The Limestone Under Everything

The story of Ocala, in the end, keeps coming back to rock. Specifically to a particular formation of white, chalky, marine limestone that geologists named the Ocala Limestone after the city where they first described it in detail. It was deposited more than thirty-five million years ago when a warm, shallow sea covered this part of what is now North America. The creatures that lived and died in that sea left behind their calcium-carbonate shells, which compressed over millions of years into the porous stone you find a few feet below ground across much of central Florida.

That limestone explains almost everything about this region.

It explains Silver Springs, where water filters down through the rock for decades, picking up minerals, emerging cold and clear at the spring vent as if from nowhere. The Floridan aquifer, one of the largest and most productive underground water systems in the world, is essentially a vast slow river moving through millions of tons of Ocala Limestone.

It explains the horse farms. The calcium in the soil, drawn up by grass, builds the bone density in thoroughbreds that makes Marion County one of the major thoroughbred breeding centers of the country.

It explains the sinkholes that still open without warning across the county, where acidic groundwater has dissolved limestone chambers until the roof gives way.

It explains why this part of Florida looks the way it does: gently rolling, unlike the flat south, because dissolved and collapsed limestone creates an undulating karst topography that feels almost like hill country. Ocala sits in the middle of this geological province, built on dissolved seashells, watered by a prehistoric aquifer, and shaped in every significant way by thirty-five million years of chemistry happening quietly underground.