The coquina ledge that gave Rockledge its name

Rockledge is named for its rock. Gardner S. Hardee, who bought land on this stretch of the Indian River in 1868, named one of his tracts “Rock Ledge” for a prominent outcrop of stone that formed, in the words of the National Park Service’s history of the town, “a natural seawall along the banks of the river.” The city’s own account says the name comes from the ledges of coquina rock that line the Indian River there.

The rock is coquina, and it has a formal name: the Anastasia Formation.

The rock

Coquina is shell turned to stone. The Florida Geological Survey describes the Anastasia Formation as mainly quartz sand and seashells cemented together, a “coquinoid limestone” in its coastal exposures, made of whole and broken mollusk shells bound by calcite. It was laid down during the last interglacial period, when sea level stood 5 to 7 meters higher than it does now. Radiometric dating puts it at about 83,000 to 118,000 years old.

The formation runs along Florida’s east coast from St. Johns County south to Palm Beach County, reaches up to 20 miles inland, and is as much as 100 feet thick in places. It underlies the Atlantic Coastal Ridge. At Rockledge it shows at the river’s edge.

Rockledge in the textbook definition

When geologists name a rock formation, they cite the places where it can be seen. The Anastasia Formation was named in 1912 by Elias H. Sellards, Florida’s first state geologist. According to the U.S. Geological Survey’s national lexicon of geologic names, Sellards described it as typically exposed on Anastasia Island at St. Augustine, in a Florida East Coast Railway cut near Ormond, and “along the coast at Rockledge.”

So the ledge that named the town is also one of the three exposures that defined the rock. Anastasia Island gave the formation its name. Rockledge got its name from the formation.

The same rock as the Castillo

The best-known coquina in Florida is at St. Augustine. The Castillo de San Marcos, the Spanish fort that has stood there for more than 300 years, is built of it. The Florida Geological Survey notes that the Spanish found the Anastasia Formation coquina soft enough to quarry easily and durable enough to build with, and that it was probably the first stone building material Europeans used in the New World.

At Rockledge the rock was never a quarry. It was a landmark, and then a name.

The riverfront since

The natural ledge didn’t stay entirely natural. In the first half of the 1920s, during the land boom, the town council took up the building of seawalls along the Indian River, according to the Park Service’s history of Rockledge, and some of those 1920s seawalls are still visible along Rockledge Drive. The Rockledge Drive Residential District, the subject of a separate page, follows that shoreline for about two and a half miles from the Cocoa line south to Park Avenue.

Further Reading

• Florida: A Short History by Michael Gannon
• Florida’s Fabulous Natural Places by Tim Ohr