flat-topped hills with steep sides or columns of rock

• butte

• delta

• desert

• dune

triangular deposit of sand and soil at the end of a river

• delta

• dune

• oasis

• source

a dry region with little or no rainfall

• desert

• dune

• sand sea

• oasis

a mound or ridge of windblown sand

• dune

• desert

• sand sea

• butte

part of the river that empties into another body of water

• mouth

• source

• tributary

• oasis

place in the desert where there is a source of water and where plants grow

• oasis

• source

• mouth

• tributary

two rivers supplying water into one river

• river system

• tributary

• mouth

• source

a vast, large region covered by sand

• sand sea

• desert

• oasis

• dune

place where the river begins

• source

• mouth

• tributary

• river system

smaller stream or river that flows into a larger one

• tributary

• source

• mouth

• river system