of mountains forms the hypotenuse; so that the real, and as it were diagonal, length of the chain, across the continent, must be very near three thousand miles from S. E. to N. W. In such a vast extent of mountains, the perpendicular height and width of base must necessarily be very unequal. We were about eight days in crossing them; whence I conclude, from our daily rate of travel, that they may have, at this point, i. e., about latitude 54°, a base of two hundred miles.
The geographer Pinkerton[169] is assuredly mistaken, {300} when he gives these mountains an elevation of but three thousand feet above the level of the sea; from my own observations I would not hesitate to give them six thousand; we attained, in crossing them, an elevation probably of fifteen hundred feet above the valleys, and were not, perhaps, nearer than half way of their total height, while the valleys themselves must be considerably elevated above the level of the Pacific, considering the prodigious number of rapids and falls which are met in the Columbia, from the first falls to Canoe river. Be that as it may, if these mountains yield to the Andes in elevation and extent, they very much surpass in both respects the Apalachian chain, regarded until recently as the principal mountains of North America: they give rise, accordingly, to an infinity of streams, and to the greatest rivers of the continent.[170]
{301} They offer a vast and unexplored field to natural history: no botanist, no mineralogist, has yet examined them. The first travellers called them the Glittering
