The day after Ferris left me I rode out upon that arrested tide--those silent breakers which for ages have threatened, but never reached, the shore. I tried to fancy it as it must once have been, a sluggish, vitreous flood, filling the great valley, and stiffening as it slowly pushed toward the bases of the hills. It climbed and spread, as dough rises and crawls over the edge of the pan. The Black Lava is always called a sea--that image is inevitable; yet its movement had never in the least the character of water. "This is where hell pops," an old plains-man feelingly described it, and the suggestion is perfect. The colors of the rock are those produced by fire: its texture is that of slag from a furnace. One sees how the lava hardened into a crust, which cracked and sank in places, mingling its tumbled edges with the creeping flood not cooled beneath. After all movement had ceased and the mass was still, time began upon its tortured configurations, crumbled and wore and broke, and sifted a little earth here and there, and sealed the burnt rock with fairy print of lichens, serpent-green and orange and rust-red. The spring rains left shallow pools which the summer dried. Across it, a few dim trails wander a little way and give out, like the water. For a hundred miles to the Snake River this Plutonian gulf obliterates the land--holds it against occupation or travel. The shoes of a marching army would be cut from their feet before they had gone a dozen miles across it; horses would have no feet left; and water would have to be packed as on an ocean, or a desert, cruise. I rode over places where the rock rang beneath my horse's hoofs like the iron cover of a manhole. I followed the hollow ridges that mounted often forty feet above my head, but always with that gruesome effect of thickening movement--that sluggish, atomic crawl; and I thought how one man pursuing another into this frozen hell might lose himself, but never find the object of his quest. If he took the wrong furrow, he could not cross from one blind gut into another, nor hope to meet the fugitive at any future turning. I don't know why the fancy of a flight and pursuit should so have haunted me, in connection with the Black Lava; probably the desperate and lawless character of our conversation at the stage-house gave rise to it.