They are present in cretaceaous rocks in the Fort Worth Formation of Texas and in the Trent River Formation of evidence indicates that people in Neolithic Europe were trading the shells of "S. gaederopus" to make bangles and other ornaments throughout much of the Neolithic period.
They are present in cretaceaous rocks in the Fort Worth Formation of Texas and in the Trent River Formation of Vancouver as well as in other parts of North America. Archaeological evidence indicates that people in Neolithic Europe were trading the shells of "S. gaederopus" to make bangles and other ornaments throughout much of the Neolithic period.