Crag and tail

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The Abbey Craig, a crag with tail near the University of Stirling. The Wallace Monument stands on the crag at the right, and the long tail slopes down leftward
Salisbury Crags to the left and Arthur's Seat to the right, with their tails sloping east to the right.

A crag (sometimes spelled cragg, or in Scotland craig) is a rocky hill or mountain, generally isolated from other high ground. Crags are formed when a glacier or ice sheet passes over an area that contains a particularly resistant rock formation (often a granite, volcanic plug or some other volcanic structure). The force of the glacier erodes the surrounding softer material, leaving the rocky block protruding from the surrounding terrain. Frequently the crag serves as a partial shelter to softer material in the wake of the glacier, which remains as a gradual fan or ridge forming a tapered ramp (called the tail) up the leeward side of the crag.

In older examples, or those latterly surrounded by the sea, the tail is often missing, having been removed by post-glacial erosion.

Examples of such crag and tail formations include:

See also[edit]

References[edit]

  • Holmes, Arthur, Principles of Physical Geology, Halsted, 1978, 3rd ed., pp 421 – 422 ISBN 0-471-07251-6