Drumlin

A drumlin, from the Irish word droimnín ("littlest ridge"), first recorded in 1833, and in the classical sense is an elongated hill in the shape of an inverted spoon or half-buried egg formed by glacial ice acting on underlying unconsolidated till or ground moraine.

Drumlin formation

Drumlins and drumlin clusters are glacial landforms, composed primarily of glacial till, which have been extensively studied. Geologists have proposed several theories about their origin. They can form both near the margin of glacial systems and within zones of fast flow deep within the ice sheet. They record the direction of ice movement at the time of formation. Drumlins occur in symmetric, spindle, parabolic, and transverse asymmetrical forms. However it is increasingly being recognised that there is no true 'drumlin' shape, and that rather subglacial bedforms can take on a wide range of shapes and sizes. Drumlins are commonly found with other major glacially-formed features and are related on a regional scale to these landforms. The large-scale patterns of these features exhibit spatial organization of the drumlin-forming flows with related tunnel valleys, eskers, scours, and exposed bedrock erosion (scalloping and sichelwannen).