The rover Curiosity found some extraordinary features on the surface of the Red Planet that have a strong similarity to the shores of the land waterways.
For example, today's image shows the small ledge of rock that most likely formed by water erosion circulating underneath. The outgoing texture appears to be a sedimentary conglomerate, ie dried debris numerous smaller rocks that stuck together.
Below the protrusion there are many pebbles, possibly were polished by the drag of the flow of water. It is likely that the pebbles were falling to the river as the bank eroded.
In the top right of the picture that heads the entrance is a larger rock, marked with a white oval. It is also likely that this rock was polished by erosion due to the current.
Curiosity has found several indications of dry riverbeds on Mars during the journey to its current location. From now explore a rare junction of three different types of terrain.