Teredina is a rather bizzare fossil. Once thought to be a long worm tube, scientists
now believe that it is a hard protective tube of a small boring clam. No definite
shell material has been found in association with the burrows. The tubes are generally
15 centimeters or more in legnth, and are found as short fragments 1 to 3 cm long.
Teredina is related to the modern ship worm (Teredo), a clam that bores into wood
and lives in a thin calcareous tube, used for protection and feeding.