Vesicular or cavernous sediment covers much of the floor of the Cagles Mill Dam spillway, southwest of Cloverdale, Indiana. Caverns are best developed in fine-grained sand and coarse-grained silt interlayered with coarse-grained sand and clay-rich material. They appear to have formed during heavy rains by entrapment of air below rapidly saturated surface layers and the consequent expulsion and concentration of bubbles in the sediment by downward movement of water. Several periods of heavy rainfall, followed by drying, enlarged the features.

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