A forced march was now necessary for the explorers, and they set out as speedily as possible, well knowing that the Indians would be on their trail. By three o’clock in the afternoon of that day they had reached Tansy River, now known as the Teton, having travelled sixty-three miles. They rested for an hour and a half to refresh their horses, and then pushed on for seventeen miles further before camping again. Having killed a buffalo, they had supper and stopped two hours. Then, travelling through vast herds of buffalo until two o’clock in the morning, they halted again, almost dead with fatigue; they rested until daylight. On awaking, they found themselves so stiff and sore with much riding that they could scarcely stand. But the lives of their friends now at or near the mouth of Maria’s River were at stake, as well as their own. Indeed, it was not certain but that the Indians had, by hard riding and a circuitous route, already attacked the river party left at the falls. So Captain Lewis told his men that they must go on, and, if attacked, they must tie their horses together by the head and stand together, selling their lives as dearly as possible, or routing their enemies. The journal now says:-- “To this they all assented, and we therefore continued our route to the eastward, till at the distance of twelve miles we came near the Missouri, when we heard a noise which seemed like the report of a gun. We therefore quickened our pace for eight miles farther, and, being about five miles from Grog Spring, now heard distinctly the noise of several rifles from the river. We hurried to the bank, and saw with exquisite satisfaction our friends descending the river. They landed to greet us, and after turning our horses loose, we embarked with our baggage, and went down to the spot where we had made a deposite. This, after reconnoitring the adjacent country, we opened; but, unfortunately, the cache had caved in, and most of the articles were injured. We took whatever was still worth preserving, and immediately proceeded to the point, where we found our deposits in good order. By a singular good fortune, we were here joined by Sergeant Gass and Willard from the Falls, who had been ordered to come with the horses here to assist in procuring meat for the voyage, as it had been calculated that the canoes would reach this place much sooner than Captain Lewis’s party. After a very heavy shower of rain and hail, attended with violent thunder and lightning, we started from the point, and giving a final discharge to our horses, went over to the island where we had left our red pirogue, which, however, we found much decayed, and we had no means of repairing her. We therefore took all the iron work out of her, and, proceeding down the river fifteen miles, encamped near some cottonwood trees, one of which was of the narrow-leafed species, and the first of that kind we had remarked in ascending the river.