One might be led to think from this statement that it would not be safe to live on the Pacific coast, and that both animals and men would shun the region. The fact is, however, that these changes usually come to pass so very slowly that we are not aware of them. Severe earthquakes and volcanic disturbances take place so rarely in comparison with the length of a man's life, that we may pass our whole lives without experiencing any of these violent disturbances. The Pacific coast region, with its forest-covered mountains, fertile valleys, and beautiful homes, presents so quiet and peaceful an appearance that it is difficult to believe that parts of its history have been so tumultuous. Perhaps you will ask how we can know so much about the past. It is true that no one was here to witness the events which are supposed to have taken place. But Nature has left a record of her doings which we have only to see and understand in order to learn with certainty many things which happened in the far distant past. Too many of us go through life seeing and understanding almost as little of the world about us as if we were blind. Our early ancestors were obliged to understand many things about Nature and to cultivate clear and close observation for the sake of self-preservation. The very life of the savage depends upon the training of his eyes. He must be able to tell the meaning of a distant object or an indistinct trail, for his enemies may have passed that way recently. If we could bring the sharp eyes of the savage to our aid, the world would mean much more to us. In order to learn something of the history of the Pacific shore line, we must see what the waves are doing at the present time. The projecting points of land are being worn away (Fig. 33). The waves form the cliffs against which they beat, and sometimes, as they eat their way slowly into the land, they cut off portions and leave them standing alone as islands. The pebbles and boulders (Fig. 34) were once angular fragments torn from the cliff. They have been washed about and hurled against the solid rock until they have been worn smooth; and the cliff in turn has had a cave ground out at its base. Above the lower cave there is a remnant of a second one, with pebbles upon its floor. This was made when the land stood ten feet lower than at present. As the waves wear away the loose earth and the solid rock below it, moving the cliffs inland, they leave a comparatively smooth surface which is partly exposed at low tide. The fact that this surface is not marked by stream channels, as is the land, helps us to realize the great difference between the irregular surface of the latter and the plain-like character of the ocean floor. [Illustration: FIG. 33.--POINT BUCHON, CALIFORNIA The waves are eating their way into the land]