Again: The river Des Plaines rises near the northern line of the State of Illinois, and running south parallel with the lake shore, at its junction with the Kankakee forms the Illinois. The Des Plaines is only ten miles west of Chicago. One of its eastern tributaries rises very near the head-waters of the south branch of the Chicago River, and often, when flooded by heavy rains, its waters flow over into the lake. At this point, also, the Jesuits and the early settlers were in the habit of crossing in their boats to the Des Plaines, and thence into the Illinois. The writer was informed by Colonel William A. Bird, the last Surveyor-in-Chief of the Boundary Commission, that when the party was at Mackinaw, in the spring of 1820, Mr. Ramsey Crooks, the adventurous and enterprising agent of John Jacob Astor, came up to that place from Joliet on the Illinois in one of the big canoes so generally used at that day for navigating the lakes, and that Mr. Crooks informed them that he crossed from the Des Plaines into Lake Michigan without taking his canoe out of the water. The deep cut in the Illinois and Michigan Canal, recently excavated by the city of Chicago in order to improve its sewer drainage, is quite uniform at its upper surface, and is sixteen to eighteen feet deep for a distance of twenty-six miles. The bottom of this cut is six feet below the lowest water-mark ever noted in the lake. At the point where the deep cut reaches the Des Plaines, it is ten feet lower than the bottom of the river. It is sixteen miles further down before the bottom of the cut and the river coincide with each other. Nearly the whole of this distance it is necessary to maintain a guard-bank, to protect the canal from the inundations of the river. Here we find there is a dam, only about twelve feet high, that once separated the waters of the lake from those of the Gulf of Mexico. There were, therefore, two courses through which the waters of Lake Michigan could once have passed into the Illinois--the first through the Des Plaines, and the second from the head-springs of the East Calumick into the great north cove of the Kankakee Pond. When we consider the immense drainage which must have been discharged through these channels into the valley of the Illinois, we can well understand the gigantic proportions of that valley when compared with the stream which now flows through it. The perpendicular and water-worn sides of Starved Rock, below Ottawa, attest the magnitude of the lake-like floods which must once have dashed around them.