The Rocky Mountains which sink down towards the Mackenzie River which is covered a large portion of the year with ice, and the highlands from which single snow-clad summits rise, are altogether distinct from the more westerly and higher mountains of the coast, or the chain of the Californian Maritime Alps, the Sierra Nevada de California. However ill selected the now generally used name of the Rocky Mountains, to designate the most northerly continuation of the Mexican Central Chain, it does not appear to me desirable to change it, as has been often proposed, for that of the Oregon Chain. Although these mountains do indeed contain the sources of Lewis’s, Clark’s, and North Fork, the three chief branches which form the mighty Oregon, or Columbia River, yet this river also breaks through the Californian chain of snow-clad Maritime Alps. The name of Oregon District is also employed politically and officially for the smaller territory west of the Coast Chain, where Fort Vancouver and the Walahmutti settlements are situated, and therefore it is the more desirable not to give the name of Oregon either to the Central or the Coast Chain. This name is connected with a most singular mistake of an eminent geographer, M. Malte Brun: reading on an old Spanish map, “And it is not yet known, (y aun se ignora) where the source of this river” (the river now called the Columbia) “is situated,” he thought he recognised in the word ignora the name of Oregon. (See my Essai politique sur la Nouvelle Espagne, T. ii. p. 314).