High quality tin was often found in the ancient riverbeds and on the surface of the hills.

Part of the Rhine today includes this ancient riverbed.

Networks of valleys that merge into larger channels imply erosion by a liquid agent, and resemble ancient riverbeds on Earth.

To the east, a jumble of mountains and chaos interrupted by ancient riverbeds flowing down to a beach.

Only the refilled ancient riverbeds looked "right"; everywhere else the terrain looked like a bomb range after a rainstorm.

Snuggled up in bed with the kids, you explore the ancient riverbeds of Mars.

They watched silently out their own windows as the bus maneuvered down a bank into the remains of an ancient riverbed.

In rocky gorges with tall conglomerate walls, they saw ancient, dry riverbeds.

They raced back down the slope, and at the bottom the mare turned towards the ancient riverbed.

In the North Sea it splits up into two arms representing the ancient riverbed at the end of the last ice age.