Yes, this stuff was on the sides of mountains composed entirely of sand. Not sandstone, sand.
That loose surface sand may simply be erosional sediments from underlying sandstone (bedrock). Such sediment is called regolith. The surfaces of the moon and mars is covered in it.
106 posted on 09/22/2015 2:04:34 PM PDT by ETL
(ALL (most?) of the Obama-commie connections at my FR Home page: http://www.freerepublic.com/~etl/)