Ripple marks

The troughs and ridges of fossilized ripple marks in sandstone and siltstones are hardened versions of the short-lived ripples in the loose sand of a modern-day stream, lake, sea, or sand dune. Ripples may be made by water or, in sand dunes, by wind. The symmetry of water-current ripple marks indicate whether they were formed by gentle waves or faster water currents.

Ripple marks are common in Kansas. They are especially notable in a sandstone in the Bandera Shale in Bourbon County and on the east side of Toronto Lake in Woodson County.