When Captain Palliser's expedition attempted to reach the head waters of the North Thompson from the sources of the North Saskatchewan River, the leader encountered a forest-growth so dense, and so encumbered with fallen timber, that it proved an insurmountable obstacle. Viscount Milton and Mr. Cheadle, in their adventurous journey across the Rocky Mountains to British Columbia, were involved in one of these wildernesses, and with difficulty effected a passage. "No one," they remark,[147] "who has not seen a primeval forest, where trees of gigantic size have grown and fallen undisturbed for ages, can form any idea of the collection of timber, or the impenetrable character of such a region. There were pines and thujas of every size--the patriarch of 300 feet in height standing alone, or thickly-clustering groups of young ones struggling for the vacant place of some prostrate giant. The fallen trees lay piled around, forming barriers often six or eight feet high on every side: trunks of huge cedars, moss-grown and decayed, lay half-buried in the ground on which others as mighty had recently fallen; trees still green and living, recently blown down, blocking the view with the walls of earth held in their matted roots; living trunks, dead trunks, rotten trunks; dry, barkless trunks, and trunks moist and green with moss; bare trunks, and trunks with branches--prostrate, reclining, horizontal, propped up at different angles; timber of every size, in every stage of growth and decay, in every possible position, entangled in every possible combination. The swampy ground was densely covered with American dog-wood, and elsewhere with thickets of the aralea, a tough-stemmed trailer, with leaves as large as those of the rhubarb-plant, and growing in many places as high as a man's shoulders. Both stem and leaves are covered with sharp spines, which pierce your clothes as you force your way through the tangled growth, and make the legs and hands of the pioneers scarlet from the inflammation of myriads of punctures." Far grander the scene, however--far richer in form and colour--which meets our gaze in the stupendous forest growth still covering the basins of the Amazon and the Orinoco. As a companion to the foregoing picture, we borrow one of this brighter and more wonderful region as painted with equal truth and vigour by Mr. Bates:--[148]