t in
coming in upon a headland or a straight shore. The result is, with the
inward retreat of the steep it enters on conditions which diminish the
effectiveness of the wave stroke. The embayment also is apt to hold
detritus, and so forms in time a beach at the foot of the cliff, over
which the waves rarely are able to mount with such energy as will
enable them to strike the wall in an effective manner. With this
sketch of the conditions of a cliff shore, we will now consider the
fate of the broken-tip rock which the waves have produced on that
section of the coast land.

By observation of sea-beaten cliffs the student readily perceives that
a great amount of rocky matter has been removed from most cliff-faced
shores. Not uncommonly it can be shown that such sea faces have
retreated for several miles. The question now arises, What becomes of
the matter which has been broken up by the wave action? In some part
the rock, when pulverized by the pounding to which it is subjected,
has dissolved in the water. Probably ninety per cent of it, however,
retains the visible state, and has a fate determined by the size of
the fragments of which it is composed. If these be as fine as mud, so
that they may float in the water, they are readily borne away by the
currents which are always created along a storm-swept shore,
particularly by the undertow or bottom outcurrent--the "sea-puss," as
it is sometimes called--that sweeps along the bottom from every shore,
against which the waves form a surf. If as coarse as sand grains, or
even very small pebbles, they are likely to be drawn out, rolling over
the bottom to an indefinite distance from the sea margin. The coarser
stones, however, either remain at the foot of the cliff until they are
beaten to pieces, or are driven along the shore until they find some
embayment into which they enter. The journey of such fragments may,
when the wind strikes obliquely to the shore, continue for many miles;
the waves, running with the wind, drive the fragments in oscillating
journeys up and down the beach, sometimes at the rate of a mile or
more a day. The effect of this action can often be seen where a vessel
loaded with brick or coal is wrecked on the coast. In a month
fragments of the materials may be stretched along for the distance of
many miles on either side of the point where the cargo came ashore.
Entering an embayment deep enough to restrain their further journey,
the fragments of rock form a