=The sand beach.=—The first effect of the shore current is to deposit some portion of the sand within the first slight recess upon the shore in the lee of the cliff. The earlier deposits near the cliff gradually force the shore current farther from the shore and so lay down a sand selvage to the shore, which is shaped in the form of an arc or crescent and known as a _beach_ (Fig. 259 and Fig. 260). [Illustration: FIG. 260.—Crescent-shaped beach formed in the lee of a headland. Santa Catalina Island, California (after a photograph by Fairbanks).] [Illustration: FIG. 261.—Cross section of a beach pebble.] =The shingle beach.=—With heavy storms and an exceptional reach of the waves, the shore currents are competent to move, not the sand alone, but pebbles, the area of whose broader surface may be as great as the palm of one’s hand. Such rock fragments are shaped by the continued wear against their neighbors under the restless breakers, until they have a lenticular or watch-shaped form (Fig. 261). Such beach pebbles are described as _shingle_, and they are usually built up into distinct ridges upon the shore, which, under the fury of the high breakers, may be piled several feet above the level of quiet water (Fig. 262). Such storm beaches have a gentle forward slope graded by the shore current, but a steep backward slope on the angle of repose. Most storm beaches have been largely shaped by the last great storm, such as comes only at intervals of a number of years. [Illustration: FIG. 262.—Storm beach of coarse shingle about four feet in height at the base of Burnt Bluff on the northeast shore of Green Bay, Lake Michigan.] =Bar, spit, and barrier.=—Wherever the shore upon which a beach is building makes a sudden landward turn at the entrance to a bay, the shore currents, by virtue of their inertia of motion, are unable longer to follow the shore. The débris which they carry is thus transported into deeper water in a direction corresponding to a continuation of the shore just before the point of turning (see Fig. 259, p. 238). The result is the formation of a _bar_, which rises to near the water surface and is extended across the entrance to the bay through continued growth at its end, after the manner of constructing a railway embankment across a valley. [Illustration: FIG. 263.—Spit of shingle on Au Train Island, Lake Superior (after Gilbert).]