Ladd's Fossil Turritella (Fossil Screw Shell fragment)
Phylum: Mollusca, Class: Gastropoda, Order: Sorbeoconcha, Family: Turritellidae, Genus: Turritella · Turritellidae (Screw Shell or Tower Shell family) · Gastropod (univalve); Fossil fragment consisting of the middle whorls of a spiral shell.
Species
Turritella sp. (likely Turritella cumberlandia or similar Pliocene species)
Shell Type
Gastropod (univalve); Fossil fragment consisting of the middle whorls of a spiral shell.
Family
Turritellidae (Screw Shell or Tower Shell family)
Size
Approximately 0.75 to 1 inch (20-25mm) in length. This is a partial specimen of a shell that could originally have reached 2-3 inches.
Color & Pattern
Dark charcoal grey to blackish-brown. This coloration is due to mineralization (fossilization) occurring in an anaerobic, iron-rich sediment environment typical of the Atlantic Coastal Plain.
Rarity
Common for the region. Holden Beach is a famous 'renourished' beach where fossil material is frequently dredged up from offshore deposits.
Habitat
Ancient shallow marine shelf. Found today as redeposited fossils in the intertidal zone of modern beaches.
Geographic Range
Commonly found in fossil-bearing formations (like the Yorktown Formation) along the US Mid-Atlantic coast, specifically North and South Carolina.
Description
A robust, cone-shaped fossil fragment featuring distinct spiral cording. The specimen shows the characteristic high-spired tower shape of the Turritellidae family, with deeply incised sutures and a series of horizontal ridges (costae) encircling each whorl.
Key Features
Tapered spiral shape, numerous fine spiral threads or ribs, and the distinct dark mineralization that indicates its prehistoric fossil origin.
Collector Value
Low monetary value ($1-$5), but high educational value. It is a favorite find for beachcombers at Holden Beach alongside shark teeth.
Condition Notes
Fair. It is a worn fossil fragment lacking the apex (tip) and the aperture (opening). The sculpture remains visible, but it is heavily eroded by wave action. Collectibility Grade: Good (as a fossil study piece).
Interesting Facts
This shell is millions of years old, likely dating to the Pliocene or Miocene epochs. While modern Turritellas still exist, these black fossils are remnants of an ancient ocean floor that once covered North Carolina.
Ecological Role
Historically a filter feeder that lived partially buried in the seafloor. Today, it serves as a geological indicator of ancient marine environments.
Similar Species
Auger shells (Terebridae) which are typically slimmer and smoother, or modern Eastern Turret Shells which would be white/tan rather than black.
Beach Finding Tips
Look in the 'shell hash' or gravel lines at low tide, particularly after a storm or beach renourishment project. Their dark color stands out against the pale sand.
Notes
Holden Beach, NC