Thick white clouds banked the mountains from peak to base, blotting out every scar and tor as a sponge might wash a slate. Valleys lay blanketed in smoking mist. As the sun came gradually up to the horizon far away east behind the mountains, scarp and pinnacle butted through the fog, stood out bodily from the mist, seemed to move like living giants from the cloud banks. "How could they do that if they were not alive?" asked the Indian. Elsewhere, shadows came from sun, moon, starlight, or camp-fire. But in these valleys were pencilled shadows of peaks upside down, shadows all the colours of the rainbow pointing to the bottom of the green Alpine lakes, hours and hours before any sun had risen to cause the shadows. All this meant "bad medicine" to the Indian, or, in white man's language, mystery. Unless they were foraging in large bands, Crows and Blackfeet shunned the mountains after nightfall. That gave the white man a chance to trap in safety. Early one morning two white men slipped out of their sequestered cabin built in hiding of the hills at the head waters of the Missouri. Under covert of brushwood lay a long odd-shaped canoe, sharp enough at the prow to cleave the narrowest waters between rocks, so sharp that French _voyageurs_ gave this queer craft the name "_canot à bec d'esturgeon_"--that is, a canoe like the nose of a sturgeon. This American adaptation of the Frenchman's craft was not of birch-bark. That would be too frail to essay the rock-ribbed cañons of the mountain streams. It was usually a common dugout, hollowed from a cottonwood or other light timber, with such an angular narrow prow that it could take the sheerest dip and mount the steepest wave-crest where a rounder boat would fill and swamp. Dragging this from cover, the two white men pushed out on the Jefferson Fork, dipping now on this side, now on that, using the reversible double-bladed paddles which only an amphibious boatman can manage. The two men shot out in mid-stream, where the mists would hide them from each shore; a moment later the white fog had enfolded them, and there was no trace of human presence but the trail of dimpling ripples in the wake of the canoe. No talking, no whistling, not a sound to betray them. And there were good reasons why these men did not wish their presence known. One was Potts, the other John Colter. Both had been with the Lewis and Clark exploring party of 1804-'05, when a Blackfoot brave had been slain for horse-thieving by the first white men to cross the Upper Missouri. Besides, the year before coming to the Jefferson, Colter had been with the Missouri Company's fur brigade under Manuel Lisa, and had gone to the Crows as an emissary from the fur company. While with the Crows, a battle had taken place against the Blackfeet, in which they suffered heavy loss owing to Colter's prowess. That made the Blackfeet sworn enemies to Colter.