Cyclopean stairs represent one of the most peculiar topographic features found in a glaciated valley the floor of which rises upstream in a series of rock steps and separated by nearly vertical cliffs.
The glacial steps or glacial stairs are associated with the glacial troughs. The stairway is determined by the geological structure with the steps or benches being formed in the extremely hard rocks.
The cliffs separating the steps range in height from about 30 meters to 330 meters. Actually descent of trough floors takes place in a series of glacial steps. It is to be borne in mind that each glacial step has three component parts- a riser, a riegel, and a tread. A riser marks the down valley end of each step.
A riegel is a kind of rock bar at the top of a riser. A tread is the relatively flat surface of the step. It has a reverse up valley slope having a chain of lakes which are called paternoster lakes.
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The formation of glacial steps is so puzzling that it has led the geomorphologists to advance various theories to account for them. However, no theory is universally applicable.
One theory explains steps as the result of differential glacial abrasion in narrow and open sections of valleys. Another theory advanced by Johnson explains the formation of steps due to the irregularity of the pre-glacial valley floors.
Matthes laid emphasis on the varying erosibility of massive and jointed rocks. Modern view considers stairways as being formed partly by glacier wave functions, rather than merely by rock structure.