Fossil Sand Dollar Fragment
cf. Mellita sp. (Sand dollar fragment) • Invertebrate body fossil, permineralized skeletal fragment
Geological Period
Neogene (Miocene to Pliocene epochs)
Estimated Age
5 to 23 million years old
Preservation Type
Permineralization and calcitic recrystallization of the original high-magnesium calcite endoskeleton
Condition Assessment
Fair; highly incomplete, missing the outer margin and complete oral/aboral surfaces, showing clean fracture edges
Taxonomic Classification
Phylum Echinodermata, Class Echinoidea, Order Clypeasteroida, Family Mellitidae, Genus cf. Mellita
Morphological Description
The specimen displays the internal trabecular structural framework and porous calcite ossicles typical of echinoid tests. Internal supportive walls, pillar structures, and remnants of the ambulacral grooves are visible within the broken matrix of the test.
Rock Matrix
Sandy limestone matrix with fine-grained quartz sand and carbonate cement partially adhering to internal cavities
Formation & Location
Peace River Formation or Tamiami Formation, Florida, USA
Size & Dimensions
Approximately 4 cm by 2.5 cm; represents a partial fragment of a larger specimen typically 6 to 8 cm in diameter
Value & Rarity
Estimated Market Value
$5 - $15
Auction Estimate
$10 - $25
Rarity Assessment
Common; widespread in coastal Neogene deposits of the southeastern United States
Scientific Significance
Demonstrates the fragile internal support architecture of irregular echinoids adapted to burrowing in high-energy sandy marine environments
Preparation Recommendations
No intensive preparation required; gentle brushing with a soft-bristled brush to remove loose sediment. Store in a stable, dry environment.
Notable Features
Exposes the complex internal bracing system and pillar anatomy of the sand dollar test, which is normally hidden inside complete specimens
Notes
This is a piece of a sand dollar