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Teredo Petrified Wood

North Dakota State Fossil

North Dakota Heritage Center exhibit: Teredo-bored petrified wood from Cannonball Formation, Morton County, ND; photo courtesy of North Dakota Geological Survey / Dept. of Paleontology (all rights reserved; used by permission).

Official State Fossil of North Dakota

North Dakota designated teredo petrified wood as the official state fossil in 1967 (one of the first states to recognize a fossil symbol). Naming Teredo petrified wood as the state fossil promoted the fossil to tourists, geologists, and rock-hounds, and caused the Smithsonian Institution to represent North Dakota in its mineral collection. Petrified wood is also a symbol of Washington, Louisiana, and Texas. All State Fossils

Teredo petrified wood is unique because of the "worming" of the original wood by the prehistoric teredo - a worm-shaped mollusk related to modern clams, mussels, and oysters. 60 to 80 million years ago during the Paleocene Epoch, the teredo was burrowing through trees growing near the edges of warm swamps in North Dakota.