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Teredo-Bored Petrified Wood

Teredo-Bored Petrified Wood

The state fossil of North Dakota is the 60 million year old Teredo (ter-Ee-doe) bored petrified wood. This name comes from little clams called “teredos” that drilled tiny holes into the wood before it fossilized. Minerals filled in the cells of the wood as it decayed so that it looked exactly like the wood that had been there in the first place, except it was now stone.

Prior to its adoption in 1967, North Dakota was not represented in the Smithsonian Institution's mineral collection. Naming of the Teredo-bored petrified wood as the state fossil remedied that situation and promoted the fossil to tourists, geologists, and “rockhounds.”

Teredo-Bored Petrified Wood - PDF