"There is no fossil network described in the geologic literature that could be held to have originated from the activity of tadpoles. With one exception all of them are not a primary (positive) but secondary (bas-relief casts or hyeroglyphs) structures and are on the lower surface of a bed. They are of an organic origin but may be only imprints of algae. . . . or as traces of worm-activity. They all are related to the group of Paleodictyonidae."