GEOLOGY.—­Rapids were encountered at various points, at which there appeared large boulders of syenite and greenstone trap.  No rock stratum appears in place, but from the size of the boulders, it seems probable that the trap formation crosses the bed of the Namakagun.  There is no limestone—­no slate.  Small boulders of amygdaloid, quartz, granite, and sandstone mark the prevalence of the drift stratum, such as overspreads the upper Mississippi uplands.  The weather was cloudy and overcast, producing coolness.  I found the air but 64 deg. at 2 o’clock, when the water stood at 69 deg..

Some fish are caught in this stream, which serve to eke out the very scanty, and precarious subsistence of the Indians at this season.  At the lodge of an Indian, whom we knew as the “Jack of Diamonds”—­being the same who loaned us a canoe—­I observed some small pieces of duck in a large kettle of boiling water, which was thickened with whortleberries, for the family supper.

PORTAGE TO LAC COURTORIELLE.—­We reached the portage at two o’clock A.M., and immediately began to cross it, the men carrying all our baggage at one load.  Just after passing the middle pause, the path mounts and is carried along a considerable ridge, from which there is a good view of the country.  It is open as far as the eye can reach.  Sometimes there is a fine range of large pines:  in by far the largest space ancient fires appear to have spread, destroying the forest and giving rise to a young growth of pines, aspen, shad-bush, and bramble.  Some portions are marshy.  A deep cup-shaped cavity exists a little to the right of the path on the ridge, denoting it to be cavernous or filled with springs.

We saw evidences of Lieut.  Clary and Mr. Woolsey’s march and encampment on this height.  We saw also evidences of Old Laporte’s prowess in voyageur life and exploits, by a notice of one of his long pauses, recorded by Lieut.  Clary in pencil, on a blazed tree.

LAKE OF THE ISLES.—­On reaching the Lake of the Isles at three o’clock P.M., we found, by a little bark letter on a pole, that Lieut.  Clary and Mr. Woolsey had slept at that spot on the 1st of August.  All things had proceeded well.  They were ahead of us but four days.

While the men were sent back to the other end of the portage after the canoes, I embarked on the lake in a small canoe found in the bushes, with Mr. Johnston, to search out the proper channel.  We found it to draw to a narrow neck and then widen out, with six or seven islands, giving a very sylvan and beautiful appearance.  We passed through it, then crossed a short portage that connects the path with Lac du Gres, and then returned to the south end of Lake of the Isles, where I determined to encamp and light up a fire, while Mr. Johnston was sent back in the little Indian canoe to bring up the canoes and men.  While thus awaiting the arrival of the party, I scrutinized the mineralogy of the pebbles and drift of its shores, where I observed small fragments of the agates, quartz, amygdaloids, &c., which characterize all the drift of the upper Mississippi.