INLAID MODERN SEDIMENTS IN PLEISTOCENE TERRACE ALLUVIUM, SOUTHERN ILLINOIS
Inlaid modern sediments occur in the base of the bluffs above the Ohio flood plain west of Joppa, Illinois. These are thought to have been deposited in reentrants or notches cut and eroded by wave action during unusually high river floods. Along the bottom edge of the notches debris dams provide small catchment basins for silt washed by rain from the bluff. Once the notches are filled or partly filled, the retreating bluff removes the debris dams, leaving the silt as an inlaid deposit in the bluff face.