After forty-eight days and seven hours out of St. Louis, on the 12th of June, they reached Fort Union, at the mouth of the Yellowstone, where the _Omega_ left them and returned down river. The country proved so interesting that the naturalist remained two months at the fort, where he occupied the room which had been used by Maximilian, Prince of Neuwied, when traveling through the western parts of America ten years before; here Audubon made many drawings. Buffalo were abundant on all sides, and a favorite occupation was shooting wolves from the ramparts of the fort. On June 18 they killed two antelope and two deer before noon, and "immediately after dinner," he said, "the head of the old male was cut off, and I went to work outlining it; first small, with the camera lucida, and then by squares." On the 30th he wrote: "I began drawing at five this morning, and worked almost without cessation till after three, when becoming fatigued for want of practice, I took a short walk, regretting that I could no longer draw twelve or fourteen hours without a pause, or thought of weariness." On the 15th of July they started up the shore of the Yellowstone in a cart. The party soon had had enough of buffalo hunting, and on one day the naturalist was nearly speared by a charging bull that had been wounded. "What a terrible destruction of life," he says, "as it were for nothing, or next to it, as the tongues only were brought in, and the flesh of these fine animals was left to beasts and birds of prey, or to rot on the spots where they fell. The prairies are literally _covered_ with the skulls of the victims, and the roads the Buffalo make in crossing the prairies have all the appearance of heavy wagon tracks." Foreseeing the departure of the buffalo, he wrote: One can hardly conceive how it happens, notwithstanding these many deaths and the immense numbers that are murdered almost daily on these boundless wastes called prairies, besides the hosts that are drowned in the freshets, and the hundreds of young calves who die in early spring, so many are yet to be found. Daily we see so many that we hardly notice them more than the cattle in our pastures about our homes. But this cannot last; even now there is a perceptible difference in the size of the herds, and before many years the Buffalo, like the Great Auk, will have disappeared. On the 9th of August he added: "I have scarcely done anything but write this day, and my memorandum books are now crowded with sketches, measurements, and descriptions." Those who maintain that a "howling wilderness" is a place that never howls, should read his note for August 19: "Wolves howling, and bulls roaring, just like the long continued roll of a hundred drums"; or this for the 21st: "Buffaloes all over the bars and prairies, and many swimming; the roaring can be heard for miles."