Paleozoic Fossiliferous Limestone Slab with Ironstone Inclusions
Indeterminate marine invertebrate hash cf. Productid brachiopods and crinoid columnals • Body fossil assemblage, invertebrate marine fossils preserved within sedimentary rock matrix
Geological Period
Carboniferous (Pennissylvanian or Mississippian) / Devonian
Estimated Age
300 to 360 million years ago
Preservation Type
Calcitic permineralization and replacement by iron oxides (limonite/hematite) within a sedimentary matrix
Condition Assessment
Fair, typical for a weathered creek bed find with natural erosion, iron staining, and fragmented fossil content rather than complete articulated specimens
Taxonomic Classification
Phylum Brachiopoda, Bryozoa, and Echinodermata (Crinoidea)
Morphological Description
The specimen is a large, irregularly shaped sedimentary rock matrix featuring embedded fossil fragments, including small circular crinoid columnal ossicles and irregular patches of reddish-brown ironstone weathering. Small skeletal fragments and partial molds are visible scattered across the dampened surface.
Rock Matrix
Iron-stained limestone and calcareous mudstone/shale with secondary iron oxide weathering
Formation & Location
Western Kentucky, derived from regional Mississippian or Pennsylvanian limestone and shale formations such as the St. Louis Limestone or similar local strata
Size & Dimensions
Approximately 30 cm by 25 cm, consistent with a medium-sized hand-sample slab of regional fossiliferous rock
Value & Rarity
Estimated Market Value
10 to 30 USD
Auction Estimate
Not typically suitable for commercial natural history auctions; educational or decorative specimen value only
Rarity Assessment
Common, widely distributed throughout the geological formations of Kentucky and the broader Ohio River valley
Scientific Significance
Illustrates typical shallow marine shelf paleoenvironments of the mid-continent region during the Paleozoic era, providing insight into ancient carbonate deposition and benthic community composition
Preparation Recommendations
Gentle washing with water and a soft nylon brush to remove loose clay; no intensive acid preparation recommended due to the delicate nature of the matrix and iron staining
Notable Features
Distinctive reddish-brown iron oxide (limonite) staining patterns contrasting against the lighter tan limestone matrix, along with scattered microscopic fossil hash
Notes
Found near Owensboro, Kentucky in a creek bed