Note: to east along bluff from section the silt zone within unit 6 thickens and becomes a prominent, grey-white, fluted unit.* The lignitic beds (lower part 6 + 5) below thin and locally become lighter gray so that contact with unit 4) is locally obscure, consisting of a change from the sand to a silty or sandy clay of same color. Question exists whether there is gradation at such places or reworking of top of unit (4). * local lens thins again farther east,