Frank Garcia, a self-taught paleontologist and asbestos worker, found fossil bones exposed by a dragline at a shell-mining pit near Cockroach Bay in July 1983. That find launched one of the richest Ice Age excavations in North America, right in Ruskin's backyard.

The dragline at the Leisey Shell Pit had torn into a thin layer of silt packed with ancient bones, according to the Florida Museum of Natural History. Garcia traced the exposed material to a fossil bed just 5 to 30 centimeters thick, spread across roughly half an acre.

Company halts mining to allow full excavation

By January 1984, Garcia and paleontologist S. David Webb had met with Leisey Shell Corporation manager Eric Hunter and owner C.E. "Bud" Leisey Jr. to plan a full-scale dig. The company halted mining at the site for 15 months, transferred fossil ownership to the Florida Museum of Natural History and provided heavy equipment to clear overburden, according to the museum's published bulletin.

Volunteers spend months digging the fossil bed

Excavation began April 1, 1984. Several hundred volunteers donated thousands of hours over the next five months, working under coordinators including Garcia, Rudi Johnson, Mickey Fowler, Ralph "Tony" Estevez, Ronald J. Shrader, Sue Bodishbaugh, Red Tincher and Donald O. Ward. The dig paused briefly during the hottest summer weeks and wrapped up in mid-September 1984.

The haul stunned scientists.

More than 20,000 fossils recovered from the site

Crews recovered more than 20,000 identifiable fossils representing 203 species: 14 sharks, nine rays, 50 bony fish, three amphibians, 26 reptiles, 52 birds and 49 mammals. More than 20 of those species were new to science, including a new genus of armadillo-like mammal and a giant condor, Gymnogyps kofordi, believed to have had a 15-foot wingspan.

Saber-toothed cats and giant sloths among finds

The saber-toothed cat Smilodon gracilis was among the most dramatic mammal finds at Leisey 1A. Scientists also found two kinds of ground sloths, ancient horses, an early mammoth and a giant tapir. The fossils date to roughly 1 million to 1.5 million years ago, when the area was a coastal mangrove bay fed by a major river.

National media spotlight follows the discovery

NBC's "Today" show aired a segment on the dig, and Newsweek ran an article. According to the museum bulletin, the Tampa Tribune published a full-color poster titled "Tampa Bay — One Million B.C."

The excavation also spawned the Tampa Bay Fossil Club, formed by members of the Tampa Bay Mineral and Science Club who saw how the Leisey discovery fired public interest in paleontology.

Historical marker and museum preserve the legacy

The original pit is a pond now, and mining has permanently ceased. But two landmarks keep the story alive.

A historical marker on Mammoth Trail, 0.2 miles south of Gulf City Road, was erected in 2017 by the Tampa Bay Fossil Club and the Hillsborough County Historical Advisory Council. It calls the dig "one of the richest Ice-Age fossil discoveries in the world."

Garcia also founded the Paleo Preserve Fossil Museum, a free nonprofit museum at 4140 24th St. SE in Ruskin, inside Camp Bayou Nature Center. Fred Hendershot, speaking on the museum's website, described the mission: "Our goal is to teach Floridians and visitors about the prehistoric creatures and people that were here long before us."

Plan a visit to the Paleo Preserve

Visitors can see a mammoth tooth, a saber-cat skull, a giant beaver specimen and a black-light booth where fossils fluoresce. School groups can book field trips at $5 per student, according to the museum's website. Teachers and chaperones enter free.

The Paleo Preserve is open Saturdays, 9 a.m. to 2 p.m., according to its website. Camp Bayou is open Thursday through Sunday, 9 a.m. to 2 p.m. Both are at the end of 24th Street SE, about 3 miles south of State Road 674. Contact Camp Bayou at 813-641-8545 for updates.