File:Symmetrical ripple marks (Berea Sandstone, Upper Devonian or Lower Mississippian; Sunbury, Ohio, USA).jpg

English: Symmetrically-rippled sandstone from the Devonian of Ohio, USA. (public display, Geology Department, Wittenberg University, Springfield, Ohio, USA)

Symmetrical ripples are moderately common sedimentary structures. In cross-section, when viewed perpendicular to the crests of the ripples, symmetrical ripple marks are more or less evenly shaped - they are symmetrical. Their presence in sedimentary rocks is diagnostic of deposition in a shallow water environment with a two-directional, back-and-forth (oscillatory) current. Symmetrical ripples marks are common in ancient shallow-water sandstone facies.

This sample is from the Berea Sandstone of Ohio. It caps a coarsening-upward succession that starts with the Olentangy Shale, followed by the Ohio Shale, the Bedford Shale, and the Berea Sandstone. The Ohio Shale and Bedford Shale are Famennian in age (= upper Upper Devonian). Traditionally, the Bedford and the Berea have been considered as Lower Mississippian. The Berea is now known to be Famennian (~latest Devonian), based on palynomorph microfossils. The Devonian-Mississippian boundary may lie within the Berea Sandstone. A Kinderhookian-aged conulariid has been found in the basal part of the overlying Sunbury Shale.

The Berea Sandstone has been quarried as building stone in northeastern Ohio.

Stratigraphy: Berea Sandstone, upper Famennian Stage to lower Kinderhookian Stage (?), upper Upper Devonian to lower Lower Mississippian (?)

Locality: unrecorded/undisclosed site at or near the town of Sunbury, eastern Delaware County, central Ohio, USA