i found this amongst some river rock. Please explain why or what happened to it.
closed as unclear what you're asking by Spencer, Fred, Jan Doggen, daniel.neumann, Gimelist Nov 5 '18 at 9:07
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These are fossil burrows... Looks like Thalassinoides or something similar. They are made by fishes, sea anemones, and crustaceans and can occur in different shapes... elongated, rounded, ending in t-sections, straight, spiral-shaped. A scalebar would be helpful for further classification.