Modern Bivalve Shell (likely Corbicula)
Corbicula fluminea (Asian Clam) • Body fossil (sub-fossil/modern); Invertebrate Mollusk
Geological Period
Quaternary (Holocene Epoch)
Estimated Age
0 to 0.01 million years (Recent to Modern)
Preservation Type
Original biogenic calcium carbonate (aragonite/calcite); minimal to no permineralization or replacement.
Condition Assessment
Good; shows slight wear on the ventral margin and mild weathering consistent with surface exposure on a beach.
Taxonomic Classification
Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Cyrenidae, Genus: Corbicula
Morphological Description
Equilateral, triangularly ovate shape with a prominent umbo. Surface exhibits distinct, concentric growth rings (ridges) that are regular and somewhat coarse. The shell displays a polished, calcic luster typical of modern or recently deceased specimens.
Rock Matrix
None; specimen is free of matrix, likely collected from beach sand or river sediment.
Formation & Location
Sterling State Park, Monroe, Michigan (Lake Erie shoreline). This area is dominated by modern lacustrine deposits.
Size & Dimensions
Approximately 1.5 cm to 2.5 cm in width, which is consistent with adult specimens of Corbicula.
Value & Rarity
Estimated Market Value
$0.00 - $1.00
Auction Estimate
N/A (Minimal commercial value beyond educational or decorative use)
Rarity Assessment
Common; extremely abundant in the Great Lakes and interconnected waterways.
Scientific Significance
As a modern invasive species in the Great Lakes, it provides data on current ecological shifts and bio-invasion rather than ancient evolutionary history. It is an index taxon for modern freshwater environments.
Preparation Recommendations
No scientific preparation required. Can be cleaned with mild soap and water and stored in a dry environment.
Notable Features
Specimen exhibits the classic 'clamshell' profile with well-defined growth lines. Note that while Michigan has Devonian fossils, this specific specimen is a modern shell from the current Lake Erie ecosystem.
Notes
Found at Sterling State Park in Michigan