One of the chief Adirondack rivers flowing into Lake Champlain is the Ausable. Its branches come out of the heart of the mountains, one through the beautiful Keene Valley and the other through the Wilmington Notch, and uniting at Ausable Forks, it flows along the northwestern side of the long ridge terminating in Trembleau Point at Port Kent, and enters the lake just above. The river escapes from the mountains through the wonderful gorge of Ausable Chasm. It is an active stream, bringing down vast amounts of sand, which wash through this gorge and are spread over the flats north of Trembleau, where the river flows out through two mouths. These prolific sand-bars, when first seen by the French, caused them to name the stream Ausable, the "river of sands." This renowned chasm, in its colossal magnificence and bold rending of the hard sandstone strata, is one of the wonders of America. A local poet has written on a little kiosk adjoining the river chasm this rhythmic explanation of its origin: "Nature one day had a spasm With grand result--Ausable Chasm." This splendid gorge, cut down in getting out of the highlands, is carved in the hardest Potsdam sandstones. It is a profound, and in most of its length a very narrow chasm, with almost vertical walls from seventy to one hundred and fifty feet high, the torrent pouring through the bottom being compressed within a width of eight to thirty feet, and rushing with quick velocity. The chasm is about two miles long, having several sharp bends, the stratified walls being built up almost like artificial masonry. The sides are frequently cut by lateral fissures, making remarkable formations, and the tops of the enclosing crags are fringed with a dense growth of cedars. The river of dark amber-colored water first comes out of the forest past Keeseville, where mills avail of its water-power, and then pours over the ledges of the Alice Falls, the finest in the Adirondacks. This splendid cataract of forty feet descent is above the entrance to the gorge, much of it being an almost sheer fall, having magnificent foaming watery stairways down the ledges, bordering it with their delicate lacework on either hand. The dark waters tumble in large volume into an immense amphitheatre, which has been rounded out by the torrent during past ages. Then bending sharply to the right, the river goes down some rapids and over a mill-dam built just above the chasm. The opening of this extraordinary rent in the earth is startling. Suddenly the river pours over a short fall, and then down another deep one strangely constructed, the line of the cataract being almost in the line of the stream. These are the Birmingham Falls, down which the Ausable plunges into the deep abyss, while high above stands a picturesque stone mill whose wheels are turned by the waters, and just below a light iron bridge carries a railway over the gorge.