GEODIZED Busycon
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 below.
Busycon
snail shell geode with yellowish calcite crystal lining. Entire rock
specimen is 11 cm across.
This specimen comes from the Anastasia Formation
(Upper Pleistocene to lower Holocene, ~126 k.y. to ~8 k.y.) 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 (see pic
below). Florida’s Anastasia Formation is well known for having true coquina
beds.
Coquinoid quartzose sandstone matrix of geodized Busycon
snail shell shown above (bottom surface of rock, 8.4 cm across).
Classification of Busycon: Animalia, Mollusca, Gastropoda, Neogastropoda,
Muricoidea, Melongenidae