is a terra incognita of at least 128000 square miles in extent, arid, almost entirely without human inhabitants, and full of salt lakes, the largest of which is 4200 English feet above the level of the sea, and is connected with the narrow lake of Utah. (Frémont, Report of the Exploring Expedition, pp. 154 and 273-276.) The last-mentioned lake receives the abundant waters of the “Rock River;” Timpan Ogo, in the Utah language. Father Escalante, in journeying, in 1776, from Santa Fé del Nuevo Mexico to Monterey in New California, discovered Frémont’s “Great Salt Lake,” and, confounding lake and river, gave it the name of Laguna de Timpanogo. As such I inserted it in my map of Mexico; and this has given rise to much uncritical discussion on the assumed non-existence of a great inland salt lake in North America,--a question previously raised by the well-informed American geographer, Tanner. (Humboldt, Atlas Mexicain, planche 2; Essai Politique sur la Nouvelle Espagne, T. i. p. 231, T. ii. pp. 243, 313, and 420; Frémont, Upper California, 1848, p. 9; and, also, Duflot de Mofras, Exploration de l’Oregon, 1844, T. ii. p. 40.) Gallatin says expressly, in the Memoir on the Aboriginal Races in the Archæologia Americana, vol. ii. p. 140, “General Ashley and Mr. J. S. Smith have found the lake Timpanogo in the same latitude and longitude nearly as had been assigned to it in Humboldt’s Atlas of Mexico.” I have dwelt on the remarkable swelling of the ground in the region of the Rocky Mountains, because, doubtless, by its elevation and extent, it exercises an influence hitherto but little considered, on the climate of the whole continent of North America, to the south and east. In the extensive continuous plateau, Frémont saw the waters covered with ice every night in the month of August. Nor is the elevation of this region less important as respects the social state and progress of the great United States of North America. Although the elevation of the line of the separation of the waters nearly equals that of the passes of the Simplon (6170 French, or 6576 English feet), of the St. Gothard (6440 French, or 6865 English feet), and of the St. Bernard (7476 French, or 7969 English feet), yet the ascent is so gradual, as to offer no obstacle to the use of wheel carriages of all kinds in the communication between the basins of the Missouri and the Oregon; in other words, between the states on the Atlantic Sea Board opposite Europe, and the new settlements on the Oregon and Columbia opposite China. The itinerary distance from Boston to Astoria on the Pacific at the mouth of the Columbia, is, according to the difference of longitude, 2200 geographical miles, or about one-sixth less than the distance of Lisbon from the Ural near Katharinenburg. From the gentleness of the ascent of the high plateau which leads from the Missouri to California and to the basin of the Oregon,--(from the River and Fort Laramie, on the northern branch of the Platte River, to Fort