Associated Smithsonian Expert: Marguerite Toscano, Ph.D.

Paleontologist Maggie Toscano with fossil shells she collected during a visit to a quarry in Naples, Florida.

Photographed by Donald E. Hurlbert, Smithsonian Institution.

Dr. Marguerite Toscano is a research geologist specializing in ancient tropical marine environments in Florida and the Caribbean. Growing up in New York City, Maggie spent summers along Long Island beaches searching for shells and other treasures of the sea, read every field guide, and knew the scientific names of just about everything marine. During college and graduate school she developed interests in marine fossils, ancient and modern coral reefs, radiometric dating, and using fossil reefs and mangrove deposits to reconstruct paleo sea levels. A highlight of graduate school in Florida was visiting the shell quarries near Sarasota and Naples where Pliocene tropical mollusks, corals, and bones were mined. After earning her doctorate in 1996, she did research on coral bleaching at NOAA, and completed the Paleontologic Inventory of the South Florida-Caribbean Network of National Parks for the National Park Service. She joined the Smithsonian in 2000. She is currently conducting geologic and sea level research in mangrove deposits in Belize, Panama and Florida, and is working with the Smithsonian’s MarineGEO and Tennenbaum Marine Observatories Network to design and install state of the art sea level monitoring stations at Smithsonian field stations.

Meet our associated expert

This image was obtained from the Smithsonian Institution. The image or its contents may be protected by international copyright laws.

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Detailed geologic time scale.
From the Geologic Society of America, used with permission

About Golden Gate Quarry

About 3 to 3.35 million years ago, when sea level was several meters higher than it is today, southern Florida was submerged by a shallow tropical sea with reefs and wetlands that were home to numerous mollusks, corals, fish, mammals, and birds. Although the shell, coral, and mollusk remains are fossils and are scientifically valuable to paleontologists and geologists, there is such a large supply of them that they can be used for other purposes. The Golden Gate Quarry uses the fossil shells and coral from this ancient environment in concrete mix in the foundations of buildings and for roads and highways in the area. Take a look when you walk down the roadways in Florida and try to find the same types of fossils from the quarry as part of the road itself.

Piles of fossils from an ancient shallow sea in Florida, ready to be used as aggregate in construction. Location: Golden Gate Quarry, Naples, FL.
Photographed by Donald E. Hurlbert, Smithsonian Institution

How People Build with Fossils from Golden Gate Quarry

It is surprising to most people that fossils are actually used to build roads and buildings. The fossils from the Golden Gate Quarry may be mixed with rocks and used as "fill" beneath roads and highways. They may also be mixed in the asphalt and be seen at the road surface. Rock and fossils from this ancient reef may also be used in producing cement, the glue of concrete. The concrete used to make curbs and gutters will contain these materials, and if you look closely, you can find shells and corals mixed in these products.

Related Resources
Modern burrowing barnacle (Acrothoracica)
Courtesy of Jaclyn McCormick, via Barcode of Life Data Systems (BOLD), CC-BY-NC-SA

About Barnacles, Copepods, and Relatives (Class Maxillopoda)

Maxillopods have been around since the mid-Cambrian, about 510 million years ago. Their shortened bodies and juvenile external features make them look like larvae. One hypothesis is that the common ancestors of all maxillopods were organisms that became reproductively mature before their bodies changed into externally adult forms (neoteny). The oldest known fossil maxillopod is a barnacle (Priscansermarinus barnetti). Unlike the barnacles of today, this species did not have an external protective shell. Later maxillopods were shelled, but their fossil record is patchy, in many cases consisting of just shell fragments. Because maxillopods often live in turbulent environments, like rocky shorelines, their remains get broken up. Beginning during the Early Devonian (about 415 million years ago), common maxillopod fossils are casts of borings where barnacles drilled into shells of other animals. Sediments infilled the boreholes and fossilized, creating trace fossils in the shape of the boreholes. Copepods are another group of tiny maxillopods that are now abundant and diverse, but are nearly absent from the fossil record.