which the writer last crossed this picturesque and rapid stream we have replaced by a strong iron bridge. Leaving the west end of that bridge, we look out of the rear car and send our final message to the Atlantic by the last stream which we shall find going thither. A stupendous, but not impracticable, system of grades next carries us over the axial water-shed of the continent, by the way of Bridger's Pass. One hundred and fifty miles of tortuous descent brings us to Green River,--the stream which farther down becomes the mysterious Colorado, and seeks the Pacific by the Gulf of California. After crossing the Green by another iron bridge substituted for rope-ferriage, our first important station will be Fort Bridger. Leaving there, we almost immediately enter the galleries of the Wahsatch Range, which form a continuous pass across Bear River and into the tremendous _canons_ conducting down to Salt-Lake City. From Salt Lake we pursue the shortest practicable route through the Desert to the Ruby-Valley Pass of the Humboldt Mountains; we cross that range to enter another desert, descend to the Sink of Carson, and reascend to Carson City, thence going nearly due north till we strike the line of the Truckee Pass, (where a branch connects us with the principal Washoe mines,) and thence to Sacramento by the long-projected California section of the Pacific Railroad. Another proposed, but still ideal, road completes our connection with the Western Ocean by way of Stockton, San Jose, and San Francisco. We do not pretend to assert that the route indicated is in all respects the most economical and practicable; a good deal more surveying must be done before that can be said of any entire route, though we think it may fairly be claimed for our ideal section between St. Louis and Denver. We have chosen this route because along its course are more completely represented the natural features to which in any case the Pacific Railroad must look for all its primary obstacles and part of its subsequent profits. To complete the conception as its reality must in time be completed, let us unite our Trans-Missouri portion with the Atlantic and Great Western Railway, under the all-inclusive title of the Atlantic and Pacific Railroad. It will not be very far out of the way to regard thirty-eight hundred miles as the entire length of the line. On the Atlantic and Great Western section express-trains will run at a speed of twenty-seven miles an hour, including stops; but to provide against every detention, let us slow our through-express to twenty-five miles. At this rate we shall traverse the continent in six days and eight hours. In other words, the San-Francisco gentleman who left the Jersey depot by the five o'clock Atlantic and Pacific express-train on Monday morning may reasonably expect (allowing for difference of longitude) to be in the bosom of his family just in time to accompany them to morning service on the following Sunday.