The Ocala Limestone Of Florida

Information obtained from a study of well samples indicates that limestones of Eocene age in peninsular Florida have a thickness of more than three thousand feet. At the time these limestones were being laid down the sea covered most, if not all, of what is now Florida as well as the southern portions of the adjacent states of Georgia and Alabama. During this period there were most likely, from time to time, islands dotting this shallow sea here and there. This is indicated by the presence of beds, or lenses, of lignite, some of which are made up largely of plant life higher than algae, within the Eocene limestones. These have been revealed by samples at different depths from wells in several portions of the State.

These lignitic materials suggest a near-shore accumulation; the swamps in which they were deposited may have been protected for a period by barrier beaches which in time disappeared and permitted the return of conditions favorable to the deposition of limestone. In this comparatively shallow, warm ocean, shell and other marine life was abundant, as is evidenced by the profuse and extremely well preserved fossil remains. The Ocala limestone is almost a pure calcium carbonate, white to cream colored, and prevailingly rather soft or friable.

The somewhat uniform physical characteristics together with the richness of fossils—those of large as well as those of microscopic size—makes the recognition of the formation an easy task. Although predominantly an invertebrate formation the remains of an extinct whale-like mammal, Zeuglodon or Basilosaurus, have been recovered from it.

From an economic and utilitarian point of view the Ocala limestone is perhaps the most important formation in Florida. It is from this limestone that the deeper wells in every section of Florida obtain their abundant supplies of palatable water. Likewise the largest and most beautiful limestone springs in the United States are found in Florida and most of these are supplied with water from the Ocala. As highly valued as is this limestone for its water resources, it has other economic values. It is the formation from which lime was first manufactured on a commercial scale in Florida.

The original quarry, opened in 1884, has been in continuous operation. In recent years the limestone has been extensively used as a road building material. Many hundreds of miles of first class highways throughout Florida have been built with it as a base.