The Indians made scant use of this territory. In an average year the passes into it are blocked with snow for nine months of the twelve. Besides, it is mostly covered with a tangle of forests. In earlier days, living in it or traveling through it was difficult. Though filled with big game during the summer, at no time of year was it equal to the surrounding country as a hunting-ground. John Colter, who first discovered the Yellowstone region in 1807, was a member of the Lewis and Clark expedition. He was a hunter and trapper, a master of woodcraft, and an outdoor man of the first class; at the time of the discovery he was thirty-five years of age, nearly six feet tall, and an athlete who could hold his own in the games of the trappers' rendezvous. His endurance, courage, and resourcefulness were marvelous. Neither wilderness nor hostile Indian had terrors for him. The five years that he spent in the Yellowstone region were so crowded with wilderness adventure that his name is immortal in the history of the American frontier. He obtained his release from the Lewis and Clark exploring party at a point on the Missouri River, some distance below the mouth of the Yellowstone, in August, 1806. He had served with the expedition more than two years. With two trappers, Colter that year proceeded up the Missouri and spent the winter somewhere on its headwaters. The following spring he left his companions and started for St. Louis. After a solitary journey of about two thousand miles, he met Manuel Lisa, the celebrated trapper and trader, who, with a large party, was on his way to found a trading-post somewhere on the headwaters of the Missouri. Lisa persuaded Colter to turn back with him. Strong is the lure of the wilderness. Although Colter had been away from civilization three years, and a triumphant welcome awaited his return, he again postponed the enjoyment of all that old friends and city attractions could offer, to resume the adventurous experiences of a trapper's life among hostile Indians in the wilds. Lisa built a trading-post, Fort Manuel, at the junction of the Big Horn and Yellowstone Rivers, about two hundred miles southeast of the Yellowstone Park. From here, with a thirty-pound pack and rifle, Colter set off alone on a thousand-mile journey into the wilderness to tell the surrounding Indian tribes of this new trading-post. He traveled a few hundred miles to the southwest without notable adventure. We now marvel at the results of this journey, for its discoveries put Colter in the front rank of geographical explorers on the American continent. He discovered the Wind River Range, Union Pass, Jackson Hole, Teton Pass, Pierre's Hole, and the Grand Teton. He was the first to see the headwaters of those two great rivers the Green Fork of the Colorado and the Snake Fork of the Columbia. These discoveries might well have been enough for any one man, but his greatest discovery was still before him.