This is inner sand on Mars. It is somehow in wet format. That means there is water under Mars upper layer.
This Image Source - http://mars.jpl.nasa.gov/msl-raw-images/msss/01091/mhli/1091MH0002270000400908R00_DXXX.jpg
This Image Source - http://mars.jpl.nasa.gov/msl-raw-images/msss/01065/mhli/1065MH0005120000400729R00_DXXX.jpg
This Image Source - http://mars.jpl.nasa.gov/msl-raw-images/msss/01065/mhli/1065MH0005100000400585R00_DXXX.jpg
This Image Source - http://mars.jpl.nasa.gov/msl-raw-images/msss/01065/mhli/1065MH0003350010400622C00_DXXX.jpg
