Following its deposition, the late Pliocene or early Pleistocene Citronelle formation was entrenched by consequent streams and then tilted toward the Gulf. Submergence in waters 190 to 210 feet above present sea level then resulted in a compound shore line and marine erosion of the Coharie terrace. Four other marine terraces occur below the Coharie level: the Sunderland at 150 to 160 feet, the Wicomico at 90 to 110 feet, the Penholoway at 60-70 feet, and the Pamlico at 20 to 30 feet. The Coharie, Penholoway, and Pamlico marine terraces are associated with fluvial or estuarine terraces in the Mobile River Valley. After Pamlico submergence, a Mobile River floodplain and delta was formed at 10 to 11 feet below present sea level.