Ripple marks

Ripple marks at Toronto Lake
Ripple marks in sandstone at Toronto Lake, Woodson County.


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.


Kansas Rocks and Minerals, Kansas Geological Survey Educational Series 2.