_Why are shingle beaches formed by heavy gales?_

Because every breaker is more or less charged with the materials
composing the beach; the shingles are forced forward as far as the
broken wave can reach, and, in their shock against the beach, drive
others before them that were not held in momentary mechanical suspension
by the breaker. By these means, and particularly at the greatest height
of the tide, the shingles are projected on the land beyond the reach of
the retiring waves: and this great accumulation of land upon beach being
effected at high water, it is clear, the ebb tide cannot deprive the
land of what it has gained. Smaller lines are formed in moderate
weather, to be swept away by heavy gales: hence it would appear, that
the sea was diminishing the beach; but attention will show that the
shingles of the lines so apparently swept away, are but accumulated
elsewhere. How often has our observation of these changes realized the
homely simile of Shakspeare:--

Like as the waves make towards the pebble shore,
So do our minutes hasten to their end;
Each changing place with that which goes before,
In sequent toil all forwards do contend.

_Why is this progressive march of beaches far from rapid?_

Because it can only take place in proportion to the greater power or
duration of one wind to another: moreover, the pebbles become comminuted
in their passage, and thus, the harder can only travel to considerable
distances. Works are sometimes constructed to arrest beaches, either to
protect land behind, or to prevent their passage round pier-heads into