Volcanic constructs on Mars are not all enormous mountains like Tharsis Montes. The elongate hill surmounted by a linear depression (see arrows) is interpreted to be a product of localized but not extremely voluminous eruptions. If the volcanic material was emplaced by ejection along a ballistic trajectory, this feature may be similar to a terrestrial cinder cone. This feature is aligned with several grabens in the area so that a structural weakness in the crust may have provided the conduit for the volcanic material to reach the surface.
36 N, 86 W; portion
of Viking Orbiter frame 627A28, shading corrected version.