Tridactyl Dinosaur Track
cf. Eubrontes or Grallator ichnogenus • Trace fossil (vertebrate footprint/cast or infilling)
Geological Period
Jurassic to Cretaceous
Estimated Age
145 to 200 million years ago
Preservation Type
Natural cast / sediment infilling within a sandstone matrix
Condition Assessment
Good condition; weathered surface with moderate preservation of fine morphological details, partially eroded margins
Taxonomic Classification
Phylum Chordata, Class Reptilia, Superorder Dinosauria, Order Ornithischia or Theropoda (Ichnotaxon)
Morphological Description
The specimen exhibits a prominent tridactyl (three-toed) impression with distinct digital pads and claw marks, suggestive of a bipedal dinosaur trackway element. The infilling preserves the structural outline of a large pedal digit configuration.
Rock Matrix
Fine-grained quartz sandstone with iron oxide staining (limonite/hematite coloration)
Formation & Location
Glen Rose Formation or equivalent Mesozoic fluvial/littoral sandstone deposits, North America
Size & Dimensions
Approximately 25 to 35 cm in length, consistent with medium to large theropod or ornithopod tracks
Value & Rarity
Estimated Market Value
$300 - $800 USD
Auction Estimate
$400 - $1,000 USD
Rarity Assessment
Uncommon to Rare depending on the specific formation and clarity of the track impression
Scientific Significance
Provides crucial behavioral evidence of Mesozoic dinosaur locomotion, gait, distribution, and paleoenvironmental conditions in ancient coastal or river floodplain settings
Preparation Recommendations
Gentle mechanical cleaning with soft brushes to remove loose matrix; avoid harsh acids; store in a climate-controlled environment with stable humidity to prevent sandstone flaking
Notable Features
Distinct reddish-brown iron staining highlighting the track infill against the lighter sandstone matrix, emphasizing the 3D relief of the footprint