Trace Fossil (likely Thalassinoides/Ophiomorpha or similar burrowing trace)
Ichnogenus: Thalassinoides cf. suevicus or Ophiomorpha ichnosp. • Ichnofossil (Trace Fossil); Invertebrate Activity
Geological Period
Indeterminate (Common from Jurassic to Neogene)
Estimated Age
Occurs throughout the last 200 million years (Mesozoic-Cenozoic)
Preservation Type
Infill/Cast preservation (The hollow burrow was filled with sediment that later lithified)
Condition Assessment
Fair to Good; robust and well-indurated, though the surface is heavily weathered and lacks fine detail such as distinct diagnostic pellet marks.
Taxonomic Classification
Phylum: Arthropoda (likely), Class: Malacostraca, Order: Decapoda (likely Crustacean)
Morphological Description
A cylindrical, three-dimensional branching or undulating tunnel system preserved in relief. The specimen shows characteristic bulbous swellings at junctions and a somewhat knobby external texture often associated with pellet-lined burrow walls (Ophiomorpha).
Rock Matrix
Silty sandstone or calcarenite; medium-grained sedimentary rock with a greyish-brown weathered surface.
Formation & Location
Common in marine sedimentary formations globally; frequently found in the Cretaceous and Tertiary coastal deposits of Europe, North America, and Australia.
Size & Dimensions
Approximately 25-30 cm in length and 5-8 cm in diameter, which is on the larger end of typical crustacean burrow casts.
Value & Rarity
Estimated Market Value
$40 - $100 USD
Auction Estimate
$30 - $80 USD
Rarity Assessment
Common; Thalassinoides and Ophiomorpha are among the most widespread and frequently encountered trace fossils in marine sequences.
Scientific Significance
Provides evidence of paleoenvironmental conditions (shallow marine, high energy) and the behavior of ancient burrowing organisms (bioturbation).
Preparation Recommendations
Requires minimal preparation; soft brushing to remove loose dirt. Conservation should focus on preventing physical impact, as sandstone can be crumbly.
Notable Features
Features a prominent Y-shaped or T-shaped branching node which is diagnostic for identifying decapod crustacean activity rather than geological concretion.