As they came alongside the Mandan brave he pointed to certain marks at his feet. Both lads saw that these were the faint impressions of moccasins. But that in itself gave them no cause for uneasiness, and it was not until the Wolf pointed once more, and uttered a word they took to be "Sioux," that they understood. Some of the deadly enemies of the Mandans had only recently been at the salt-lick; and that might mean they were contemplating an attack on the great Mandan village, hardly more than half a day's journey away. Efforts had plainly been made to erase the footprints, which would indicate that the Sioux had some reason for not wanting their enemies to know of their presence so close by. Somehow the fact gave both boys an uneasy feeling, and again Dick found himself wishing that he had thought to bring the horses; then, in case of trouble, they would have had a means for beating a successful retreat. Roger did not look so far ahead as his comrade, as a rule. He was even now wondering what the Wolf saw in these old tracks to cause him alarm. Why, from time to time no doubt lots of Indians, perhaps belonging to various tribes, must visit this spot, since it was the only salt-lick in all the surrounding country, he had been told. "Now, for my part," he started to say, "I don't see why he should bother with a lot of tracks. Perhaps they are days old. What if the Sioux did try to hide the marks of their moccasins; they'd know the Mandans could tell from the tread that Sioux braves had been here, and, if they were just out on a hunt, it might be they wouldn't want to have any trouble with their old-time enemies." "Yes, that might be as you say, Roger; but if you look close you'll see that it _wasn't_ days ago these tracks were made. No dew has ever fallen in this footprint, which would go to show it was not here at dawn this morning." "Oh!" exclaimed Roger, "then, if these marks have been made since sun-up, that's a different story; and perhaps the Wolf does well to look serious. These fierce Sioux are a lot of fighters, they say. The expedition has had ever so much trouble with them while on the way. Now, if we have to leave here before we meet Jasper Williams, it will be too mean for anything." "That must be as the Wolf says, and perhaps he can make us understand by motions what he thinks about it. There, see him bending down again over yonder, as if he had discovered something else. Those eyes of his are like a hawk's, and little can escape them." "I wish he would hurry up then, and let us know the worst," grumbled Roger. Dick was about to say something more, when the words seemed to cleave to the roof of his mouth, for something remarkable had happened, something that was so utterly unexpected that he could hardly believe his eyes.