It would seem that the country through which the River Rhine now flows was at first very uneven, presenting valleys and broad depressions, which the waters of the river filled, thus forming great shallow lakes, that extended over very considerable tracts of country. In process of time, however, these lakes became filled with the sediment which was brought down by the river, and thus great flat plains of very rich and level land were formed. At every inundation of the river, of course, these plains, or intervals, as they are sometimes called, would be overflowed, and fresh deposits would be laid upon them; so that in the course of ages the surface of them would rise several feet above the ordinary level of the river. In fact they would continue to rise in this way until they were out of the reach of the highest inundations. Immense plains of the most fertile land, which seem to have been formed in this way, exist at the present time along the banks of the Rhine at various places. These plains are all very highly cultivated, and are rich and beautiful beyond description. To see them, however, it is necessary to travel over them in a diligence, or post chaise, or by railway trains; for in sailing up and down the river, along the margin of them, in a steam-boat, you are not high enough to overlook them. You see nothing all the way, in these places, but a low, green bank on each side of the river, with a fringe of trees and shrubbery along the margin of it. For about one hundred miles of its course, however, near the central portion of it, the river flows through a very wild and mountainous district of country, or rather through a district which was once wild, though now, even in the steepest slopes and declivities, it is cultivated like a garden. The reason why these mountainous regions are so highly cultivated is because the soil and climate are such that they produce the best and most delicious grapes in the world. They have consequently, from time immemorial, been inhabited by a dense population. Every foot of ground where there is room for a vine to grow is valuable, and where the slope was originally steep and rocky, the peasants of former ages have gathered out the rocks and stones, and built walls of them to terrace up the land. The villages of these peasants, too, are seen every where nestling in the valleys, and clinging to the sides of the hills, while the summits of almost all the elevations are crowned with the ruins of old feudal castles built by barons, or chiefs, or kings, or military bishops of ancient times, famous in history. This picturesque portion of the river, which extends from Bonn, a little above Cologne, to Mayence,--which towns you will readily find on almost any map of Europe,--was the part which Mr. George and Rollo particularly desired to see. When they left Switzerland they intended to come down the river, and see the scenery in descending. But Mr.