Fossiliferous Limestone Matrix with Brachiopods and Bryozoans
Indeterminate colonial bryozoans and articulate brachiopods cf. Spiriferida / Orthida • Body fossils, shell hashes, and molds/casts, invertebrate marine assemblage
Geological Period
Ordovician to Devonian (likely Ordovician or Silurian)
Estimated Age
440 to 410 million years
Preservation Type
Permineralization and selective replacement with recrystallized calcite, alongside natural molds and casts where shells have weathered out
Condition Assessment
Fair to Good. Weathered surface showing natural exposure of fossils with significant fragmentation typical of high-energy shallow marine shell beds
Taxonomic Classification
Phylum Brachiopoda (Class Articulata) and Phylum Bryozoa within a mixed invertebrate fossil assemblage
Morphological Description
The specimen is a chaotic hash of broken and intact shelly debris. Distinctive ribbed brachiopod valve fragments showing internal structures and radial ornamentation are visible alongside branching and encrusting bryozoan tubular cross-sections embedded within the matrix.
Rock Matrix
Buff-to-tan weathering fossiliferous limestone (micrite/biomicrite) with secondary iron oxide/limonite staining giving the brownish coloration
Formation & Location
Commonly found in Paleozoic platform carbonates such as the Cincinnati Arch region (USA), Trenton Limestone, or Silurian Lockport Formation equivalents
Size & Dimensions
Approximately 12 cm x 8 cm x 5 cm, representing a consolidated fragment of a much larger coquina bed
Value & Rarity
Estimated Market Value
$10 - $25
Auction Estimate
$15 - $30
Rarity Assessment
Common
Scientific Significance
Demonstrates high-energy shallow marine depositional environments (coquina shoals or tempestites), providing insights into Paleozoic benthic community composition and storm-event sedimentation
Preparation Recommendations
Wash gently with water and a soft brush to remove loose dirt. Avoid strong acids as the limestone matrix will dissolve. Store in a dry indoor environment.
Notable Features
Rich biogenic density with numerous cross-sections of brachiopod ribs and tubular bryozoan zooecia exposed in relief due to differential weathering of the limestone matrix