88 SHINGLE BEACHES AND THEIR FIXATION
the tidal currents, they may be drifted in certain definite directions. The driving ashore of these materials to form beaches is effected in the main by wind-wave action, as already described. The principal types of beach may be distinguished as follows :—
   i.	The Fringing Beach.—This is the simplest case, the shingle being directed and moulded by the shore currents and forming a strip in contact with the land behind. Illustrated on the English Channel, as on the coast of Sussex, and in France, S. W. of Dieppe.
Fig-. 18.—Sketch Map of the Chesil Bank (after Bristow and Whitaker), to show the relations of Bank, Mainland, and Fleet. Shingle is rendered in heavy black
   2.	The Shingle Spit.—This is produced when a coast-line suddenly changes its direction, turning landward, whilst the current pursues its original course so that it separates from the shore. The transported shingle accumulates along the line of the current to form a bank or causeway, often reaching a length of several miles. This type is attached to the shore at the point where the current leaves it, and then runs straight on with a gentle curvature to its growing extremity. The apex of this type is particularly liable to deflection as a landward hook.
   Examples'. Hurst Castle, Blakeney Point (with hooks), Northam Pebble Ridge (Devon), Aldeburgh, Calshot Point, Heacham Bank, Cemlyn (Anglesea).
   3.	The term Bar is given to a beach which runs parallel to the shore line but at some little distance therefrom, and is tied