearly indicates that the land level formerly stood lower than at present, the coquina rock and sand dunes having accumulated along what was then the beach.
Conrad as early as 1846 noted the occurrence of marine sheiks of post-Pliocene age along the bank of the St. Johns River at aut elevation of from ten to fifteen feet above the present high tide.

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