"They're surely queer places," said Hugh. "I've seen it down in Kansas, and down on Henry's fork of Green River, and up in Oregon, where the ground was stuck full of bones and teeth. Some of the leg-bones was nigh as thick as my body, and some of the big heads had long teeth as long as my hand. They must have been big animals, and mighty dangerous too, I reckon." "What makes the dirt all those different colours, Uncle Will," asked Jack; "In some places it's white, in others yellow or brown or black, and in some, bright red, like bricks." "That red colour," said Mr. Sturgis, "is where the earth has been burnt. All through the soil here there are seams or veins of a crumbly brown substance, which is called lignite. It is a sort of coal about half made, and like coal it will burn. Sometimes a seam of this lignite catches fire from some cause or other, and may burn for years, baking the earth close to it. The heat turns it red, just as bricks which have been burned turn red." By this time they were passing out of the bad lands and down into a flat through which flowed a broad river. There was no bridge over it, and Jack wondered how they were going to get across, but when they came to the water's edge the horses trotted in, were stopped to drink, and then walked on across, although the water came up to their bellies and washed and gurgled about the waggon, so that Jack began to think that perhaps they might be swept away. Pretty soon it grew more shallow, and then they came to the bank, and once more the waggon started off down the valley at a brisk rate. Soon they crossed a narrow little stream flowing between deep banks, climbed another hill, and then turning away from the river, went up a narrow valley, shut in on one side by a high wall of rock and on the other by a great mountain dotted with cedars. On this mountain Hugh said there were some mountain sheep, and he pointed out to Jack tracks in the road where some of these animals had crossed that morning. Further on, in a broad rolling valley, they saw some antelope, but by this time the cold wind had made Jack chilly and tired, and his uncle wrapped him up to the throat with blankets and robes, and propping him up between Hugh and himself, told him to go to sleep. Just as he was about to do this, something happened which woke him up very thoroughly. CHAPTER IV A GRIZZLY KILLED