Fossiliferous Limestone Rock / Invertebrate Hash
Indeterminate shelly fragments cf. Brachiopoda and Bryozoa • Body fossil and hash/fragment assemblage, invertebrate
Geological Period
Paleozoic or Mesozoic (commonly Silurian/Devonian or Ordovician)
Estimated Age
450 to 350 million years old
Preservation Type
Permineralization and recrystallization with weathered external impressions
Condition Assessment
Fair to Poor, highly weathered and waterworn with eroded surface details obscuring fine taxonomic features
Taxonomic Classification
Phylum Brachiopoda / Bryozoa / Crinoidea (indeterminate mixed invertebrate fragments)
Morphological Description
The specimen presents as a weathered, rounded rock matrix containing various embedded fragmental skeletal remains, weathered impressions, and recrystallized calcite patches representing ancient shell hash.
Rock Matrix
Silicified limestone or calcareous sandstone with secondary calcite veining
Formation & Location
Midwestern or Eastern North America (e.g., Silurian/Devonian formations of Ohio, Indiana, or New York)
Size & Dimensions
Approximately 15 to 20 cm across, typical for a hand-sample sized fossiliferous nodule
Value & Rarity
Estimated Market Value
$10 - $25
Auction Estimate
$5 - $15
Rarity Assessment
Common
Scientific Significance
Demonstrates high-energy shallow marine depositional environments and tempestite shell-bed accumulation in ancient seas
Preparation Recommendations
Basic washing with water and a soft brush to remove dirt. Acid preparation is not recommended due to silty matrix composition. Store in a dry environment.
Notable Features
Rounded pebble shape indicating secondary transport and significant surface weathering highlighting mixed fossiliferous debris