These include shallow pools and a well-developed hummock and lawn complex.
hummock complexes have been mapped, adding to the habitat and species diversity.
Some hours later the Phoenix landed on a low hummock amidst the swamps of the northeastern corner of Roister Island.
A large hummock or ridge of ice lay in front of the man, blocking his view of the horizon in that direction.
These tend to merge into an enlarging, horseshoe-shaped bare slope which may threaten to reduce the dune to an eroded hummock.