"See," said Henri, turning to Dick and pointing to a circular spot of green as they rode along, "that is one old _dry_ waller." "Ay," remarked Joe; "after the waller dries, it becomes a ring o' greener grass than the rest o' the plain, as ye see. Tis said the first hunters used to wonder greatly at these myster'ous circles, and they invented all sorts o' stories to account for 'em. Some said they wos fairy-rings, but at last they comed to know they wos nothin' more nor less than places where buffaloes wos used to waller in. It's often seemed to me that if we knowed the _raisons_ o' things, we wouldn't be so much puzzled wi' them as we are." The truth of this last remark was so self-evident and incontrovertible that it elicited no reply, and the three friends rode on for a considerable time in silence. It was now past noon, and they were thinking of calling a halt for a short rest to the horses and a pipe to themselves, when Joe was heard to give vent to one of those peculiar hisses that always accompanied either a surprise or a caution. In the present case it indicated both. "What now, Joe?" "Injuns!" ejaculated Joe. "Eh! fat you say? Ou is dey?" Crusoe at this moment uttered a low growl. Ever since the day he had been partially roasted he had maintained a rooted antipathy to Red-men. Joe immediately dismounted, and placing his ear to the ground listened intently. It is a curious fact that by placing the ear close to the ground sounds can be heard distinctly which could not be heard at all if the listener were to maintain an erect position. "They're arter the buffalo," said Joe, rising, "an' I think it's likely they're a band o' Pawnees. Listen an' ye'll hear their shouts quite plain." Dick and Henri immediately lay down and placed their ears to the ground. "Now, me hear noting," said Henri, jumping up, "but me ear is like me eyes--ver' short-sighted." "I do hear something," said Dick as he got up, "but the beating o' my own heart makes row enough to spoil my hearin'." Joe Blunt smiled. "Ah! lad, ye're young, an' yer blood's too hot yet; but bide a bit--you'll cool down soon. I wos like you once. Now, lads, what think ye we should do?" "You know best, Joe." "Oui, nodoubtedly.' "Then wot I advise is that we gallop to the broken sand hillocks ye see yonder, get behind them, an' take a peep at the Redskins. If they are Pawnees, we'll go up to them at once; if not, we'll hold a council o' war on the spot."