Rollo then went to where Mary and Lucy were, and began to collect shells. They found quite a number of different kinds, all along the shore. Some were large and coarse,--broken and worn by the water. Some were so thin and delicate that he had to wrap them up carefully in a paper, and put them into his waistcoat pocket, in order to get them home safely. The children found several other curiosities besides shells. They collected pebbles, and specimens of sand, of different colors. Mary found an old iron spike, perhaps part of a vessel, with the sand and gravel concreted around it. It looked like stone growing upon iron. Rollo also found a small piece of wood, battered and worn by the long-continued action of the waves, and he thought it was very curious indeed. In fine, the children filled their baskets with wonders, and, after about three quarters of an hour, they set out on their return home. When Rollo went to get his shoes, he found the water almost up to them. If he had staid away a little longer, they would have been washed away again. The truth was, the tide was rising. THE CLIFFS. As the party slowly rode away from the beach, Rollo's mother asked if it was too late to go to the cliffs. There was a splendid prospect from the cliffs. They were rocky precipices overhanging the sea, at the extremity of a point of land, about a mile from the beach where they had been. The two girls wanted to go very much; but Rollo did not care so much about it. He was in haste to get home and arrange his curiosities. His father, however, after looking at his watch, said that he thought there would be time to go. So he turned his horse's head in the right direction, and they went to the cliffs. The precipices were very high, and the swell of the sea dashed and roared against them at their foot; and yet the water looked very smooth at a little distance from the land. Rollo wondered why there should be waves along the beach and against the rocks, when there were none out in the open sea. "I should think, father," said he, "that it would be calmer near the shore, and more windy out upon the water." "It is," said his father. "Then, why are not the waves bigger?" "They _are_ full as big." "Why, father," said Rollo, "there are no waves at all out from the land." "You can't see them very well," said his father, "because we look down upon them. When we are upon a mountain, the small hills below almost disappear. Besides, the waves out in the open sea, in such a still time as this, are in the form of broad swells; but these swells are broken when they roll against the shore, and so this makes the surf." "I mean to look over and see," said Rollo, and he walked cautiously along towards the precipice. "O Rollo," exclaimed Mary, "don't go so near!" "Why, there is no danger," said Rollo. "Rollo! Rollo!" exclaimed Mary again, as Rollo went nearer and nearer.