hi CD, yes I would agree, there is always an alternative, Mars has an atmosphere although its tenuous and consists mostly of C02. it still produces dust devils and on occasions planetary wide sand storms. the sand I would say will round off stones and create pebbles, and as always here is the but.............some, not all of the pebbles and those dry river beds I mentioned on my last post according to the data sent back from the various Mars rovers could only be formed in free flowing water. the pebbles in such areas have a chemical signature that can only be attained via being in water.

now for an off topic thought, I wonder if they will ever find water on Venus.........a 700C hell hole., maybe in the clouds of the planet?