Ripple Marks are a series of wavy lines formed from wind or water flowing across a surface. You can see these markings when you walk on the shore of a sandy beach. You may have noticed that the ripple marks in the sand on the beach can get washed away or filled in easily. Ripple marks on stones do not wash away nearly as easily. When these markings are in a rock, we say that it is fossilized. It can tell us a lot about what used to be in an area before we were there.
Ripple Mark Sandstone. University of Waterloo Rock Garden
The rock in the photograph above is made of sandstone. Sandstone is a sedimentary rock, formed from billions of tiny grains of sand being heated up and squished together so much that they turn into a rock! This usually happens deep underground.