Potamides trizonanus gastropod molluscs collected from the Oligocene Headon Beds of Collwell Bay, Isle of Wight. These specimens exhibit many of the textbook gastropod morphological features however they have been somewhat worn. They exhibit an elongate shell and some feeble ribbing and measure between 1.5 and 3.5 cm in length. The Headon Beds in which these gastropods were found are comprised of freshwater, brackish and marine deposits but it is brackish environments which Potamides gastropods favour. Supplied in a small plastic bag with an information label.