We moved down the river on the east bank, part of the way through an open valley and part through fallen timber. At about eight miles we came upon an enormous spring of dark blue water, the largest we have seen. Mr. Hauser measured it, and says it is four hundred feet in diameter. The mineral solution has been deposited by the overflow on all sides for two hundred yards, the spring itself being thirty feet above the general level of the valley. Out near the center of the lake the water boils up a few feet, but without any especial violent action. The lake has no well-defined outlet, but overflows on many sides, the water flowing down the slopes of the incrusted mound about one-quarter of an inch deep. As we stood on the margin of this immense lake a small flock of ducks came sailing down as if to alight; but as they skimmed the water a few inches above the surface, they seemed to scent danger, and with rapid flapping of their wings, all except one rose into the air. This one, in his descent, had gained too great an impetus to check his progress, and came down into the water, and his frantic efforts to rise again were futile, and with one or two loud squawks of distress, which were responded to by his mates who had escaped, he was in a moment "a dead duck." We gave no name to this lake.[AB] About one hundred yards from the lake on the side towards the river, the incrustation breaks off perpendicularly, and another large lake is formed, the surface of which is about fifteen feet below the upper and larger lake. There are a few other springs near the river farther down the stream. Jake Smith, for the first time on this trip, selected at this large lake a curious specimen of tufa. It was a circumstance so unusual that Hedges called our attention to it, but as Smith was riding along holding his treasure carefully in his hand, his horse stumbled, and he accidentally dropped his specimen, and with a remark which I will not here record, and which is at variance with his own Bible instruction, he denounced as worthless all the specimens of the party which he had seen, and inveighed against the folly of spending any time in gathering them. From this point we passed down the valley close by the bank of the river. The valley on our right was very marshy, and we saw at a considerable distance one very large fountain of water spouting into the atmosphere to a considerable height, and many steam jets, but, owing to the swampy character of the ground, we did not visit them.[AC] When we left Helena on August 17th, we believed that twenty-five days would be the limit of time which would be consumed before our return; but to meet all exigencies we laid in a thirty days' supply of provisions. We have now been absent thirty-four days, and as we cached some of our supply on Yellowstone lake for Mr. Everts' relief, we are now on short rations, but the fish we dried while camped on Yellowstone lake are doing good service.