Dr. Wolcott, to whom I had handed my geological note-book, made the following observations. "We left the vertical strata of slate, about two miles above the Portage aux Coteaux. They were succeeded by rocks of hornblende, which continued the whole distance to the head of the Grand Rapid. These rocks were only to be observed in the bed of the river, and appeared to be much water-worn, and manifestly out of place. Soon after we left the Portage aux Coteaux, the hills receded from the river, and its banks for the rest of the way were generally low, often alluvial, and always covered with a thick growth of birch, elm, sugar-tree (acer saccharinum), and the whole tribe of pines, with an almost impenetrable thicket of underbrush. "The appearances of this day (11th) have been similar to those of yesterday, except that the country bordering the river became entirely alluvial, and the poplar became the predominating growth, while the evergreen almost entirely disappeared. The rocks were seldom visible, except upon the rapids, and then only in the bed of the river, and were entirely composed of hornblende, all out of place, and exhibiting no signs of stratification, but evidently thrown confusedly together by the force of the current. "The Savannè River is about twenty yards broad at its junction with the St. Louis, but soon narrows to about half the breadth, which it retains until it forks at the distance of about twelve miles from its mouth. Its whole course runs through a low marshy meadow, the timbered land occasionally reaching to the banks of the river, but generally keeping a distance of about twenty rods on either side. The meadow is, for the most part, covered with tufts of willow and other shrubs, common to marshes. The woods, which skirt it, are of the same kinds observed on the preceding days, except that a species of small oak frequently appears among it. The river becomes so narrow towards its head, that it is with great difficulty canoes can make their way through its windings; and the portage commences a mile or two from its source, which is in a tamarak swamp." The height of land between the east and west Savannè, Dr. Wolcott estimates at about thirty feet. Adding to this elevation the estimates of Capt. Douglass, before mentioned, the entire elevation between the foot of the falls of the St. Louis and the apex of this summit is three hundred and sixty-eight feet.[64] [64] For heights and distances, _vide_ Appendix.