About one hundred miles of the river are comprised within the Ramparts, which do not rise as rocky walls, but rather as steep sparsely wooded slopes, formerly beloved of the mountain sheep. Above the Ramparts the river spreads out upon a wide alluvial plain, dividing itself amongst innumerable islands.
Just below the lower end of the cañon enters from the south the Tanana, River of the Mountain Men, a noble tributary. Here lay Nuklukahyet the neutral trading ground for many years.
On the border of Alaska, just above the Arctic Circle, enters the Porcupine River from the northeast, the channel by which MacMurray won his way into the Yukon valley in the early forties. Here the great river bends to the southeast, enters British territory, and carries its navigable waters further nearly five hundred miles. In this stretch its hitherto pellucid waters receive the milky flow of the White River, glacier-fed, which tinges their flood henceforward, to the sea.
The Yukon is the highway of all this land. When the frosts of October lock the streamlets and choke the outlets of the mountain springs, the wide stream is quickly ice-bound. At some points where the swifter current ripples, open water still remains, giving out feathery streaks of mist to the crisp air.
Migratory fishes hurry to the sea. Already the water fowl have departed. The first snow lies feathery soft amongst the seedling willows on the sandbars. The broad sheets of ice on either shore glisten in the enfeebled sunlight, and as the river falls, they sink, creaking and crashing until the early ice of the shallows lies unevenly on the gravelly river-bed. The turbidity of summer lessens and the current flows steely-dark along the open spaces. Sharper grows the cold; the heavy sun relinquishes more and more of its meridian arc. The skies turn gray, and presently comes the snow, steady, silent, soft, incessant, clothing the world.
Deep under the fleecy blanket nestle the little green herbs. The field mouse tunnels the drifts where he may roam unseen and nibble the sweet bark of the young birches. Stately, silent, vigorous, the ptarmigan cock treads pathways amongst the willows, in snow no whiter than his plumage. Here the admiring flock may pluck the spicy buds to their content, heedless of the fowler's snare, and hardly disturbed when the lesser hare, like them snow white, avails himself of their convenient runway.
The red squirrel chirrups in the branches of the spruce, nipping off the loaded cones. Around him chirp the winter redbirds, cheeriest of residents, while in a neighboring poplar the raucous voice of the whisky-jack declares that the world owes him a living. The yellow-headed woodpecker hammers busily away on some decaying alder and from the steep bluff among the rocks comes with solemn repetition the hoarse cry of the raven.
