The waves are eating their way into the land
Along the whole coast of California there are many old sea beaches and cliffs which the waves abandoned long ago. The highest of these beaches lies so far up the slopes of the mountains bordering the ocean that it makes us wonder what the geography of California could have been like when the region was so deeply submerged.
The lowest and newest terrace is the one shown in Fig. 35, ten feet above the ocean. Each succeeding terrace is less distinct, and the highest, fourteen hundred feet in elevation, can now be distinguished in only a few places. Where the old sea cliffs are best preserved they form a series of broad, flat steps, rising one above the other. Each bench, or terrace as it is commonly called, is a part of an old plain cut out of the land by the waves when the ocean stood at that level. The steeper slope rising at the back is the remnant of the cliff against which the waves used to beat. If we are fortunate, we shall find at its base some water-worn pebbles and possibly a few fragments of sea-shells. The crumbling of the rocks and the erosive action of the rills are fast destroying the old cliffs, so that in many places they have entirely disappeared.
FIG. 34.—OCEAN CAVE AT LOW TIDE
Pebbles of a former beach are seen above
Upon the seaward face of San Pedro Hill, in southern California, there are eleven terraces, rising to a height of twelve hundred feet. What an interesting record this shows! Long ago the land stood twelve hundred feet lower than at present, and the waves beat about San Pedro Hill, nearly submerging it. Then the land began to rise, but stopped after a time, and the waves cut a terrace. The upward movement was continued, with repeated intervals of rest, until the land stood higher than it does now.
FIG. 35.—WAVE-CUT TERRACES
Point San Pedro, California