Crinoid Columnal (Stem Segment)
Indeterminate Crinoid morphospecies (often referred to as 'sea lily' stem) • Body fossil (invertebrate, echinoderm segment)
Geological Period
Mississippian subperiod (Carboniferous) to Devonian
Estimated Age
320 to 380 million years
Preservation Type
Recrystallization (calcite replacement) with potential silicification
Condition Assessment
Good; shows significant weathering but maintains clear axial symmetry and a well-defined central canal.
Taxonomic Classification
Phylum: Echinodermata, Class: Crinoidea
Morphological Description
A single conical columnal or ossicle featuring a distinct central lumen (the hole). The specimen shows a truncated circular profile with slightly tapering sides, common in larger crinoid stem segments near the calyx or anchor points.
Rock Matrix
Likely sourced from a limestone or calcareous shale matrix, though this specimen is fully weathered out or prepared free from matrix.
Formation & Location
Common in the Burlington Limestone (USA, Midwest), the Wenlock Group (UK), or similar Paleozoic marine shelf deposits worldwide.
Size & Dimensions
Approximately 2 to 3 cm in diameter; reflects a medium-to-large sized individual within typical Carboniferous crinoid standard sizes.
Value & Rarity
Estimated Market Value
$5.00 - $15.00 USD
Auction Estimate
$10.00 - $25.00 USD (typically sold in lots)
Rarity Assessment
Common; crinoid stem fragments are among the most abundant Paleozoic fossils globally.
Scientific Significance
Provides evidence of Paleozoic marine biodiversity and the 'Crinoid Gardens' that once dominated shallow epicontinental seas; useful for paleoenvironmental reconstruction.
Preparation Recommendations
No further preparation required; store in a dry environment and handle with care as calcite can be brittle. Display in a small lucite case or float frame.
Notable Features
The specimen has an unusually 'volcano-like' shape which suggests it may be a basal columnal or specifically weathered to emphasize the lumen's aperture.