Indeed, an hour later the youngest of the party came in at dark, carrying a pair of long-legged jacks, one of them young and fat. “I always was good on antelopes,” said he. “These were in at the edge of a farmer’s clover field. I’m glad we’re getting into good game country!”

“Yes,” Uncle Dick said, “between the Mandans and the mouth of the Yellowstone, Lewis and Clark began to find the bighorn, which was new to them. And as we’ve said, they now were meeting the first ‘white bears’ or grizzlies. All along, from here to Great Falls, was the best grizzly country they found in all the way across.”

“If only they were in there now!” said John.

“Why, would you dare tackle a grizzly?” smiled their friend. John did not say much.

“These boys have done it,” replied their uncle for them. “I’d hate to be the bear. They shoot straight, and the rifles they have are far more powerful than the ones the first explorers had.”

“We’ll call this exploring,” said Jesse, with sarcasm. “I’ll have to get help to hang up my antelopes so they’ll cool out.

“But, anyhow,” he added, “this is as much fun as plugging along among the sand bars in the motor boat. We beat the oars, and now this gas wagon beats our boat motors!”

“Uncle Dick,” suddenly interrupted Rob, “we’ve been talking about the fur trade on the river a hundred years ago. I understand the fur posts were supplied by steamboats, at the height of the fur trade, anyhow. Now, how long did it take a steamer in those days to make the run, say, from St. Louis to the mouth of the Yellowstone?”

“That’s easy to answer,” his uncle replied. “The records and logs of some of the old boats still exist in St. Louis, and while I was there I looked up some of them.

“Now as nearly as I can learn there was no exact way of estimating distances by any of those travelers—the speedometer was not invented, nor the odometer, nor the ship’s log. Now I don’t know how the steamboat captains got at it, but they kept a daily log of distance, and they had the different stopping places all logged for distance. We make it a little less than sixteen hundred miles to Mandan. The Journal makes it sixteen hundred and ten—close enough. The river chart calls it fourteen hundred and fifty-two to the bridge; over fifty miles below the Mandan villages.