Gravity and water are filling with débris and sediment these basins which the glaciers dug. Many lakes have long since faded from the landscape. The earthy surface as it emerges above the water is in time overspread with a carpet of plushy sedge or grass, a tangle of willow, a grove of aspen, or a forest of pine or spruce. The rapidity of this filling is dependent on a number of things,--the situation of the lake, the stability of the watershed, its relation to forests, slopes, meadows, and other lakes, which may intercept a part of the down-coming sediment or wreckage. This filling material may be deposited evenly over the bottom, the lake steadily becoming shallower, though maintaining its original size, with its edge clean until the last; or it may be heaped at one end or piled along one side. In some lakes the entering stream builds a slowly extending delta, which in time gains the surface and extends over the entire basin. In other lakes a side stream may form an expanding dry delta which the grass, willows or aspens eagerly follow outward and cover long before water is displaced from the remainder of the lake's rock-bound shores. With many, the lower end of the basin, shallow from the first, is filled with sediment and changed to meadow, while the deep upper end lies almost unchanged in its rock basin. Now and then a plunging landslide forms an island, on which the spruces and firs make haste to wave triumphant plumes. Lake Agnes on the northern slope of Mt. Richthofen was formed with a rounded dome of glaciated rock remaining near the centre. This lake is being filled by the slow inflow of a "rock stream." Landslides, large and small, often plunge into these lakes. One of the largest rock avalanches that I ever saw made one wild leap into Chasm Lake and buried itself. This was about the middle of June. This glacier lake is on the eastern side of Long's Peak and is in a most utterly wild place. The lake was still covered with thick ice, and on the ice the snow lay deep. But spring was melting and loosening things in the alpine heights. As I stood on a talus slope above the outlet of the lake, an echoing on the opposite cliffs told me that a rock-slide was coming down. Almost instantly there was the ripping whizz of falling stone. A huge stone struck and pierced twenty feet of snow and more than four feet of ice, which covered the lake. At the same instant there came sounds of riot from above. More stones were coming down. The crash of their striking, repeated and reëchoed by surrounding cliffs and steeps, made an uproarious crashing as though the top of Long's Peak had collapsed. It was an avalanche of several thousand tons off the slope of Mt. Washington.