Description: Busycon fossil snail shell geode lined with yellowish calcite crystals from the Quaternary of Florida, USA. (entire rock specimen is 11 cm across) Unusual & beautiful geodized shells from Florida have appeared in the fossil retail market in recent years. These were first discovered by Tom Scott, the Florida State Geologist. The geodes are developed in large mollusc shells, and are typically lined with golden yellow calcite crystals. Most of the geodized fossils are large Mercenaria clam shells. Some of the geodes are developed in large Busycon snail shells, such as the specimen shown here. This specimen comes from the Anastasia Formation (Upper Pleistocene to lower Holocene, ~126 ka to ~8 ka) from the Indrio Pit on the northern side of the town of Fort Pierce, southeastern Florida, USA. The matrix surrounding the large snail shell is a coquinoid quartzose sandstone having abundant whole bivalve shells. Florida’s Anastasia Formation is well known for having true coquina beds. Classification of Busycon: Animalia, Mollusca, Gastropoda, Neogastropoda, Muricoidea, Melongenidae. Date: 13 September 2014, 20:30. Source: Geodized fossil Busycon snail with yellowish calcite crystals (Anastasia Formation, Upper Pleistocene to lower Holocene, 126 to 8 ka; Indrio Pit, northern side of the town of Fort Pierce, southeastern Florida, USA). Author: James St. John.