A part of the rocky material gathered is carried to the end of the glacier, where the melting of the ice unloads and releases it. This accumulation at the end is called the terminal moraine, and corresponds to the delta of a river. For years the bulk of the ice may melt away at about the same place; thus at this point accumulates an enormous amount of débris. An advance of the ice may plow through this and repile it, or the retreat of the ice, or a changed direction of its flow, may pile débris elsewhere. Many of these terminal moraines are an array of broken embankments with small basin-like holes and smooth, level spaces. Many of the lakes have been filled with sediment, and in them and on them forests now flourish. The glacier lakes were slowly created. Most of them are being slowly filled. Those most favorably situated may still live on for thousands of years, but an avalanche may extinguish one in a single day. Eventually all must be filled and lost. They come into existence as a part of the work of the glacier. For a period they lie beautiful in the sunlight; then they are gone forever. The extensive glacial records that show the past triumphs of the Ice King sometimes make the mind restless, and it wants to know: "Will the Ice King come again? Will mountains of white and silent snow again pile upon a lifeless world?" 4. HIGH PEAKS Those who go up into the clouds and sky on high mountains will find a variety of lofty and magnificent peaks in the National Parks. These peaks rise amid and above wildernesses of superb scenes, splendid combinations of peaks, streams, lakes, passes, forests, and moorlands. My three favorite peaks in the United States are Mount Rainier, Long's Peak, and the Grand Teton, which is near Jackson's Hole, Wyoming. In many respects Mount Rainier is the noblest mountain in the world. It is high, and to reach its summit is to make a journey that requires preparation and care. Much ice work is necessary in order to attain the top. Once there, the climber looks down upon extensive landscapes of forests and sea, islands and rivers, and snowy peaks. Long's Peak is a rugged, vast monolith of granite 14,255 feet high. Usually it is almost entirely free of both ice and snow. It is a rock climb. It stands not in but immediately in front of the Continental Divide, whose near-by ruggedness is tremendously impressive. Far away one looks out over seas of mountains and on ocean plains. Standing side by side with Long's Peak, and of almost equal height, is Mount Meeker, also a rock climb that reveals scenes of unusual interest. The Yellowstone has three excellent mountain-top view-points: Mount Washburn, Mount Sheridan, and Electric Peak. One can motor to the top of Mount Washburn, and the climbs to the tops of the other two are not extremely difficult.