Colter was with a band of Crows near Pierre's Hole when it was attacked by marauding Blackfeet. Of necessity Colter fought with the Crows, who were victorious. The Blackfeet blamed Colter for their defeat, and from this incident may have arisen the long-continued hostility of the Blackfeet tribes against the whites. Again alone, Colter set forth from Pierre's Hole, St. Anthony, Idaho, and traveled straight across the mountains to Fort Manuel. A wound in the leg, which he had received in the fight with the Blackfeet, was not yet healed. The direct route that he took for his return may have been chosen as the shortest, but most probably was selected in order to avoid the Blackfeet. The crowning achievement of this remarkable journey was the discovery and traversing of the Yellowstone wonderland. His course took Colter diagonally, from southwest to northeast, across what now is the Yellowstone National Park. He probably passed along the west shore of Yellowstone Lake, and may have followed the Yellowstone River from the lake to the falls. He saw numerous geysers, hot springs, paint-pots, and possibly Sulphur Mountain. He noted that numerous rivers had their sources in the Park and flowed from it in all directions, thus justifying the Indian name for the region, "Top of the World." After crossing Mount Washburn he probably forded the river near Tower Falls and then followed the east fork of the Yellowstone. Colter arrived safely at Fort Manuel after a journey of about three hundred miles from Pierre's Hole and a round trip of about eight hundred miles. Aside from its geographical value, this was a remarkable wilderness achievement. A little later came the most extraordinary chapter of Colter's adventurous life. In 1809, with a companion named John Potts, he was trapping beavers near the Three Forks of the Missouri. They were rowing up a small stream that flowed into the Jefferson River, the most western of the forks. At a point on this stream about five miles from the Jefferson, they heard a great trampling. High banks and brushwood shut off their view. Presently about five hundred Blackfeet appeared on the banks and ordered them to come ashore. Escape was impossible. The two men had the hardihood to throw the beaver-traps overboard, hoping to recover them later. As the canoe touched the shore, an Indian snatched Potts's rifle from him. Thereupon Colter sprang ashore, wrested the rifle from the Indian, and handed it to Potts who immediately pushed off into the stream. Colter told him to come back and not to try to escape. An arrow whizzed by Colter, and Potts fell back in the canoe, crying out, "I'm done for!" as he shot an Indian dead. In an instant his body was filled with arrows.