The Crary Mountains are a chain of either three or two shield volcanoes long which extends in northwest-southeast direction. The volume of the volcanoes exceeds and the edifices consist of lavas, hydrovolcanic deposits such as hyaloclastite, fragments of pillow lavas and tuffs, and scoria. Unlike many other mountains in Marie Byrd Land, which owing to a lack of erosion display only their highest and youngest parts, in the Crary Mountains the internal structure of the volcanoes are well exposed. The Crary Mountains form a drainage divide for the West Antarctic Ice Sheet; they dam it, which is thus higher on one side of the range. Debris stripes have been observed on the ice near the foot of the mountains.