Early History of Lake Agassiz in Southeast North Dakota
Extensive accumulations of collapsed lake and shore sediment are present above the Herman level adjacent to the Agassiz lake plain in southeast North Dakota. The presence of these deposits indicates that ice-dammed lakes existed on top of stagnant glacial ice while Lake Agassiz was developing. Lake Agassiz did not simply expand northward from its southern end; but rather, when the superglacial lakes coalesced, the resulting Lake Agassiz flooded areas along much of the length of the Herman Beach.