Our third day's ascent witnessed no diminution of the strength and alacrity with which our canoemen urged our way up the stream. We were off betimes, in a lowering and dense atmosphere, which obscured objects. After advancing some six miles, there are a series of small rapids, which are, taken together, called Ka-ka-bi-ka,[70] where I estimated the river to sink its level sixteen feet, in a short distance; at none of these is the navigation, however, impeded. The rock stratification appears too compact for sand-rock, and is obscured by contiguous boulders, which are indicative of the strong drift-formation, which has spread from the north and east over this region. Four miles after ascending the last of the Kakabika Rapids, we landed at the foot of the Pakagama Falls. Here the lading was immediately put ashore, the canoes landed, and the whole carried over an Indian portage path of two hundred and seventy-five yards. This delay afforded an opportunity to view the falls. The Mississippi, at this point, forces its way through a formation of quartzy rock, during which it sinks its level, as estimated, twenty feet, in a distance of about three hundred yards. There is no perceptible cascade or abrupt fall, but the river rushes with the utmost velocity down a highly inclined rocky bed towards the northeast. It forms a complete interruption to navigation, and must, hereafter, be the terminus of the navigation of that class of small steamboats which may be introduced above the Falls of St. Anthony. The general elevation of the geological stratum at the top of this fall must be but little under fourteen hundred feet above the Gulf of Mexico.[71] This summit bears a growth of the yellow pine. I observed, amongst the shrubs, the vaccinium dumosum. Immediately above the falls is a small rocky island, bearing a growth of spruce and cedars, being the first island noticed above Sandy Lake. This island parts the channel into two, at the precise point of its precipitation. On coming to the head of these falls, we appear to have reached a vast geological plateau, consisting of horizontal deposits of clay and drift on the nucleus of granitical and metamorphic rocks, which underlie the sources of the Mississippi River. The vast and irregular bodies of water called Leech Lake, Winnipek, and Cass Lakes, together with a thousand lesser lakes of a mile or two in circumference, lie on this great diluvial summit. These lakes spread east and west over a surface of not less than two hundred miles; most of them are connected with channels of communication forming a tortuous and intricate system of waters, only well known to the Indians; and there seems the less wonder that the absolute and most remote source of the Mississippi has so long remained a matter of doubt. [70] From _ka_, a particle affirmative of an adverse quality, _aubik_, rock, and _ons_, a diminutive inflection. [71] Mr. Nicollet places the summit of the falls at 1,340 feet above the Gulf.