Thompson, David & Tyrrell, Joseph Burr (1916) David Thompson's Narrative of His Explorations in Western America, 1784-1812, The Champlain Society.

... [28 September 1807:] The Old Chief & others related that in the Woods of the Mountains there is a very large Animal, of abt the height of 3 fms & great bulk that never lies down, but in sleeping always leans against a large Tree to support his weight; they believe, they say, that he has no joints in the mid of his Legs, but they are not sure as they never killed any of them, & by this acct they are rarely or never seen--this is no doubt some Animal of their Nurses Fables, as they cannot say they ever saw the least remains of a dead one.

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January 5 [1811]: ... we are now entering the defiles of the Rocky Mountains by the Athabasca River... strange to say, here is a strong belief that the haunt of the Mammoth is about this defile... I questioned several, none could positively say they had seen him, but their belief I found firm and not to be shaken.... All I could say did not shake their belief in his existence...

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January 7: Continuing on our journey in the afternoon we came on the track of a large animal... I measured it; four large toes each of four inches in length to each a short claw; the ball of the foot sunk three inches lower than the toes, the hinder part of the foot did not mark well, the length fourteen inches, by eight inches in breadth, walking from north to south, and having passed about six hours. We were in no humour to follow him; the Men and Indians would have it to be a young Mammoth and I held it to be the track of a large old grizzled Bear; yet the shortness of the nails, the ball of the foot, and itsgreat size were not that of a Bear, otherwise that of a very large old Bear, his claws worn away; this the Indians would not allow...

... As the snow was about six inches in depth the track was well defined, and we could see it for a full one hundred yards from us... We did not attempt to follow it, we had no time for it, and the Hunters, eager as they are to follow and shoot every animal made no attempt to follow this beast, for what could the balls of our fowling guns do against such an animal. Report from old times had made the head branches of this River, and the Mountains in the vicinity the abode of one, or more, very large animals, to which I never appeared to give credence; for these reports appeared to arise from that fondness for the marvellous so common to mankind; but the sight of the track of that large beast staggered me, and I often thought of it, yet never could bring myself to believe such an animal existed, but thought it might be the track of some monster Bear.

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... On the sixth of October... the Hunters there pointed out to me a low Mountain apparently close to us, and said that on the top of that eminence, there was a Lake of several miles ...that these animals fed there, they were sure from the great quantity of moss torn up...the hunters all agreed this animal was not carnivorous, but fed on moss, and vegetables. Yet they all agree that not one of them had ever seen the animal; I told them I thought curiosity alone ought to have prompted them to get a sight of one of them; they replied, that they were curious enough to see them, but at a distance, the search forthem, might bring them so near that they could not get away; I had known these men for years, and could always depend on their word, they had no interest to deceive themselves, or other persons. The circumstantial evidence of the existence of this animal is sufficient, but notwithstanding the many months the Hunters have traversed this extent of country in all directions, and this animal having never been seen, there is no direct evidence of it's existence. Yet when I think of all I have seen and heard, if put on my oath, I could neither assert, nor deny, it's existence; for many hundreds of miles of the Rocky Mountains are yet unknown, and through the defiles by which we pass, distant one hundred and twenty miles from each other, we hasten our march as much as possible.