Ripple marks

Clues in the ripples

Ripple marks provide a clue about the environment in which the rocks formed. Today ripples like these form in shallow water, so it’s reasonable to conclude that this rock was deposited in shallow water too. We also know that it was still or standing water, rather than a flowing current, because the ripples are symmetrical, formed by wavelets moving backwards and forwards. Ripples in a current are asymmetric; that is, they have a steep side and a shallow side caused by the movement of water in one direction only.

Find out more on the rocks and pseudofossils page.

Common name

Ripple marks

Type

Rocks and Pseudofossils


Strata

Otter Sandstone

Time period

Triassic

Age

225 million years

Where found

On beach below Peak Hill, Sidmouth

Found by

Unknown

Museum

Sidmouth Museum

Accession number

SID.G146.2009